Updated on 2022/05/17

写真a

 
OSU, Rieko
 
Affiliation
Faculty of Human Sciences, School of Human Sciences
Job title
Professor

Concurrent Post

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

  • Faculty of Human Sciences   School of Human Sciences (Online Degree Program)

  • Faculty of Human Sciences   Graduate School of Human Sciences

  • Affiliated organization   Global Education Center

Degree

  • 博士

 

Research Areas

  • Cognitive and brain science

Papers

  • Difference in gaze control ability between low and high skill players of a real-time strategy game in esports

    Inhyeok Jeong, Kento Nakagawa, Rieko Osu, Kazuyuki Kanosue

    PLOS ONE   17 ( 3 ) e0265526 - e0265526  2022.03

     View Summary

    This research investigated the difference in aspects of gaze control between esports experts (Expert) and players with lower skills (Low Skill) while playing the real-time strategy game called StarCraft. Three versions of this game at different difficulty levels were made with the StarCraft Editor, and the gaze movements of seven Expert and nine Low Skill players were analyzed while they played the games. The gaze of Expert players covered a significantly larger area in the horizontal direction than the gaze of Low Skill players. Furthermore, the magnitude and number of saccadic eye movements were greater, and saccade velocity was faster in the Expert than in the Low Skill players. In conclusion, StarCraft experts have a specific gaze control ability that enables them to quickly and widely take visual information from all over the monitor. This could be one of the factors enabling StarCraft experts to perform better than players with lower skills when playing games that require task-switching ability.

    DOI

  • Development and validation of new evaluation scale for measuring stroke patients’ motivation for rehabilitation in rehabilitation wards

    Taiki Yoshida, Yohei Otaka, Shin Kitamura, Kazuki Ushizawa, Masashi Kumagai, Yuto Kurihara, Jun Yaeda, Rieko Osu

    PLOS ONE   17 ( 3 ) e0265214 - e0265214  2022.03

     View Summary

    Objective

    This study aimed to develop the Motivation in stroke patients for rehabilitation scale (MORE scale), following the Consensus-based standards for the selection of health measurement instruments (COSMIN).

    Method

    Study participants included rehabilitation professionals working at the convalescent rehabilitation hospital and stroke patients admitted to the hospital. The original MORE scale was developed from an item pool, which was created through discussions of nine rehabilitation professionals. After the content validity of the scale was verified using the Delphi method with 61 rehabilitation professionals and 22 stroke patients, the scale’s validity and reliability were examined for 201 stroke patients. The construct validity of the scale was investigated using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and item response theory analysis. Cronbach’s alpha confirmed its internal consistency. Regarding convergent, discriminant, and criterion validity, Spearman’s rho was calculated between the MORE scale and the Apathy Scale (AS), Self-rating Depression Scale (SDS), and Visual Analogue Scale (VAS), which rates the subjective feelings of motivation.

    Results

    Using the Delphi method, 17 items were incorporated into the MORE scale. According to EFA and CFA, a one-factor model was suggested. All MORE scale items demonstrated satisfactory item response, with item slopes ranging from 0.811 to 2.142, and item difficulty parameters ranging from -3.203 to 0.522. Cronbach’s alpha was 0.948. Regarding test-retest reliability, a moderate correlation was found between scores at the beginning and one month after hospitalization (rho = 0.612. p < 0.001). The MORE scale showed significant correlation with AS (rho = -0.536, p < 0.001), SDS (rho = -0.347, p < 0.001), and VAS (rho = 0.536, p < 0.001), confirming the convergent, discriminant, and criterion validity, respectively.

    Conclusions

    The MORE scale was verified as a valid and reliable scale for evaluating stroke patients’ motivation for rehabilitation.

    DOI

  • The relationship between stability of interpersonal coordination and inter-brain EEG synchronization during anti-phase tapping

    Yuto Kurihara, Toru Takahashi, Rieko Osu

    Scientific Reports   12 ( 1 )  2022.03  [Refereed]

     View Summary

    Abstract

    Inter-brain synchronization is enhanced when individuals perform rhythmic interpersonal coordination tasks, such as playing instruments in music ensembles. Experimentally, synchronization has been shown to correlate with the performance of joint tapping tasks. However, it is unclear whether inter-brain synchronization is related to the stability of interpersonal coordination represented as the standard deviation of relative phase (SDRP). In this study, we simultaneously recorded electroencephalograms of two paired individuals during anti-phase tapping in three interactive tapping conditions: slow (reference inter-tap interval [ITI]: 0.5 s), fast (reference ITI: 0.25 s), and free (preferred ITI), and pseudo tapping where each participant tapped according to the metronome sounds without interaction. We calculated the inter-brain synchronization between pairs of six regions of interest (ROI): frontal, central, left/right temporal, parietal, and occipital regions. During the fast tapping, the inter-brain synchronization significantly increased in multiple ROI pairs including temporoparietal junction in comparison to pseudo tapping. Synchronization between the central and left-temporal regions was positively correlated with SDRP in the theta in the fast condition. These results demonstrate that inter-brain synchronization occurs when task requirements are high and increases with the instability of the coordination.

    DOI

  • Efficiency and Stability of Step-To Gait in Slow Walking

    Kento Hirayama, Yohei Otaka, Taichi Kurayama, Toru Takahashi, Yutaka Tomita, Seigo Inoue, Kaoru Honaga, Kunitsugu Kondo, Rieko Osu

    Frontiers in Human Neuroscience   15  2022.01

     View Summary

    As humans, we constantly change our movement strategies to adapt to changes in physical functions and the external environment. We have to walk very slowly in situations with a high risk of falling, such as walking on slippery ice, carrying an overflowing cup of water, or muscle weakness owing to aging or motor deficit. However, previous studies have shown that a normal gait pattern at low speeds results in reduced efficiency and stability in comparison with those at a normal speed. Another possible strategy is to change the gait pattern from normal to step-to gait, in which the other foot is aligned with the first swing foot. However, the efficiency and stability of the step-to gait pattern at low speeds have not been investigated yet. Therefore, in this study, we compared the efficiency and stability of the normal and step-to gait patterns at intermediate, low, and very low speeds. Eleven healthy participants were asked to walk with a normal gait and step-to gait on a treadmill at five different speeds (i.e., 10, 20, 30, 40, and 60 m/min), ranging from very low to normal walking speed. The efficiency parameters (percent recovery and walk ratio) and stability parameters (center of mass lateral displacement) were analyzed from the motion capture data and then compared for the two gait patterns. The results suggested that step-to gait had a more efficient gait pattern at very low speeds of 10–30 m/min, with a larger percent recovery, and was more stable at 10–60 m/min in comparison with a normal gait. However, the efficiency of the normal gait was better than that of the step-to gait pattern at 60 m/min. Therefore, step-to gait is effective in improving gait efficiency and stability when faced with situations that force us to walk slowly or hinder quick walking because of muscle weakness owing to aging or motor deficit along with a high risk of falling.

    DOI

  • Global perspectives on autism acceptance, camouflaging behaviours and mental health in autism spectrum disorder: A registered report protocol

    Connor Tom Keating, Lydia Hickman, Philippine Geelhand, Toru Takahashi, Joan Leung, Bianca Schuster, Alicia Rybicki, Teresa Marie Girolamo, Elise Clin, Fanny Papastamou, Marie Belenger, Inge-Marie Eigsti, Jennifer Louise Cook, Hirotaka Kosaka, Rieko Osu, Yuko Okamoto, Sophie Sowden

    PLOS ONE   16 ( 12 ) e0261774 - e0261774  2021.12  [Refereed]

    DOI

  • 経頭蓋静磁場刺激が自己注目状態時の前頭前野に与える影響の予備的検討

    片山 広大, 富田 望, 二瓶 穂香, 髙橋 徹, 栗原 勇人, 芝田 純也, 美馬 達哉, 大須 理英子, 熊野 宏昭

    早稲田大学臨床心理学研究   21 ( 1 ) 35 - 41  2021.12

  • Wrist and finger motor representations embedded in the cerebral and cerebellar resting-state activation.

    Toshiki Kusano, Hiroki Kurashige, Isao Nambu, Yoshiya Moriguchi, Takashi Hanakawa, Yasuhiro Wada, Rieko Osu

    Brain structure & function    2021.07  [International journal]

     View Summary

    Several functional magnetic resonance imaging (fMRI) studies have demonstrated that resting-state brain activity consists of multiple components, each corresponding to the spatial pattern of brain activity induced by performing a task. Especially in a movement task, such components have been shown to correspond to the brain activity pattern of the relevant anatomical region, meaning that the voxels of pattern that are cooperatively activated while using a body part (e.g., foot, hand, and tongue) also behave cooperatively in the resting state. However, it is unclear whether the components involved in resting-state brain activity correspond to those induced by the movement of discrete body parts. To address this issue, in the present study, we focused on wrist and finger movements in the hand, and a cross-decoding technique trained to discriminate between the multi-voxel patterns induced by wrist and finger movement was applied to the resting-state fMRI. We found that the multi-voxel pattern in resting-state brain activity corresponds to either wrist or finger movements in the motor-related areas of each hemisphere of the cerebrum and cerebellum. These results suggest that resting-state brain activity in the motor-related areas consists of the components corresponding to the elementary movements of individual body parts. Therefore, the resting-state brain activity possibly has a finer structure than considered previously.

    DOI PubMed

  • Motivation for Rehabilitation in Patients With Subacute Stroke: A Qualitative Study

    Taiki Yoshida, Yohei Otaka, Rieko Osu, Masashi Kumagai, Shin Kitamura, Jun Yaeda

    Frontiers in Rehabilitation Sciences   2  2021.06

     View Summary

    <bold>Background:</bold> Motivation is essential for patients with subacute stroke undergoing intensive rehabilitation. Although it is known that motivation induces behavioral changes toward rehabilitation, detailed description has been lacking. Motivation can be intrinsic or extrinsic; however, it is unclear which type of factors mainly motivates patients' daily rehabilitation.

    <bold>Purpose:</bold> This study aimed to examine the factors influencing patients' motivation and to explore the behavioral changes induced by motivation, especially age-related differences.

    <bold>Method:</bold> Twenty participants (mean age 65.8 years [standard deviation 13.7]) who had a subacute stroke and underwent rehabilitation at a convalescent hospital were recruited using convenience sampling. Semi-structured interviews were conducted by an occupational therapist with an interview topic guide regarding factors influencing motivation and how it affects behavioral change. Interviews were recorded, transcribed to text, and analyzed by three occupational therapists using thematic analysis. The participants were divided into two groups: aged patients (aged ≥ 65 years) and middle-aged patients (aged &amp;lt; 65 years), and data were analyzed according to the groups. This study was conducted according to the consolidated criteria for reporting qualitative research.

    <bold>Results:</bold> Seven core categories were identified as factors influencing patients' motivation: patients' goals, experiences of success and failure, physical condition and cognitive function, resilience, influence of rehabilitation professionals, relationships between patients, and patients' supporters. The first four and last three core categories were further classified as personal and social-relationship factors, respectively. The categories related to intrinsic motivation such as enjoyment of rehabilitation itself were not derived. In both age-groups, motivation affected the frequency of self-training and activity in daily lives. In some aged patients, however, high motivation restrained their self-training to conserve their physical strength for rehabilitation by professionals. Some aged patients do not express their high motivation through their facial expressions and conversations compared to middle-aged patients; therefore, motivation is not always observable in aged patients.

    <bold>Conclusions:</bold> Interventions tailored to extrinsic factors are important for maintaining patients' motivation. Observational evaluation may lead to mislabeling of their motivation, especially for aged patients. Rehabilitation professionals should use validated evaluation scales or patients' narratives to assess patients' motivation.

    DOI

  • Aberrant Cerebello-Cortical Connectivity in Pianists With Focal Task-Specific Dystonia.

    Kahori Kita, Shinichi Furuya, Rieko Osu, Takashi Sakamoto, Takashi Hanakawa

    Cerebral cortex (New York, N.Y. : 1991)    2021.05  [International journal]

     View Summary

    Musician's dystonia is a type of focal task-specific dystonia (FTSD) characterized by abnormal muscle hypercontraction and loss of fine motor control specifically during instrument playing. Although the neuropathophysiology of musician's dystonia remains unclear, it has been suggested that maladaptive functional abnormalities in subcortical and cortical regions may be involved. Here, we hypothesized that aberrant effective connectivity between the cerebellum (subcortical) and motor/somatosensory cortex may underlie the neuropathophysiology of musician's dystonia. Using functional magnetic resonance imaging, we measured the brain activity of 30 pianists with or without FTSD as they played a magnetic resonance imaging-compatible piano-like keyboard, which elicited dystonic symptoms in many but not all pianists with FTSD. Pianists with FTSD showed greater activation of the right cerebellum during the task than healthy pianists. Furthermore, patients who reported dystonic symptoms during the task demonstrated greater cerebellar activation than those who did not, establishing a link between cerebellar activity and overt dystonic symptoms. Using multivoxel pattern analysis, moreover, we found that dystonic and healthy pianists differed in the task-related effective connectivity between the right cerebellum and left premotor/somatosensory cortex. The present study indicates that abnormal cerebellar activity and cerebello-cortical connectivity may underlie the pathophysiology of FTSD in musicians.

    DOI PubMed

  • The Relationship between Stability of Interpersonal Coordination and Inter-Brain EEG Synchronization during Anti-phase Tapping

    Yuto Kurihara, Toru Takahashi, Rieko Osu

       2021.04

     View Summary

    <title>Abstract</title>Inter-brain synchronization is enhanced when individuals perform rhythmic interpersonal coordination tasks, such as playing instruments in music ensembles. Experimentally, synchronization has been shown to correlate with the performance of joint tapping tasks. However, it is unclear whether inter-brain synchronization is related to the stability of interpersonal coordination represented as the standard deviation of relative phase (SDRP). In this study, we simultaneously recorded electroencephalograms of two paired individuals during anti-phase tapping in three speed conditions: slow (reference inter-tap interval [ITI]: 0.5 s), fast (reference ITI: 0.25 s), and free (preferred ITI). We calculated the inter-brain synchronization within six regions of interest: frontal, central, left/right temporal, parietal, and occipital regions. We found that synchronization of the central-temporal regions was positively correlated with SDRP in the theta and alpha bands, while synchronization of the frontal-frontal and frontal-central was positively correlated with SDRP in the beta band. These results demonstrate that inter-brain synchronization occurs only when task requirements are high, and that it increases with the instability of the coordination. This may be explained by the stronger mutual prediction required in unstable coordination than that in stable coordination, which increases inter-brain synchronization.

    DOI

  • Hierarchical motor adaptations negotiate failures during force field learning

    Tsuyoshi Ikegami, Gowrishankar Ganesh, Tricia L. Gibo, Toshinori Yoshioka, Rieko Osu, Mitsuo Kawato

    PLOS Computational Biology   17 ( 4 ) e1008481 - e1008481  2021.04

     View Summary

    Humans have the amazing ability to learn the dynamics of the body and environment to develop motor skills. Traditional motor studies using arm reaching paradigms have viewed this ability as the process of ‘internal model adaptation’. However, the behaviors have not been fully explored in the case when reaches fail to attain the intended target. Here we examined human reaching under two force fields types; one that induces failures (i.e., target errors), and the other that does not. Our results show the presence of a distinct failure-driven adaptation process that enables quick task success after failures, and before completion of internal model adaptation, but that can result in persistent changes to the undisturbed trajectory. These behaviors can be explained by considering a hierarchical interaction between internal model adaptation and the failure-driven adaptation of reach direction. Our findings suggest that movement failure is negotiated using hierarchical motor adaptations by humans.

    DOI

  • アスリートの外傷と運動学習能力の関係に関する予備的検討

    大須理英子, 早川梨香子, 古賀敬之, 平山健人, 江川陽介

    人間科学研究   33 ( 2 )  2021.03

  • Transcranial direct current stimulation of the posterior parietal cortex biases human hand choice

    Kento Hirayama, Takayuki Koga, Toru Takahashi, Rieko Osu

    Scientific Reports   11 ( 1 )  2021.01  [Refereed]

    Authorship:Corresponding author

     View Summary

    <title>Abstract</title>Hand choices—deciding which hand to use to reach for targets—represent continuous, daily, unconscious decisions. The posterior parietal cortex (PPC) contralateral to the selected hand is activated during a hand-choice task, and disruption of left PPC activity with a single-pulse transcranial magnetic stimulation prior to the execution of the motion suppresses the choice to use the right hand but not vice versa. These findings imply the involvement of either bilateral or left PPC in hand choice. To determine whether the effects of PPC’s activity are essential and/or symmetrical in hand choice, we increased or decreased PPC excitability in 16 healthy participants using transcranial direct current stimulation (tDCS; 10 min, 2 mA, 5 × 7 cm) and examined its online and residual effects on hand-choice probability and reaction time. After the right PPC was stimulated with an anode and the left PPC with a cathode, the probability of left-hand choice significantly increased and reaction time significantly decreased. However, no significant changes were observed with the stimulation of the right PPC with a cathode and the left PPC with an anode. These findings, thus, reveal the asymmetry of PPC-mediated regulation in hand choice.

    DOI

  • リハビリテーションへのモチベーション評価尺度(MORE scale)の尺度特性の検討

    吉田 太樹, 大高 洋平, 北村 新, 栗原 勇人, 大須 理英子

    日本作業療法学会抄録集   54回   OA - 45  2020.09

  • 脳卒中患者のリハビリテーションへのモチベーションに関するシステマティックレビュー

    吉田 太樹, 伊藤 大将, 渡邉 翔太, 大須 理英子, 大高 洋平

    作業療法   39 ( 4 ) 468 - 477  2020.08

     View Summary

    脳卒中患者におけるリハビリテーション(以下、リハ)のモチベーションに関する知見をシステマティックレビューを用いて整理した。PubMed、CENTRAL、医中誌Webのデータベースから1,930文献が検索され、適格基準・除外基準を満たした13論文が抽出された。脳卒中患者のモチベーション評価には、リハのモチベーションに特化していない尺度や医療者による観察評価が用いられていた。モチベーションとリハの相互作用については、モチベーションに影響を与える要因、モチベーションが機能や活動に及ぼす影響について報告されていたが、報告の質・量共に不十分であった。今後は脳卒中患者のリハに対するモチベーションの概念形成や評価尺度開発が必要である。(著者抄録)

  • Plastic frontal pole cortex structure related to individual persistence for goal achievement.

    Chihiro Hosoda, Satoshi Tsujimoto, Masaru Tatekawa, Manabu Honda, Rieko Osu, Takashi Hanakawa

    Communications biology   3 ( 1 ) 194 - 194  2020.04  [Refereed]  [International journal]

     View Summary

    Persistent goal-directed behaviours result in achievements in many fields. However, the underlying neural mechanisms of persistence and the methods that enhance the neuroplasticity underlying persistence, remain unclear. We here demonstrate that the structural properties of the frontal pole cortex (FPC) before tasks contain information that can classify Achievers and Non-achievers (goal-directed persistence) participating in three tasks that differ in time scale (hours to months) and task domains (cognitive, language, and motor learning). We also found that most Achievers exhibit experience-dependent neuroplastic changes in the FPC after completing language and motor learning tasks. Moreover, we confirmed that a coaching strategy that used subgoals modified goal-directed persistence and increased the likelihood of becoming an Achiever. Notably, we discovered that neuroplastic changes in the FPC were facilitated by the subgoal strategy, suggesting that goal-striving, using effective coaching, optimizes the FPC for goal persistence.

    DOI PubMed

  • 脳卒中患者のリハビリテーションへのモチベーションに関するシステマティックレビュー

    吉田太樹, 伊藤大将, 渡邉翔太, 大須理英子, 大高洋平

    作業療法   in press ( 4 ) 468 - 477  2020  [Refereed]

     View Summary

    脳卒中患者におけるリハビリテーション(以下、リハ)のモチベーションに関する知見をシステマティックレビューを用いて整理した。PubMed、CENTRAL、医中誌Webのデータベースから1,930文献が検索され、適格基準・除外基準を満たした13論文が抽出された。脳卒中患者のモチベーション評価には、リハのモチベーションに特化していない尺度や医療者による観察評価が用いられていた。モチベーションとリハの相互作用については、モチベーションに影響を与える要因、モチベーションが機能や活動に及ぼす影響について報告されていたが、報告の質・量共に不十分であった。今後は脳卒中患者のリハに対するモチベーションの概念形成や評価尺度開発が必要である。(著者抄録)

  • Convolutional Neural Networkを用いた区画数検出の検討

    古賀敬之, 髙橋友太, 岡崎俊太郎, 大須理英子

    人間科学研究   32 ( 2 ) 217 - 223  2019.10  [Refereed]

  • Teacher-learner interaction quantifies scaffolding behaviour in imitation learning

    Okazaki S, Muraoka Y, Osu R

    Sci Rep   9   7543  2019.05  [Refereed]

     View Summary

    Teachers often believe that they take into account learners’ ongoing learning progress in their teaching. Can behavioural data support this belief? To address this question, we investigated the interactive behavioural coordination between teachers and learners during imitation learning to solve a puzzle. The teacher manually demonstrated the puzzle solution to a learner who immediately imitated and learned it. Manual movements of teachers and learners were analysed using a bivariate autoregressive model. To identify bidirectional information exchange and information shared between the two agents, we calculated causality and noise covariance from the model. Information transfer observed from teacher to learner in the lateral component of their motion indicated imitation of the spatial information of the puzzle solution. Information transfer from learner to teacher in the vertical component of their motion indicated the monitoring process through which teachers adjust their timing of demonstration to the learner’s progress. The shared information in the lateral component increased as learning progressed, indicating the knowledge was shared between the two agents. Our findings demonstrated that the teacher interactively engaged in and contingently supported (i.e. scaffolded) imitation. We thus provide a behavioural signature of the teacher’s intention to promote learning indispensable for understanding the nature of teaching.

  • Neuroanatomical Basis of Individuality in Muscle Tuning Function: Neural Correlates of Muscle Tuning

    Kita K, Osu R, Hosoda C, Honda M, Hanakawa T, Izawa J

    Front Behav Neurosci   13   28  2019.03  [Refereed]

     View Summary

    In a conventional view of motor control, the human brain might employ an optimization principle that leads a stereotypical motor behavior which we observe as an averaged behavioral data over subjects. In this scenario, the inter-individual motor variability is considered as an observation noise. Here, we challenged this view. We considered a motor control task where the human participants manipulated arm force by coordinating shoulder and elbow torques and investigated the muscle-tuning function that represents how the brain distributed the ideal joint torques to multiple muscles. In the experimental data, we observed large inter-individual variability in the profile of a muscle-tuning function. This contradicts with a well-established optimization theory that is based on minimization of muscle energy consumption and minimization of motor variability. We then hypothesized the inter-subject differences in the structure of the motor cortical areas might be the source of the across-subjects variability of the motor behavior. This was supported by a voxel-based morphometry analysis of magnetic resonance imaging; The inter-individual variability of the muscle tuning profile was correlated with that of the gray matter volume in the premotor cortex which is ipsilateral to the used arm (i.e., right hemisphere for the right arm). This study suggests that motor individuality may originate from inter-individual variation in the cortical structure.

    DOI

  • Revealing Relationships Among Cognitive Functions Using Functional Connectivity and a Large-Scale Meta-Analysis Database.

    Hiroki Kurashige, Jun Kaneko, Yuichi Yamashita, Rieko Osu, Yohei Otaka, Takashi Hanakawa, Manabu Honda, Hideaki Kawabata

    Frontiers in human neuroscience   13   457 - 457  2019  [Refereed]  [International journal]

     View Summary

    To characterize each cognitive function per se and to understand the brain as an aggregate of those functions, it is vital to relate dozens of these functions to each other. Knowledge about the relationships among cognitive functions is informative not only for basic neuroscientific research but also for clinical applications and developments of brain-inspired artificial intelligence. In the present study, we propose an exhaustive data mining approach to reveal relationships among cognitive functions based on functional brain mapping and network analysis. We began our analysis with 109 pseudo-activation maps (cognitive function maps; CFM) that were reconstructed from a functional magnetic resonance imaging meta-analysis database, each of which corresponds to one of 109 cognitive functions such as 'emotion,' 'attention,' 'episodic memory,' etc. Based on the resting-state functional connectivity between the CFMs, we mapped the cognitive functions onto a two-dimensional space where the relevant functions were located close to each other, which provided a rough picture of the brain as an aggregate of cognitive functions. Then, we conducted so-called conceptual analysis of cognitive functions using clustering of voxels in each CFM connected to the other 108 CFMs with various strengths. As a result, a CFM for each cognitive function was subdivided into several parts, each of which is strongly associated with some CFMs for a subset of the other cognitive functions, which brought in sub-concepts (i.e., sub-functions) of the cognitive function. Moreover, we conducted network analysis for the network whose nodes were parcels derived from whole-brain parcellation based on the whole-brain voxel-to-CFM resting-state functional connectivities. Since each parcel is characterized by associations with the 109 cognitive functions, network analyses using them are expected to inform about relationships between cognitive and network characteristics. Indeed, we found that informational diversities of interaction between parcels and densities of local connectivity were dependent on the kinds of associated functions. In addition, we identified the homogeneous and inhomogeneous network communities about the associated functions. Altogether, we suggested the effectiveness of our approach in which we fused the large-scale meta-analysis of functional brain mapping with the methods of network neuroscience to investigate the relationships among cognitive functions.

