Recently, several new materials for mattresses have been introduced. Although some of these, such as low rebound (pressure-absorbing/memory foam) and high rebound mattresses have fairly different characteristics, effects of these mattresses on sleep have never been scientifically evaluated. In the current study, we have evaluated effects of a high rebound mattress topper [HR] on sleep and its associated physiology, and the effects were compared to those of a low rebound mattress toppers (LR) in healthy young (n = 10) and old (n = 20) adult males with a randomized, single-blind, cross over design. We found that sleeping with HR compared to LR induced a larger decline in core body temperature (CBT) in the initial phase of nocturnal sleep both in young (minimum CBT: 36.05 vs 36.35°C) and old (minimum CBT: 36.47 vs. 36.55°C) subjects, and declines in the CBT were associated with increases in deep sleep/delta power (+27.8% in young and +24.7% in old subjects between 11:00-01:00). We also found significantly smaller muscle activities during roll over motions with HR (-53.0 to -66.1%, depending on the muscle) during a separate daytime testing. These results suggest that sleeping with HR in comparison to with LR, may facilitate restorative sleep at the initial phase of sleep.

Psychological studies have shown that when individuals move their gaze between two alternative objects, they tend to choose the object that holds their gaze for longer (the gaze-manipulation effect). This effect is especially evident when both alternatives appeal to the viewer. We hypothesized that if individuals have an interest in sports and/or fashion, and thus view varieties of sportswear favorably, then gaze manipulation would influence their choice. Japanese university students participated in our experiments. The participants made preference choices between two uniforms of European football teams, which were presented alternately across the left and right sides of a computer screen six times for different durations (900 ms vs. 300 ms). They were required to compare the uniforms with or without fixing their gaze directly on them. They also completed questionnaires designed to assess their interest in football and fashion. The results showed that the gaze-manipulation effect was not significant across all participants or across those participants who merely liked fashion, or who merely watched football or casually played it. However, the effect was significant in participants who had been members of football teams. Our results suggest that application of the gaze-manipulation technique would be more effective for visual advertisement of sports items if it was focused on sports players.<br>

The effects of sleep restriction on energy metabolism and appetite remain controversial. We examined the effects of shortened sleep duration on energy metabolism, core body temperature (CBT), and appetite profiles. Nine healthy men were evaluated in a randomised crossover study under two conditions: a 3.5-h sleep duration and a 7-h sleep duration for three consecutive nights followed by one 7-h recovery sleep night. The subjects' energy expenditure (EE), substrate utilisation, and CBT were continually measured for 48 h using a whole-room calorimeter. The subjects completed an appetite questionnaire every hour while in the calorimeter. Sleep restriction did not affect total EE or substrate utilisation. The 48-h mean CBT decreased significantly during the 3.5-h sleep condition compared with the 7-h sleep condition (7-h sleep, 36.75 ± 0.11 °C; 3.5-h sleep, 36.68 ± 0.14 °C; p = 0.016). After three consecutive nights of sleep restriction, fasting peptide YY levels and fullness were significantly decreased (p = 0.011), whereas hunger and prospective food consumption were significantly increased, compared to those under the 7-h sleep condition. Shortened sleep increased appetite by decreasing gastric hormone levels, but did not affect EE, suggesting that greater caloric intake during a shortened sleep cycle increases the risk of weight gain.

Procedural learning is subject to consolidation processes believed to depend on the modulation of functional connections involved in representing the acquired skill. While sleep provides the most commonly studied framework for such consolidation processes, posttraining modulation of oscillatory brain activity may also impact on plasticity processes. Under the hypothesis that consolidation of motor learning is associated with theta band activity, we used EEG neurofeedback (NFB) to enable participants to selectively increase either theta or beta power in their EEG spectra following the acquisition phase of motor sequence learning. We tested performance on a motor task before and after training, right after the NFB session to assess immediate NFB effects, 1 day after NFB to assess interaction between NFB effects and overnight sleep-dependent stabilization, and 1 week after the initial session, to assess the effects of NFB on long-term stabilization of motor training. We also explored the extent of the influence of single-electrode NFB on EEG recorded across the scalp. Results revealed a significantly greater improvement in performance immediately after NFB in the theta group than in the beta group. This effect continued for testing up to 1 week following training. Across participants, post-NFB improvement correlated positively with theta/beta ratio change achieved during NFB. Additionally, NFB was found to cause widespread band-power modulation beyond the electrode used for feedback. Thus, upregulating postlearning theta power may yield contributions to the immediate performance and subsequent consolidation of an acquired motor skill.

The present study is aimed to ascertain whether differences in meditation proficiency alter rapid eye movement sleep (REM sleep) as well as the overall sleep-organization. Whole-night polysomnography was carried out using 32-channel digital EEG system. 20 senior Vipassana meditators, 16 novice Vipassana meditators and 19 non-meditating control subjects participated in the study. The REM sleep characteristics were analyzed from the sleep-architecture of participants with a sleep efficiency index >85%. Senior meditators showed distinct changes in sleep-organization due to enhanced slow wave sleep and REM sleep, reduced number of intermittent awakenings and reduced duration of non-REM stage 2 sleep. The REM sleep-organization was significantly different in senior meditators with more number of REM episodes and increased duration of each episode, distinct changes in rapid eye movement activity (REMA) dynamics due to increased phasic and tonic activity and enhanced burst events (sharp and slow bursts) during the second and fourth REM episodes. No significant differences in REM sleep organization was observed between novice and control groups. Changes in REM sleep-organization among the senior practitioners of meditation could be attributed to the intense brain plasticity events associated with intense meditative practices on brain functions.