    DOI PubMed

  • 異なる姿勢制御方略が運動準備電位に与える影響

    高木 大輔, 倉山 太一, Ilker Sonmezisik, 兪 文偉, 須藤 千尋, 松澤 大輔, 大須 理英子

    臨床神経生理学   45 ( 5 ) 434 - 434  2017.10

  • Relationship of Subjective Visual Vertical with Static Postural Balance and Gait Asymmetry in Patients with the Lateral Medullary Infarction

    ARAI Kazuki, MATSUURA Daisuke, SUGITA Sho, OSU Rieko, KONDO Kunitsugu, OTAKA Yohei

    Physical Therapy Japan   44 ( 5 ) 364 - 371  2017.10

     View Summary

    <p>Purpose: To examine the relationship of subjective visual vertical (SVV) with static postural balance and gait asymmetry in patients with lateral medullary infarction.</p><p>Method: Nine participants with body lateropulsion (BL) due to lateral medullary infarction were enrolled. The relationships of SVV with three stabilometric parameters (length of center of pressure, envelopment area, and weight-bearing asymmetry during standing) and gait asymmetry were investigated.</p><p>Results: The mean (SD) SVV was found to be 7.4° (9.5°). SVV values significantly correlated with weight-bearing asymmetry in the eye-closed condition (r = 0.75, P < 0.05), whereas they did not significantly correlate with weight-bearing asymmetry in the eye-open condition. In addition, the absolute values of SVV significantly correlated with gait asymmetry (r = –0.78, P < 0.05).</p><p>Conclusion: In patients with lateral medullary infarction with BL, SVV was related to static postural balance in the eye-closed condition and gait asymmetry. Further investigation is needed to examine the causality between SVV and these measures.</p>

    CiNii

  • Transcranial Direct Current Stimulation Improves Audioverbal Memory in Stroke Patients

    Toshinari Kazuta, Kotaro Takeda, Rieko Osu, Satoshi Tanaka, Ayako Oishi, Kunitsugu Kondo, Meigen Liu

    AMERICAN JOURNAL OF PHYSICAL MEDICINE & REHABILITATION   96 ( 8 ) 565 - 571  2017.08  [Refereed]

     View Summary

    Objective The aim of this study was to investigate whether anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance in stroke patients.
    Design Twelve stroke patients with audioverbal memory impairment participated in a single-masked, crossover, and sham-controlled experiment. The anodal or sham transcranial direct current stimulation was applied during the Rey Auditory Verbal Learning Test, which evaluates the ability to recall a list of 15 heard words over five trials. The number of correctly recalled words was compared between the anodal and sham conditions and the influence of transcranial direct current stimulation on serial position effect of the 15 words was also examined.
    Results The increase in the number of correctly recalled words from the first to the fifth trial was significantly greater in the anodal condition than in the sham condition (P &lt; 0.01). There was a significant difference (P &lt; 0.01) between the anodal and sham conditions in the number of correctly recalled words within the first five words (primacy region) over the second to fifth trial trials, but not in the middle (next five words) or recency (last five words) regions.
    Conclusions Anodal transcranial direct current stimulation over the left temporoparietal area improved audioverbal memory performance and induced the primacy effect in stroke patients.

    DOI PubMed

  • New portable voice guidance device for the manual wheelchair transfer: a pilot study in patients with hemiplegia.

    Taiki Yoshida, Yohei Otaka, Rieko Osu, Kahori Kita, Sachiko Sakata, Kunitsugu Kondo

    Disability and rehabilitation. Assistive technology   12 ( 4 ) 411 - 416  2017.05  [International journal]

     View Summary

    PURPOSE: Older and/or cognitively impaired patients require verbal guidance to prevent accidents during wheelchair operation, thus increasing the burden on caregivers. This study aimed to develop a new portable voice guidance device for manual wheelchairs and examine its clinical usefulness. METHOD: We developed a portable voice guidance device to monitor the statuses of wheelchair brakes and footrests and automatically provide voice guidance for operation. The device comprises a microcomputer, four magnets and magnetic sensors, speaker and battery. Device operation was assessed during the transfer from a wheelchair to bed six times per day over three days for a total of 90 transfers in five stroke patients (mean age: 79.6 years) who required verbal guidance to direct wheelchair operation. Device usability was also assessed using a questionnaire. RESULTS: The device performed perfectly during all attempted transfers (100%). To ensure safety, the assessor needed to add verbal guidance during 33 of 90 attempted transfers (36.6%). Overall, the device usability was favourable. However, some assessors were unsatisfied with the volume of the device voice, guidance timing and burden reduction. CONCLUSIONS: Our device could facilitate wheelchair operation and might potentially be used to reduce fall risk in stroke patients and the burden on caregivers. Implications for Rehabilitation The acquisition of transfer independence is an important step in the rehabilitation of patients with mobility issues. Many patients require supervision and guidance regarding the operation of brakes and footrests on manual wheelchairs. This newly developed voice guidance device for manual wheelchair transfers worked well in patients with hemiplegia and might be helpful to reduce the fall risks and the burden of care.

    DOI PubMed

  • Transient increase in systemic interferences in the superficial layer and its influence on event-related motor tasks: a functional near-infrared spectroscopy study

    Isao Nambu, Takuya Ozawa, Takanori Sato, Takatsugu Aihara, Yusuke Fujiwara, Yohei Otaka, Rieko Osu, Jun Izawa, Yasuhiro Wada

    JOURNAL OF BIOMEDICAL OPTICS   22 ( 3 )  2017.03  [Refereed]

     View Summary

    Functional near-infrared spectroscopy (fNIRS) is a widely utilized neuroimaging tool in fundamental neuroscience research and clinical investigation. Previous research has revealed that task-evoked systemic artifacts mainly originating from the superficial-tissue may preclude the identification of cerebral activation during a given task. We examined the influence of such artifacts on event-related brain activity during a brisk squeezing movement. We estimated task-evoked superficial-tissue hemodynamics from short source-detector distance channels (15 mm) by applying principal component analysis. The estimated superficial-tissue hemodynamics exhibited temporal profiles similar to the canonical cerebral hemodynamic model. Importantly, this task-evoked profile was also observed in data from a block design motor experiment, suggesting a transient increase in superficial-tissue hemodynamics occurs following motor behavior, irrespective of task design. We also confirmed that estimation of event-related cerebral hemodynamics was improved by a simple superficial-tissue hemodynamic artifact removal process using 15-mm short distance channels, compared to the results when no artifact removal was applied. Thus, our results elucidate task design-independent characteristics of superficial-tissue hemodynamics and highlight the need for the application of superficial-tissue hemodynamic artifact removal methods when analyzing fNIRS data obtained during event-related motor tasks. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

    DOI

  • Neural pattern similarity between contra- and ipsilateral movements in high-frequency band of human electrocorticograms

    Yusuke Fujiwara, Riki Matsumoto, Takuro Nakae, Kiyohide Usami, Masao Matsuhashi, Takayuki Kikuchi, Kazumichi Yoshida, Takeharu Kunieda, Susumu Miyamoto, Tatsuya Mima, Akio Ikeda, Rieko Osu

    NEUROIMAGE   147   302 - 313  2017.02  [Refereed]

     View Summary

    The cortical motor areas are activated not only during contralateral limb movements but also during ipsilateral limb movements. Although these ipsilateral activities have been observed in several brain imaging studies, their functional role is poorly understood. Due to its high temporal resolution and low susceptibility to artifacts from body movements, the electrocorticogram (ECoG) is an advantageous measurement method for assessing the human brain function of motor behaviors. Here, we demonstrate that contra- and ipsilateral movements share a similarity in the high-frequency band of human ECoG signals. The ECoG signals were measured from the unilateral sensorimotor cortex while patients conducted self-paced movements of different body parts, contra or ipsilateral to the measurement side. The movement categories (wrist, shoulder, or ankle) of ipsilateral movements were decoded as accurately as those of contralateral movements from spatial patterns of the high frequency band of the precentral motor area (the primary motor and premotor areas). The decoder, trained in the high-frequency band of ipsilateral movements generalized to contralateral movements, and vice versa, confirmed that the activity patterns related to ipsilateral limb movements were similar to contralateral ones in the precentral motor area. Our results suggest that the high-frequency band activity patterns of ipsilateral and contralateral movements might be functionally coupled to control limbs, even during unilateral movements.

    DOI

  • Reduction of global interference of scalp-hemodynamics in functional near-infrared spectroscopy using short distance probes

    Takanori Sato, Isao Nambu, Kotaro Takeda, Takatsugu Aihara, Okito Yamashita, Yuko Isogaya, Yoshihiro Inoue, Yohei Otaka, Yasuhiro Wada, Mitsuo Kawato, Masa-aki Sato, Rieko Osu

    NEUROIMAGE   141   120 - 132  2016.11  [Refereed]

     View Summary

    Functional near-infrared spectroscopy (fNIRS) is used to measure cerebral activity because it is simple and portable. However, scalp-hemodynamics often contaminates fNIRS signals, leading to detection of cortical activity in regions that are actually inactive. Methods for removing these artifacts using standard source-detector distance channels (Long-channel) tend to over-estimate the artifacts, while methods using additional short source-detector distance channels (Short-channel) require numerous probes to cover broad cortical areas, which leads to a high cost and prolonged experimental time. Here, we propose a new method that effectively combines the existing techniques, preserving the accuracy of estimating cerebral activity and avoiding the disadvantages inherent when applying the techniques individually. Our new method accomplishes this by estimating a global scalp-hemodynamic component from a small number of Short-channels, and removing its influence from the Long-channels using a general linear model (GLM). To demonstrate the feasibility of this method, we collected fNIRS and functional magnetic resonance imaging (fMRI) measurements during a motor task. First, we measured changes in oxygenated hemoglobin concentration (Delta Oxy-Hb) from 18 Short-channels placed over motor-related areas, and confirmed that the majority of scalp-hemodynamics was globally consistent and could be estimated from as few as four Short-channels using principal component analysis. We then measured Delta Oxy-Hb from 4 Short- and 43 Long-channels. The GLM identified cerebral activity comparable to that measured separately by fMRI, even when scalp-hemodynamics exhibited substantial task-related modulation. These results suggest that combining measurements from four Short-channels with a GLM provides robust estimation of cerebral activity at a low cost. (C) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license.

    DOI

  • 脳波(EEG)およびアイトラッキングによる生体反応の測定 (特集 ニューロマーケティング)

    大須 理英子, 古畑 裕之

    オペレーションズ・リサーチ   61 ( 7 ) 442 - 448  2016.07

    CiNii

  • Effectiveness of Sensory Feedback by Transcutaneous Electrical Nerve Stimulation for Stroke Rehabilitation:—A Case Series—

    KITA Kahori, OSU Rieko, SAKATA Sachiko, OTAKA Yohei

    Transactions of the Society of Instrument and Control Engineers   52 ( 3 ) 120 - 126  2016

     View Summary

    Sensory disturbance is a very common following stroke, and severe sensory loss may inhibit the ability of patients to use the affected upper limb in daily activities, even when they have good motor function. We hypothesized that task-specific training with sensory feedback may improve patients' ability to manipulate objects. We developed a system of sensory feedback using transcutaneous electrical nerve stimulation (SENS) for stroke rehabilitation and investigated its effectiveness. In this study, we conducted a case studies with stroke patients. The instability of tip pressure during a cube pinch and lifting task was improved after one hour's training with SENS, although it was not changed by training without SENS. We concluded that SENS would be useful in the rehabilitation of stroke patients with sensory loss.

    CiNii

  • Motor control and learning theories

    Cristiano Alessandro, Niek Beckers, Peter Goebel, Francisco Resquin, José González, Rieko Osu

    Biosystems and Biorobotics   10   225 - 250  2016

     View Summary

    Patients who have suffered impairment of their neuromotor abilities due to a disease or accident have to relearn to control their bodies. For example, after stroke the ability to coordinate the movements of the upper limb in order to reach and grasp an object could be severely damaged. Or in the case of amputees, the functional ability is completely lost.

    DOI

  • Practice reduces task relevant variance modulation and forms nominal trajectory

    Rieko Osu, Ken-ichi Morishige, Jun Nakanishi, Hiroyuki Miyamoto, Mitsuo Kawato

    SCIENTIFIC REPORTS   5  2015.12  [Refereed]

     View Summary

    Humans are capable of achieving complex tasks with redundant degrees of freedom. Much attention has been paid to task relevant variance modulation as an indication of online feedback control strategies to cope with motor variability. Meanwhile, it has been discussed that the brain learns internal models of environments to realize feedforward control with nominal trajectories. Here we examined trajectory variance in both spatial and temporal domains to elucidate the relative contribution of these control schemas. We asked subjects to learn reaching movements with multiple via-points, and found that hand trajectories converged to stereotyped trajectories with the reduction of task relevant variance modulation as learning proceeded. Furthermore, variance reduction was not always associated with task constraints but was highly correlated with the velocity profile. A model assuming noise both on the nominal trajectory and motor command was able to reproduce the observed variance modulation, supporting an expression of nominal trajectories in the brain. The learning-related decrease in task-relevant modulation revealed a reduction in the influence of optimal feedback around the task constraints. After practice, the major part of computation seems to be taken over by the feedforward controller around the nominal trajectory with feedback added only when it becomes necessary.

    DOI PubMed

  • Effort, success, and nonuse determine arm choice

    Nicolas Schweighofer, Yupeng Xiao, Sujin Kim, Toshinori Yoshioka, James Gordon, Rieko Osu

    JOURNAL OF NEUROPHYSIOLOGY   114 ( 1 ) 551 - 559  2015.07  [Refereed]

     View Summary

    How do humans choose one arm or the other to reach single targets in front of the body? Current theories of reward-driven decisionmaking predict that choice results from a comparison of "action values," which are the expected rewards for possible actions in a given state. In addition, current theories of motor control predict that in planning arm movements, humans minimize an expected motor cost that balances motor effort and endpoint accuracy. Here, we test the hypotheses that arm choice is determined by comparison of action values comprising expected effort and expected task success for each arm, as well as a handedness bias. Right-handed subjects, in either a large or small target condition, were first instructed to use each hand in turn to shoot through an array of targets and then to choose either hand to shoot through the same targets. Effort was estimated via inverse kinematics and dynamics. A mixed-effects logistic-regression analysis showed that, as predicted, both expected effort and expected success predicted choice, as did arm use in the preceding trial. Finally, individual parameter estimation showed that the handedness bias correlated with mean difference between right- and left-arm success, leading to overall lower use of the left arm. We discuss our results in light of arm nonuse in individuals' poststroke.

    DOI PubMed

  • Resting-state brain activity in the motor cortex reflects task-induced activity: A multi-voxel pattern analysis

    Toshiki Kusano, Hiroki Kurashige, Isao Nambu, Yoshiya Moriguchi, Takashi Hanakawa, Yasuhiro Wada, Rieko Osu

    2015 37TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)   2015-November   4290 - 4293  2015  [Refereed]

     View Summary

    It has been suggested that resting-state brain activity reflects task-induced brain activity patterns. In this study, we examined whether neural representations of specific movements can be observed in the resting-state brain activity patterns of motor areas. First, we defined two regions of interest (ROIs) to examine brain activity associated with two different behavioral tasks. Using multi-voxel pattern analysis with regularized logistic regression, we designed a decoder to detect voxel-level neural representations corresponding to the tasks in each ROI. Next, we applied the decoder to resting-state brain activity. We found that the decoder discriminated resting-state neural activity with accuracy comparable to that associated with task-induced neural activity. The distribution of learned weighted parameters for each ROI was similar for resting-state and task-induced activities. Large weighted parameters were mainly located on conjunctive areas. Moreover, the accuracy of detection was higher than that for a decoder whose weights were randomly shuffled, indicating that the resting-state brain activity includes multi-voxel patterns similar to the neural representation for the tasks. Therefore, these results suggest that the neural representation of resting-state brain activity is more finely organized and more complex than conventionally considered.

    DOI

  • The influence of an uncertain force environment on reshaping trial-to-trial motor variability

    Jun Izawa, Toshinori Yoshioka, Rieko Osu

    NEUROREPORT   25 ( 13 ) 979 - 984  2014.09  [Refereed]

     View Summary

    Motor memory is updated to generate ideal movements in a novel environment. When the environment changes every trial randomly, how does the brain incorporate this uncertainty into motor memory? To investigate how the brain adapts to an uncertain environment, we considered a reach adaptation protocol where individuals practiced moving in a force field where a noise was injected. After they had adapted, we measured the trial-to-trial variability in the temporal profiles of the produced hand force. We found that the motor variability was significantly magnified by the adaptation to the random force field. Temporal profiles of the motor variance were significantly dissociable between two different types of random force fields experienced. A model-based analysis suggests that the variability is generated by noise in the gains of the internal model. It further suggests that the trial-to-trial motor variability magnified by the adaptation in a random force field is generated by the uncertainty of the internal model formed in the brain as a result of the adaptation. (C) 2014 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

    DOI PubMed

  • Immediate tool incorporation processes determine human motor planning with tools

    G. Ganesh, T. Yoshioka, R. Osu, T. Ikegami

    NATURE COMMUNICATIONS   5  2014.07  [Refereed]

     View Summary

    Human dexterity with tools is believed to stem from our ability to incorporate and use tools as parts of our body. However tool incorporation, evident as extensions in our body representation and peri-personal space, has been observed predominantly after extended tool exposures and does not explain our immediate motor behaviours when we change tools. Here we utilize two novel experiments to elucidate the presence of additional immediate tool incorporation effects that determine motor planning with tools. Interestingly, tools were observed to immediately induce a trial-by-trial, tool length dependent shortening of the perceived limb lengths, opposite to observations of elongations after extended tool use. Our results thus exhibit that tools induce a dual effect on our body representation; an immediate shortening that critically affects motor planning with a new tool, and the slow elongation, probably a consequence of skill related changes in sensory-motor mappings with the repeated use of the tool.

    DOI PubMed

  • Two is better than one: Physical interactions improve motor performance in humans

    G. Ganesh, A. Takagi, R. Osu, T. Yoshioka, M. Kawato, E. Burdet

    SCIENTIFIC REPORTS   4  2014.01  [Refereed]

     View Summary

    How do physical interactions with others change our own motor behavior? Utilizing a novel motor learning paradigm in which the hands of two - individuals are physically connected without their conscious awareness, we investigated how the interaction forces from a partner adapt the motor behavior in physically interacting humans. We observed the motor adaptations during physical interactions to be mutually beneficial such that both the worse and better of the interacting partners improve motor performance during and after interactive practice. We show that these benefits cannot be explained by multi-sensory integration by an individual, but require physical interaction with a reactive partner. Furthermore, the benefits are determined by both the interacting partner's performance and similarity of the partner's behavior to one's own. Our results demonstrate the fundamental neural processes underlying human physical interactions and suggest advantages of interactive paradigms for sport-training and physical rehabilitation.

    DOI PubMed

  • Feeling the force: Returning haptic signals influence effort inference during motor coordination

    G. Ganesh, R. Osu, E. Naito

    SCIENTIFIC REPORTS   3  2013.09  [Refereed]

     View Summary

    Our brain is known to automatically optimize effort expenditure during motor coordination, such that for example, during bimanual braking of a bicycle, a well-oiled brake will automatically be used more than a corroded, heavy brake. But how does our brain infer the effort expenditure? All previous motor coordination models have believed that the effort in a task is known precisely to our brain, solely from the motor commands it generates. Here we show that this belief is incorrect. Through experiments and simulation we exhibit that in addition to the motor commands, the returning haptic signals play a crucial role in the inference of the effort during a force sharing task. Our results thus elucidate a previously unknown sensory-motor association that has major ramifications for our understanding of motor coordination and provides new insights into how sensory modifications due to ergonomics, stroke and disease can affect motor coordination in humans.

    DOI PubMed

  • A pilot study of sensory feedback by transcutaneous electrical nerve stimulation to improve manipulation deficit caused by severe sensory loss after stroke.

    Kahori Kita, Yohei Otaka, Kotaro Takeda, Sachiko Sakata, Junichi Ushiba, Kunitsugu Kondo, Meigen Liu, Rieko Osu

    Journal of neuroengineering and rehabilitation   10 ( 1 ) 55 - 55  2013.06  [International journal]

     View Summary

    BACKGROUND: Sensory disturbance is common following stroke and can exacerbate functional deficits, even in patients with relatively good motor function. In particular, loss of appropriate sensory feedback in severe sensory loss impairs manipulation capability. We hypothesized that task-oriented training with sensory feedback assistance would improve manipulation capability even without sensory pathway recovery. METHODS: We developed a system that provides sensory feedback by transcutaneous electrical nerve stimulation (SENS) for patients with sensory loss, and investigated the feasibility of the system in a stroke patient with severe sensory impairment and mild motor deficit. The electrical current was modulated by the force exerted by the fingertips so as to allow the patient to identify the intensity. The patient had severe sensory loss due to a right thalamic hemorrhage suffered 27 months prior to participation in the study. The patient first practiced a cylindrical grasp task with SENS for 1 hour daily over 29 days. Pressure information from the affected thumb was fed back to the unaffected shoulder. The same patient practiced a tip pinch task with SENS for 1 hour daily over 4 days. Pressure information from the affected thumb and index finger was fed back to the unaffected and affected shoulders, respectively. We assessed the feasibility of SENS and examined the improvement of manipulation capability after training with SENS. RESULTS: The fluctuation in fingertip force during the cylindrical grasp task gradually decreased as the training progressed. The patient was able to maintain a stable grip force after training, even without SENS. Pressure exerted by the tip pinch of the affected hand was unstable before intervention with SENS compared with that of the unaffected hand. However, they were similar to each other immediately after SENS was initiated, suggesting that the somatosensory information improved tip pinch performance. The patient's manipulation capability assessed by the Box and Block Test score improved through SENS intervention and was partly maintained after SENS was removed, until at least 7 months after the intervention. The sensory test score, however, showed no recovery after intervention. CONCLUSIONS: We conclude that the proposed system would be useful in the rehabilitation of patients with sensory loss.

    DOI PubMed

  • Quantifying Arm Nonuse in Individuals Poststroke

    Cheol E. Han, Sujin Kim, Shuya Chen, Yi-Hsuan Lai, Jeong-Yoon Lee, Rieko Osu, Carolee J. Winstein, Nicolas Schweighofer

    NEUROREHABILITATION AND NEURAL REPAIR   27 ( 5 ) 439 - 447  2013.06  [Refereed]

     View Summary

    Background. Arm nonuse, defined as the difference between what the individual can do when constrained to use the paretic arm and what the individual does when given a free choice to use either arm, has not yet been quantified in individuals poststroke. Objectives. (1) To quantify nonuse poststroke and (2) to develop and test a novel, simple, objective, reliable, and valid instrument, the Bilateral Arm Reaching Test (BART), to quantify arm use and nonuse poststroke. Methods. First, we quantify nonuse with the Quality of Movement (QOM) subscale of the Actual Amount of Use Test (AAUT) by subtracting the AAUT QOM score in the spontaneous use condition from the AAUT QOM score in a subsequent constrained use condition. Second, we quantify arm use and nonuse with BART by comparing reaching performance to visual targets projected over a 2D horizontal hemi-work space in a spontaneous-use condition (in which participants are free to use either arm at each trial) with reaching performance in a constrained-use condition. Results. All participants (N = 24) with chronic stroke and with mild to moderate impairment exhibited nonuse with the AAUT QOM. Nonuse with BART had excellent test-retest reliability and good external validity. Conclusions. BART is the first instrument that can be used repeatedly and practically in the clinic to quantify the effects of neurorehabilitation on arm use and nonuse and in the laboratory for advancing theoretical knowledge about the recovery of arm use and the development of nonuse and "learned nonuse" after stroke.

    DOI PubMed

  • The effect of active pedaling combined with electrical stimulation on spinal reciprocal inhibition

    Tomofumi Yamaguchi, Toshiyuki Fujiwara, Kei Saito, Shigeo Tanabe, Yoshihiro Muraoka, Yohei Otaka, Rieko Osu, Tetsuya Tsuji, Kimitaka Hase, Meigen Liu

    JOURNAL OF ELECTROMYOGRAPHY AND KINESIOLOGY   23 ( 1 ) 190 - 194  2013.02  [Refereed]

     View Summary

    Objective: Pedaling is widely used for rehabilitation of locomotion because it induces muscle activity very similar to locomotion. Afferent stimulation is important for the modulation of spinal reflexes. Furthermore, supraspinal modulation plays an important role in spinal plasticity induced by electrical stimulation. We, therefore, expected that active pedaling combined with electrical stimulation could induce strong after-effects on spinal reflexes.
    Design: Twelve healthy adults participated in this study. They were instructed to perform 7 min of pedaling. We applied electrical stimulation to the common peroneal nerve during the extension phase of the pedaling cycle. We assessed reciprocal inhibition using a soleus H-reflex conditioning-test paradigm. The magnitude of reciprocal inhibition was measured before, immediately after, 15 and 30 min after active pedaling alone, electrical stimulation alone and active pedaling combined with electrical stimulation (pedaling + ES).
    Results: The amount of reciprocal inhibition was significantly increased after pedaling + ES. The aftereffect of pedaling + ES on reciprocal inhibition was more prominent and longer lasting compared with pedaling or electrical stimulation alone.
    Conclusions: Pedaling + ES could induce stronger after-effects on spinal reciprocal inhibitory neurons compared with either intervention alone. Pedaling + ES might be used as a tool to improve locomotion and functional abnormalities in the patient with central nervous lesion. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI PubMed

  • Transcranial direct current stimulation improves audioverbal short-term memory in healthy subjects

    Kazuta Toshinari, Takeda Kotaro, Tanaka Satoshi, Odagaki Seiji, Osu Rieko, Otaka Yohei, Kondo Kunitsugu, Liu Meigen

    Jpn J Clin Neurophysiol   41 ( 1 ) 18 - 22  2013

     View Summary

    Transcranial direct current stimulation (tDCS) is a noninvasive, painless cortical stimulation technique. Depending on the polarity of the current flow, brain excitability can either be increased by the anodal tDCS or decreased by the cathodal tDCS. The aim of the present study was to examine the behavioral effects of direct current delivery on left posterior temporal and inferior parietal cortices during the Rey's auditory verbal learning test (RAVLT) that examine audioverbal short-term memory. The RAVLT includes a list of 15 common words to be read one-by-one. After the presentation of 15 words, the subjects are required to repeat as many words as they can. The encoding-recall procedure is repeated five times. Twelve healthy subjects performed the RAVLT, during which, 10 minutes anodal and 15 seconds sham current was applied on left posterior temporal and inferior parietal cortex from the second encoding process. There was a significant difference in the mean number of remembered words between anodal and sham stimulation on the second process. Anodal tDCS increased the number of remembered words when compared to sham stimulation. Our results imply that anodal tDCS induced short-term modulation of the left posterior temporal and inferior parietal cortex while learning auditory presented words. tDCS is a promising tool for improving memory performance.

    CiNii

  • Exploring Optimal Neurofeedback for Rehabilitation

    Osu Rieko

    BME   51 ( 0 ) M - 136-M-136  2013

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  • Detecting Event-Related Motor Activity Using Functional Near-Infrared Spectroscopy

    Takuya Ozawa, Takatsugu Aihara, Yusuke Fujiwara, Yohei Otaka, Isao Nambu, Rieko Osu, Jun Izawa, Yasuhiro Wada

    2013 6TH INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING (NER)     1529 - 1532  2013  [Refereed]

     View Summary

    Measuring discrete-trial motor-related brain activity using functional near-infrared spectroscopy (fNIRS) is considered difficult. This is because its spatial resolution is much lower than that of functional magnetic resonance imaging (fMRI), and its signals include non-motion-related artifacts. To detect changes in hemoglobin induced by movements, most fNIRS studies have used a block design in which a subject conducts a set of repetitive movements for over a few seconds. Changes in hemoglobin induced by the series of movements are accumulated. Here, we address whether fNIRS can detect a phasic change induced by a discrete ballistic movement using an event-related design similar to those often adopted in fMRI experiments. To detect only event-related brain activity and to reduce the effect of artifacts, we adopted a general linear model whose design matrix contains data from the short transmitter-receiver distance channels that are considered components of artifacts. As a result, high event-related activity was detected in the contralateral sensorimotor cortex. We also compared the topographic functional map produced by fNIRS with the map given by an event-related fMRI experiment in which the same subjects performed exactly the same task. Both maps showed activity in equivalent areas, and the similarity was significant. We conclude that fNIRS affords the opportunity to explore motor-related brain activity even for discrete ballistic movements.

    DOI

  • A pilot study of contralateral homonymous muscle activity simulated electrical stimulation in chronic hemiplegia

    Rieko Osu, Yohei Otaka, Junichi Ushiba, Sachiko Sakata, Tomofumi Yamaguchi, Toshiyuki Fujiwara, Kunitsugu Kondo, Meigen Liu

    BRAIN INJURY   26 ( 9 ) 1105 - 1112  2012.08  [Refereed]

     View Summary

    Objective: For the recovery of hemiparetic hand function, a therapy was developed called contralateral homonymous muscle activity stimulated electrical stimulation (CHASE), which combines electrical stimulation and bilateral movements, and its feasibility was studued in three chronic stroke patients with severe hand hemiparesis.
    Methods: Patients with a subcortical lesion were asked to extend their wrist and fingers bilaterally while an electromyogram (EMG) was recorded from the extensor carpi radialis (ECR) muscle in the unaffected hand. Electric stimulation was applied to the homonymous wrist and finger extensors of the affected side. The intensity of the electrical stimulation was computed based on the EMG and scaled so that the movements of the paretic hand looked similar to those of the unaffected side. The patients received 30-minutes of therapy per day for 2 weeks.
    Results: Improvement in the active range of motion of wrist extension was observed for all patients. There was a decrease in the scores of modified Ashworth scale in the flexors. Fugl-Meyer assessment scores of motor function of the upper extremities improved in two of the patients.
    Conclusions: The results suggest a positive outcome can be obtained using the CHASE system for upper extremity rehabilitation of patients with severe hemiplegia.

    DOI

  • Event related desynchronization-modulated functional electrical stimulation system for stroke rehabilitation: A feasibility study

    Mitsuru Takahashi, Kotaro Takeda, Yohei Otaka, Rieko Osu, Takashi Hanakawa, Manabu Gouko, Koji Ito

    JOURNAL OF NEUROENGINEERING AND REHABILITATION   9 ( 1 )  2012.08  [Refereed]

     View Summary

    Background: We developed an electroencephalogram-based brain computer interface system to modulate functional electrical stimulation (FES) to the affected tibialis anterior muscle in a stroke patient. The intensity of FES current increased in a stepwise manner when the event-related desynchronization (ERD) reflecting motor intent was continuously detected from the primary cortical motor area.
    Methods: We tested the feasibility of the ERD-modulated FES system in comparison with FES without ERD modulation. The stroke patient who presented with severe hemiparesis attempted to perform dorsiflexion of the paralyzed ankle during which FES was applied either with or without ERD modulation.
    Results: After 20 minutes of training, the range of movement at the ankle joint and the electromyography amplitude of the affected tibialis anterior muscle were significantly increased following the ERD-modulated FES compared with the FES alone.
    Conclusions: The proposed rehabilitation technique using ERD-modulated FES for stroke patients was feasible. The system holds potentials to improve the limb function and to benefit stroke patients.

    DOI PubMed

  • Cortical current source estimation from electroencephalography in combination with near-infrared spectroscopy as a hierarchical prior

    Takatsugu Aihara, Yusuke Takeda, Kotaro Takeda, Wataru Yasuda, Takanori Sato, Yohei Otaka, Takashi Hanakawa, Manabu Honda, Meigen Liu, Mitsuo Kawato, Masa-aki Sato, Rieko Osu

    NEUROIMAGE   59 ( 4 ) 4006 - 4021  2012.02  [Refereed]

     View Summary

    Previous simulation and experimental studies have demonstrated that the application of Variational Bayesian Multimodal EncephaloGraphy (VBMEG) to magnetoencephalography (MEG) data can be used to estimate cortical currents with high spatio-temporal resolution, by incorporating functional magnetic resonance imaging (fMRI) activity as a hierarchical prior. However, the use of combined MEG and fMRI is restricted by the high costs involved, a lack of portability and high sensitivity to body-motion artifacts. One possible solution for overcoming these limitations is to use a combination of electroencephalography (EEG) and near-infrared spectroscopy (NIRS). This study therefore aimed to extend the possible applications of VBMEG to include EEG data with NIRS activity as a hierarchical prior. Using computer simulations and real experimental data, we evaluated the performance of VBMEG applied to EEG data under different conditions, including different numbers of EEG sensors and different prior information. The results suggest that VBMEG with NIRS prior performs well, even with as few as 19 EEG sensors. These findings indicate the potential value of clinically applying VBMEG using a combination of EEG and NIRS. (C) 2011 Elsevier Inc. All rights reserved.

    DOI PubMed

  • Intermittent Visual Feedback Can Boost Motor Learning of Rhythmic Movements: Evidence for Error Feedback Beyond Cycles

    Tsuyoshi Ikegami, Masaya Hirashima, Rieko Osu, Daichi Nozaki

    JOURNAL OF NEUROSCIENCE   32 ( 2 ) 653 - 657  2012.01  [Refereed]

     View Summary

    Movement error is a driving force behind motor learning. For motor learning with discrete movements, such as point-to-point reaching, it is believed that the brain uses error information of the immediately preceding movement only. However, in the case of continuous and repetitive movements (i.e., rhythmic movements), there is a ceaseless inflow of performance information. Thus, an accurate temporal association of the motor commands with the resultant movement errors is not necessarily guaranteed. We investigated how the brain overcomes this challenging situation. Human participants adapted rhythmic movements between two targets to visuomotor rotations, the amplitudes of which changed randomly from cycle to cycle (the duration of one cycle was similar to 400 ms). A system identification technique revealed that the motor adaptation was affected not just by the preceding movement error, but also by a history of errors from the previous cycles. Error information obtained from more than one previous cycle tended to increase, rather than decrease, movement error. This result led to a counterintuitive prediction: providing visual error feedback for only a fraction of cycles should enhance visuomotor adaptation. As predicted, we observed that motor adaptation to a constant visual rotation (30 degrees) was significantly enhanced by providing visual feedback once every fourth or fifth cycle rather than for every cycle. These results suggest that the brain requires a specific processing time to modify the motor command, based on the error information, and so is unable to deal appropriately with the overwhelming flow of error information generated during rhythmic movements.

    DOI PubMed

  • Quantifying the quality of hand movement in stroke patients through three-dimensional curvature

    Rieko Osu, Kazuko Ota, Toshiyuki Fujiwara, Yohei Otaka, Mitsuo Kawato, Meigen Liu

    JOURNAL OF NEUROENGINEERING AND REHABILITATION   8 ( 1 )  2011.10  [Refereed]

     View Summary

    Background: To more accurately evaluate rehabilitation outcomes in stroke patients, movement irregularities should be quantified. Previous work in stroke patients has revealed a reduction in the trajectory smoothness and segmentation of continuous movements. Clinically, the Stroke Impairment Assessment Set (SIAS) evaluates the clumsiness of arm movements using an ordinal scale based on the examiner&apos;s observations. In this study, we focused on three-dimensional curvature of hand trajectory to quantify movement, and aimed to establish a novel measurement that is independent of movement duration. We compared the proposed measurement with the SIAS score and the jerk measure representing temporal smoothness.
    Methods: Sixteen stroke patients with SIAS upper limb proximal motor function (Knee-Mouth test) scores ranging from 2 (incomplete performance) to 4 (mild clumsiness) were recruited. Nine healthy participant with a SIAS score of 5 (normal) also participated. Participants were asked to grasp a plastic glass and repetitively move it from the lap to the mouth and back at a conformable speed for 30 s, during which the hand movement was measured using OPTOTRAK. The position data was numerically differentiated and the three-dimensional curvature was computed. To compare against a previously proposed measure, the mean squared jerk normalized by its minimum value was computed. Age-matched healthy participants were instructed to move the glass at three different movement speeds.
    Results: There was an inverse relationship between the curvature of the movement trajectory and the patient&apos;s SIAS score. The median of the -log of curvature (MedianLC) correlated well with the SIAS score, upper extremity subsection of Fugl-Meyer Assessment, and the jerk measure in the paretic arm. When the healthy participants moved slowly, the increase in the jerk measure was comparable to the paretic movements with a SIAS score of 2 to 4, while the MedianLC was distinguishable from paretic movements.
    Conclusions: Measurement based on curvature was able to quantify movement irregularities and matched well with the examiner&apos;s observations. The results suggest that the quality of paretic movements is well characterized using spatial smoothness represented by curvature. The smaller computational costs associated with this measurement suggest that this method has potential clinical utility.

    DOI PubMed

  • Movement Initiation-Locked Activity of the Anterior Putamen Predicts Future Movement Instability in Periodic Bimanual Movement

    Yu Aramaki, Masahiko Haruno, Rieko Osu, Norihiro Sadato

    JOURNAL OF NEUROSCIENCE   31 ( 27 ) 9819 - 9823  2011.07  [Refereed]

     View Summary

    In periodic bimanual movements, anti-phase-coordinated patterns often change into in-phase patterns suddenly and involuntarily. Because behavior in the initial period of a sequence of cycles often does not show any obvious errors, it is difficult to predict subsequent movement errors in the later period of the cyclical sequence. Here, we evaluated performance in the later period of the cyclical sequence of bimanual periodic movements using human brain activity measured with functional magnetic resonance imaging as well as using initial movement features. Eighteen subjects performed a 30 s bimanual finger-tapping task. We calculated differences in initiation-locked transient brain activity between antiphase and in-phase tapping conditions. Correlation analysis revealed that the difference in the anterior putamen activity during antiphase compared within-phase tapping conditions was strongly correlated with future instability as measured by the mean absolute deviation of the left-hand intertap interval during antiphase movements relative to in-phase movements (r = 0.81). Among the initial movement features we measured, only the number of taps to establish the antiphase movement pattern exhibited a significant correlation. However, the correlation efficient of 0.60 was not high enough to predict the characteristics of subsequent movement. There was no significant correlation between putamen activity and initial movement features. It is likely that initiating unskilled difficult movements requires increased anterior putamen activity, and this activity increase may facilitate the initiation of movement via the basal ganglia-thalamocortical circuit. Our results suggest that initiation-locked transient activity of the anterior putamen can be used to predict future motor performance.

    DOI PubMed

  • Single Session of Transcranial Direct Current Stimulation Transiently Increases Knee Extensor Force in Patients With Hemiparetic Stroke

    Satoshi Tanaka, Kotaro Takeda, Yohei Otaka, Kahori Kita, Rieko Osu, Manabu Honda, Norihiro Sadato, Takashi Hanakawa, Katsumi Watanabe

    NEUROREHABILITATION AND NEURAL REPAIR   25 ( 6 ) 565 - 569  2011.07

     View Summary

    Background. Transcranial direct current stimulation (tDCS) of the motor cortex can enhance the performance of a paretic upper extremity after stroke. Reported effects on lower limb (LL) function are sparse. Objective. The authors examined whether tDCS can increase the force production of the paretic quadriceps. Methods. In this double-blind, crossover, sham-controlled experimental design, 8 participants with chronic subcortical stroke performed knee extension using their hemiparetic leg before, during, and after anodal or sham tDCS of the LL motor cortex representation in the affected hemisphere. Affected hand-grip force was also recorded. Results. The maximal knee-extension force increased by 21 N (13.2%, P < .01) during anodal tDCS compared with baseline and sham stimulation. The increase persisted less than 30 minutes. Maximal hand-grip force did not change. Conclusions. Anodal tDCS transiently enhanced knee extensor strength. The modest increase was specific to the LL. Thus, tDCS might augment the rehabilitation of stroke patients when combined with lower extremity strengthening or functional training.

    DOI PubMed

  • 接触センサとフットスイッチによる踵接地タイミングの比較

    鎌田 浩志, 武田 湖太郎, 末長 宏康, 倉山 太一, 橋爪 善光, 近藤 国嗣, 西井 淳, 大須 理英子, 大高 洋平

    関東甲信越ブロック理学療法士学会   30   101 - 101  2011

     View Summary

    【目的】<BR>踵接地の検出は歩行解析を行う上で必要不可欠であり,その検出にはフットスイッチを使用することが多い.フットスイッチはある圧力が加わったことにより踵接地のタイミングを検出するため,装着位置により計測データがばらつく可能性がある.我々は足底に導電性の布を装着し,導電性の素材を貼付したトレッドミルとの接触を感知することで踵接地タイミングを検出するシステムを開発した.本研究は高速度カメラ,従来のフットスイッチ,開発した接触センサを同時に用いて踵接地のタイミングを計測し,フットスイッチと接触センサの精度を比較した.<BR>【方法】<BR>健常成人7名(25.1±4.1歳)を対象とした.被験者は75 m/minに設定したトレッドミル上を歩行した.踵接地タイミングの計測には高速度カメラ(200 frames/s),接触センサ(Sampling: 1 kHz),フットスイッチ(踵に1 cm間隔で2か所に貼付,Sampling: 1 kHz)を用いた.20歩分の右踵接地タイミングを分析対象とし,高速度カメラをコマ送りして目視で接地タイミングを検出した.カメラで得られたタイミングと,接触センサ・踵後部フットスイッチ・踵前部フットスイッチの検出タイミングの差について7名の平均値と標準偏差(SD)を算出した.平均値,SDに対して3群間でWilcoxon signed-rank testにより差を検定した.<BR>【結果】<BR>高速度カメラで得られた踵接地タイミングとの差の平均値について,3群間すべてで有意差があり,接触センサ,踵後部,踵前部の順に差が小さく,いずれも高速度カメラより接地タイミングが遅かった.SDは踵前部フットスイッチが接触センサよりも有意に大きかった(いずれもBonferroni corrected p<.05).<BR>【考察】<BR>接触センサと高速度カメラとの検出タイミングの差が最も小さかったことより,接触センサはフットスイッチより正確に踵接地を計測できることが示された.また,フットスイッチの貼付位置により踵接地タイミングがずれ得ることが示された.踵接地時に足関節は背屈位であり踵後部から前方へ順に接地していくため,フットスイッチの検出タイミングに差が生じたと考えられる.Initial contactが踵接地でないまたは一定しない脳卒中片麻痺患者などの歩行を分析する際,フットスイッチでは踵接地タイミングを正確に計測できない場合が生じる可能性が考えられる.<BR>【まとめ】<BR>本研究結果より,フットスイッチは貼付位置や異常歩行により踵接地タイミングを正確に計測できない可能性があり,接触センサはより正確に踵接地を計測できることが示された.今後,測定条件や対象者を変えて,接触センサとフットスイッチの検出タイミングについて検討していきたい.

    DOI CiNii

  • EEG current source estimation with NIRS as a hierarchical prior

    Takatsugu Aihara, Yusuke Takeda, Kotaro Takeda, Wataru Yasuda, Takanori Sato, Yohei Otaka, Takashi Hanakawa, Manabu Honda, Meigen Liu, Mitsuo Kawato, Masa-aki Sato, Rieko Osu

    NEUROSCIENCE RESEARCH   71   E305 - E305  2011  [Refereed]

    DOI

  • A Sensory Feedback System Utilizing Cutaneous Electrical Stimulation for Stroke Patients with Sensory Loss

    Kahori Kita, Kotaro Takeda, Rieko Osu, Junichi Ushiba, Sachiko Sakata, Yohei Otaka

    2011 IEEE INTERNATIONAL CONFERENCE ON REHABILITATION ROBOTICS (ICORR)    2011  [Refereed]

     View Summary

    Sensory disturbance is very common following stroke and may exacerbate a patient's functional impairment, even if the patient has good motor function. For instance, patients with sensory disturbances will often grip an object with excessive or underestimated pinch pressure, because they do not receive the appropriate sensory feedback and must rely only on visual feedback. In this study, we developed a sensory feedback system that used cutaneous electrical stimulation for patients with sensory loss. In the system, electrical stimulation is modulated by the strength of pinch pressure and the patients are able to identify their fingertip pinch pressure. To evaluate the efficacy of the system, a clinical case study was conducted in a stroke patient with severe sensory loss. The fluctuation in force control during grasping was gradually decreased as the training progressed and the patient was able to maintain a stable pinch pressure during grasping even without the system following 2 months of intervention. We conclude that the system described in this study may be a useful contribution towards the rehabilitation of patients with sensory loss.

    DOI PubMed

  • A Computational Model of Limb Impedance Control Based on Principles of Internal Model Uncertainty

    Djordje Mitrovic, Stefan Klanke, Rieko Osu, Mitsuo Kawato, Sethu Vijayakumar

    PLOS ONE   5 ( 10 )  2010.10  [Refereed]

     View Summary

    Efficient human motor control is characterized by an extensive use of joint impedance modulation, which is achieved by co-contracting antagonistic muscles in a way that is beneficial to the specific task. While there is much experimental evidence available that the nervous system employs such strategies, no generally-valid computational model of impedance control derived from first principles has been proposed so far. Here we develop a new impedance control model for antagonistic limb systems which is based on a minimization of uncertainties in the internal model predictions. In contrast to previously proposed models, our framework predicts a wide range of impedance control patterns, during stationary and adaptive tasks. This indicates that many well-known impedance control phenomena naturally emerge from the first principles of a stochastic optimization process that minimizes for internal model prediction uncertainties, along with energy and accuracy demands. The insights from this computational model could be used to interpret existing experimental impedance control data from the viewpoint of optimality or could even govern the design of future experiments based on principles of internal model uncertainty.

    DOI PubMed

  • Resource-demanding versus cost-effective bimanual interaction in the brain

    Yu Aramaki, Rieko Osu, Norihiro Sadato

    EXPERIMENTAL BRAIN RESEARCH   203 ( 2 ) 407 - 418  2010.06  [Refereed]

     View Summary

    When two hands require different information in bimanual asymmetric movements, interference can occur via callosal connections and ipsilateral corticospinal pathways. This interference could potentially work as a cost-effective measure in symmetric movements, allowing the same information to be commonly available to both hands at once. Using functional magnetic resonance imaging, we investigated supra-additive and sub-additive neural interactions in bimanual movements during the initiation and continuation phases of movement. We compared activity during bimanual asymmetric and symmetric movements with the sum of activity during unimanual right and left finger-tapping. Supra-additive continuation-related activation was found in the right dorsal premotor cortex and left cerebellum (lobule V) during asymmetric movements. In addition, for unimanual movements, the right dorsal premotor cortex and left cerebellum (lobule V) showed significant activation only for left-hand (non-dominant) movements, but not for right-hand movements. These results suggest that resource-demanding interactions in bimanual asymmetric movements are involved in a non-dominant hand motor network that functions to keep non-dominant hand movements stable. We found sub-additive continuation-related activation in the supplementary motor area (SMA), bilateral cerebellum (lobule VI) in symmetric movements, and the SMA in asymmetric movements. This suggests that no extra demands were placed on these areas in bimanual movements despite the conventional notion that they play crucial roles in bimanual coordination. Sub-additive initiation-related activation in the left anterior putamen suggests that symmetric movements place lower demands on motor programming. These findings indicate that, depending on coordination patterns, the neural substrates of bimanual movements either exhibit greater effort to keep non-dominant hand movements stable, or save neural cost by sharing information commonly to both hands.

    DOI PubMed

  • 上肢機能回復と脳の可塑性 (特集 脳の可塑性とリハビリテーションへの応用)

    大須 理英子

    Monthly book medical rehabilitation   ( 118 ) 19 - 23  2010.05

    CiNii

  • ATR脳情報研究所 運動制御・機能回復研究室

    大須 理英子

    バイオメカニズム学会誌 = Journal of the Society of Biomechanisms   34 ( 1 ) 84 - 86  2010.02

    CiNii

  • EFFECTIVE UTILIZATION OF GRAVITY DURING ARM DOWNSWING IN KEYSTROKES BY EXPERT PIANISTS

    S. Furuya, R. Osu, H. Kinoshita

    NEUROSCIENCE   164 ( 2 ) 822 - 831  2009.12  [Refereed]

     View Summary

    The present study investigated a skill-level-dependent interaction between gravity and muscular force when striking piano keys. Kinetic analysis of the arm during the downswing motion performed by expert and novice piano players was made using an inverse dynamic technique. The corresponding activities of the elbow agonist and antagonist muscles were simultaneously recorded using electromyography (EMG). Muscular torque at the elbow joint was computed while excluding the effects of gravitational and motion-dependent interaction torques. During descending the forearm to strike the keys, the experts kept the activation of the triceps (movement agonist) muscle close to the resting level, and decreased anti-gravity activity of the biceps muscle across all loudness levels. This suggested that elbow extension torque was produced by gravity without the contribution of agonist muscular work. For the novices, on the other hand, a distinct activity in the triceps muscle appeared during the middle of the downswing, and its amount and duration we e increased with increasing loudness. Therefore, for the novices, agonist muscular force was the predominant contributor to the acceleration of elbow extension during the downswing. We concluded that a balance shift from muscular force dependency to gravity dependency for the generation of a target joint torque occurs with long-term piano training. This shift would support the notion of non-muscular force utilization for improving physiological efficiency of limb movement with respect to the effective use of gravity. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.

    DOI PubMed

  • Neural Correlates of Resolving Uncertainty in Driver&apos;s Decision Making

    Akiko M. Callan, Rieko Osu, Yuya Yamagishi, Daniel E. Callan, Naomi Inoue

    HUMAN BRAIN MAPPING   30 ( 9 ) 2804 - 2812  2009.09  [Refereed]

     View Summary

    Neural correlates of driving and of decision making have been investigated separately, but little is known about the underlying neural mechanisms of decision making in driving. Previous research discusses two types of decision making: reward-weighted decision making and cost-weighted decision making. There are many reward-weighted decision making neuroimaging Studies but there are few cost-weighted studies. Considering that driving involves serious risk, it is assumed that decision making in driving is cost weighted. Therefore, neural substrates of cost-weighted decision making can be assessed by investigation of driver&apos;s decision making. In this study, neural correlates of resolving uncertainty in driver&apos;s decision making were investigated. Turning right in left-hand traffic at a signalized intersection was simulated by computer graphic animation based videos. When the driver&apos;s view was occluded by a big truck, the uncertainty of the oncoming traffic was resolved by an in-car video assist system that presented the driver&apos;s occluded view. Resolving the uncertainty reduced activity in a distributed area including the amygdala and anterior cingulate. These results implicate the amygdala and anterior cingulate as serving a role in cost-weighted decision making. Hum Brain Mapp 30:5804-2812, 2009. (C) 2008 Wiley-Liss. Inc.

    DOI PubMed

  • Feedforward impedance control efficiently reduce motor variability

    Rieko Osu, Ken-ichi Morishige, Hiroyuki Miyamoto, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   65 ( 1 ) 6 - 10  2009.09  [Refereed]

     View Summary

    Despite the existence of neural noise, which leads variability in motor commands, the central nervous system can effectively reduce movement variance at the end effector to meet task requirements. Although online correction based on feedback information is essential for reducing error, feedforward impedance control is another way to regulate motor variability. This Update Article reviews key studies examining the relation between task constraints and impedance control for human arm movement. When a smaller reaching target is given as a task constraint, flexor and extensor muscles are co-activated, and positional variance is decreased around the task constraint. Trial-by-trial muscle activations revealed no on-line feedback correction, indicating that humans are able to regulate their impedance in advance. These results demonstrate that not only on-line feedback correction, but also feedforward impedance control, helps reduce the motor variability caused by internal noise to realize dexterous movements of human arms. A computational model of movement planning considering the presence of signal-dependent noise provides a unifying framework that potentially accounts for optimizing impedance to maximize accuracy. A recently proposed learning algorism formulated as a V-shaped learning function explains how the central nervous system acquires impedance to optimize accuracy as well as stability and efficiency. (C) 2009 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI PubMed

  • Feedforward impedance control efficiently reduce motor variability

    Rieko Osu, Ken-ichi Morishige, Hiroyuki Miyamoto, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   65 ( 1 ) 6 - 10  2009.09  [Refereed]

     View Summary

    Despite the existence of neural noise, which leads variability in motor commands, the central nervous system can effectively reduce movement variance at the end effector to meet task requirements. Although online correction based on feedback information is essential for reducing error, feedforward impedance control is another way to regulate motor variability. This Update Article reviews key studies examining the relation between task constraints and impedance control for human arm movement. When a smaller reaching target is given as a task constraint, flexor and extensor muscles are co-activated, and positional variance is decreased around the task constraint. Trial-by-trial muscle activations revealed no on-line feedback correction, indicating that humans are able to regulate their impedance in advance. These results demonstrate that not only on-line feedback correction, but also feedforward impedance control, helps reduce the motor variability caused by internal noise to realize dexterous movements of human arms. A computational model of movement planning considering the presence of signal-dependent noise provides a unifying framework that potentially accounts for optimizing impedance to maximize accuracy. A recently proposed learning algorism formulated as a V-shaped learning function explains how the central nervous system acquires impedance to optimize accuracy as well as stability and efficiency. (C) 2009 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI CiNii

  • Single-trial reconstruction of finger-pinch forces from human motor-cortical activation measured by near-infrared spectroscopy (NIRS)

    Isao Nambu, Rieko Osu, Masa-aki Sato, Soichi Ando, Mitsuo Kawato, Eiichi Naito

    NEUROIMAGE   47 ( 2 ) 628 - 637  2009.08  [Refereed]

     View Summary

    Near-infrared spectroscopy (NIRS) has recently been used to measure human motor-cortical activation, enabling the classification of the content of a sensory-motor event such as whether the left or right hand was used. Here, we advance this NIRS application by demonstrating quantitative estimates of multiple sensory-motor events from single-trial NIRS signals. It is known that different degrees of sensory-motor activation are required to generate various hand/finger force levels. Thus, using a sparse linear regression method, we examined whether the temporal changes in different force levels could be reconstructed from NIRS signals. We measured the relative changes in oxyhemoglobin concentrations in the bilateral sensory-motor cortices while participants performed an isometric finger-pinch force production with their thumb and index finger by repeatedly exerting one of three target forces (25, 50, or 75% of the maximum voluntary contraction) for 12 s. To reconstruct the generated forces, we determined the regression parameters from the training datasets and applied these parameters to new test datasets to validate the parameters in the single-trial reconstruction. The temporal changes in the three different levels of generated forces, as well as the baseline resting state, could be reconstructed, even for the test datasets. The best reconstruction was achieved when using only the selected NIRS channels dominantly located in the contralateral sensory-motor cortex, and with a four second hemodynamic delay. These data demonstrate the potential for reconstructing different levels of external loads (forces) from those of the internal loads (activation) in the human brain using NIRS. (C) 2009 Elsevier Inc. All rights reserved.