PURPOSE: The purpose of this study was to evaluate the effects of five nights' sleep under normobaric hypoxia on ventilatory acclimatization and sleep quality. METHODS: Seven men initially slept for six nights under normoxia and then for five nights under normobaric hypoxia equivalent to a 2000-m altitude. Nocturnal polysomnograms (PSGs), arterial blood oxygen saturation (SpO2), and respiratory events were recorded on the first and fifth nights under both conditions. RESULTS: The hypoxic ventilatory response (HVR), hypercapnic ventilatory response (HCVR), and resting end-tidal CO2 (resting PETCO2) were measured three times during the experimental period. The duration of slow-wave sleep (SWS: stage N3) and the whole-night delta (1-3 Hz) power of nonrapid eye movement (NREM) sleep EEG decreased on the first night under hypoxia. This hypoxia-induced sleep quality deterioration on the first night was accompanied by a lower mean and minimum SpO2, a longer time spent with SpO2 below 90% (<90% SpO2 time), and more episodes of respiratory disturbance. On the fifth night, the SWS duration and whole-night delta power did not differ between the conditions. Although the mean SpO2 under hypoxia was still lower than under normoxia, the minimum SpO2 increased, and the <90% SpO2 time and number of episodes of respiratory disturbance decreased during the five nights under hypoxia. The HVR increased and resting PETCO2 decreased after five nights under hypoxia. CONCLUSIONS: The results suggest that five nights under hypoxia improves the sleep quality. This may be derived from improvements of respiratory disturbances, the minimum SpO2, and <90% SpO2 time.

The present study evaluated whether slow-wave sleep and whole-night delta power of the non-rapid eye movement (NREM) sleep electroencephalogram (EEG) decrease during sleep at a simulated altitude of 2000 m, and whether such changes related to measures of hypoxic ventilatory response (HVR). This study consisted of two parts; in the first, HVR was measured in 41 subjects and each seven subjects with the lowest or the highest HVR were selected for the subsequent sleep study. In the second part, polysomnogram, arterial oxygen saturation (SpO2) and respiratory events are recorded on the selected subjects under normoxic and hypoxic conditions. Hypoxia decreased SpO2 and increased respiratory disturbances for both groups. The low HVR group, but not the high HVR group, showed decreases in the whole-night delta power of NREM sleep EEG under hypoxia. On the other hand, two subjects in the high HVR group, who showed relatively high apnoea indices, also showed lower SpO2 nadirs and decreases in the whole-night delta power under hypoxia. These results suggest that acute hypoxia equivalent to that at a 2000 m altitude decreases slow-wave sleep in individuals that show low HVR. However, low HVR may not be the only, but one of some factors that decrease the whole-night delta power under hypoxia. Therefore, it was not sufficient to identify individuals likely to be susceptible to deteriorated sleep quality at a simulated altitude of 2000 m only using the HVR test. Other factors, which relate to respiratory instabilities, should be taken into consideration to identify them.

This study was designed to determine endocrine responses during 2 days of strenuous resistance training. Ten healthy men performed resistance training twice a day for two successive days to induce acute fatigue (excessive physical stress). The resistance training consisted of four exercises for the lower body in the morning and seven exercises for the upper body in the afternoon. Maximal isometric and isokinetic strengths were measured from day 1 (before the training period) to day 3 (after the training period). Fasting blood samples were taken on days 1-3. Maximal isometric and isokinetic strengths significantly decreased with two successive days of training (P<0·05), with significant increases in serum creatine phosphokinase and myoglobin concentrations (P<0·05). Significant reductions in the fasting concentrations of serum insulin-like growth factor-1, free testosterone, insulin and high-molecular-weight adiponectin were observed on day 3 (P<0·05), whereas there were no changes in the serum cortisol concentration or the free testosterone/cortisol ratio. Plasma active ghrelin and serum leptin concentrations decreased by -20·7 ± 2·8% and -29·6 ± 4·1%, respectively (P<0·05). Two days strenuous resistance training significantly affects the profiles of anabolic hormone and endocrine regulators of appetite and energy balance, such as ghrelin and leptin. The present findings suggest that decreased ghrelin and leptin concentrations might reflect excessive physical stress and may be early signs of accumulated fatigue.

The present study examined whether three-ball cascade juggling was improved by sleep. To elucidate sleep functions related to motor memory consolidation, sleep EEG spectral analysis was performed for each recorded sleep stage. Sixteen female college students practiced juggling in the morning, and were tested immediately afterward. Eight of the subjects took a 2-hour nap after practice juggling (nap group), while another 8 stayed awake (control group). Juggling performance was then re-tested in the evening. Juggling performance improved after the 2-hour nap, while subjects in the control group did not show improvement. Slow oscillation, delta wave, and sigma wave EEG spectral power all increased significantly during non-REM sleep, especially during slow-wave sleep, after the post-motor learning nap (mNap) compared to an earlier baseline nap that preceded learning the task. Such EEG alterations have been suggested to relate to explicit declarative (hippocampus-dependent) memory consolidation; however, motor learning is considered to rely upon implicit procedural memory. We found that while sleep facilitated the consolidation of motor memory similar to that following real sport activities, the alterations in sleep EEG suggest that the initial motor learning of complex, highly coordinated 3-ball cascade juggling may involve substantial use of explicit memory.