    DOI PubMed

  • The Future of Medical Cyborg Technology

    OSU Rieko, KAWATO Mitsuo

      48 ( 4 ) 376 - 382  2009.04

    CiNii

  • Motor Improvement and Corticospinal Modulation Induced by Hybrid Assistive Neuromuscular Dynamic Stimulation (HANDS) Therapy in Patients With Chronic Stroke

    Toshiyuki Fujiwara, Yuko Kasashima, Kaoru Honaga, Yoshihiro Muraoka, Tetsuya Tsuji, Rieko Osu, Kimitaka Hase, Yoshihisa Masakado, Meigen Liu

    NEUROREHABILITATION AND NEURAL REPAIR   23 ( 2 ) 125 - 132  2009.02  [Refereed]

     View Summary

    Background and objective. We devised a therapeutic approach to facilitate the use of the hemiparetic upper extremity (UE) in daily life by combining integrated volitional control electrical stimulation with a wrist splint, called hybrid assistive neuromuscular dynamic stimulation (HANDS). Methods. Twenty patients with chronic hemiparetic stroke ( median 17.5 months) had moderate to severe UE weakness. Before and immediately after completing 3 weeks of training in 40-minute sessions, 5 days per week over 3 weeks and wearing the system for 8 hours each day, clinical measures of motor impairment, spasticity, and UE functional scores, as well as neurophysiological measures including electromyography activity, reciprocal inhibition, and intracortical inhibition were assessed. A follow-up clinical assessment was performed 3 months later. Results. UE motor function, spasticity, and functional scores improved after the intervention. Neurophysiologically, the intervention induced restoration of presynaptic and long loop inhibitory connections as well as disynaptic reciprocal inhibition. Paired pulse transcranial magnetic stimulation study indicated disinhibition of the short intracortical inhibition in the affected hemisphere. The follow-up assessment showed that improved UE functions were maintained at 3 months. Conclusion. The combination of hand splint and volitional and electrically induced muscle contraction can induce corticospinal plasticity and may offer a promising option for the management of the paretic UE in patients with stroke. A larger sample size with randomized controls is needed to demonstrate effectiveness.

    DOI PubMed

  • Integration of multi-level postural balancing on humanoid robots

    Sang-Ho Hyon, Rieko Osu, Yohei Otaka

    ICRA: 2009 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-7     1607 - +  2009  [Refereed]

     View Summary

    This paper discusses an integration issue of multi-level postural balancing on humanoid robot. We give a unified viewpoint of postural balancing, which covers Ankle Strategy to Hip Strategy. Two kinds of distributor of desired ground reaction force to whole-body joint torque are presented. The one distributor leads to a dynamic balancer which covers Hip strategy, with the under-actuated situation. A simple angular momentum regulator is also proposed to stabilize the internal motions due to the joint redundancy. The other distributor leads to a static balancer which lies between Ankle and Hip strategy. Furthermore, this paper demonstrates that replacement of the center of mass feedback with the local joint stiffness makes the robot much stabler for some fast motions. Motivated by the practicability of the static balancer and the strong push-recovery performance of the dynamic balancer, this paper presents a simple integration by superposition of the both balancers on a compliant human-sized biped robot. The simulation and experimental videos are supplemented.

  • CNS Learns Stable, Accurate, and Efficient Movements Using a Simple Algorithm

    David W. Franklin, Etienne Burdet, Keng Peng Tee, Rieko Osu, Chee-Meng Chew, Theodore E. Milner, Mitsuo Kawato

    JOURNAL OF NEUROSCIENCE   28 ( 44 ) 11165 - 11173  2008.10  [Refereed]

     View Summary

    We propose a new model of motor learning to explain the exceptional dexterity and rapid adaptation to change, which characterize human motor control. It is based on the brain simultaneously optimizing stability, accuracy and efficiency. Formulated as a V-shaped learning function, it stipulates precisely how feedforward commands to individual muscles are adjusted based on error. Changes in muscle activation patterns recorded in experiments provide direct support for this control scheme. In simulated motor learning of novel environmental interactions, muscle activation, force and impedance evolved in a manner similar to humans, demonstrating its efficiency and plausibility. This model of motor learning offers new insights as to how the brain controls the complex musculoskeletal system and iteratively adjusts motor commands to improve motor skills with practice.

    DOI PubMed

  • An involuntary muscular response induced by perceived visual errors in hand position

    David W. Franklin, Udell So, Rieko Osu, Mitsuo Kawato

    NEURAL INFORMATION PROCESSING, PART I   4984 ( PART 1 ) 1012 - +  2008  [Refereed]

     View Summary

    The visually induced corrective motor responses of hand position during reaching movements were investigated. Subjects performed reaching movements on a robotic manipulandum where the hand position was presented to the subjects by means of a projected display. On random reaching trials the projected hand position was perturbed relative to the actual hand position while the hand was constrained to the straight line to the target. Electromyographic activity of eight arm muscles were collected. A corrective muscular response starting at 150 ms from the onset of the visual perturbation was found. This response was found to be reflexive in nature and not suppressed by prior instruction. A second study found that the reflexive response was not modified by changes in the background muscle activity level or by the size of the perturbation. The results suggest that the visual system elicits simple motor reflexes in response to visual errors from the expected hand position.

    DOI

  • Conflicting visual and proprioceptive reflex responses during reaching movements

    David W. Franklin, Udell So, Rieko Osu, Mitsuo Kawato

    NEURAL INFORMATION PROCESSING, PART I   4984 ( PART 1 ) 1002 - +  2008  [Refereed]

     View Summary

    The visually and mechanically induced corrective motor responses of hand position during reaching movements were investigated. Subjects performed reaching movements on a robotic manipulandum where the hand position was presented to the subjects by means of a projected display. On random reaching trials the subject's hand position was mechanically perturbed relative to the predicted hand trajectory. The visual representation of the hand position was either perturbed in the same direction as the hand, mirrored relative to the hand, or not perturbed at all. The visually induced reflexive responses were still elicited after a mechanical perturbation, whether or not the information agreed with the mechanical perturbation. The visually induced reflexes contributed to limb stiffness after 200 ms from the onset. If the visual and mechanical errors were consistent, the restoring force to a perturbation (or the effective stiffness) was increased at long latencies. The results suggest that on short time scales, error signals from different sensory modalities are processed separately, combined only at the output stage.

    DOI

  • Decoding syllables from human fMRI activity

    Yohei Otaka, Rieko Osu, Mitsuo Kawato, Meigen Liu, Satoshi Murata, Yukiyasu Kamitani

    NEURAL INFORMATION PROCESSING, PART II   4985 ( PART 2 ) 979 - +  2008  [Refereed]

     View Summary

    Language plays essential roles in human cognition and social communication, and therefore technology of reading out speech using non-invasively measured brain activity will have both scientific and clinical merits. Here, we examined whether it is possible to decode each syllable from human fMRI activity. Four healthy subjects participated in the experiments. In a decoding session, the subjects repeatedly uttered a syllable presented on a screen at 3Hz for a 12-s block. Nine different syllables are presented in a single experimental run which was repeated 8 times. We also specified the voxels which showed articulation-related activities by utterance of all the syllables in Japanese phonology in a conventional task-rest sequence. Then, we used either all of these voxels or a part of these voxels that exist in anatomically specified ROIs (M1, cerebellum) during decoding sessions as data samples for training and testing a decoder (linear support vector machine) that classifies brain activity patterns for different syllables. To evaluate decoding performance, we performed cross-validation by testing the sample of one decoding session using a decoder trained with the samples of the remaining sessions. As a result, syllables were correctly decoded at above-chance levels. The results suggest the possibility of using non-invasively measured brain activity to read out the intended speech of disabled patients in speech motor control.

    DOI

  • The brain and safe driving

    JARI research journal   29 ( 10 ) 553 - 556  2007.10

    CiNii

  • Explicit contextual information selectively contributes to predictive switching of internal models

    Hiroshi Imamizu, Norikazu Sugimoto, Rieko Osu, Kiyoka Tsutsui, Kouichi Sugiyama, Yasuhiro Wada, Mitsuo Kawato

    EXPERIMENTAL BRAIN RESEARCH   181 ( 3 ) 395 - 408  2007.08  [Refereed]

     View Summary

    Many evidences suggest that the central nervous system (CNS) acquires and switches internal models for adaptive control in various environments. However, little is known about the neural mechanisms responsible for the switching. A recent computational model for simultaneous learning and switching of internal models proposes two separate switching mechanisms: a predictive mechanism purely based on contextual information and a postdictive mechanism based on the difference between actual and predicted sensorimotor feedbacks. This model can switch internal models solely based on contextual information in a predictive fashion immediately after alteration of the environment. Here we show that when subjects simultaneously adapted to alternating blocks of opposing visuomotor rotations, explicit contextual information about the rotations improved the initial performance at block alternations and asymptotic levels of performance within each block but not readaptation speeds. Our simulations using separate switching mechanisms duplicated these effects of contextual information on subject performance and suggest that improvement of initial performance was caused by improved accuracy of the predictive switch while adaptation speed corresponds to a switch dependent on sensorimotor feedback. Simulations also suggested that a slow change in output signals from the switching mechanisms causes contamination of motor commands from an internal model used in the previous context (anterograde interference) and partial destruction of internal models (retrograde interference). Explicit contextual information prevents destruction and assists memory retention by improving the changes in output signals. Thus, the asymptotic levels of performance improved.

    DOI PubMed

  • Endpoint stiffness of the arm is directionally tuned to instability in the environment

    David W. Franklin, Gary Liaw, Theodore E. Milner, Rieko Osu, Etienne Burdet, Mitsuo Kawato

    JOURNAL OF NEUROSCIENCE   27 ( 29 ) 7705 - 7716  2007.07  [Refereed]

     View Summary

    It has been shown that humans are able to selectively control the endpoint impedance of their arms when moving in an unstable environment. However, directional instability was only examined for the case in which the main contribution was from coactivation of biarticular muscles. The goal of this study was to examine whether, in general, the CNS activates the sets of muscles that contribute to selective control of impedance in particular directions. Subjects performed reaching movements in three differently oriented unstable environments generated by a robotic manipulandum. After subjects had learned to make relatively straight reaching movements in the unstable force field, the endpoint stiffness of the limb was measured at the midpoint of the movements. For each force field, the endpoint stiffness increased in a specific direction, whereas there was little change in stiffness in the orthogonal direction. The increase in stiffness was oriented along the direction of instability in the environment, which caused the major axis of the stiffness ellipse to rotate toward the instability in the environment. This study confirms that the CNS is able to control the endpoint impedance of the limbs and selectively adapt it to the environment. Furthermore, it supports the idea that the CNS incorporates an impedance controller that acts to ensure stability, reduce movement variability, and reduce metabolic cost.

    DOI PubMed

  • How can we realize skillful and precise movement?

    Ken-ichi Morishige, Rieko Osu, Naoki Kamimura, Hiroshi Iwasaki, Hiroyuki Miyamoto, Yasuhiro Wada, Mitsuo Kawato

    International Congress Series   1301   188 - 191  2007.07

     View Summary

    Although human motor variability inevitably exists because of neural noises, it is not clear how humans can effectively reduce this variability for task accuracy. We examined the ability of humans to compensate for this variability during task-constraint reaching movements. The positional variance and muscle activations of reaching movements with task-constraints were compared with those without task-constraints. Flexor and extensor muscles were co-activated for the movements with task-constraints, and the positional variance was decreased to obtain accuracy. The results indicated that subjects were able to regulate their muscle impedance and to modulate the variability to meet the task requirements. © 2007 Elsevier B.V. All rights reserved.

    DOI

  • Feedforward Impedance Control Improve Accuracy in Rapid Reaching Movement

    MORISHIGE Ken-ichi, OSU Rieko, KAMIMURA Naoki, IWASAKI Hiroshi, MIYAMOTO Hiroyuki, WADA Yasuhiro, KAWATO Mitsuo

    The IEICE transactions on information and systems   89 ( 7 ) 1588 - 1598  2006.07

    CiNii

  • Learning the dynamics of the external world: Brain inspired learning for robotic applications

    David W. Franklin, Etienne Burdet, Rieko Osu, Udell So, Keng Peng Tee, Theodore E. Milner, Mitsuo Kawato

    International Congress Series   1291   109 - 112  2006.06

     View Summary

    Humans have exceptional abilities to learn new skills, manipulate tools and objects, and interact with our environment. In order to be successful at these tasks, our brain has become exceptionally well adapted to learning to deal not only with the complex dynamics of our own limbs but also with novel dynamics in the external world. While learning of these dynamics includes learning the complex time-varying forces at the end of limbs through the updating of internal models, it must also include learning the appropriate mechanical impedance in order to stabilize both the limb and any objects contacted in the environment. This article reviews the field of human learning by examining recent experimental evidence about adaptation to novel unstable dynamics and explores how this knowledge about the brain and neuro-muscular system can expand the learning capabilities of robotics and prosthetics. © 2006.

    DOI

  • The sources of variability in the time course of reaching movements

    Ken-ichi Morishige, Rieko Osu, Hiroyuki Miyamoto, Mitsuo Kawato

    International Congress Series   1291   105 - 108  2006.06

     View Summary

    Movement variability plays a vital role in motor control. Although previous studies have examined the size and direction of the variability at end points, little research has examined how the variability changes during the time of move. The time course of the variability on point-to-point movements seems to be composed of two different properties: one increases monotonically and the other has an increasing-decreasing property. The first one can be explained by neural noise at the control level, such as the signal-dependent noise (SDN). However, how do we explain the latter one? Our numerical experiment hypothesized the time-jitter noise at trajectory planning level, which represents local advance or delay time of the reference trajectory for reaching movements. The simulation result could well reproduce the feature of the behavioral results. © 2006.

    DOI

  • Simultaneous adaptation and switching for two viscous force fields

    Satomi Hirai, Rieko Osu, Toshinori Yoshioka, Mitsuo Kawato

    ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS   89 ( 7 ) 29 - 39  2006  [Refereed]

     View Summary

    In this study, two different viscous force fields are generated by using a PFM (parallel link direct-drive air-magnet floating manipulandum), and the responding human learning process for multi-joint reaching motion is observed. In this experiment, the subject is given a certain cue for the force field. The cues are provided as follows: (I) audiovisual cue (a color and a peep sound corresponding to the force field, and a feather pattern representing the direction and magnitude of the force) and (2) movement cue (two trials are defined as a set, and the first movement is used as the cue). The task of the experiment is to learn the movement in force fields which are switched at random. Whichever cue (1) or (2) is used, there is a tendency that the area error from the desired straight trajectory decreases with an increasing number of trials. It is also observed that when the force field is eliminated at random after learning, a marked aftereffect arises in the group to which the audiovisual cue is given. The aftereffect is also observed in the group to which the movement cue is given, but is not as marked as in the group to which the audiovisual cue is given. The above results suggest that the internal models for two different viscous force fields can be acquired simultaneously without time separation by providing an appropriate cue to indicate the force field and learning in the environment in which the force field is switched at random. (c) 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(7): 29-39,2006; Published online in Wiley InterScience (www.interscience.wiley.com).

    DOI

  • Stability and motor adaptation in human arm movements

    E Burdet, KP Tee, Mareels, I, TE Milner, CM Chew, DW Franklin, R Osu, M Kawato

    BIOLOGICAL CYBERNETICS   94 ( 1 ) 20 - 32  2006.01  [Refereed]

     View Summary

    In control, stability captures the reproducibility of motions and the robustness to environmental and internal perturbations. This paper examines how stability can be evaluated in human movements, and possible mechanisms by which humans ensure stability. First, a measure of stability is introduced, which is simple to apply to human movements and corresponds to Lyapunov exponents. Its application to real data shows that it is able to distinguish effectively between stable and unstable dynamics. A computational model is then used to investigate stability in human arm movements, which takes into account motor output variability and computes the force to perform a task according to an inverse dynamics model. Simulation results suggest that even a large time delay does not affect movement stability as long as the reflex feedback is small relative to muscle elasticity. Simulations are also used to demonstrate that existing learning schemes, using a monotonic antisymmetric update law, cannot compensate for unstable dynamics. An impedance compensation algorithm is introduced to learn unstable dynamics, which produces similar adaptation responses to those found in experiments.

    DOI PubMed

  • 運動の制御と学習--リハビリテーションの視点から (第10回認知神経科学会) -- (シンポジウム1 リハビリテーションの科学:脳の可塑性)

    大須 理英子

    認知神経科学   7 ( 3 ) 217 - 222  2005.12

    CiNii

  • Is There Desired Trajectory for Skilled Reaching Movements?

    MORISHIGE Ken-ichi, KAMIMURA Naoki, IWASAKI Hiroshi, MIYAMOTO Hiroyuki, WADA Yasuhiro, OSU Rieko, KAWATO Mitsuo

    The IEICE transactions on information and systems Pt. 2   88 ( 12 ) 2358 - 2367  2005.12

    CiNii

  • A model of the coupling between grip aperture and hand transport during human prehension

    YP Hu, R Osu, M Okada, MA Goodale, M Kawato

    EXPERIMENTAL BRAIN RESEARCH   167 ( 2 ) 301 - 304  2005.11  [Refereed]

     View Summary

    It has been repeatedly demonstrated that the opening between the index finger and thumb (grasp component) during an object-directed reach-to-grasp movement achieves maximum aperture approximately two-thirds of the way through the duration of the reaching movement (transport component). Here we offer a quantitative model of the temporal coupling between grip aperture and wrist velocity which shows experimentally that the correlation between grip aperture and object size is a sigmoidal function of movement duration. When wrist velocity reaches its peak value, the correlation between the grip aperture and the size of the goal object has reached half of the correlation that is achieved by the end of the movement.

    DOI PubMed

  • Trajectory formation based on the minimum commanded torque change model using the euler-poisson equation

    Yuichi Kaneko, Eri Nakano, Rieko Osu, Yasuhiro Wada, Mitsuo Kawato

    Systems and Computers in Japan   36 ( 2 ) 92 - 103  2005.02

     View Summary

    A minimum commanded torque change criterion based on the optimization principle is proposed as a model that accounts for human voluntary motion. It is shown that the trajectory of human arm motion can be well reproduced by the model. In the point-to-point movement, the calculation of the torque based on the minimum commanded torque change criterion requires a highly nonlinear calculation, and it is difficult to determine the optimal trajectory. As solution methods, a Newton-like method and a steepest descent method have been proposed. However, an optimal solution cannot be obtained by these methods, for several reasons. This paper proposes a method in which the trajectory of the joint angle is analytically represented by a system of orthogonal polynomials, and the coefficients of the orthogonal polynomials are estimated by a linear iterative calculation so that the parameters satisfy the EulerPoisson equation, as a necessary condition for the optimal solution. As a result of numerical experiments, it is shown that a solution satisfying the Euler-Poisson equation with high numerical accuracy is obtained in a short time, regardless of the parameters such as those of the boundary conditions. © 2005 Wiley Periodicals, Inc.

    DOI

  • 運動の制御と学習リハビリテーションの視点から

    大須 理英子

    認知神経科学   7 ( 3 ) 217 - 222  2005

     View Summary

    脳が手足を制御するときに解決すべき問題は、制御プログラムが手足のあるロボットを制御するとき解決すべき問題と類似している。計算論的神経科学では、このような視点から、脳に実装されていると思われる機構を同定する。これまでの研究により、例えば速くて正確な腕の運動を実現するためには、フィードフォワード制御が必要であることがわかってきた。このためには、制御対象(例えば腕)のダイナミクスを表現する内部モデルが脳内に獲得されていなければならない。リハビリテーションが必要な状態というのは、このような脳内の制御機構に何らかの異常を来したか、その制御対象である手足に異常を来したのかどちらかであることが多い。いずれの場合にも、速くて正確な運動を取り戻すには、内部モデルの再構築が必要である。これまでのリハビリテーション訓練は、フィードバック制御を必要とする運動が多く、内部モデルを再構築するには最適ではない可能性がある。このような視点からリハビリテーション手法を見直すことでよりよい機能回復がはかれる可能性がある。

    CiNii

  • How are internal models of unstable tasks formed?

    Burdet, E, Franklin, D. W, Osu, R, Tee, K. P, Kawato, M, Milner, T. E

    Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings   26 VI   4491 - 4494  2004.12

     View Summary

    The results of recent studies suggest that humans can form internal models that they use in a feedforward manner to compensate for both stable and unstable dynamics. To examine how internal models are formed, we performed adaptation experiments in novel dynamics, and measured the endpoint force, trajectory and EMG during learning. Analysis of reflex feedback and change of feedforward commands between consecutive trials suggested a unified model of motor learning, which can coherently unify the learning processes observed in stable and unstable dynamics and reproduce available data on motor learning. To our knowledge, this algorithm, based on the concurrent minimization of (reflex) feedback and muscle activation, is also the first nonlinear adaptive controller able to stabilize unstable dynamics.

  • Simultaneous Adaptation and Switching for Two Viscous Force Fields

    HIRAI Satomi, OSU Rieko, YOSHIOKA Toshinori, KAWATO Mitsuo

    The IEICE transactions on information and systems Pt. 2   87 ( 12 ) 2231 - 2241  2004.12

    CiNii

  • Failure to consolidate the consolidation theory of learning for sensorimotor adaptation tasks

    G Caithness, R Osu, P Bays, H Chase, J Klassen, M Kawato, DM Wolpert, Flanagan, JR

    JOURNAL OF NEUROSCIENCE   24 ( 40 ) 8662 - 8671  2004.10  [Refereed]

     View Summary

    An influential idea in human motor learning is that there is a consolidation period during which motor memories are transformed from a fragile to a permanent state, no longer susceptible to interference from new learning. The evidence supporting this idea comes from studies showing that the motor memory of a task ( A) is lost when an opposing task ( B) is experienced soon after, but not if sufficient time is allowed to pass (similar to6 hr). We report results from three laboratories challenging this consolidation idea. We used an ABA paradigm in the context of a reaching task to assess the influence of experiencing B after A on the retention of A. In two experiments using visuomotor rotations, we found that B fully interferes with the retention of A even when B is experienced 24 hr after A. Contrary to previous reports, in four experiments on learning force fields, we also observed full interference between A and B when they are separated by 24 hr or even 1 week. This latter result holds for both position-dependent and velocity-dependent force fields. For both the visuomotor and force-field tasks, complete interference is still observed when the possible affects of anterograde interference are controlled through the use of washout trials. Our results fail to support the idea that motor memories become consolidated into a protected state. Rather, they are consistent with recent ideas of memory formation, which propose that memories can shift between active and inactive states.

    DOI PubMed

  • 講座 運動学習とリハビリテーション(4)環境の変化に対する適応

    大高 洋平, 大須 理英子

    総合リハビリテ-ション   32 ( 10 ) 957 - 965  2004.10

    CiNii

  • Rhythmic arm movement is not discrete

    S Schaal, D Sternad, R Osu, M Kawato

    NATURE NEUROSCIENCE   7 ( 10 ) 1137 - 1144  2004.10  [Refereed]

     View Summary

    Rhythmic movements, such as walking, chewing or scratching, are phylogenetically old motor behaviors found in many organisms, ranging from insects to primates. In contrast, discrete movements, such as reaching, grasping or kicking, are behaviors that have reached sophistication primarily in younger species, particularly primates. Neurophysiological and computational research on arm motor control has focused almost exclusively on discrete movements, essentially assuming similar neural circuitry for rhythmic tasks. In contrast, many behavioral studies have focused on rhythmic models, subsuming discrete movement as a special case. Here, using a human functional neuroimaging experiment, we show that in addition to areas activated in rhythmic movement, discrete movement involves several higher cortical planning areas, even when both movement conditions are confined to the same single wrist joint. These results provide neuroscientific evidence that rhythmic arm movement cannot be part of a more general discrete movement system and may require separate neurophysiological and theoretical treatment.

    DOI PubMed

  • Optimal impedance control for task achievement in the presence of signal-dependent noise

    R Osu, N Kamimura, H Iwasaki, E Nakano, CM Harris, Y Wada, M Kawato

    JOURNAL OF NEUROPHYSIOLOGY   92 ( 2 ) 1199 - 1215  2004.08  [Refereed]

     View Summary

    There is an infinity of impedance parameter values, and thus different co-contraction levels, that can produce similar movement kinematics from which the CNS must select one. Although signal-dependent noise (SDN) predicts larger motor-command variability during higher co-contraction, the relationship between impedance and task performance is not theoretically obvious and thus was examined here. Subjects made goal-directed, single-joint elbow movements to either move naturally to different target sizes or voluntarily co-contract at different levels. Stiffness was estimated as the weighted summation of rectified EMG signals through the index of muscle co-contraction around the joint (IMCJ) proposed previously. When subjects made movements to targets of different sizes, IMCJ increased with the accuracy requirements, leading to reduced endpoint deviations. Therefore without the need for great accuracy, subjects accepted worse performance with lower co-contraction. When subjects were asked to increase co-contraction, the variability of EMG and torque both increased, suggesting that noise in the neuromotor command increased with muscle activation. In contrast, the final positional error was smallest for the highest IMCJ level. Although co-contraction increases the motor-command noise, the effect of this noise on the task performance is reduced. Subjects were able to regulate their impedance and control endpoint variance as the task requirements changed, and they did not voluntarily select the high impedance that generated the minimum endpoint error. These data contradict predictions of the SDN-based theory, which postulates minimization of only endpoint variance and thus require its revision.

    DOI PubMed

  • Random presentation enables subjects to adapt to two opposing forces on the hand

    R Osu, S Hirai, T Yoshioka, M Kawato

    NATURE NEUROSCIENCE   7 ( 2 ) 111 - 112  2004.02  [Refereed]

     View Summary

    Studies have shown that humans cannot simultaneously learn opposing force fields or opposing visuomotor rotations, even when provided with arbitrary contextual information, probably because of interference in their working memory(1-6). In contrast, we found that subjects can adapt to two opposing force fields when provided with contextual cues and can consolidate motor memories if random and frequent switching occurs. Because significant aftereffects were seen, this study suggests that multiple internal models can be acquired simultaneously during learning and predictively switched, depending only on contextual information.

    DOI PubMed

  • Positional Variance on Via-Point Reaching Movement Supports Sequential Trajectory Planning and Execution Model

    MORISHIGE Ken-ichi, MIYAMOTO Hiroyuki, OSU Rieko, KAWATO Mitsuo

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   87 ( 2 ) 716 - 725  2004.02

    CiNii

  • How are internal models of unstable tasks formed?

    E Burdet, DW Franklin, R Osu, K Tee, M Kawato, TE Milner

    PROCEEDINGS OF THE 26TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-7   26   4491 - 4494  2004  [Refereed]

     View Summary

    The results of recent studies suggest that humans can form internal models that they use in a feedforward manner to compensate for both stable and unstable dynamics. To examine how internal models are formed, we performed adaptation experiments in novel dynamics, and measured the endpoint force, trajectory and EMG during learning. Analysis of reflex feedback and change of feedforward commands between consecutive trials suggested a unified model of motor learning, which can coherently unify the learning processes observed in stable and unstable dynamics and reproduce available data on motor learning. To our knowledge, this algorithm, based on the concurrent minimization of (reflex) feedback and muscle activation, is also the first nonlinear adaptive controller able to stabilize unstable dynamics.

  • Relation among duration, position variance, and muscle activity in human arm movement control

    H Iwasaki, R Osu, N Kamimura, E Nakano, CM Harris, Y Wada, M Kawato

    SICE 2004 ANNUAL CONFERENCE, VOLS 1-3     1725 - 1729  2004  [Refereed]

     View Summary

    To research the relation between joint impedance and signal dependent noise which opposes each other at the end-point error, we performed 2 types of experiments. Their results suggested that muscle activity increased as demanded accuracy increases, and the relation between duration and accuracy (Fitts' law) varied by conscious control of muscle activity.

  • Different mechanisms involved in adaptation to stable and unstable dynamics

    R Osu, E Burdet, DW Franklin, TE Milner, M Kawato

    JOURNAL OF NEUROPHYSIOLOGY   90 ( 5 ) 3255 - 3269  2003.11  [Refereed]

     View Summary

    Recently, we demonstrated that humans can learn to make accurate movements in an unstable environment by controlling magnitude, shape, and orientation of the endpoint impedance. Although previous studies of human motor learning suggest that the brain acquires an inverse dynamics model of the novel environment, it is not known whether this control mechanism is operative in unstable environments. We compared learning of multijoint arm movements in a "velocity-dependent force field" (VF), which interacted with the arm in a stable manner, and learning in a "divergent force field" (DF), where the interaction was unstable. The characteristics of error evolution were markedly different in the 2 fields. The direction of trajectory error in the DF alternated to the left and right during the early stage of learning; that is, signed error was inconsistent from movement to movement and could not have guided learning of an inverse dynamics model. This contrasted sharply with trajectory error in the VF, which was initially biased and decayed in a manner that was consistent with rapid feedback error learning. EMG recorded before and after learning in the DF and VF are also consistent with different learning and control mechanisms for adapting to stable and unstable dynamics, that is, inverse dynamics model formation and impedance control. We also investigated adaptation to a rotated DF to examine the interplay between inverse dynamics model formation and impedance control. Our results suggest that an inverse dynamics model can function in parallel with an impedance controller to compensate for consistent perturbing force in unstable environments.

    DOI PubMed

  • Adaptation to stable and unstable dynamics achieved by combined impedance control and inverse dynamics model

    DW Franklin, R Osu, E Burdet, M Kawato, TE Milner

    JOURNAL OF NEUROPHYSIOLOGY   90 ( 5 ) 3270 - 3282  2003.11  [Refereed]

     View Summary

    This study compared adaptation in novel force fields where trajectories were initially either stable or unstable to elucidate the processes of learning novel skills and adapting to new environments. Subjects learned to move in a null force field (NF), which was unexpectedly changed either to a velocity-dependent force field (VF), which resulted in perturbed but stable hand trajectories, or a position-dependent divergent force field (DF), which resulted in unstable trajectories. With practice, subjects learned to compensate for the perturbations produced by both force fields. Adaptation was characterized by an initial increase in the activation of all muscles followed by a gradual reduction. The time course of the increase in activation was correlated with a reduction in hand-path error for the DF but not for the VF. Adaptation to the VF could have been achieved solely by formation of an inverse dynamics model and adaptation to the DF solely by impedance control. However, indices of learning, such as hand-path error, joint torque, and electromyographic activation and deactivation suggest that the CNS combined these processes during adaptation to both force fields. Our results suggest that during the early phase of learning there is an increase in endpoint stiffness that serves to reduce hand-path error and provides additional stability, regardless of whether the dynamics are stable or unstable. We suggest that the motor control system utilizes an inverse dynamics model to learn the mean dynamics and an impedance controller to assist in the formation of the inverse dynamics model and to generate needed stability.

    DOI PubMed

  • Motor adaptation to the novel muscle condition generated by electrical stimulation

    OTAKA YOHEI, OSU RIEKO, DOMEN KAZUHISA, CHINO NAOICHI, KAWATO MITSUO

      31 ( 5 ) 444 - 452  2003.10

    CiNii

  • Functional significance of stiffness in adaptation of multijoint arm movements to stable and unstable dynamics

    DW Franklin, E Burdet, R Osu, M Kawato, TE Milner

    EXPERIMENTAL BRAIN RESEARCH   151 ( 2 ) 145 - 157  2003.07  [Refereed]

     View Summary

    This study compared the mechanisms of adaptation to stable and unstable dynamics from the perspective of changes in joint mechanics. Subjects were instructed to make point to point movements in force fields generated by a robotic manipulandum which interacted with the arm in either a stable or an unstable manner. After subjects adjusted to the initial disturbing effects of the force fields they were able to produce normal straight movements to the target. In the case of the stable interaction, subjects modified the joint torques in order to appropriately compensate for the force field. No change in joint torque or endpoint force was required or observed in the case of the unstable interaction. After adaptation, the endpoint stiffness of the arm was measured by applying displacements to the hand in eight different directions midway through the movements. This was compared to the stiffness measured similarly during movements in a null force field. After adaptation, the endpoint stiffness under both the stable and unstable dynamics was modified relative to the null field. Adaptation to unstable dynamics was achieved by selective modification of endpoint stiffness in the direction of the instability. To investigate whether the change in endpoint stiffness could be accounted for by change in joint torque or endpoint force, we estimated the change in stiffness on each trial based on the change in joint torque relative to the null field. For stable dynamics the change in endpoint stiffness was accurately predicted. However, for unstable dynamics the change in endpoint stiffness could not be reproduced. In fact, the predicted endpoint stiffness was similar to that in the null force field. Thus, the change in endpoint stiffness seen after adaptation to stable dynamics was directly related to changes in net joint torque necessary to compensate for the dynamics in contrast to adaptation to unstable dynamics, where a selective change in endpoint stiffness occurred without any modification of net joint torque.

    DOI PubMed

  • Independence of Internal Models in Velocity and Position Dependent Force Field : Examination of Multiple Internal Models

    KAWABATA Yasuhiro, OSU Rieko, WADA Yasuhiro, KAWATO Mitsuo

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   86 ( 5 ) 727 - 736  2003.05

    CiNii

  • Composition and decomposition learning of reaching movements under altered environments: An examination of the multiplicity of internal models

    Eri Nakano, John R. Flanagan, Hiroshi Imamizu, Rieko Osu, Toshinori Yoshioka, Mitsuo Kawato

    Systems and Computers in Japan   33 ( 11 ) 80 - 94  2002.10

     View Summary

    We have studied the learning processes of reaching movements under novel environments whose kinematic and dynamic properties are altered. In the experiments, we have used, as the kinematic transformation, a rotational transformation which is displayed by rotating a cursor indicating hand position in the orthogonal coordinate system on a CRT
    a viscous transformation using viscous field as the dynamic transformation
    and a combined transformation of these two transformations. It is observed that the hand trajectory approaches a straight line along with learning and accurately reaches the target. When the combined transformation is learned after the rotational transformation and viscous transformation are learned first, respectively, the final error becomes smaller and the path length also becomes shorter than the case when the combined transformation is learned first. Moreover, the final error and path length of the movement under rotation al transformation and viscous transformation when the combined transformation is learned first also become smaller than the case when the rotational and viscous transformations are learned first. These results suggest that the central nervous system has learned separately the multiple internal models which compensate the respective transformations, and has composed or decomposed the respective internal models in accordance with the environmental changes. It may be considered that such multiplicity of internal models makes, it possible for the living body to flexibly cope with the environments or tools having various dynamic and kinematic properties. © 2002 Wiley Periodicals, Inc. Syst. Comp. Jpn., 33(11).

    DOI

  • The adequacy of using forward models for multi-limb coordination in humans

    UGATA Masaomi, KURODA Tomoe, OSU Rieko, IMAMIZU Hiroshi, YOSHIOKA Toshinori, WADA Yasuhiro, KAWATO Mitsuo

      17   243 - 244  2002.09

    CiNii

  • Short- and long-term changes in joint co-contraction associated with motor learning as revealed from surface EMG

    R Osu, DW Franklin, H Kato, H Gomi, K Domen, T Yoshioka, M Kawato

    JOURNAL OF NEUROPHYSIOLOGY   88 ( 2 ) 991 - 1004  2002.08  [Refereed]

     View Summary

    In the field of motor control, two hypotheses have been controversial: whether the brain acquires internal models that generate accurate motor commands, or whether the brain avoids this by using the viscoelasticity of musculoskeletal system. Recent observations on relatively low stiffness during trained movements support the existence of internal models. However, no study has revealed the decrease in viscoelasticity associated with learning that would imply improvement of internal models as well as synergy between the two hypothetical mechanisms. Previously observed decreases in electromyogram (EMG) might have other explanations, such as trajectory modifications that reduce joint torques. To circumvent such complications, we required strict trajectory control and examined only successful trials having identical trajectory and torque profiles. Subjects were asked to perform a hand movement in unison with a target moving along a specified and unusual trajectory, with shoulder and elbow in the horizontal plane at the shoulder level. To evaluate joint viscoelasticity during the learning of this movement, we proposed an index of muscle co-contraction around the joint (IMCJ). The IMCJ was defined as the summation of the absolute values of antagonistic muscle torques around the joint and computed from the linear relation between surface EMG and joint torque. The IMCJ during isometric contraction, as well as during movements, was confirmed to correlate well with joint stiffness estimated using the conventional method, i.e., applying mechanical perturbations. Accordingly, the IMCJ during the learning of the movement was computed for each joint of each trial using estimated EMG-torque relationship. At the same time, the performance error for each trial was specified as the root mean square of the distance between the target and hand at each time step over the entire trajectory. The time-series data of IMCJ and performance error were decomposed into long-term components that showed decreases in IMCJ in accordance with learning with little change in the trajectory and short-term interactions between the IMCJ and performance error. A cross-correlation analysis and impulse responses both suggested that higher IMCJs follow poor performances, and lower IMCJs follow good performances within a few successive trials. Our results support the hypothesis that viscoelasticity contributes more when internal models are inaccurate, while internal models contribute more after the completion of learning. It is demonstrated that the CNS regulates viscoelasticity on a short- and long-term basis depending on performance error and finally acquires smooth and accurate movements while maintaining stability during the entire learning process.

    DOI PubMed

  • The neural substrates of biological motion perception: An fMRI study

    P Servos, R Osu, A Santi, M Kawato

    CEREBRAL CORTEX   12 ( 7 ) 772 - 782  2002.07  [Refereed]

     View Summary

    We used fMRI to identify the brain areas related to the perception of biological motion (4 T EPI; whole brain). In experiment 1, 10 subjects viewed biological motion (a human figure jumping up and down, composed of 21 dots), alternating with a control stimulus created by applying autoregressive models to the biological motion stimulus (such that the dots' speeds and amplitudes were preserved whereas their linking structure was not). The lengths of the stimulus bouts varied, and therefore the transitions between biological motion and control stimuli were unpredictable. Subjects had to indicate with a button press when each transition occurred. In a related biological motion task, subjects detected short (1 s) disturbances within these displays. We also examined the neural substrates of motion and shape perception, as well as motor imagery, to determine whether or not the cortical regions involved in these processes are also recruited during biological motion perception. Subjects viewed linear motion displays alternating with static dots and a series of common objects alternating with band-limited white noise patterns. Subjects also generated imagery of their own arm movements alternating with visual imagery of common objects. Biological motion specific BOLD signal was found within regions of the lingual gyrus at the cuneus border, showing little overlap with object recognition, linear motion or motion imagery areas. The lingual gyrus activation was replicated in a second experiment that also mapped retinotopic visual areas in three subjects. The results suggest that a region of the lingual gyrus within VP is involved in higher-order processing of motion information.

    PubMed

  • The central nervous system stabilizes unstable dynamics by learning optimal impedance

    E Burdet, R Osu, DW Franklin, TE Milner, M Kawato

    NATURE   414 ( 6862 ) 446 - 449  2001.11  [Refereed]

     View Summary

    To manipulate objects or to use tools we must compensate for any forces arising from interaction with the physical environment. Recent studies indicate that this compensation is achieved by learning an internal model of the dynamics(1-6), that is, a neural representation of the relation between motor command and movement(5,7). In these studies interaction with the physical environment was stable, but many common tasks are intrinsically unstable(8,9). For example, keeping a screwdriver in the slot of a screw is unstable because excessive force parallel to the slot can cause the screwdriver to slip and because misdirected force can cause loss of contact between the screwdriver and the screw. Stability may be dependent on the control of mechanical impedance in the human arm because mechanical impedance can generate forces which resist destabilizing motion. Here we examined arm movements in an unstable dynamic environment created by a robotic interface. Our results show that humans learn to stabilize unstable dynamics using the skilful and energy-efficient strategy of selective control of impedance geometry.

    DOI PubMed

  • Quantitative examinations for multi joint arm trajectory planning - using a robust calculation algorithm of the minimum commanded torque change trajectory

    Y Wada, Y Kaneko, E Nakano, R Osu, M Kawato

    NEURAL NETWORKS   14 ( 4-5 ) 381 - 393  2001.05  [Refereed]

     View Summary

    In previous research, criteria based on optimal theories were examined to explain trajectory features in time and space in multi joint arm movement. Four criteria have been proposed. They were the minimum hand jerk criterion (by which a trajectory is planned in an extrinsic-kinematic space), the minimum angle jerk criterion (which is planned in an intrinsic-kinematic space), the minimum torque change criterion (where control objects are joint links; it is planned in an intrinsic-dynamic-mechanical space), and the minimum commanded torque change criterion (which is planned in an intrinsic space considering the arm and muscle dynamics). Which of these is proper as a criterion for trajectory planning in the central nervous system has been investigated by comparing predicted trajectories based on these criteria with previously measured trajectories. Optimal trajectories based on the two former criteria can be calculated analytically. In contrast, optimal trajectories based on the minimum commanded torque change criterion are difficult to be calculated, even with numerical methods. In some cases, they can be computed by a Newton-like method or a steepest descent method combined with a penalty method. However, for a realistic physical parameter range, the former becomes unstable quite often and the latter is unreliable about the optimality of the obtained solution.
    In this paper, we propose a new method to stably calculate optimal trajectories based on the minimum commanded torque change criterion. The method can obtain trajectories satisfying Euler-Poisson equations with a sufficiently high accuracy. In the method, a joint angle trajectory, which satisfies the boundary conditions strictly, is expressed by using orthogonal polynomials. The coefficients of the orthogonal polynomials are estimated by using a linear iterative calculation so as to satisfy the Euler-Poisson equations with a sufficiently high accuracy. In numerical experiments, we show that the optimal solution can be computed in a wide work space and can also be obtained in a short lime compared with the previous methods.
    Finally, we perform supplementary examinations of the experiments by Nakano, Imamizu, Osu, Uno, Gomi, Yoshioka et al. (1999). Estimation of dynamic joint torques and trajectory formation from surface electromyography signals using a neural network model. Biological Cybernetics, 73, 291-300. Their experiments showed that the measured trajectory is the closest to the minimum commanded torque change trajectory by statistical examination of many point-to-point trajectories over a wide range in a horizontal and sagittal work space. We recalculated the minimum commanded torque change trajectory using the proposed method, and performed the same examinations as previous investigations. As a result, it could be reconfirmed that the measured trajectory is closest to the minimum commanded torque change trajectory previously reported. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI PubMed

  • 運動技能の獲得とそれに伴う柔軟性の変化:表面筋電図による検討(<特集>運動学習)

    大須 理英子

    バイオメカニズム学会誌   25 ( 4 ) 161 - 166  2001

     View Summary

    練習を繰り返すことにより運動技能は向上する.身体の柔軟性はこのときどのように変化しているのだろうか.表面筋電図を用いた方法により,学習に伴い剛性が低下すること,また失敗が直後の試行の剛性に影響を与えることがわかった.これは内部モデルを用いた予測的制御と剛性を用いたフィードバック制御がうまく組み合わされていることを示す.また,不安定な状況では,剛性を予測的,適応的に変化させて対応しており,生体がインピーダンスコントロールを実現していることがわかった.このように,神経系は外界を予測し,巧みに適応している.このような機能に注目したリハビリテーションの可能性を探ることも有用であろう.

    CiNii

  • Multi-joint arm trajectory formation based on the minimization principle using the Euler-Poisson equation

    Y Wada, Y Kaneko, E Nakano, R Osu, M Kawato

    ARTIFICIAL NEURAL NETWORKS-ICANN 2001, PROCEEDINGS   2130   977 - 984  2001  [Refereed]

     View Summary

    In previous research, criteria based on optimal theories were examined to explain trajectory features in time and space in multi joint arm movements. Four criteria have been proposed. They were the minimum hand jerk criterion, the minimum angle jerk criterion, the minimum torque change criterion, and the minimum commanded torque change criterion. Optimal trajectories based on the two former criteria can be calculated analytically. In contrast, optimal trajectories based on the minimum commanded torque change criterion are difficult to be calculated even with numerical methods. In some cases, they can be computed by a Newton-like method or a steepest descent method combined with a penalty method. However, for a realistic physical parameter range, a former becomes unstable quite often, and the latter is unreliable about the optimality of the obtained solution. In this paper, we propose a new method to stably calculate optimal trajectories based on the minimum commanded torque change criterion. The method can obtain trajectories satisfying Euler-Poisson equations with a sufficiently high accuracy. In the method, a joint angle trajectory, which satisfies the boundary conditions strictly, is expressed by using orthogonal polynomials. The coefficients of the orthogonal polynomials are estimated by using a linear iterative calculation so as to satisfy the Euler-Poisson equations with a sufficiently high accuracy. In numerical experiments, we show that the optimal solution can be computed in a wide work space and can also be obtained in a short time compared with the previous methods.

    DOI

  • A method for measuring endpoint stiffness during multi-joint arm movements

    E Burdet, R Osu, DW Franklin, T Yoshioka, TE Milner, M Kawato

    JOURNAL OF BIOMECHANICS   33 ( 12 ) 1705 - 1709  2000.12  [Refereed]

     View Summary

    Current methods for measuring stiffness during human arm movements are either limited to one-joint motions, or lead to systematic errors. The technique presented here enables a simple, accurate and unbiased measurement of endpoint stiffness during multi-joint movements. Using a computer-controlled mechanical interface, the hand is displaced relative to a prediction of the undisturbed trajectory. Stiffness is then computed as the ratio of restoring force to displacement amplitude. Because of the accuracy of the prediction ( &lt; 1 cm error after 200 ms) and the quality of the implementation, the movement is not disrupted by the perturbation. This technique requires only 1/3 as many trials to identify stiffness as the method of Gomi and Kawato (1997, Biological Cybernetics 76, 163-171) and may, therefore, be used to investigate the evolution of stiffness during motor adaptation. (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI PubMed

  • An Explanation for the Predection of a Hand Trajectory Generated by an Imperfect Internal Model Representation

    SAKURABA Hisayoshi, OSU Rieko, NAKANO Eri, WADA Yasuhiro, KAWATO Mitsuo

    Transactions of the Society of Instrument and Control Engineers   36 ( 7 ) 599 - 608  2000.07

     View Summary

    In multi-joint planar reaching movement, hand trajectories tend to be gently curved depending on the hand position in extracorporal space. Following two explanations are possible for the observed curvature; (i) planned trajectories themselves are curved, (ii) planned trajectories are straight but realized trajectories are curved because of the reasons other than planning. We examined one of the possible reasons that belongs to the second explanation. That is, the realized trajectories are curved because the internal model in the central nervous system is imperfect. We represented imperfect internal model by (1) parametoric method, (2) neural metwork method (3) table look up method, and compared the trajectory predicted by imperfect internal model with the measured trajectories. The results suggest that the imperfect internal model cannot explain the observed curvature better than the minimum commanded torque change model that plans curved trajectories.

    CiNii

  • An Explanation for the Predection of a Hand Trajectory Generated by an Imperfect Internal Model Representation

    SAKURABA Hisayoshi, OSU Rieko, NAKANO Eri, WADA Yasuhiro, KAWATO Mitsuo

      36 ( 7 ) 599 - 608  2000.07

    CiNii

  • 片麻痺上肢のフィードフォワード運動訓練 (特集 リハビリテーション医学の進歩と展開)

    道免 和久, 大須 理英子

    現代医療   32 ( 6 ) 1445 - 1450  2000.06

    CiNii

  • Trajectory Formation Based on the Minimum Commanded Torque Change Model Using the Euler-Poisson Equation

    KANEKO Yuichi, NAKANO Eri, OSU Rieko, WADA Yasuhiro, KAWATO Mitsuo

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   83 ( 5 ) 1381 - 1391  2000.05

    CiNii

  • Composition and Decomposition Learning of Reaching Movements under Altered Environments: An Examination for Multiplicity of Internal Model

    NAKANO Eri, FLANAGAN John R, IMAMIZU Hiroshi, OSU Rieko, YOSHIOKA Toshinori, KAWATO Mitsuo

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   83 ( 2 ) 814 - 826  2000.02

    CiNii

  • An Explanation for the Feature of a Hand Trajectory Controlled by an Imperfect Inverse Dynamics Model

    SAKURABA Hisayoshi, OSU Rieko, NAKANO Eri, WADA Yasuhiro, KAWATO Mitsuo

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   83 ( 2 ) 784 - 794  2000.02

    CiNii

  • Reciprocal excitation between biological and robotic research

    S Schaal, D Sternad, W Dean, S Kotosaka, R Osu, M Kawato

    SENSOR FUSION AND DECENTRALIZED CONTROL IN ROBOTIC SYSTEMS III   4196 ( 1 ) 1 - 12  2000  [Refereed]

     View Summary

    While biological principles have inspired researchers in computational and engineering research for a long time, there is still rather limited knowledge flow back from computational to biological domains. This paper presents examples of our work where research on anthropomorphic robots lead us to new insights into explaining biological movement phenomena, starting from behavioral studies up to brain imaging studies. Our research over the past years has focused on principles of trajectory formation with nonlinear dynamical systems, on learning internal models for nonlinear control, and on advanced topics like imitation learning. The formal and empirical analyses of the kinematics and dynamics of movements systems and the tasks that they need to perform lead us to suggest principles of motor control that later on we found surprisingly related to human behavior and even brain activity.

    DOI

  • Measuring stiffness during arm movements in various dynamic environments

    Burdet, E, Osu, R, Franklin, D, Milner, T. E, Kawato, M

    American Society of Mechanical Engineers, Dynamic Systems and Control Division (Publication) DSC   67   421 - 428  1999.12

     View Summary

    The technique presented in this paper enables a simple, accurate and unbiased measurement of hand stiffness during human arm movements. Using a computer-controlled mechanical interface, the hand is shifted relative to a prediction of the undisturbed trajectory. Stiffness is then computed as the restoring force divided by the position amplitude of the perturbation. A precise prediction algorithm insures the measurement quality. We used this technique to measure stiffness in free movements and after adaptation to a linear velocity dependent force field. The subjects compensated for the external force by co-contracting muscles selectively. The stiffness geometry changed with learning and stiffness tended to increase in the direction of the external force.

  • Quantitative examinations of internal representations for arm trajectory planning: Minimum commanded torque change model

    Eri Nakano, Hiroshi Imamizu, Rieko Osu, Yoji Uno, Hiroaki Gomi, Toshinori Yoshioka, Mitsuo Kawato

    Journal of Neurophysiology   81 ( 5 ) 2140 - 2155  1999  [Refereed]

     View Summary

    A number of invariant features of multijoint planar reaching movements have been observed in measured hand trajectories. These features include roughly straight hand paths and bell-shaped speed profiles where the trajectory curvatures between transverse and radial movements have been found to be different. For quantitative and statistical investigations, we obtained a large amount of trajectory data within a wide range of the workspace in the horizontal and sagittal planes (400 trajectories for each subject). A pair of movements within the horizontal and sagittal planes was set to be equivalent in the elbow and shoulder flexion/extension. The trajectory curvatures of the corresponding pair in these planes were almost the same. Moreover, these curvatures can be accurately reproduced with a linear regression from the summation of rotations in the elbow and shoulder joints. This means that trajectory curvatures systematically depend on the movement location and direction represented in the intrinsic body coordinates. We then examined the following four candidates as planning spaces and the four corresponding computational models for trajectory planning. The candidates were as follows: the minimum hand jerk model in an extrinsic-kinematic space, the minimum angle jerk model in an intrinsic-kinematic space, the minimum torque change model in an intrinsic-dynamic-mechanical space, and the minimum commanded torque change model in an intrinsic-dynamic-neural space. The minimum commanded torque change model, which is proposed here as a computable version of the minimum motor command change model, reproduced actual trajectories best for curvature, position, velocity, acceleration, and torque. The model's prediction that the longer the duration of the movement the larger the trajectory curvature was also confirmed. Movements passing through via- points in the horizontal plane were also measured, and they converged to those predicted by the minimum commanded torque change model with training. Our results indicated that the brain may plan, and learn to plan, the optimal trajectory in the intrinsic coordinates considering arm and muscle dynamics and using representations for motor commands controlling muscle tensions.

    DOI PubMed

  • Composition and decomposition of internal models in motor learning under altered kinematic and dynamic environments.