This mini-review focuses on the effects of exercise on sleep. In its early days, sleep research largely focused on central nervous system (CNS) physiology using standardized tabulations of several sleep-specific landmark electroencephalogram (EEG) waveforms. Though coarse, this method has enabled the observation and inspection of numerous uninterrupted sleep phenomena. The research on the effects of exercise on sleep began, in the 1960s, with a focus primarily on sleep related EEG changes (CNS sleep). Those early studies found only small effects of exercise on sleep. However, more recent sleep research has explored not only CNS functioning, but somatic physiology as well. Sleep should be affected by daytime exercise, as physical activity alters endocrine, autonomic nervous system (ANS), and somatic functions. Since endocrinological, metabolic, and autonomic changes can be measured during sleep, it should be possible to assess exercise effects on somatic physiology in addition to CNS sleep quality, evaluated by standard polysomnographic (PSG) techniques. Additional measures of somatic physiology have provided enough evidences to conclude that the auto-regulatory, global regulation of sleep is not the exclusive domain of the CNS, but it is heavily influenced by inputs from the rest of the body.

This study compared the fat metabolism between 'a single bout of 30-min exercise' and 'three bouts of 10-min exercise' of the same intensity (60% maximal oxygen uptake) and total exercise duration (30 min). Nine healthy men participated in three trials: (1) a single 30-min bout of exercise (Single), (2) three 10-min bouts of exercise, separated by a 10-min rest (Repeated) and (3) rest (Rest). Each exercise was performed with a cycle ergometer at 60% of maximal oxygen uptake, followed by 180-min rest. Blood lactate concentration increased significantly after exercise in the Single and Repeated trials (P < 0.05), but the Single trial showed a significantly higher value during the recovery period (P < 0.05). No significant difference was observed in the responses of plasma glycerol concentration. The Repeated trial produced a smaller increase in the ratings of perceived exertion during the exercise (P < 0.01). During the exercise, no significant difference was observed in respiratory exchange ratio (RER) between the Single and Repeated trials. However, the RER values during the recovery period were significantly lower in the Repeated trial than in the Single and Rest trials (P < 0.05), indicating higher relative contribution of fat oxidation in the Repeated trial (P < 0.05). These results suggest that the repetition of 10-min of moderate exercise can contribute to greater exercise-induced fat oxidation compared with a single 30-min bout of continuous exercise.

The aim of this study was to investigate the relationships between cognitive functions and daily physical activities in primary school children. Subjects were 153 pupils (Age 6-12 years old), and visual Go/Nogo task for cognitive functions and parents questionnaire for daily physical activities were used.<br>As results, male children exhibited negative correlation between duration of exercise and information processing time, and positive correlation between duration of exercise and the number of false response. Female children exhibited positive correlation between time of indoor play and number of false response. All these correlations were statistically significant. Further in females, those who spent longer time in playing video games exhibited statistically shorter reaction time.<br>These findings suggested that the cognitive functions evaluated from visual Go/Nogo task were related to daily physical activities, especially the exercise and the indoor play. Further these factors and relationships could be different between males and females in preadolescent children.

In the present study, we evaluated the duration of slow-wave sleep (Stage 3 and 4) and total delta power ( 3Hz) in all-night non-rapid eye movement (NREM) sleep electroencephalograms (EEGs) of athletes during normobaric hypoxia at simulated altitudes of 1500 m. Seven male athletes slept for two nights in a normoxic condition and one night in an hypoxic condition equivalent to an altitude of 1500 m. Whole-night polysomnographic recordings, thoracic and abdominal motion, nasal and oral airflow, and blood oxygen saturation (SpO2) were recorded. Visual sleep stage scoring and fast Fourier transformation analyses of EEG were performed using 30-s epochs. Mean and minimum SpO2 decreased significantly during sleep in the hypoxic condition. Between groups, changes in heart rate, respiratory disturbance measures including apnoea and hypopnoea, slow-wave sleep and total delta power of the all-night NREM sleep EEG were small and non-significant for the hypoxic condition. However, individual difference in time at an SpO2 below 90% were large in the hypoxic condition, and both slow-wave sleep and total delta power of all-night NREM sleep EEG decreased in three participants who spent a prolonged time below 90% SpO2. The present results suggest that monitoring time below 90% SpO2 is recommended when studying individuals' living-high schedule even under hypoxic conditions equivalent to an altitude of 1500 m.

It is well known that visual feedback of exerted force enhances muscle force during maximal voluntary contraction (MVC). Based on the previous reports on the force exertion tasks and the other tasks using the visual feedback paradigm, we hypothesized that the prefrontal cortex (PFC) is related to the enhancement of voluntary contraction force. The purpose of this study was to test the hypothesis and to identify the detail active regions in the PFC that correlates with the muscle force enhancement with visual feedback of exerted force, using near-infrared spectroscopy (NIRS). The cerebral blood flow of 11 male subjects was measured by NIRS during the MVC tasks with visual feedback of exerted torque (VFB) and without visual feedback (nVFB). As a result, both the elbow flexion torque during MVC and cerebral blood flow of the right PFC significantly increased under the VFB condition (p<0.05). In addition, the increased cerebral blood flow of the right PFC was correlated with the torque enhancement (p<0.05). The present results suggest that the right PFC is related to the increase of torque under the VFB condition. Since the PFC has a significant role in motivation, the enhancement of torque with visual feedback may be associated with such a function.