    Flanagan, J. R, Nakano, E, Imamizu, H, Osu, R, Yoshioka, T, Kawato, M

    The Journal of neuroscience : the official journal of the Society for Neuroscience   19 ( 20 )  1999.01

     View Summary

    The learning process of reaching movements was examined under novel environments whose kinematic and dynamic properties were altered. We used a kinematic transformation (visuomotor rotation), a dynamic transformation (viscous curl field), and a combination of these transformations. When the subjects learned the combined transformation, reaching errors were smaller if the subject first learned the separate kinematic and dynamic transformations. Reaching errors under the kinematic (but not the dynamic) transformation were smaller if subjects first learned the combined transformation. These results suggest that the brain learns multiple internal models to compensate for each transformation and has some ability to combine and decompose these internal models as called for by the occasion.

    PubMed

  • Multijoint muscle regulation mechanisms examined by measured human arm stiffness and EMG signals

    Rieko Osu, Hiroaki Gomi

    Journal of Neurophysiology   81 ( 4 ) 1458 - 1468  1999

     View Summary

    Stiffness properties of the musculoskeletal system can be controlled by regulating muscle activation and neural feedback gain. To understand the regulation of multijoint stiffness, we examined the relationship between human arm joint stiffness and muscle activation during static force control in the horizontal plane by means of surface electromyographic (EMG) studies. Subjects were asked to produce a specified force in a specified direction without cocontraction or they were asked to keep different cocontractions while producing or not producing an external force. The stiffness components of shoulder, elbow, and their cross-term and the EMG of six related muscles were measured during the tasks. Assuming that the EMG reflects the corresponding muscle stiffness, the joint stiffness was predicted from the EMG by using a two-link six-muscle arm model and a constrained least-square- error regression method. Using the parameters estimated in this regression, single-joint stiffness (diagonal terms of the joint-stiffness matrix) was decomposed successfully into biarticular and monoarticular muscle components. Although biarticular muscles act on both shoulder and elbow, they were found to covary strongly with elbow monoarticular muscles. The preferred force directions of biarticular muscles were biased to the directions of elbow monoarticular muscles. Namely, the elbow joint is regulated by the simultaneous activation of monoarticular and biarticular muscles, whereas the shoulder joint is regulated dominantly by monoarticular muscles. These results suggest that biarticular muscles are innervated mainly to control the elbow joint during static force-regulation tasks. In addition, muscle regulation mechanisms for static force control tasks were found to be quite different from those during movements previously reported. The elbow single- joint stiffness was always higher than cross-joint stiffness (off-diagonal terms of the matrix) in static tasks while elbow single-joint stiffness is reported to be sometimes as small as cross-joint stiffness during movement. That is, during movements, the elbow monoarticular muscles were occasionally not activated when biarticular muscles were activated. In static tasks, however, monoarticular muscle components in single-joint stiffness were increased considerably whenever biarticular muscle components in single- and cross-joint stiffness increased. These observations suggest that biarticular muscles are not simply coupled with the innervation of elbow monoarticular muscles but also are regulated independently according to the required task. During static force-regulation tasks, covariation between biarticular and elbow monoarticular muscles may be required to increase stability and/or controllability or to distribute effort among the appropriate muscles.

    DOI PubMed

  • Task-dependent viscoelasticity of human multijoint arm and its spatial characteristics for interaction with environments

    H Gomi, R Osu

    JOURNAL OF NEUROSCIENCE   18 ( 21 ) 8965 - 8978  1998.11  [Refereed]

     View Summary

    Human arm viscoelasticity is important in stabilizing posture, movement, and in interacting with objects. Viscoelastic spatial characteristics are usually indexed by the size, shape, and orientation of a hand stiffness ellipse. It is well known that arm posture is a dominant factor in determining the properties of the stiffness ellipse. However, it is still unclear how much joint stiffness can change under different conditions, and the effects of that change on the spatial characteristics of hand stiffness are poorly examined. To investigate the dexterous control mechanisms of the human arm, we studied the controllability and spatial characteristics of viscoelastic properties of human multijoint arm during different cocontractions and force interactions in various directions and amplitudes in a horizontal plane. We found that different cocontraction ratios between shoulder and elbow joints can produce changes in the shape and orientation of the stiffness ellipse, especially at proximal hand positions. During force regulation tasks we found that shoulder and elbow single-joint stiffness was each roughly proportional to the torque of its own joint, and cross-joint stiffness was correlated with elbow torque. Similar tendencies were also found in the viscosity-torque relationships. As a result of the joint stiffness changes, the orientation and shape of the stiffness ellipses varied during force regulation tasks as well. Based on these observations, we consider why we can change the ellipse characteristics especially in the proximal posture. The present results suggest that humans control directional characteristics of hand stiffness by changing joint stiffness to achieve various interactions with objects.

    PubMed

  • Quantitative Examinations of Trajectory Planning Criteria in Multijoint Movement -Minimum elastic torque Change Model-

    NAKANO Eri, IMAMIZU Hiroshi, OSU Rieko, UNO Yoji, GOMI Hiroaki, YOSHIOKA Toshinori, KAWATO Mitsuo

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   81 ( 7 ) 1666 - 1678  1998.07

    CiNii

  • Decomposition and combination of multiple internal models

    Eri Nakano, Randy Flanagan, Hiroshi Imamizu, Rieko Osu, Toshinori Yoshioka, Mitsuo Kawato

    Neuroscience Research   31   S233  1998.01  [Refereed]

    DOI

  • Estimation of human multi-joint arm stiffness during force control by using EMG signals

    OSU Rieko, GOMI Hiroaki

      12   361 - 364  1997.09

    CiNii

  • Possible explanations for trajectory curvature in multijoint arm movements

    R Osu, Y Uno, Y Koike, M Kawato

    JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE   23 ( 3 ) 890 - 913  1997.06  [Refereed]

     View Summary

    Although the straightness of hand paths is a widely accepted feature of human multijoint reaching movement, detailed examinations have revealed slight curvatures in some regions of the workspace. This observation raises the question of whether planned trajectories are straight or curved. If they are straight, 3 possible factors can explain the observed curvatures: (a) imperfect control, (b) visual distortion, or (c) interaction between straight virtual trajectories and the dynamics of the arm. Participants instructed to generate straight movement paths produced movements much straighter than those generated spontaneously. Participants generated spontaneously curved trajectories in the frontoparallel plane, where visual distortion is not expected. Electromyograms suggested that participants generated straighter paths without an increase in arm stiffness. These findings argue against the 3 factors. It follows that planned trajectories are likely to be curved.

    PubMed

  • Contributions of single and double joint stiffness of human arm during force control

    H Gomi, R Osu

    PROCEEDINGS OF THE 18TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 18, PTS 1-5   18   2244 - 2245  1997  [Refereed]

     View Summary

    To investigate tile motion control mechanism of human arm during force control, shoulder, elbow, and double-joint stiffness were measured by applying a small perturbation, and their contributions to joint torques were estimated, Each joint stiffness greatly altered for the different force direction at hand, and shoulder and elbow single joint stiffness were linearly correlated to each joint torques, ny assuming a linear joint stiffness, generated torques were decomposed into torques produced by each stiffness component. This analysis has revealed that the elbow torque was produced complementary by the single and double-joint stiffness, and that the shoulder torque was mainly produced by the shoulder single joint stiffness, Additionally, the double-joint stiffness was linearly correlated to tile decomposed elbow joint torques produced by double-joint stiffness, These results suggest that shoulder and elbow torques are separately controlled by different muscles in this task.

  • Quantitative examinations for trajectory planning criteria in multi-joint reaching movement

    E NAKANO, H IMAMIZU, R OSU, Y UNO, H GOMI, T YOSHIOKA, M KAWATO

    Neuroscience Research   28   S203  1997  [Refereed]

    DOI

  • Estimation of change in arm stiffness during motor learning using EMG signals

    R OSU, K DOMEN, H GOMI, T YOSHIOKA, H IMAMIZU, M KAWATO

    Neuroscience Research   28   S202  1997  [Refereed]

    DOI

  • A Kendama learning robot based on bi-directional theory

    H Miyamoto, S Schaal, F Gandolfo, H Gomi, Y Koike, R Osu, E Nakano, Y Wada, M Kawato

    NEURAL NETWORKS   9 ( 8 ) 1281 - 1302  1996.11  [Refereed]

     View Summary

    A general theory of movement-pattern perception based on bi-directional theory for sensory-motor integration can be used for motion capture and learning by watching in robotics. We demonstrate our methods using the game of Kendama, executed by the SARCOS Dextrous Slave Arm, which has a very similar kinematic structure to the human arm. Three ingredients have to be integrated for the successful execution of this task. The ingredients are (1) to extract via-points from a human movement trajectory using a forward-inverse relaxation model, (2) to treat via-points as a control variable while reconstructing the desired trajectory from all the via-points, and (3) to modify the via-points for successful execution. In order to test the validity of the via-point representation, we utilized a numerical model of the SARCOS arm, and examined the behavior of the system under several conditions. Copyright (C) 1996 Elsevier Science Ltd.

    DOI

  • Systems Approach to Brain Functions. The Curvature of Hand Paths in Multi-joint Movement: Examinations of Computational Theories for Trajectory Planning.:Examinations of Computational Theories for Trajectory Planning

    NAKANO Eri, IMAMIZU Hiroshi, OSU Rieko, UNO Yoji, KAWATO Mitsuo

    BME   34 ( 4 ) 406 - 417  1996

     View Summary

    In multi-joint movements, possible trajectories for a given target are infinite, but actually have certain invariant features. It has been discussed whether trajectories of the human arm are planned in an extrinsic space or in an intrinsic space. Hand paths planned in the former are predicted to be always straight, while those in the latter are generally curved. Both Uno et al. and Osu et al. reported that actual hand paths tended to significantly curve for some specific arm postures, movement distances, and movement durations. We have extended the previous studies by using various initial and final positions located within a workspace and examined if the curvature of a trajectory quantitatively varies with arm posture when subjects make point to point reaching movements on a horizontal plane. Curvatures of measured hand trajectories were linearly estimated using two models, hand position and hand translation, which are represented by extrinsic coordinates, and other two models, joint angle and joint rotation, which are represented by intrinsic coordinates. In experiment I and II, movement durations were restricted, and in experiment III, movement durations were flexible and added to parameters. Movement durations and joint rotation significantly contributed to curvature. We succeeded in predicting the curvature of hand paths by using the arm posture before and after a movement. The results suggest that trajectory curvature depends on arm posture and is in accordance with predictions made under planning in the intrinsic space, rather than that in the extrinsic space. Furthermore, the result that a longer movement duration causes a larger curvature is in agreement with the predictions of Uno and Kawato, in which a longer movement duration makes paths expand toward the outer side because of an effectively larger viscosity ratio.

    CiNii

  • Calculating Optimal Criteria for Trajectory Planning Using Observed Movement Data

    Rieko Osu, Mitsuo Kawato, Yoji Uno, Yasuharu Koike

    Japanese Journal of Medical Electronics and Biological Engineering   34 ( 4 ) 394 - 405  1996

     View Summary

    Various optimal criteria have been proposed for trajectory planning in multi-joint arm movements. The minimumjerk criterion plans smooth trajectories in the extrinsic task space. The minimum-joint-angle-jerk criterion, the minimum-torque-change criterion, and the minimum-motor-command-change criterion plan smooth trajectories in the intrinsic body space. Assuming that realized trajectories reflect planned trajectories, we compared the values of above four optimal criteria calculated from observed movement data. If the value of a certain criterion is larger in a spontaneously generated movement than in some other movement, that criterion can be rejected. If, however, the value of a certain criterion is smaller in a spontaneously generated movement than in any other movement, it supports that criterion. Subjects were instructed to move their hand to a target passing through a via-point. Several via-points were given randomly to make subjects generate hand paths with various curvatures. The curvatures of the paths that have minimum values of a certain criterion are compared to curvatures of the spontaneously generated paths. The values of hand-jerk and joint-angle-jerk were obtained from measured position data. The values of torque-change were obtained using the dynamics equation of a two-joint arm model with estimated physical parameters. The values of motor-command-change were obtained from quasi-tension calculated from rectified EMG using a second-order low-pass-filter. The minimum-jerk criterion was larger in spontaneously curved movements than in movements with straighter hand paths. This result rejects the minimum-hand-jerk criterion. However, joint angle jerk was not always minimum around the hand paths predicted by the minimum-joint-angle-jerk criterion. Subjects tend to generate trajectories that have lower values of minimum-motor-command-change criterion. © 1996, Japanese Society for Medical and Biological Engineering. All rights reserved.

    DOI CiNii

  • The Curvature of Hand Paths in Multi-joint Movements: Examinations of Computational Theories for Trajectory Planning

    Eri Nakano, Hiroshi Imamizu, Rieko Osu, Mitsuo Kawato, Eri Nakano, Yoji Uno

    Japanese Journal of Medical Electronics and Biological Engineering   34 ( 4 ) 406 - 417  1996

     View Summary

    In multi-joint movements, possible trajectories for a given target are infinite, but actually have certain invariant features. It has been discussed whether trajectories of the human arm are planned in an extrinsic space or in an intrinsic space. Hand paths planned in the former are predicted to be always straight, while those in the latter are generally curved. Both Uno et al. and Osu et al. reported that actual hand paths tended to significantly curve for some specific arm postures, movement distances, and movement durations. We have extended the previous studies by using various initial and final positions located within a workspace and examined if the curvature of a trajectory quantitatively varies with arm posture when subjects make point to point reaching movements on a horizontal plane. Curvatures of measured hand trajectories were linearly estimated using two models, hand position and hand translation, which are represented by extrinsic coordinates, and other two models, joint angle and joint rotation, which are represented by intrinsic coordinates. In experiment I and II, movement durations were restricted, and in experiment III, movement durations were flexible and added to parameters. Movement durations and joint rotation significantly contributed to curvature. We succeeded in predicting the curvature of hand paths by using the arm posture before and after a movement. The results suggest that trajectory curvature depends on arm posture and is in accordance with predictions made under planning in the intrinsic space, rather than that in the extrinsic space. Furthermore, the result that a longer movement duration causes a larger curvature is in agreement with the predictions of Uno and Kawato, in which a longer movement duration makes paths expand toward the outer side because of an effectively larger viscosity ratio. © 1996, Japanese Society for Medical and Biological Engineering. All rights reserved.

    DOI CiNii

  • Calculating Optimal Criteria for Trajectory Planning Using Observed Movement Data

    Rieko Osu, Mitsuo Kawato, Yoji Uno, Yasuharu Koike

    Japanese Journal of Medical Electronics and Biological Engineering   34 ( 4 ) 394 - 405  1996

     View Summary

    Various optimal criteria have been proposed for trajectory planning in multi-joint arm movements. The minimumjerk criterion plans smooth trajectories in the extrinsic task space. The minimum-joint-angle-jerk criterion, the minimum-torque-change criterion, and the minimum-motor-command-change criterion plan smooth trajectories in the intrinsic body space. Assuming that realized trajectories reflect planned trajectories, we compared the values of above four optimal criteria calculated from observed movement data. If the value of a certain criterion is larger in a spontaneously generated movement than in some other movement, that criterion can be rejected. If, however, the value of a certain criterion is smaller in a spontaneously generated movement than in any other movement, it supports that criterion. Subjects were instructed to move their hand to a target passing through a via-point. Several via-points were given randomly to make subjects generate hand paths with various curvatures. The curvatures of the paths that have minimum values of a certain criterion are compared to curvatures of the spontaneously generated paths. The values of hand-jerk and joint-angle-jerk were obtained from measured position data. The values of torque-change were obtained using the dynamics equation of a two-joint arm model with estimated physical parameters. The values of motor-command-change were obtained from quasi-tension calculated from rectified EMG using a second-order low-pass-filter. The minimum-jerk criterion was larger in spontaneously curved movements than in movements with straighter hand paths. This result rejects the minimum-hand-jerk criterion. However, joint angle jerk was not always minimum around the hand paths predicted by the minimum-joint-angle-jerk criterion. Subjects tend to generate trajectories that have lower values of minimum-motor-command-change criterion. © 1996, Japanese Society for Medical and Biological Engineering. All rights reserved.

    DOI CiNii

  • A Kendama learning robot based on a dynamic optimization theory

    K Miyamoto, F Gandolfo, H Gomi, S Schaal, Y Koike, R Osu, E Nakano, Y Wada, M Kawato

    RO-MAN'95 TOKYO: 4TH IEEE INTERNATIONAL WORKSHOP ON ROBOT AND HUMAN COMMUNICATION, PROCEEDINGS     327 - 332  1995  [Refereed]

  • The Control Mechanism of Voluntary Arm Movements

    OSU Rieko

    Japanese psychological review   38 ( 3 ) 368 - 395  1995

    CiNii

▼display all

Misc

  • 脳卒中患者のリハビリテーションへのモチベーションに関するシステマティックレビュー

    吉田太樹, 伊藤大将, 伊藤大将, 渡邉翔太, 大須理英子, 大高洋平, 大高洋平

    日本作業療法学会抄録集(CD-ROM)   53rd  2019

    J-GLOBAL

  • 脳卒中回復期における小脳灰白質の容積変化

    大須 理英子, 森田 とわ, 田中 悟志, 磯谷 悠子, 倉重 宏樹, 近藤 国嗣, 大高 洋平, 荒牧 勇

    日本心理学会大会発表論文集   82回   620 - 620  2018.08

  • 脳卒中回復期における小脳灰白質の容積変化

    大須 理英子, 森田 とわ, 田中 悟志, 磯谷 悠子, 倉重 宏樹, 近藤 国嗣, 大高 洋平, 荒牧 勇

    日本心理学会大会発表論文集   82回   620 - 620  2018.08

  • つり革につかまったときの筋緊張部位の変化の機序は? 転倒の危険性が減じ、緊張がゆるむためだが、反射ではなく随意運動

    大高 洋平, 大須 理英子

    日本医事新報   ( 4898 ) 59 - 60  2018.03

  • Cortical volume changes in sub-acute stroke patients: a voxel-based morphometry study

       2017.03

  • 携帯端末を用いた歩行解析ソフトウェアの開発

    小宅一彰, 倉山太一, 安田恒, 大須理英子, 大高洋平

    Jpn J Rehabil Med   52   S396  2015.05

    J-GLOBAL

  • Transcranial direct current stimulation improves tactile discrimination in stroke patients.

    Fujimoto S, Kon N, Otaka Y, Yamaguchi T, Osu R, Kondo K, Tanaka S

    World Confederation for Physical Therapy Congress 2015,   Singapore.  2015.05  [Refereed]

  • 延髄外側梗塞患者における自覚的視性垂直位とバランス能力および歩行能力の関連

    荒井 一樹, 松浦 大輔, 杉田 翔, 大須 理英子, 近藤 国嗣, 大高 洋平

    理学療法学   42 ( Suppl.2 ) P1 - 0269  2015.04

  • 経頭蓋直流電気刺激は脳卒中患者の触覚弁別能力を向上する 二重盲検ランダム化クロスオーバー比較試験

    藤本 修平, 今 法子, 大高 洋平, 山口 智史, 大須 理英子, 近藤 国嗣, 田中 悟志

    理学療法学   42 ( Suppl.2 ) P1 - 0263  2015.04

  • 科学的根拠に基づいた医療の創設を目指す回復期リハビリテーション病院の取り組み

    井上 靖悟, 大高 洋平, 山口 智史, 小宅 一彰, 大須 理英子, 田中 悟志, 倉山 太一, 坂田 祥子, 補永 薫, 近藤 国嗣

    理学療法学   42 ( Suppl.2 ) P2 - 0458  2015.04

  • Task specific movement representations of primary motor cortex inherent in resting-state brain activity measured by functional magnetic resonance imaging

    KUSANO Toshiki, KURASHIGE Hiroki, NAMBU Isao, MORIGUCHI Yoshiya, HANAKAWA Takashi, WADA Yasuhiro, OSU Rieko

    IEICE technical report. ME and bio cybernetics   114 ( 514 ) 189 - 194  2015.03

    CiNii

  • 二重課題歩行がMismatch negativity(MMN)に与える影響

    田所 祐介, 倉山 太一, 今度 知夏, 松澤 大輔, 大高 洋平, 大須 理英子, 清水 栄司

    臨床神経生理学   42 ( 5 ) 313 - 313  2014.10

  • 健常者における上肢内外転運動を利用したAPA(Anticipatory Postural Adjustment)の検討

    今度 知夏, 倉山 太一, 田所 祐介, 大須 理英子, 松澤 大輔, 清水 栄司, 大高 洋平

    臨床神経生理学   42 ( 5 ) 313 - 313  2014.10

  • Dual-hemisphere direct current stimulation over the secondary somatosensory cortex improves spatial tactile acuity in human.

    Fujimoto S, Yamaguchi T, Kon N, Osu R, Otaka Y, Kondo K, Kitada R, Tanaka S

    Neuroscience 2014,   Yokoyama, Japan.  2014.09

  • 二次体性感覚野への経頭蓋直流電気刺激は触覚方位弁別能力を向上する

    藤本 修平, 山口 智史, 今 法子, 大須 理英子, 大高 洋平, 近藤 国嗣, 田中 悟志

    理学療法学   41 ( 大会特別号2 ) 0145 - 0145  2014.05

  • Voxel-level representations of motor actions inherent in resting-state brain activity

    KUSANO Toshiki, KUSASHIGE Hiroki, NAMBU Isao, MORIGUCHI Yoshiya, HANAKAWA Takashi, WADA Yasuhiro, OSU Rieko

    IEICE technical report. Neurocomputing   113 ( 500 ) 221 - 226  2014.03

    CiNii

  • 歩行解析のための新しい足底接地センサ(STANS)の開発

    鎌田 浩志, 武田 湖太郎, 橋爪 善光, 倉山 太一, 末長 宏康, 近藤 国嗣, 西井 淳, 大須 理英子, 大高 洋平

    総合リハビリテーション   42 ( 1 ) 67 - 71  2014  [Refereed]

     View Summary

    歩行解析のための新しい足底接地センサ(STANS)を開発した。STANSの機構は、検出回路部は電源および抵抗器を有し、装着部は非伝導性の靴下と、その足底部に配された導電糸で形成される電極からなる。歩行面は平らな床面に導電性シートを配置したものである。健常成人7例を対象とした。導電性シートを帯状床面に貼付し、分速75mの速度に設定したトレッドミル上を歩行した。安定歩容時における20歩分の右踵接地タイミングを分析対象とした。閾値を25%とした場合、すべての被験者で、STANSよりも圧センサのタイミングが遅く、また、踵後部、踵前部の順に応答が遅かった。各センサの閾値25%時と閾値75%時の時間差では、STANSは踵後部や踵前部圧センサに対し、有意に小さく変化が急峻であった。

    DOI

  • 脳卒中患者における経頭蓋直流電気刺激による聴覚言語性記憶の増強作用

    數田俊成, 武田湖太郎, 田中悟志, 大須理英子, 補永薫, 近藤国嗣, 忽那岳志, 松浦大輔, 上垣内梨恵, 富岡曜平, 岡阿沙子, 里宇明元

    臨床神経生理学   41 ( 5 ) 408 - 408  2013.10

  • EEGを用いた視覚運動変換を決定する意思決定変数の動的変化の推定

    加藤 大陽, 藤原 祐介, 相原 孝次, 大高 洋平, 大須 理英子, 井澤 淳

    電子情報通信学会技術研究報告(MEとバイオサイバネティックス)   112 ( 479 ) 83 - 88  2013.03

     View Summary

    視覚刺激を知覚してから運動開始までの潜時は、文脈や環境情報に依存して状況ごとに変化する。この潜時のばらつきの存在は、脳における視覚運動変換が、事前知識や環境情報によって影響を受ける脳の内部状態に確率的に依存していることを示唆している。そのような視覚運動変換を決定する意思決定変数の変化をEEGにより観測し、EEG信号から将来起こる事象に対して生成される運動を予測することによって、意思決定変数の脳内表現を明らかにする。そのために、Go/No-Go刺激の前に手がかり刺激を与える実験を行なった。その結果、与えられる手がかり刺激に従って、No-Go刺激に対する成功確率と潜時が変化することがわかった。さらに、計測したEEG信号から、No-Go刺激に対する2つの行動(成功、失敗)を予測する頭皮上電位のトポグラフィを描くとともに、EEG振幅と反応時間との相関を確認した。これらの結果は、No-Go刺激に対する運動の生成を決定する意思決定変数が、手がかり刺激の不確実性を表現しながら発展し、脳活動の時空間マップを変化させることを示唆している。(著者抄録)

  • 脳卒中片麻痺のリハビリテーションとNear-infrared Spectroscopy

    武田 湖太郎, 佐藤 貴紀, 南部 功夫, 山田 亨, 梅山 伸二, 大高 洋平, 井上 芳浩, 大須 理英子, 和田 安弘, 加藤 宏之

    認知神経科学   14 ( 3 ) 157 - 161  2013.03

    Article, review, commentary, editorial, etc. (scientific journal)  

    DOI

  • Facilitative effect of dual-hemispheric transcranial direct current stimulation (tDCS) on performance in tactile discrimination task.

    Fujimoto S, Yamaguchi T, Okata Y, Sadato N, Osu R, Kondo K, Tanaka S

    Neuro2013,   Kyoto, Japan,  2013

  • Dual-hemispheric transcranial direct current stimulation (tDCS) improves performance in tactile discrimination task.