Changes in sleep quality of athletes under normobaric hypoxia equivalent to 2,000-m altitude: a polysomnographic study. J Appl Physiol 103: 2005-2011, 2007. First published August 9, 2007; doi: 10.1152/japplphysiol.00315.2007.-This study evaluated the sleep quality of athletes in normobaric hypoxia at a simulated altitude of 2,000 m. Eight male athletes slept in normoxic condition (NC) and hypoxic conditions equivalent to those at 2,000-m altitude (HC). Polysomnographic recordings of sleep included the electroencephalogram (EEG), electrooculogram, chin surface electromyogram, and electrocardiogram. Thoracic and abdominal motion, nasal and oral airflow, and arterial blood oxygen saturation (Sa(O2)) were also recorded. Standard visual sleep stage scoring and fast Fourier transformation analyses of the EEG were performed on 30-s epochs. Subjective sleepiness and urinary catecholamines were also monitored. Mean SaO2 decreased and respiratory disturbances increased with HC. The increase in respiratory disturbances was significant, but the increase was small and subclinical. The duration of slow-wave sleep (stage 3 and 4) and total delta power (&lt; 3 Hz) of the all-night non-rapid eye movement sleep EEG decreased for HC compared with NC. Subjective sleepiness and amounts of urinary catecholamines did not differ between the conditions. These results indicate that acute exposure to normobaric hypoxia equivalent to that at 2,000-m altitude decreased slow-wave sleep in athletes, but it did not change subjective sleepiness or amounts of urinary catecholamines.

Human judgment of the temporal order of two sensory signals is liable to change depending on our prior experiences. Previous studies have reported that signals presented at short intervals but in the same order as the most frequently repeated signal are perceived as occurring simultaneously. Here we report opposite perceptual changes that conform to a Bayesian integration theory in judging the order of two stimuli delivered one to each hand.

We recorded human orbitofrontal electrocorticogram during wakefulness and sleep in epileptic patients using subdural electrodes. During wakefulness and rapid eye movement (REM) sleep, we observed beta activity in the raw orbitofrontal signals. Power spectral analysis demonstrated beta enhancement during wakefulness and REM sleep when compared to slow wave sleep (SWS). During the phasic REM periods, the beta power was significantly lower than during the tonic REM periods. Gamma enhancement manifested itself in four out of six subjects during the phasic periods. This study is the first that has focused on electrical activity in the human orbitofrontal cortex. Although the role of the orbitofrontal cortex during sleep still remains unclear, high frequency activities give us important suggestions in elucidating the human sleep mechanism. (c) 2004 Elsevier Ireland Ltd. All rights reserved.

Ten epileptic patients each with subdural electrodes surgically attached to the anterior cingulate cortex (ACC; two cases), the orbitofrontal cortex (OFC: seven cases), or both (one case) were included in this study. We recorded each patient's ACC or OFC electrocorticogram (ECoG) during the time period that the patient was awake and naturally asleep. We performed a Fast Fourier Transformation (FFT) power spectral analysis on each ECoG to examine its frequency component. We found that the ACC showed regular and continuous theta oscillation (5-7Hz) during wakefulness and rapid eye movement (REM) sleep, but not during slow wave sleep. Theta waves observed in REM sleep were not as distinct as those found in wakefulness. We also discovered that the orbitofrontal signals represented spectral peaks in the theta band only during wakefulness. This suggests the coexistence of theta oscillation in the ACC. Considering our previous observations of gamma and beta oscillations in the human hippocampus, we hypothesize that the human limbic system manifests two oscillatory activities. The results obtained in this study suggest that electrophysiological activity in the ACC could be related to particular psychological functions in wakefulness and in REM sleep. These results are useful in elucidating the human brain mechanism. (C) 2004 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

The power spectra of night sleep EEGs of 12 breast-feeding 9-13 week postpartum mothers were analyzed and compared with those of 12 non-pregnant women. The power spectra in the delta and theta frequency range during NREM sleep for breast-feeding mothers were significantly higher than those for non-pregnant women. In addition, the all-night sleep patterns of the mothers were classified into two groups - interrupted sleep due to taking care of their infants and non-interrupted sleep - in order to observe the influence of partial sleep deprivation. The power spectra in the delta and theta frequency range were not significantly different between them. This result suggests that increased delta and theta power spectra during postpartum sleep do not result from partial sleep deprivation. The role of prolactin in breast-feeding mothers' sleep is also discussed. (C) 2004 Elsevier Ireland Ltd. All rights reserved.

The purpose of this study is to propose and investigate a new approach for discriminating between focal and non-focal hemispheres in intractable temporal lobe epilepsy, based on applying multivariate time series analysis to the discharge-free background brain activity observed in nocturnal electrocorticogram (ECoG) time series.
Five unilateral focal patients and one bilateral focal patient were studied. In order to detect the location of epileptic foci, linear multivariate autoregressive (MAR) models were fitted to the ECoG data; as a new approach for the purpose of summarizing these models in a single relevant parameter, the behaviour of the corresponding impulse response functions was studied and described by an attenuation coefficient.
In the majority of unilateral focal patients, the averaged attenuation coefficient was found to be almost always significantly larger in the focal hemisphere, as compared to the non-focal hemisphere. Also the amplitude of the fluctuations of the attenuation coefficient was significantly larger in the focal hemisphere. Moreover, in one patient showing a typical regular sleep cycle, the attenuation coefficient in the focal hemisphere tended to be larger during REM sleep and smaller during Non-REM sleep. In the bilateral focal patient, no statistically significant distinction between the hemispheres was found.
This study provides encouraging results for new investigations of brain dynamics by multivariate parametric modeling. It opens up the possibility of relating diseases like epilepsy to the properties of inconspicuous background brain dynamics, without the need to record and analyze epileptic seizures or other evidently pathological waveforms. (C) 2004 Elsevier B.V. All rights reserved.

Norepinephrine (NE) is considered to play a permissive role in the occurrence of rapid eye movement (REM) sleep. Clonidine is an NE alpha-2-receptor agonist, which has been considered to act mainly on the autoreceptors of presynaptic noradrenergic neurons to reduce their release of NE. However, previous studies of clonidine effects on REM sleep have produced controversial results and the effects of clonidine remain uncertain. To clarify the pharmacological effects of clonidine on human sleep, the sleep electroencephalograms (EEG) recorded from 15 young normal subjects after a single administration of either a low (25 mug) or medium (150 mug) dose of clonidine were examined, and fast Fourier transformation (FFT) spectral analyses of the C3-A2 EEG were performed. Low-dose clonidine significantly increased the amount of REM sleep and decreased the amount of non-REM (NREM) sleep during the second one-third of the drug nights compared to the corresponding hours of baseline night recordings. In contrast, medium-dose clonidine significantly decreased REM and increased NREM on drug nights compared to baseline nights in the entire night. The opposite actions of low and medium doses of clonidine on NREM-REM proportion may indicate that low-dose clonidine mainly affects the alpha-2-receptors on locus coeruleus-NE neurons presynaptically, reducing the release of NE, whereas medium-dose clonidine acts more post-synaptically.

We recorded the magnetoencephalographic (MEG) signal from three subjects before, during and after eye movements cued to a tone, self-paced, awake and during rapid eye movement (REM) sleep. During sleep we recorded the MEG signal throughout the night together with electroencephalographic (EEG) and electromyographic (EMG) channels to construct a hypnogram. While awake, just prior to and during eye movements, the expected well time-locked physiological activations were imaged in pontine regions, with early 3 s priming. Activity in the frontal eye fields (FEF) was identified in the 300 ms before the saccade onset. Visual cortex activation occurred 200 ms after saccades. During REM, compared to the eyes closed awake condition, activity was higher in supplementary motor area (SMA) and lower in inferior parietal and precuneus cortex. Electro-occulographic (EOG) activity just prior to REM saccades correlated with bilateral pontine and FEF activity some 250-400 ms before REM saccade onset, which in turn was preceded 200 ms earlier by reciprocal activation of the pons and FEF. An orbitofrontal-amygdalo-parahippocampal-pontine sequence, possibly related to emotional activation during REM sleep, was identified in the last 100 ms leading to the REM saccade, but not linked to saccade initiation.

Most reports of micrographia associated with focal brain lesions have related this finding to damage in the left basal ganglia. Here we describe the case of a 68-year-old man presenting with reversible micrographia accompanied by hypophonia in the absence of extrapyramidal signs after cerebral infarction in the left subcortical region. At the time of the patient's admission, diffusion-weighted magnetic resonance imaging sequence showed the lesion to principally involve the corona radiata, with some involvement of the putamen. Neurologically, mild right-sided brachiofacial hemiparesis and grasp reflexes - a frontal lobe sign - were observed. As his micrographia and hypophonia improved, the patient's grasp reflexes improved in parallel. In addition, recovery of regional cerebral blood flow in the left frontal lobe was confirmed by single photon emission computed tomography (technetium-99 m HMPAO). The present case suggests the possibility that the function of frontal-subcortical circuit might also be involved in the production and improvement of micrographia and that micrographia and hypophonia may share a common pathophysiology.

In previous studies we observed gamma (30-150 Hz) and beta-1 (10-20 Hz) oscillations in the medial temporal lobe (MTL) using subdural electrodes. The beta-1 was present during wake and REM sleep while gamma was present in all states. Recently we studied a patient (35 years M) with electrodes attached to the anterior cingulate cortex (ACC). This structure showed regular theta (5-6 Hz) oscillations. In the first recording, electrodes were attached to the MTL, that demonstrated the beta-1 and gamma oscillations. Two months later, electrodes were placed on orbitofrontal and ACC and an all night sleep recording was carried out. The ACC exhibited a highly regular and continuous theta oscillation during wakefulness and REM sleep, but not during NREM sleep. Since this same subject showed beta-1 oscillations in the MTL, it is probable that the theta in the ACC is independent of beta-1 in the MTL. This single case suggests the existence of two different frequency oscillators in the human limbic system. Elucidating their functional roles will be an interesting challenge for future studies.

To investigate the sleep spindle activity of the human prefrontal cortex (PFC), we simultaneously recorded whole nights of polysomnographic and electrocorticographic (ECoG) activities during the natural sleep of epileptic patients. Subjects were nine patients with intractable epilepsy who had subdural electrodes surgically attached to the orbital (seven cases), medial (three cases), or dorsolateral (two cases) PFC, and in one case to the frontal pole. To examine spindle frequencies, fast Fourier transformation (FFT) and auto-correlation analyses were performed on the PFC ECoG and Cz EEG data, primarily on epochs of stage 2 sleep. Lower sigma band ECoG oscillations of about 12 Hz were widely distributed across all prefrontal cortical areas including the frontal limbic regions, but none of the PFC sigma frequency peaks coincided with the faster (about 14 Hz) Cz EEG sleep spindles. Combining our results with anatomical and electrophysiological facts, it is suggested that the thalamofrontal circuit involving the rostral reticular and the mediodorsal nucleus of the thalamus is responsible for the generation of 12 Hz frontal spindles in humans. (C) 2003 Elsevier Science Ireland Ltd. and the Japan Neuroscience Society. All rights reserved.