    Fujimoto S, Yamaguchi T, Okata Y, Sadato N, Osu R, Kondo K, Tanaka S

    WCPT-AWP & ACPT congress,   Taichung, Taiwan,  2013

  • 脳卒中リハビリテーションのためのERD-modulated FESシステムの開発

    武田 湖太郎, 高橋 光, 大高 洋平, 大須 理英子, 花川 隆, 郷古 学, 伊藤 宏司

    第25回バイオエンジニアリング講演会 講演論文集     357 - 358  2013.01

    Research paper, summary (national, other academic conference)  

    DOI

  • Association between brain structure and muscle force distribution

    KITA Kahori, IZAWA Jun, HANAKAWA Takashi, OSU Rieko

    IEICE technical report. ME and bio cybernetics   112 ( 220 ) 19 - 24  2012.09

    CiNii

  • Simulation of method to remove skin blood flow artifact in functional near-infrared spectroscopy using short-distance probe

    Sato T, Takeda K, Osu R, Nambu I, Wada Y

    第27回生体・生理工学シンポジウム論文集     337 - 341  2012.09

    Research paper, summary (national, other academic conference)  

  • 近赤外分光法(NIRS)における頭皮血流の影響と除去手法の提案

    佐藤 貴紀, 武田 湖太郎, 山下 宙人, 井上 芳浩, 大高 洋平, 和田 安弘, 川人 光男, 佐藤 雅昭, 大須 理英子

    脳科学とリハビリテーション   12   36 - 36  2012.06

  • 近赤外分光法(NIRS)の計測プローブの角度変化による擬陽的・擬陰的アーチファクト

    神谷 修平, 武田 湖太郎, 山田 亨, 梅山 伸二, 井上 芳浩, 近藤 国嗣, 大高 洋平, 大須 理英子

    脳科学とリハビリテーション   12   39 - 39  2012.06

  • 近赤外分光法における計測プローブの角度変化によるアーチファクト

    神谷 修平, 武田 湖太郎, 山田 亨, 梅山 伸二, 近藤 国嗣, 大高 洋平, 大須 理英子

    脳科学とリハビリテーション   12   13 - 18  2012.06

    DOI

  • 圧覚を皮膚電気刺激に変換してフィードバックし重度感覚障害者の握り・つまみ動作を改善させる試み

    大高 洋平, 北 佳保里, 武田 湖太郎, 牛場 潤一, 坂田 祥子, 大須 理英子, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   49 ( Suppl. ) S316 - S316  2012.05

  • 事象関連NIRSによる素早い把持動作に関連する脳活動の計測に必要な諸条件の検討

    小澤 拓也, 相原 孝次, 藤原 祐介, 大高 洋平, 和田 安弘, 大須 理英子, 井澤 淳

    電子情報通信学会技術研究報告(MEとバイオサイバネティックス)   111 ( 482 ) 225 - 228  2012.03

     View Summary

    これまでに報告された近赤外分光法(NIRS)を用いた運動時の脳活動計測の多くは、タスクを実行する時間ブロックと休止中の時間ブロック中の脳活動の差に着目するブロックデザインを用いていた。そのため、例えば意思決定、運動準備、運動実行や感覚処理といった、運動に関わる様々な神経活動に由来する血流変化が混在し、それぞれを分離して計測することが難しかった。そこで、本報告では事象関連デザインを素早い把持動作に適用し、NIRSによる計測が可能であるか、およびそのために必要となる条件について検討した。(著者抄録)

  • 経頭蓋直流電気刺激(tDCS)による慢性期脳卒中患者の下肢筋力促進

    花川 隆, 田中 悟志, 武田 湖太郎, 大高 洋平, 北 佳保里, 大須 理英子, 本田 学, 定藤 規弘, 渡邊 克巳

    臨床神経学   51 ( 12 ) 1217 - 1217  2011.12

  • 経頭蓋直流電気刺激が聴覚言語性短期記憶に及ぼす影響

    數田 俊成, 武田 湖太郎, 田中 悟志, 大須 理英子, 大高 洋平, 新城 吾郎, 近藤 国嗣, 忽那 岳志, 松浦 大輔, 上垣内 梨恵, 川上 路華, 倉片 治郎, 里宇 明元

    臨床神経生理学   39 ( 5 ) 428 - 428  2011.10

  • 電極の貼付位置の違いが経頭蓋直流電気刺激による下肢運動皮質興奮性に及ぼす影響

    立本 将士, 山口 智史, 田中 悟志, 大高 洋平, 大須 理英子, 近藤 国嗣, 定藤 規弘

    臨床神経生理学   39 ( 5 ) 462 - 462  2011.10

  • A proposal of EEG-FES based rehabilitation system for lower limbs

    Takata Y, Takeda K, Osu R, Otaka Y, Kondo T, Ito K

    第26回生体・生理工学シンポジウム論文集     718 - 721  2011.09

    Research paper, summary (national, other academic conference)  

  • Cortical silent periodの客観的検出法の検討

    竹中 健治, 武田 湖太郎, 山口 智史, 近藤 国嗣, 大高 洋平, 大須 理英子

    理学療法学   38 ( Suppl.2 ) OF2 - 009  2011.04

  • Symbiosis of motor interaction

    Ganesh Gowrishankar, Rieko Osu, Toshinori Yoshioka, Mitsuo Kawato, Etienne Burdet

    NEUROSCIENCE RESEARCH   71   E254 - E254  2011

    Research paper, summary (international conference)  

    DOI

  • Isolating cortical activities from artifacts in simulated EEG data during smooth pursuit eye movements

    Ken-ichi Morishige, Takatsugu Aihara, Mitsuo Kawato, Rieko Osu, Masa-aki Sato

    NEUROSCIENCE RESEARCH   71   E209 - E209  2011

    Research paper, summary (international conference)  

    DOI

  • Reduction of the skin blood flow artifact from near-infrared spectroscopy signals

    Takanori Sato, Kotaro Takeda, Okito Yamashita, Yoshihiro Inoue, Yohei Otaka, Yasuhiro Wada, Mitsuo Kawato, Masaaki Sato, Rieko Osu

    NEUROSCIENCE RESEARCH   71   E306 - E306  2011

    Research paper, summary (international conference)  

    DOI

  • Different motor plans before and after motor learning in the presence of endpoint error

    Tsuyoshi Ikegami, Gawrishankar Ganesh, Tricia Gibo, Toshinori Yoshioka, Mitsuo Kawato, Rieko Osu

    NEUROSCIENCE RESEARCH   71   E250 - E250  2011

    Research paper, summary (international conference)  

    DOI

  • 経頭蓋直流電気刺激(tDCS)による慢性期脳卒中患者の下肢筋力促進

    花川隆, 田中悟志, 武田湖太郎, 大高洋平, 北佳保里, 大須理英子, 本田学, 定藤規弘, 渡邊克巳

    日本神経学会学術大会プログラム・抄録集   52nd   274  2011

    J-GLOBAL

  • Non-invasive cortical stimulation enhances lower limb function in chronic stroke patients.

    Tanaka S, Takeda K, Otaka Y, Kita K, Osu R, Honda M, Sadato N, Hanakawa T, Watanabe K

    14th European Congress on Clinical Neurophysiology,   Rome, ITALY,  2011

  • 経頭蓋直流電気刺激による慢性期脳卒中患者の下肢筋力増強

    田中 悟志, 武田 湖太郎, 大高 洋平, 北 佳保里, 大須 理英子, 花川 隆, 渡邊 克巳

    臨床神経生理学   38 ( 5 ) 326 - 326  2010.10

  • EEGを使用した階層変分ベイズ法とスパース判別法による脳機能イメージング(Brain imaging of motor control activity using EEG and a combination of Hierarchical Variational Bayesian method and Sparse Logistic Regression)

    安田 恒, 相原 孝次, 武田 湖太郎, 山下 宙人, 佐藤 雅昭, 大高 洋平, 川人 光男, 大須 理英子

    神経化学   49 ( 2-3 ) 688 - 688  2010.08

  • NIRS-EEGによる脳卒中片麻痺例における手指運動時の脳機能計測(Load-dependent and abnormal lateralization during paretic finger movement: A NIRS-EEG study)

    武田 湖太郎, 安田 恒, 相原 孝次, 大高 洋平, 佐藤 雅昭, 川人 光男, 大須 理英子

    神経化学   49 ( 2-3 ) 719 - 719  2010.08

  • ペダリング運動が2シナプス性Ia相反抑制に及ぼす影響(Effects of pedaling exercise on disynaptic reciprocal Ia inhibition in healthy persons)

    齊藤 慧, 山口 智史, 小宅 一彰, 田辺 茂雄, 村岡 慶裕, 大須 理英子, 近藤 国嗣, 大高 洋平

    神経化学   49 ( 2-3 ) 633 - 633  2010.08

  • ペダリング運動と電気刺激の同時適用が脊髄介在ニューロンに与える効果(Effects of active pedaling exercise combined with electrical stimulation on spinal interneurons in healthy persons)

    山口 智史, 藤原 俊之, 齋藤 慧, 田辺 茂雄, 村岡 慶裕, 大須 理英子, 大高 洋平, 近藤 国嗣, 里宇 明元

    神経化学   49 ( 2-3 ) 633 - 633  2010.08

  • 集中訓練前後の脳卒中片麻痺患者のリーチ動作における体幹代償の変化

    坂田 祥子, 浦川 佳奈, 武田 湖太郎, 大須 理英子, 大高 洋平

    日本作業療法学会抄録集   44回   O109 - O109  2010.06

  • 近赤外線分光法(NIRS)を用いた心的回転課題時の脳賦活量の検討

    吉田 太樹, 武田 湖太郎, 熊谷 将志, 大須 理英子, 大高 洋平

    日本作業療法学会抄録集   44回   P29 - P29  2010.06

  • Case study of EEG (electroencephalogram) - FES (functional electrical stimulation) system for stroke rehabilitation

    Takahashi M, Takeda K, Otaka Y, Osu R, Hanakawa T, Gouko M, Ito K

    Proc 4th IMEKO TC 18 Symp Meas Anal Model Hum Funct     47 - 52  2010.06  [Refereed]

  • 近赤外線分光法(NIRS)によるWolf motor function test施行中の脳皮質血流測定

    倉山 太一, 山口 智史, 小宮 全, 大高 洋平, 武田 湖太郎, 大須 理英子, 田辺 茂雄, 清水 栄司

    脳科学とリハビリテーション   10   17 - 24  2010.04  [Refereed]

     View Summary

    WMFTはCI療法の治療効果判定を目的に開発された上肢運動機能評価である。今回WMFT運動課題の中から難易度の異なる3課題"Hand to table"、"Lift can"、"Lift pencil"を選択し課題施行中の運動学的解析を行うとともに、大脳皮質血中ヘモグロビン濃度長の変化について近赤外線分光法を用いて測定した。対象は健常成人13名とし、課題間の一次感覚運動野および補足運動野の活性化を比較した。結果"Lift pencil"においては"Hand to table"に比べて総軌跡長、ピーク速度、躍度が、また"Lift can"に比べてピーク速度、躍度が有意に低下し、補足運動野の皮質血流は"Lift pencil"が"Hand to table"よりも有意に増加することが観察された。本研究によりWMFT運動課題と皮質血流との関連が初めて示され、特に本研究で検討した3課題においては補足運動野の活動との関連が示唆された。(著者抄録)

  • ペダリング運動と経皮的電気刺激の併用治療の効果

    山口 智史, 藤原 俊之, 田辺 茂雄, 村岡 慶裕, 齊藤 慧, 小宅 一彰, 大須 理英子, 大高 洋平, 里宇 明元

    理学療法学   37 ( Suppl.2 ) 777 - 777  2010.03

  • Effects of pedaling exercise on disynaptic reciprocal Ia inhibition in healthy persons

    Kei Saito, Tomofumi Yamaguchi, Kazuaki Oyake, Shigeo Tanabe, Yoshihiro Muraoka, Rieko Osu, Kunitsugu Kondo, Yohei Otaka

    NEUROSCIENCE RESEARCH   68   E260 - E260  2010

    Research paper, summary (international conference)  

    DOI

  • Modification of effective connectivity of cerebro-cerebellar loop by movement of the opposing limb

    Yu Aramaki, Takanori Kochiyama, Rieko Osu, Daichi Nozaki

    NEUROSCIENCE RESEARCH   68   E373 - E373  2010

    Research paper, summary (international conference)  

    DOI

  • Effects of active pedaling exercise combined with electrical stimulation on spinal interneurons in healthy persons

    Tomofumi Yamaguchi, Toshiyuki Fujiwara, Kei Saito, Shigeo Tanabe, Yoshihiro Muraoka, Rieko Osu, Yohei Otaka, Kunitsugu Kondo, Meigen Liu

    NEUROSCIENCE RESEARCH   68   E260 - E260  2010

    Research paper, summary (international conference)  

    DOI

  • EEG current source estimation based on variational Bayes - a simulation study

    Takatsugu Aihara, Masa-aki Sato, Wataru Yasuda, Kotaro Takeda, Mitsuo Kawato, Rieko Osu

    NEUROSCIENCE RESEARCH   68   E333 - E333  2010

    Research paper, summary (international conference)  

    DOI

  • Intermittent visual feedback can boost visuomotor learning in rhythmic movements

    Tsuyoshi Ikegami, Masaya Hirashima, Rieko Osu, Daichi Nozaki

    NEUROSCIENCE RESEARCH   68   E105 - E105  2010

    Research paper, summary (international conference)  

    DOI

  • Load-dependent and abnormal lateralization during paretic finger movement: A NIRS-EEG study

    Kotaro Takeda, Wataru Yasuda, Takatsugu Aihara, Yohei Otaka, Masa-aki Sato, Mitsuo Kawato, Rieko Osu

    NEUROSCIENCE RESEARCH   68   E374 - E374  2010

    Research paper, summary (international conference)  

    DOI

  • Brain imaging of motor control activity using EEG and a combination of Hierarchical Variational Bayesian method and Sparse Logistic Regression

    Wataru Yasuda, Takatsugu Aihara, Kotaro Takeda, Okito Yamashita, Masaaki Sato, Yohei Otaka, Mitsuo Kawato, Rieko Osu

    NEUROSCIENCE RESEARCH   68   E332 - E332  2010

    Research paper, summary (international conference)  

    DOI

  • Initial training schedule pre-determines subsequent performanice in dual adaptation to conflicting environments

    Rieko Osu, Nicolas Schweighofer, Satomi Hirai, Toshinori Yoshioka, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   68   E148 - E148  2010

    Research paper, summary (international conference)  

    DOI

  • Electroencephalogram (EEG) measurement during ankle motion

    Takahashi M, Takeda K, Osu R, Otaka Y, Hanakawa T, Gouko M, Ito K

    Proc 3rd Int Symp Mobiligence     149 - 152  2009.11  [Refereed]

  • 脳卒中片麻痺患者の重度上肢麻痺に対するCHASE療法の効果

    大高 洋平, 大須 理英子, 山口 智史, 藤原 俊之, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   46 ( Suppl. ) S152 - S152  2009.05

  • 失語症患者における歌唱時の経時的脳活動 近赤外光を用いて

    數田 俊成, 大高 洋平, 大須 理英子, 山口 智史, 近藤 国嗣, 新城 吾朗, 宮田 知恵子, 辻川 将弘, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   46 ( Suppl. ) S227 - S227  2009.05

  • 異なる難易度の上肢運動課題時の脳皮質血流量の違い Wolf Motor Function Testを課題として用いて

    倉山 太一, 山口 智史, 大高 洋平, 田辺 茂雄, 大須 理英子, 坂田 祥子, 小宮 全, 須賀 晴彦, 影原 彰人, 清水 栄司

    理学療法学   36 ( Suppl.2 ) 790 - 790  2009.03

  • 経皮的電気刺激前後における運動イメージ中の運動誘発電位の変化

    木村 紀彦, 山口 智史, 大須 理英子, 田辺 茂雄, 影原 彰人, 須賀 晴彦, 近藤 国嗣, 大高 洋平

    理学療法学   36 ( Suppl.2 ) 1326 - 1326  2009.03

  • トレッドミル歩行速度の違いが脳皮質血流量変化に及ぼす影響

    井坂 俊洋, 山口 智史, 大須 理英子, 田辺 茂雄, 横山 明正, 近藤 国嗣, 大高 洋平

    理学療法学   36 ( Suppl.2 ) 203 - 203  2009.03

  • ペダリング運動前後の皮質脊髄路および単シナプス反射経路の興奮性変化

    齊藤 慧, 山口 智史, 田辺 茂雄, 大須 理英子, 横山 明正, 近藤 国嗣, 大高 洋平

    理学療法学   36 ( Suppl.2 ) 205 - 205  2009.03

  • 異なる歩行様式と速度における脳皮質血流量

    守屋 耕平, 大高 洋平, 山口 智史, 大須 理英子, 田辺 茂雄, 横山 明正, 近藤 国嗣

    理学療法学   36 ( Suppl.2 ) 765 - 765  2009.03

  • 重度片麻痺患者における両手・片手運動時の大脳皮質血流量

    山本 紗織, 山口 智史, 大高 洋平, 大須 理英子, 田辺 茂雄, 横山 明正, 近藤 国嗣

    理学療法学   36 ( Suppl.2 ) 908 - 908  2009.03

  • ペダリング運動とトレッドミル歩行における脳活動の比較 近赤外分光法を用いて

    山口 智史, 藤原 俊之, 斎藤 慧, 井坂 俊洋, 横山 明正, 田辺 茂雄, 大須 理英子, 大高 洋平, 近藤 国嗣, 里宇 明元

    理学療法学   36 ( Suppl.2 ) 251 - 251  2009.03

  • Initiation-related activity of the ventral putamen predicts future motor performance in bimanual coordination

    Yu Aramaki, Masahiko Haruno, Rieko Osu, Norihiro Sadato

    NEUROSCIENCE RESEARCH   65   S203 - S203  2009

    Research paper, summary (international conference)  

    DOI

  • Motor control strategy inferred from trajectory variance modulation

    Rieko Osu, Ken-ichi Morishige, Hirokazu Tanaka, Hiroyuki Miyamoto, Mitsuo Kawata

    NEUROSCIENCE RESEARCH   65   S103 - S103  2009

    Research paper, summary (international conference)  

    DOI

  • Push-recovery strategies implemented on a compliant humanoid robot

    Sang-Ho Hyon, Rieko Osu, Yohei Otaka, Jun Morimoto

    NEUROSCIENCE RESEARCH   65   S183 - S183  2009

    Research paper, summary (international conference)  

    DOI

  • 片手/両手運動による半球間抑制の変化

    補永 薫, 藤原 俊之, 大高 洋平, 大須 理英子, 辻 哲也, 近藤 国嗣, 長谷 公隆, 木村 彰男, 里宇 明元

    臨床神経生理学   36 ( 5 ) 577 - 578  2008.10

  • 失語症患者における歌唱時の脳活動 近赤外光を用いて

    数田 俊成, 大高 洋平, 大須 理英子, 山口 智史, 近藤 国嗣, 新城 吾朗, 宮田 知恵子, 児山 遊, 里宇 明元

    臨床神経生理学   36 ( 5 ) 595 - 595  2008.10

  • 運動イメージ中の経皮的電気刺激が大脳皮質血流量に与える影響

    山口 智史, 加藤 誠, 横山 明正, 田辺 茂雄, 村岡 慶裕, 大須 理英子, 大高 洋平, 藤原 俊之, 近藤 国嗣, 里宇 明元

    日本運動療法学会大会抄録集   33回   4 - 4  2008.06

  • 一側手指運動が半球間抑制に与える影響 健常成人における電気生理学的検討

    補永 薫, 藤原 俊之, 大高 洋平, 大須 理英子, 近藤 国嗣, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   45 ( Suppl. ) S215 - S215  2008.05

  • 片麻痺上肢へのアプローチ HANDS療法導入に際し、CHASE訓練が有効であった1例

    松浦 大輔, 藤原 俊之, 大須 理英子, 大高 洋平, 牛場 潤一, 長田 麻衣子, 辻 哲也, 近藤 国嗣, 長谷 公隆, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   45 ( Suppl. ) S140 - S140  2008.05

  • 重度失語症患者における歌唱時の脳活動 近赤外光を用いて

    數田 俊成, 大高 洋平, 大須 理英子, 近藤 国嗣, 新城 吾朗, 宮田 知恵子, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   45 ( Suppl. ) S211 - S211  2008.05

  • 重度片麻痺に対する新手法 CHASE療法の提案

    大高 洋平, 大須 理英子, 藤原 俊之, 牛場 潤一, 近藤 国嗣, 數田 俊成, 新城 吾朗, 宮田 知恵子, 里宇 明元

    The Japanese Journal of Rehabilitation Medicine   45 ( Suppl. ) S395 - S395  2008.05

  • 1075 負荷量の異なるペダリング運動中における脳活動の比較(理学療法基礎系,一般演題(ポスター発表演題),第43回日本理学療法学術大会)

    横山 明正, 山口 智史, 田辺 茂雄, 大高 洋平, 近藤 国嗣, 大須 理英子

    理学療法学   35 ( 2 ) 564 - 564  2008.04

    CiNii

  • メンタルプラクティスによる大脳皮質血流量の変化について

    加藤 誠, 山口 智史, 横山 明正, 田辺 茂雄, 大高 洋平, 近藤 国嗣, 大須 理英子

    理学療法学   35 ( Suppl.2 ) 800 - 800  2008.04

  • 随意運動中の電気刺激が大脳皮質血流量に及ぼす影響

    山口 智史, 加藤 誠, 横山 明正, 田辺 茂雄, 村岡 慶裕, 大須 理英子, 大高 洋平, 藤原 俊之, 近藤 国嗣, 里宇 明元

    理学療法学   35 ( Suppl.2 ) 798 - 798  2008.04

  • Motor improvement and corticospinal modulation induced by HANDS therapy in patients with chronic stroke

    Toshiyuki Fujiwara, Yoshihiro Muraoka, Tetsuya Tsuji, Rieko Osu, Kimitaka Hase, Msakado Yoshihisa, Meigen Liu

    NEUROSCIENCE RESEARCH   61   S167 - S167  2008

    Research paper, summary (international conference)  

  • Reconstruction of finger force from NIRS signal-Methodological perspective

    Isao Nambu, Rieko Osu, Soichi Ando, Masa-aki Sato, Eiichi Naito, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   61   S212 - S212  2008

    Research paper, summary (international conference)  

  • Quantitative evaluation of upper-limb control following stroke based on trajectory curvature

    Rieko Osu, Kazuko Ota, Toshiyuki Fujiwara, Maiko Osada, Daisuke Matsuura, Mari Ito, Yohei Otaka, Mitsuo Kawato, Meigen Liu

    NEUROSCIENCE RESEARCH   61   S167 - S167  2008

    Research paper, summary (international conference)  

  • 三次元動作解析を効果判定に用いて治療を行ったLance-Adams症候群の1例

    大高 洋平, 志沢 昭彦, 牛場 潤一, 大須 理英子, 川嶋 千香, 芝野 佳音里, 近藤 国嗣, 数田 俊成, 新城 吾朗, 宮田 知恵子, 里宇 明元

    臨床神経生理学   35 ( 5 ) 410 - 410  2007.10

  • Prediction for finger force from cortical activity measured by near-infrared spectroscopy (NIRS)

    Isao Nambu, Rieko Osu, Soichi Ando, Eiichi Naito, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   58   S128 - S128  2007

    Research paper, summary (international conference)  

    DOI

  • Isometric movement direction is encoded at the voxel level in human fMRI

    Todd Pataky, Rieko Osu, Hiroshi Imamizu, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   55   S124 - S124  2006

    Research paper, summary (international conference)  

  • Hierarchical representations for biological motor control

    Rieko Osu, Ken-ich Morishige, Jun Nakanishi, Hiroyuki Miyamoto, Mitsuo Kawato

    NEUROSCIENCE RESEARCH   55   S124 - S124  2006

    Research paper, summary (international conference)  

  • 健常人におけるつまずきの動作解析

    大高 洋平, 田村 貴行, 大須 理英子, 門脇 千智, 川人 光男, 里宇 明元

    臨床歩行分析研究会定例会抄録集   27回   38 - 39  2005.12

     View Summary

    転倒の様式としてもっとも頻度が多いつまずきに着目し,繰り返しの実験が可能なトレッドミル上において,ヒトが障害物につまずいた際の動作の分析を試みた.71回のつまずきのなかで,2回がElevating strategyでその他は,全てLowering strategyであった.上下肢ともにつまずきの約100ms以降に,strategyに関係すると思われる軌跡の変化を認めた.つまずき後は,歩行の位相が若干進むことが多かった.障害物の形状や大きさによって最終的に観察されるstrategyは異なることが示唆された

  • Relationship between finger-pinch force and motor activation : Comparison between NIRS with fMRI

    NAMBU Isao, OSU Rieko, NAITO Eiichi, KAWATO Mitsuo

    IEICE technical report. Neurocomputing   104 ( 758 ) 25 - 30  2005.03

     View Summary

    Previous studies using fMRI or PET in humans have shown that neuronal activity of the primary motor cortex (Ml) well reflects level of generated force by hand. In the present study, we investigated relationship between finger-pinch force and brain activity (Oxy-Hb) by utilizing near infrared spectroscopy (NIRS). We measured the motor cortical activity for 15 sec while four right-handed healthy subjects repetitively generated a target force {0.5, 1.5, 2.5 or 3.0} kgf with right thumb and index finger at 1 Hz. The activity in the contralateral primary motor cortex (Ml) was positively correlated with the level of force. We also measured BOLD signal with functional magnetic resonance imaging (fMRI) while the identical subjects performed the identical tasks. The Ml activity was also positively correlated with the level of force. The NIRS signal was strongly correlated with BOLD signal. These results suggest that NIRS can be a useful and convenient technique to measure human motor cortical activity.

    CiNii

  • Rhythmic arm movement is not discrete (vol 7, pg 1136, 2004)

    S Schaal, D Sternad, R Osu, M Kawato

    NATURE NEUROSCIENCE   7 ( 11 ) 1279 - 1279  2004.11

    Other  

    DOI

  • Random presentation enables subjects to adapt to two opposing forces on the hand (vol 7, pg 111, 2004)

    R Osu, S Hirai, T Yoshioka, M Kawato

    NATURE NEUROSCIENCE   7 ( 3 ) 314 - 314  2004.03

    Other  

  • 幻肢感覚が身体に多発出現した右上肢切断症例の脳機能画像による検討

    大高 洋平, 大須 理英子, 千野 直一, 川人 光男

    リハビリテーション医学   40 ( Suppl. ) S191 - S191  2003.05

  • 筋活動の変化に対する適応 力制御課題施行中の筋へ,電気刺激を外乱として用いて

    大高 洋平, 大須 理英子, 道免 和久, 千野 直一, 吉岡 利福, 川人 光男

    リハビリテーション医学   39 ( Suppl. ) S363 - S363  2002.04

  • Decomposition and composition of multiple inernal models.

    中野恵理, FLANAGAN R, 今水寛, 大須理英子, 吉岡利福, 川人光男

    電子情報通信学会技術研究報告   98 ( 219(NC98 30-42) ) 17 - 24  1998.07

     View Summary

    The learning process of reaching movements was examined under novel environments whose kinematic and dynamic properties were altered. We used kinematic transformation of rotations, dynamic transformation using a viscous force field, and a combination of these transformations. When subjects learned the combined transformation after learning the kinematic and dynamic transformations separately, target errors and trajectory curvatures were smaller than those without prior separate learning. The target errors and trajectory curvatures in kinematic or dynamic transformation after learning the combination were smaller than those before learning it. These results suggest that the CNS learns multiple internal models to compensate for each transformation and composes or decomposes these models as occasion calls.

    CiNii J-GLOBAL

  • Changes in Muscle Activation during Motor Learning.