To investigate the pathophysiology of narcoleptic patients' sleep in detail, we analysed and compared the whole-night polysomnograms of narcoleptic patients and normal human subjects. Eight drug-naive narcoleptic patients and eight age-matched normal volunteers underwent polysomnography (PSG) on two consecutive nights. In addition to conventional visual scoring of the polysomnograms, rapid eye movement (REM)-density and electroencephalograph (EEG) power spectra analyses were also performed. Sleep onset REM periods and fragmented nocturnal sleep were observed as expected in our narcoleptic patients. In the narcoleptic patients, REM period duration across the night did not show the significant increasing trend that is usually observed in normal subjects. In all narcoleptic patient REM periods, eye movement densities were significantly increased. The power spectra of narcoleptic REM sleep significantly increased between 0.3 and 0.9 Hz and decreased between 1.0 and 5.4 Hz. Further analysis revealed that non-rapid eye movement (NREM) period duration and the declining trend of delta power density in the narcoleptic patients were not significantly different from the normal subjects. Compared with normal subjects, the power spectra of narcoleptic NREM sleep increased in the 1.0-1.4 Hz and 11.0-11.9 Hz frequency bands, and decreased in a 24.0-26.9 Hz frequency band. Thus, increased EEG delta and decreased beta power densities were commonly observed in both the NREM and REM sleep of the narcoleptic patients, although the decrease in beta power during REM sleep was not statistically significant. Our visual analysis revealed fragmented nocturnal sleep and increased phasic REM components in the narcoleptic patients, which suggest the disturbance of sleep maintenance mechanism(s) and excessive effects of the mechanism(s) underlying eye movement activities during REM sleep in narcolepsy. Spectral analysis revealed significant increases in delta components and decreases in beta components, which suggest decreased activity in central arousal mechanisms. These characteristics lead us to hypothesize that two countervailing mechanisms underlie narcoleptic sleep pathology.

The effects of 10 mg haloxazolam (HAX), 4 mg flunitrazepam (FNZ), and 0.5 mg triazolam (TRI), each administered for seven consecutive nights were studied in the sleep electroencephalograms (EEG) of 17 (six HAX, five FNZ and six TRI) healthy male student volunteers. Recordings of C3-A1 EEG data from one baseline night, three drug nights (first, fourth and seventh) and two withdrawal nights (second and fourth) were analyzed using a fast Fourier transformation method. All three drugs induced similar changes in the 0.5 Hz to 40 Hz power spectrum; namely (i) higher frequency (including the sigma and beta bands) activity increased and lower frequency activity reduced on the drug nights; (ii) the enhancement of sigma activity peaked during non-rapid eye movement sleep following the first administration and was maintained at high levels on all drug nights; (iii) beta activity increased through the night after administration of HAX and FNZ, but not TRI, which suggests a blood concentration level dependent increase of beta activity; and (iv) only HAX showed a residual effect on the fourth withdrawal night. These results indicate that (i) chronic administration of these three benzodiazepine derivatives produce similar profiles in sleep EEG spectral changes, with some differences depending on their half-lives and doses; (ii) the mechanism of sigma enhancement is sensitive to even the initial administration night of BDZ; and (iii) frequencies below and above the sigma band are less sensitive to BDZ and also show an increase through the night after administration, suggesting differences in the mechanisms reflected by these EEG frequency bands.

It is known that autonomic nervous activities change in correspondence with sleep stages. However, the characteristics of continuous fluctuations in nocturnal autonomic nerve tone have not been clarified in detail. The study aimed to determine the possible correlation between the electroencephalogram (EEG) and autonomic nervous activities, and to clarify in detail the nocturnal fluctuations in autonomic nerve activities. Overnight EEGs and electrocardiograms of seven healthy males were obtained. These EEGs were analyzed by fast Fourier transformation algorithm to extract delta, sigma and beta power. Heart rate and heart rate variability (HRV) were calculated in consecutive 5-min epochs. The HRV indices of low frequency (LF), high frequency (HF) and LF/HF ratio were calculated from the spectral analysis of R-R intervals. The sleep stages were manually scored according to Rechtschaffen and Kales' criteria. Low frequency and LF/HF were significantly lower during non-rapid eye movement (NREM) than REM, and were lower in stages 3 and 4 than in stages 1 and 2. Furthermore, delta EEG showed inverse correlations with LF (r = - 0.44, P &lt; 0.001) and LF/HF (r = - 0.41, P &lt; 0.001). In contrast, HF differed neither between REM and NREM nor among NREM sleep stages. Detailed analysis revealed that correlation was evident from the first to third NREM, but not in the fourth and fifth NREM. Delta EEG power showed negative correlations with LF and LF/HF, suggesting that sympathetic nervous activities continuously fluctuate in accordance with sleep deepening and lightening.

We have recorded electrocorticographic activities (ECoG) from subdural electrodes on the human medial temporal lobe (MTL) and basal temporal lobe (BTL) in epileptic patients during cognitive visual tasks designed to evoke the P300 event related potential (ERP). From those recordings we examined the event related gamma band oscillation (ERGBO) and P300 ERP. While P300 was predominantly observed in the MTL, ERGBO was observed in both MTL and BTL. Resembling to P300, ERGBO responses were more often observed following rare stimuli than frequent stimuli. In average responses the ERGBO to rare stimuli followed P300, beginning at 440.5 ms and continuing for about 100 ms. Past studies suggest P300 ERP component reflects a role in cognitive function. Since ERGBO in the present study appeared in different regions and at a different latency from P300, ERGBO may reflect a different physiological role in the cognitive process. (C) 2002 Elsevier Science Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

In order to know when and how infants obtain their circadian sleep-wake rhythm, infants' developing circadian rest-activity rhythm and mothers' circadian rhythm in the postpartum period were examined using actigraph monitoring. The subjects were l 1 primipara and their infants. Actigraphic recordings for the infants and their mothers were made over 3-5 continuous days during the 3rd, 6th, 9th and 12th weeks after birth. A 24-h peak on a mean autocorrelogram of the infants' movements was detected at the 3rd week. The infants' circadian rest-activity, rhythm already existed in the 3rd week. The amplitude of this 24-h peak gradually increased from the 6th to 12th week. This may be useful as an index of the development of infants' circadian rest-activity rhythm. An 11-h peak was also observed at the 3rd week. This 11-h peak was thought to be a semi-circadian rhythm. Regarding the mothers, the amplitude of the 24-h peak on the mean autocorrelogram at the 3rd week was the smallest of all other weeks, and it became larger from the 3rd to 12th week. This meant that the mothers' circadian rhythm at the 3rd week was influenced by their interrupted sleep at night to take care of their infants. The mother-infant synchronization is probably the 1st factor in the entrainment of infants' circadian sleep-wake rhythm. In this study, we also propose a novel method for compensating for missing data in autocorrelogram analysis. (C) 2002 Elsevier Science Inc. All rights reserved.

The medial temporal lobe (MTL) is known to play important roles in learning and memory in both humans and animals. Some investigators have proposed that the rhythmic slow activity (RSA) or theta that can be recorded in an animal hippocampus is related to learning and memory. It is unclear whether the human hippocampus displays a similar activity. In the past few years, we have studied electrophysiological properties of the human medial temporal lobe (MTL) during wake and all-night sleep. In this paper, we will summarize our results in the electrophysiology of the human medial temporal lobe during sleep and wake and discuss their physiological significances. Electrocorticograms (ECoG) during wake, slow wave sleep (SWS) and rapid eye movement (REM) sleep were subjected to fast Fourier transformation (FFT) analysis. During wake, two peaks, beta-1 (10–20 Hz) and gamma (30–150 Hz) were consistently observed across the subjects. In SWS, the beta-1 peak disappeared but gamma remained although slightly reduced. During REM sleep, beta-1 appeared again, but the peak frequency was slightly lower than that during wake. The gamma peak was also present in REM sleep. These results indicate similarities in the human MTL gamma and beta-1 when compared to animal gamma and RSA in the hippocampus. Thus, this suggests the functional significances of these two MTL oscillations in relation to learning and memory throughout wake and sleep. © 2001 Elsevier Science B.V.

In 2002, psychiatrically disabled athletes joined an historic first open game of volleyball at the national sports games for the disabled. Compared to the competitive sports and Paralympic Games that physically and intellectually disabled athletes have participated in, activities for the psychiatrically disabled have not been well-organized. In this paper, we examine a number of problems that have arisen when the psychiatrically disabled joined competitive sports games. We identify two major characteristics of the psychiatrically disabled of particular relevance when organizing competitive sports activities. First, all psychiatrically disabled athletes need treatment of their individual diseases. For example, psychiatric symptoms fluctuate markedly over time, unlike physical or intellectual disabilities, whose symptoms are much more stable. Exacerbations of psychiatric illness are also likely to occur due to the stresses of competitiveness. Second, psychiatric disabilities are manifestations of disorders in the central nervous system, which makes the classification of psychiatric disabilities less straightforward than classification of the physically disabled. These two characteristics require special attention when organizing competitive athletic challenges that include the psychiatrically disabled. However, promoting sports activities that include the psychiatrically disabled would be expected to reduce the prejudice toward and subsequent social disadvantages experienced by psychiatric patients. Thus, with careful planning to successfully integrate psychiatrically disabled athletes, we expect increased promotion of such sports activities in the future.

In order to evaluate two patterns of interrupted and non-interrupted sleep for the post-partum mothers from 9 to 12 weeks after delivery, we compared them with sleep patterns of non-pregnant women. Subjects were 10 primipara and 12 non-pregnant women. Their polysomnographic recordings were made using a Medilog recorder at home. In interrupted sleep, low sleep efficiency, decreased total sleep time, and a decreased percentage of stage 2 were significantly observed compared with non-pregnant women. Sleep parameters of non-interrupted sleep, except for increased percentage of stage 4, did not show any significant differences from non-pregnant women. Mothers&#039; sleep fluctuated between interrupted sleep similar to the early post-partum sleep from 1 to 6 weeks and non-interrupted sleep with increased stage 4.

Background: Among 15 monozygotic twin pairs described in the literature, only four pairs were considered to be concordant There is no derailed report of HLA-DRB1*1501/DQBI*0602 positive monozygotic twins concordant for narcolepsy, with marked difference in the age of onset.
Methods: We compared a pair of female narcoleptic twins clinically.
Results: Diagnosis of narcolepsy and monozygosity of the twins were confirmed. The second-born twin demonstrated a typical course of narcolepsy, whereas the first-born twin had a very late onset of recurrent daytime sleep episodes at age 45 and cataplexy at age 50 years, which was apparently triggered by chronic emotional stresses and sleep insufficiency.
Conclusions: The atypical course of narcolepsy in the first-bent twin supports the multifactorial model for the development of narcolepsy. It was noted that cataplexy was preceded by sustained polyphasic sleep conditions. Our observation implies that the unaffected co-twins in discordant pairs could develop narcolepsy in stressful situations later in their lives. (C) 2001 Society of Biological Psychiatry.