    大須理英子, 道免和久, 五味裕章, 吉岡利福, 今水寛, 川人光男

    電子情報通信学会技術研究報告   96 ( 583(NC96 113-154) ) 201 - 208  1997.03

     View Summary

    We observed changes of muscle activation and hand trajectories during motor learning. Subjects were asked to learn planar reaching movement which included a via-point while EMG and position data were recorded. Arm stiffness was estimated from the sum of flexor muscle torque and extensor muscle torque reconstructed from EMG. Joint torque was also calculated from hand position data. As learning proceeded, muscle activation decreased, although, in some case, there was little change in the joint torque profile. The results suggest that learning enables us to realize similar trajectories with lower arm stiffness.

    CiNii J-GLOBAL

  • Quantitative examination of trajectory planning criteria based on many data of trajectories. (II).

    中野恵理, 今水寛, 大須理英子, 宇野洋二, 五味裕章, 吉岡利福, 川人光男

    電子情報通信学会技術研究報告   96 ( 583(NC96 113-154) ) 217 - 224  1997.03

     View Summary

    We quantitatively compared actual point to point planer movements constrained to pass through a via-point to the movements predicted by three models ; 1)minimum hand jerk model, 2)minimum angle jerk model and 3)minimum torque change model. We defined the difference between the tangential velocity of unconstrained point to point movement and that of via-point movement as a distortion of tangential velocity. The distortion of tangential velocity varied with workspace and whether the position of the via-point was set near or far from body. Furthermore, we studied how learning effected distortion as the via-point varied in distance from the center midline separating the start and end points. If the via-point was at approximately the center between start and end point, then learning caused the tangential velocity profile to approach that found in unconstrained point to point movement. However, if the via-point was placed near the body, then the learned movements had a velocity profile that was dissimilar with that found in unconstrained point to point movements. This pattern of results is similar with that predicted by minimum torque change model.

    CiNii J-GLOBAL

  • Quantitative examination of trajectory planning criteria based on many data of trajectories.

    中野恵理, 今水寛, 大須理英子, 宇野洋二, 五味裕章, 吉岡利福, 川人光男

    電子情報通信学会技術研究報告   96 ( 430(NC96 58-77) ) 111 - 118  1996.12

     View Summary

    We quantitatively and statistically compared actual point to point movements to movements predicted by three models; 1) minimum hand Jerk model, 2) minimum angle Jerk model and 3) minimum torque change model. Hand trajectories were measured in various initial and final positions located within a large workspace. These actual trajectories were compared with simulated trajectories for each model by using a curvature index and the sum of square difference between actual and simulated movement. Results confirmed that the minimum torque change model predicted the trajectories closest to the measured ones with respect to spatial and temporal aspects. The results of this experiment supported the hypothesis that hand traJectory is planned in intrinsic-dynamic space. Furthermore, it is considered that hand traJectory is planned to minimize the torque change which depends on change of viscosity.

    CiNii J-GLOBAL

  • 運動軌道データから計算される評価関数による軌道計画規範の検討

    大須理英子, 宇野洋二, 小池康晴, 川人光男

    電子情報通信学会技術研究報告. NC, ニューロコンピューティング   96 ( 331 ) 71 - 78  1996.10

     View Summary

    腕の到達運動における軌道計画の規範として, 作業座標系に基づいた手先躍度最小, 身体座標系に基づいた関節角躍度最小, トルク変化最小, 運動指令変化最小などの評価関数が提案されている. 実現された軌道から算出した評価関数の値は, 軌道計画における規範をある程度反映していると考えられる. ある評価関数の値が, 自然に動かした場合よりもそれ以外の場合に低ければ,「中枢がその評価関数を最小にするような軌道を計画する」と考えるのは適切ではない. ある評価関数の値が, 自然に動かした場合にそれ以外の場合に比べて低ければ, その評価関数は軌道計画の規範の候補となりえる. 本研究では, 自然に動かした場合の軌道とそれ以外の場合の軌道における評価関数の値を比較することで, 各規範の妥当性を検討した.

    CiNii

  • Teaching By Showing for Task Level Robot Learning.

    宮本弘之, 今水寛, 大須理英子, 琴坂信哉, SCHAAL S, 川人光男

    電子情報通信学会技術研究報告   96 ( 331(NC96 39-49) ) 63 - 70  1996.10

     View Summary

    A general theory of movement pattern perception based on dynamic optimization theory can be used for motion capture, movement pattern recognition, and teaching by showing in robotics. We integrated three ingredients for tennis serve executed by the SRC (Sarcos Research Corporation) arm which has exactly the same kinematic structure as the human arm. (1)via-points extraction from human movement trajectory using forward-inverse relaxation model (FIRM), (2)computational understanding of tennis serve so that only a few via points have the essential roles for successful execution, (3)treat these via-points as a control variable while reconstructing desired trajectory from all the via-points. We demonstrated that the arm can execute tennis serve with this strategy.

    CiNii J-GLOBAL

  • The curvature of hand paths in multi-joint reaching movements: dependence on arm posture.

    中野恵理, 今水寛, 大須理英子, 宇野洋二, 川人光男

    電子情報通信学会技術研究報告   96 ( 178(NC96 22-38) ) 55 - 62  1996.07

     View Summary

    We examined if the curvature of a trajectory quantitatively varies with arm posture when humans make point ot point multi-joint reaching movements on a horizontal plane. It has been discussed whether trajectories of the human arm are planned in extrinsic space or in intrinsic space. Hand paths planned in the former are predicted to be always straight, while those in the latter are gentlly curved. In the previous studies, it has been reported that actual hand paths tended to significantly curve for some specific arm postures, movement distances, and movement durations. We have extended the previous studies using various initial and final positions located within a workspace. The trajectory curvature was finearly estimated from elbow and shoulder joint angles at initial and final positions. These results suggest that trajectory curvature depends on arm posture and is in accordance with predictions made under planning in the intrinsic space, rather than in the extrinsic space.

    CiNii J-GLOBAL

  • ケン玉ロボットの開発

    宮本弘之, 大須理英子, 中野恵理, 川人光男, GANDOLFO F, 五味裕章, SCHAAL S, 小池康晴, 和田安弘

    発明   92 ( 6 ) 44 - 49  1995.06

    J-GLOBAL

  • 最適化原理に基づく見まねによるけん玉学習

    宮本弘之, GANDOLFO F, 五味裕章, SCHAAL S, 小池康晴, 大須理英子, 中野恵理, 和田安弘, 川人光男

    電子情報通信学会技術研究報告   94 ( 563(NC94 114-155) ) 223 - 230  1995.03

    J-GLOBAL

▼display all

Awards

  • 優秀研究賞

    2016   日本神経回路学会  

  • The Best Paper Award

    2007   ICONIP  

  • 奨励賞

    2004   日本神経科学学会  

  • ATR表彰

    2003   株式会社国際電気通信基礎技術研究所  

  • 研究賞

    2002   日本神経回路学会  

Research Projects

  • A cohort study of mental habit and brain in middle-aged people: Aiming to predict and improve mental health

    Project Year :

    2020.04
    -
    2025.03
     

  • 新規非侵襲的脳刺激が拓くネオ・リハビリテーションとそのシステム脳科学的解明

    Project Year :

    2019.04
    -
    2023.03
     

     View Summary

    本研究の目的は、新規非侵襲的脳刺激法(NIBS)を従来のリハと組み合わせた革新的な手法(ネオ・リハビリテーション)を開発し、その生理機構をシステム脳科学の観点から解明することである。新規NIBSとして静磁場刺激法(tSMS)とtDCSを応用したパターン電流刺激法を検討し、脳波での領域間結合測定によって脳機能ネットワークへの影響を明らかにし、動物実験による生理機構解明を目指す

  • 対人インタラクションにおける脳・身体同期への文化差の影響

    Project Year :

    2020.04
    -
    2022.03
     

     View Summary

    対人インタラクションの場面において、脳活動が同期したり、身体が協調的に動いたりすることが知られている。では、このような脳-身体の同期協調ダイナミクスに、文化や文化差はどのような影響をもたらすのであろうか。心理的・社会的な文化差や、身体表現・身体コミュニケーションの文化差の影響を受けるであろうか。それとも、異文化の人どうしが向き合ったときに、文化の壁を越えた同期や協調が観察されるのであろうか。本研究提案では、対人インタラクション課題における脳活動および身体の同期協調ダイナミクスについて、同文化間のペアと異文化間のペアで比較することで、無意識的な社会的相互作用に及ぼす文化的影響を考察する

  • 脳刺激やモチベーション操作による障害側身体空間を志向する神経回路の活性化

    Project Year :

    2020.04
    -
    2022.03
     

     View Summary

    脳卒中などの中枢神経系の損傷による機能障害を回復し、その機能を維持するためには、障害を受けた機能そのものを回復するだけではなく、障害を受けた身体空間に注意を向け、日常生活の中で、その部位を意識せずとも積極的に使用したくなる気持ちを醸成することが必要である。すなわち、嫌悪し無視しがちな障害側の身体や空間に対する志向性、preferenceを向上させることが重要である。そこで、本研究課題では、脳刺激による神経モジュレーションやVR技術をつかった空間の操作、モチベーションの操作により、障害側の身体空間へのpreference神経回路を顕在化・活性化する手法とメカニズムを明らかにすることを目指す

  • Using attentional function to detecting early stage of mental illness and recovery from it

    Project Year :

    2019.04
    -
    2022.03
     

  • 中枢神経疾患後の機能障害の進行と回復過程への学習メカニズムの関与

    Project Year :

    2017.04
    -
    2022.03
     

     View Summary

    1)麻痺手の使用を促進する訓練システムの開発と検証: 麻痺手の機能を訓練する手法は多く提案されているが、麻痺手の使用確率の向上をメインのターゲットとした訓練手法はあまり提案されていない。本項目では、左右どちらの手を使ってもよいからできるだけ速く正確にターゲットをヒットするという課題に、難易度を調整したり麻痺手をアシストしたりして、行動変容(使用確率向上)に貢献し、使用を促進する訓練装置を開発することを目的としている。本年度は、末梢へ電気刺激を加えて選択を変化させる実験システムを構築し、予備実験を実施した。その結果、選択の直前に触覚刺激を付加することで、左右の手の選択率が変化する可能性が示唆された。2)脳刺激による麻痺手の使用向上可能性の探索: 経頭蓋直流電気刺激により、一過的に脳活動を調整することが可能である。一般的に、陽極刺激は脳活動を促進し、陰極刺激は抑制すると言われており、それに対応して、運動野に陽極をおいた場合はその対側の手が使われやすく、陰極をおいた場合は同側の手が使われやすい傾向にあることが報告されている。本年度は、運動野より高次な選択の中枢と考えられている後頭頂葉をターゲットとした刺激を行う実験を実施した。経頭蓋直流電気刺激を付加し、その前後に、右手、左手どちらかの手を自分で決めてターゲットに向かってリーチする課題を実施した。その結果、左の後頭頂葉に陰極を配置して脳活動を抑制し、右の後頭頂葉に陽極を配置して脳活動を賦活した場合には、左手の選択率が上昇することが判明した。一方、逆に、右の後頭頂葉に陰極を配置し、左の後頭頂葉に謡曲を配置した場合には、選択率には変化が認められなかった。これらのことから、手の選択には、左の後頭頂葉がより深く関わっていることが示唆された。年内は比較的順調に進めることができたが、2月以降、新型コロナのため、実験が中断し、進捗が鈍っている。2)麻痺手の使用を促進する訓練システムの開発と検証: 実験環境を整え予備実験を開始することができた。しかし、新型コロナのため、2月以降、実験を中断せざるを得なかった。3)脳刺激による麻痺手の使用向上可能性の探索: 大学院生とともに本実験を実施し、論文執筆まで進めることができた。本年度は、すでに取得したデータについては、論文の投稿と掲載を進める。実験については、可能になり次第、再開する。1)麻痺手の使用を促進する訓練システムの開発と検証: 末梢への電気刺激を使用して左右の手の選択にバイアスを加える実験について、すでに予備実験において、ある程度の効果が得られる可能性が示唆されているので、実験再開が可能になり次第、本実験に着手する。3)脳刺激による麻痺手の使用向上可能性の探索: 左右の後頭頂葉に経頭蓋磁気刺激の電極を同時に配置した実験については、すでに論文の執筆を進めており、投稿、掲載を目指す。また、より刺激脳部位を限定することが可能な高精細経頭蓋磁気刺激を使用して、左右の後頭頂葉を別々に独立して刺激する実験について、電極の形状や配置などの検討を始めており、実験再開が可能になり次第、予備実験に着手する

  • 個体間脳波オシレーションのニューロフィードバックコントロール

    Project Year :

    2018.04
    -
    2020.03
     

     View Summary

    本研究課題では、ブレインマシンインターフェース技術やニューロフィードバック技術を社会神経科学に導入し、二者間の脳波同期レベルをリアルタイムフィードバックスするシステムを構築する。同期レベルをモニターしながら二者が様々なインタラクションを試みることで、どのような条件で個体間の脳波の同期がおこるのかを探索することを目指す。本年度は、オフラインの同時計測について、本実験を実施した。また、リアルタイム処理NFシステムを構築した。<NFシステム設計> LSLを使用して16チャンネルの脳波計(OpenBCI)2台を同期させ、二個体の脳波をリアルタイム表示しフィードバックするシステムを構築した。<二個体間脳波同期の要因の探索> 二人が交互タッピング課題を行っている際の脳波を、Quick30を用いて29チャンネルずつ同時計測した。タッピングはマウスを用いて早いテンポ、テンポ、任意のテンポで実施し、音によるフィードバックで相手とタイミングを合わせられるように設定した。脳波に加え、タッピングの速さや精度、社会性を測る指標(Social Skills Inventory(SSI))、自閉症スペクトラム指数(AQ)、相手との心理的距離を評価する指標(VAS)を取得した。各被験者の脳内の部位間での同期、二人の脳と脳の間での同期を、Circular Correlation Coefficient (CCorr)、Phase Lag Index(PLI)などの、同期を測る指標を使用して評価した。その結果、二人の社会性の関係性や、ダッピングのパフォーマンスと、脳波同期が関連している可能性が示唆された。令和元年度が最終年度であるため、記入しない。令和元年度が最終年度であるため、記入しない

  • Anatomo-functional investigation of ventral language pathway: A combined electrocorticographic recording and stimulation study

    Project Year :

    2014.04
    -
    2018.03
     

     View Summary

    The ventral language pathway has been recently highlighted with regards to language comprehension. However, its anatomy including connectivity, functions, and plasticity still remain elusive. We aimed to reveal their details by means of a multidisciplinary approach. We applied invasive neurophysiology, neuropsychology and neuroimaging methods to patients who underwent presurgical evaluation of epilepsy/tumor surgery. In this study, (i) we revealed that the ventral part of the anterior temporal lobe plays a crucial role in semantic cognition, (ii) we delineated the functional connectivity of the ventral fronto-temporal pathway by means of cortico-cortical evoked potential recording, and (iii) we could obtain the evidence for the dynamic reorganization of semantic processing from the longitudinal neuropsychological assessments in the patients with the resection of anterior temporal lobe

  • Prediction of finger movements from electroencephalogram for constructing a virtual keyboard using brain signals

    Project Year :

    2014.04
    -
    2017.03
     

     View Summary

    In this research, we explored a possibility to make a virtual keyboard system using brain signals. First, we measured brain activity using an electroencephalogram (EEG) and showed a possibility for decoding individual finger movements or its imagery from EEG signals. Next, using functional magnetic resonance imaging, we found that types of sequential finger movements can be decoded from preparatory brain activities in the premotor and supplementary motor areas contralateral to the moving hand. Finally, we proposed a method for reduction of systemic artifacts from scalp layers in functional near-infrared spectroscopy and evaluated its effectiveness. Taken all together, our results suggest that we can predict finger movements from non-invasive brain imaging techniques. This techniques could be used for constructing a brain-based virtual keyboard in future

  • ブレインマシンインターフェース技術によるてんかん発作予防訓練システムの開発

    公益財団法人立石科学技術振興財団  研究助成(A)

    Project Year :

    2014
     
     
     

  • 計算神経リハビリテーションの創出による脳可塑性解明とテーラーメードリハビリの提案

    内閣府  最先端・次世代研究開発支援プログラム

    Project Year :

    2011
    -
    2013
     

  • 高齢者のストレスレス・ネットワークを実現する感覚運動オーグメンテーション技術の研究開発

    総務省  戦略的情報通信研究開発推進制度

    Project Year :

    2006
    -
    2008
     

  • 安定な対象物操作を可能にする上肢インピーダンスの制御と最適化

     View Summary

    インピーダンス制御と内部モデル制御の統合的学習モデル従来の学習モデルでは、インピーダンス制御と内部モデル制御を同時に獲得することは不可能であった。そこで、本プロジェクトでは、生理学的データに基づく3つの法則から、新たな学習モデルを提案し、それを実験的に検証すると同時に計算機シュミレーションを実施した。その計算機シュミレーション部分が英語論文として掲載された。さらに実験部分に関する論文を投稿し現在修正中である。タスクの拘束とインピーダンス制御正確さが要求されるとき、前もってインピーダンスを上昇させるという考え方に対して、最適フィードバック則に則りオンラインで軌道修正を行っている考え方が最近提案されている。そこで本プロジェクトでは、到達運動において運動の中央部分に通過目標点を設定し、筋電図信号を測定することで、精度の要求に対してインピーダンス制御で対応しているのか最適フィードバック制御で対応しているのかを調べた。その結果、インピーダンス制御をしている可能性の方が高まった。結果は2本の日本語論文として掲載された。インピーダンス制御の神経機構の解明内部モデル制御に関わる神経機構については徐々に明らかになっているが、インピーダンス制御に関わる神経機構については研究されていない。主な理由は、今まで機能的磁気共鳴画像装置(fMRI)内で被験者にインピーダンス制御を実現させることのできる装置が無かったことである。そこで本プロジェクトでは、新たに開発した1自由度fMRI対応マニピュランダムで被験者の手首に2Hzの正弦波で振動する力を加えた結果、被験者に様々なレベルのインピーダンスを実現させることが可能となった。現在、実験を終了し、論文を準備中である

▼display all

Presentations

  • リハビリテーション医学への計算神経科学の導入例

    大須理英子  [Invited]

    日本リハビリテーション医学会学術集会  (神戸)  日本リハビリテーション医学会

    Presentation date: 2019.06

     View Summary

    共催シンポジウム:Novel findings from Bench to Bedside~リハビリテーション医学における神経可塑性研究の最前線 (共催:エーザイ)

  • 「脳機能計測とニューロリハビリテーション」 リハビリテーション医学と計算神経科学の融合の先にあるもの

    大須理英子  [Invited]

    高崎健康福祉大学公開講座  (高崎)  高崎健康福祉大学

    Presentation date: 2019.03

  • Human motor control / learning and neurorehabilitation

    Rieko Osu  [Invited]

    OIST workshop, Neuronal circuits in motor behavior  (Okinawa)  The Okinawa Institute of Science and Technology Graduate University

    Presentation date: 2019.02

  • 脳・認知機能系の話題提供

    大須理英子  [Invited]

    東京医科歯科大学—早稲田大学連携ワークショップ  (東京)  早稲田大学

    Presentation date: 2017.07

  • 脳科学は世の役に立つのか?

    大須理英子  [Invited]

    オープンフォーラムVol.3技術経営(MOT)の新潮流-脳科学とICTの融合によるビジネスの可能性-  (大阪)  立命館大学テクノロジーマネジメント研究科

    Presentation date: 2017.03

  • 脳科学の社会活用への試みと課題ーリハビリやマーケティングを例としてー

     [Invited]

    応用脳科学シンポジウム2017  (東京)  早稲田大学応用脳科学研究所

    Presentation date: 2017.02

  • What does society expect from neuroscience?

    Rieko Osu  [Invited]

    Friday lunch seminar  (Osaka)  The Center for Information and Neural Networks (CiNet)

    Presentation date: 2015.07

  • 「学」から「産」へ

    大須理英子  [Invited]

    産学連携シンポジウム「応用脳科学に求められる人材育成」  第39回日本神経科学大会

    Presentation date: 2015.07

  • ニューロリハビリテーションの現状と将来

     [Invited]

    第52回医工学研究会  (千葉)  千葉大学フロンティア医工学センター

    Presentation date: 2014.12

  • 脳とリハビリテーション

    企画シンポジウム「脳から知る心と体の現在・過去・未来-個性の理解から教育・スポーツ・リハビリへの応用まで-」  日本心理学会第78回大会

    Presentation date: 2014.09

  • Understanding the brain function through computational neuroscience

    Rieko Osu  [Invited]

    Summer School on Neurorehabilitation, Plenary lecture  (Baion, Spain)  Spanish National Research Council (CSIC)

    Presentation date: 2014.09

  • リハビリテーションと脳と運動学習

    大須理英子  [Invited]

    Japan Society for motor Control and Neuro-rehabilitation 

    Presentation date: 2014.08

  • 計算-神経-リハビリテーションの試み:「計算」をつけるとメリットがある?

    大須理英子  [Invited]

    (大阪)  身体性情報学研究会

    Presentation date: 2013.10

  • How do humans choose one arm from the other?

    大須理英子  [Invited]

    神経オシレーションカンファレンス シンポジウム  (愛知)  自然科学研究機構

    Presentation date: 2013.07

  • Exploring Optimal Neurofeedback for Rehabilitation

    Rieko Osu  [Invited]

    Minisymposium on Robot-Assisted and BMI-Based Neurorehabilitation  (Osaka)  The 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC’13)

    Presentation date: 2013.07

  • Behavioral simulation and computational model of stroke rehabilitation and recovery process

    大須理英子

    Symposium on Integration of computational sensorimotor control and rehabilitation  (京都)  第36回日本神経科学大会

    Presentation date: 2013.06

  • 脳とリハビリテーション

    大須理英子  [Invited]

    けいはんな情報通信フェア  (京都) 

    Presentation date: 2012.11

  • Stroke rehabilitation inspired by computational neuroscience

    Rieko Osu  [Invited]

    workshop "Robotics for neuro-rehabilitation: challenges for improving impact on clinical practice"  (Rome, Italy)  IEEE International Conference on Biomedical Robotics and Biomechatronics (BIOROB 2012)

    Presentation date: 2012.06

  • Stroke rehabilitation inspired by motor learning, motor learning theory inspired by rehabilitation

    Rieko Osu  [Invited]

    IMN Seminar  (London, UK)  Institute of Movement Neurosceince, UCL

    Presentation date: 2012.06

  • Watching brain activity during rehabilitation

    Rieko Osu  [Invited]

    Workshop on Rehabilitation Engineering  (Seoul, Korea)  Korea Institute of Science and Technology (KIST)

    Presentation date: 2011.12

  • 運動制御、学習のモデルはリハビリテーションに役立つのか?

    大須理英子  [Invited]

    (静岡)  第41回日本臨床神経生理学会学術大会

    Presentation date: 2011.11

  • Estimating brain activity during rehabilitation

    Rieko Osu  [Invited]

    Workshop on Motor Intention and Sensory Feedbacks in Rehabilitation  (Zurich, Switzerland)  Rehab Week Zurich / IEEE 12th International Conference on Rehabilitation Robotics (ICORR2011)

    Presentation date: 2011.06

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Specific Research

  • 非侵襲脳刺激法による前頭前野を中心とした脳活動モジュレーション

    2020   熊野宏昭, 髙橋徹

     View Summary

    前頭前野の脳活動は緊張や不安に関わっていることが知られている。近赤外分光計測法(fNIRS)を使用し、社交不安が高いと右前頭極の血流が増加することが示されている。そこで、本研究では、前頭前野や連携する脳部位を非侵襲脳刺激法である経頭蓋静磁場刺激(tSMS)によって修飾することで、社交不安に改善が見られるかどうかを検証するための予備的実験を実施した。また、期待するように脳活動が修飾されているかどうかを確認するために、刺激の前後で近赤外分光計測法により脳活動の変化をモニターした。その結果、tSMSにより、社交不安の要因である主観的な⾃⼰注⽬状態の緩和に繋がる可能性が⽰唆された。

  • 身体活動を伴うヨガの実践による脳の変化

    2019   津野 千枝, 緒方 洋輔

     View Summary

    メディテーションによる効果や、その神経基盤についての研究は盛んに行われ、精神疾患などの治療に使われるまでになっている。また、身体活動によって海馬や前頭前野の質量が増加することも近年の研究で明らかになっている。身体活動、呼吸の調整に加え、瞑想の側面も併せ持つメソッドであるハタヨガはそれらと共通する効果や脳構造の変化などが見られことが想像できるが、神経基盤についての研究は少ない。そこで、健常成人のヨガ初心者18名において、3ヶ月のヨガクラスを実践し、クラス開始前と実施した後、磁気共鳴画像装置(MRI)にて脳画像を撮像し、構造画像によりクラス前後の灰白質の容積変化を評価した。

  • 入力情報の文化差で生じる顔身体認知・行動の相違を深層学習で検証する

    2018   松居辰則

     View Summary

    本研究は、文化圏ごとに人工知能を設計し、各文化圏に対応した画像・動画を入力することで、顔や身体に対する認知の文化差が再現できるかどうかを検証することを目指す。その準備のため、深層学習を実施するGPUを整備した計算機環境を構築した。深層学習の実装にはPyTorchを使用した。これらを使用し、試験的に深層学習を用いた画像の判別実験を実施した。具体的には、CNN(畳み込みニューラルネットワーク)を使用し、画像からエリアの数を学習する課題を行い、その汎化特性を検証した。これらの結果をもとに、文化差を検証する方法と使用するデータベースについての研究打合せを実施した。

  • 脳波による内部状態の推定と反応の予測

    2017  

     View Summary

    日々の生活は、意思決定・行動選択の連続である。判断は論理的な計算に基づく部分もあるが、意識にのぼらない脳の内部状態が重要な役割を果たしている。このような内部状態を推定し、その後の判断を予測することができれば、脳内機序の解明と同時に行動の改善などに広く応用可能である。そこで、脳波と機械学習を用いて、意思決定を事前の脳内状態から予測できるかどうかを検討した。具体的には、左右の手の選択を伴うリーチング課題において、ターゲット提示前の自発脳波から手の選択を判別したところ、正答率はチャンスレベルより高かった。脳の内部状態の揺らぎが手の選択に影響を及ぼす可能性が示唆された。

 

Syllabus

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Committee Memberships

  • 2017
    -
     

    Japanese Neural Network Society  board member

  • 2017
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    日本神経回路学会  理事