All-night recordings from subdural electrocorticographic (ECoG) electrodes on the human medial and basal temporal lobes were analysed to examine spindling activities during sleep. Subjects were three males and three females who were candidates for neurosurgical treatments of partial epilepsy. Subdural electrodes were attached to the medial and basal temporal lobe cortices, allowing ECoG and electroencephalogram from the scalp vertex (Cz EEG) to be recorded simultaneously during all night sleep. In one case, subdural electrodes were attached also on the parietal lobe. Fast Fourier transformation (FFT) analyses were performed on the ECoG and Cz EEG signals. No organized sleep spindles or sigma band (12-16 Hz) peaks in FFT power spectra were observed from the medial or basal temporal lobes of the non-epileptogenic hemispheres during non-rapid eye movement (NREM) sleep. In a case with parietal electrodes, organized spindle bursts were observed in parietal signals synchronized with Cz spindles. Although delta band (0.3-3 Hz) power from both the medial and basal temporal lobes fluctuated across each night as expected, sigma activity changed little. However, 14 Hz oscillatory bursts were observed in the medial basal temporal lobe of epileptogenic hemisphere in two cases and bilaterally in one case during not only NREM sleep but rapid eye movement (REM) sleep and wakefulness. From the present study we conclude that sleep spindle activities are absent in the medial and basal temporal lobes. Fourteen Hz oscillatory bursts observed from the medial or basal temporal lobe in some cases were not considered to be sleep spindles since they also appeared during REM sleep and wakefulness. These waveforms could have originated due to epileptic pathology, since they frequently appeared in epileptic regions.

We have recorded human medial temporal lobe electrocorticogram during wakefulness and natural sleep in epileptic patients with subdural electrodes. From these recordings, we have found gamma (30-150 Hz) [Neuroscience 90 (1999) 1149] and beta-1 (10-20 Hz) [NeuroReport 10 (1999) 3055] activities during wakefulness in human medial temporal lobe. In this paper, we will report changes of these frequencies across wake and natural sleep. Electrocorticograms during wake, slow wave sleep and rapid eye movement (REM) sleep were subjected to fast Fourier transformation analysis. During wake two spectral enhancements, beta-1 and gamma, were consistently observed across subjects. In the raw signal, beta-1 was observed as a regular rhythmic oscillation. In slow wave sleep, the beta-1 peak disappeared but gamma remained, although slightly reduced in power. During REM sleep, beta-1 appeared again, but the peak frequency was significantly lower than during wake (mean frequency: wake=16.6, REM=12.8 Hz). The gamma peak was also present in REM sleep. It has been known that the rhythmic slow activity (RSA) or theta is observed in some animals. However, it is unclear whether the human hippocampus displays similar activity. Since human beta-1 appears during wake and REM sleep when RSA is observed in other species, and since beta-1 is also a regular rhythmic oscillation, we propose that beta-1 may be the functional equivalent of hippocampal RSA (theta) observed in some animals. Functional significances of the gamma activity should be further investigated. (C) 2001 Elsevier Science BN. All rights reserved.

All-night recordings from subdural electrocorticographic (ECoG) electrodes on the human medial and basal temporal lobes were analysed to examine spindling activities during sleep. Subjects were three males and three females who were candidates for neurosurgical treatments of partial epilepsy. Subdural electrodes were attached to the medial and basal temporal lobe cortices, allowing ECoG and electroencephalogram from the scalp vertex (Cz EEG) to be recorded simultaneously during all night sleep. In one case, subdural electrodes were attached also on the parietal lobe. Fast Fourier transformation (FFT) analyses were performed on the ECoG and Cz EEG signals. No organized sleep spindles or sigma band (12-16 Hz) peaks in FFT power spectra were observed from the medial or basal temporal lobes of the non-epileptogenic hemispheres during non-rapid eye movement (NREM) sleep. In a case with parietal electrodes, organized spindle bursts were observed in parietal signals synchronized with Cz spindles. Although delta band (0.3-3 Hz) power from both the medial and basal temporal lobes fluctuated across each night as expected, sigma activity changed little. However, 14 Hz oscillatory bursts were observed in the medial basal temporal lobe of epileptogenic hemisphere in two cases and bilaterally in one case during not only NREM sleep but rapid eye movement (REM) sleep and wakefulness. From the present study we conclude that sleep spindle activities are absent in the medial and basal temporal lobes. Fourteen Hz oscillatory bursts observed from the medial or basal temporal lobe in some cases were not considered to be sleep spindles since they also appeared during REM sleep and wakefulness. These waveforms could have originated due to epileptic pathology, since they frequently appeared in epileptic regions.

Benign adult familial myoclonus epilepsy (BAFME) is a rare epileptic disease that has predominantly been reported in the Japanese population. To date, there have been no reports of psychotic symptoms in BAFME patients. We recently encountered one patient with BAFME accompanied by an apparently related major depressive episode. The depressive state did not improve after trials of several antidepressive agents, including clomipramine, fluvoxamine and alprazolam. However, clonazapam was very effective and immediately improved both the affective disorder and epileptic symptoms. Electroencephalographic (EEG) findings also improved, reflected by normalization of background activity and spikey waves. This clinical course could indicate that the depressive state derived from epileptic pathophysiology.

The relationship between a post-partum mother's wakefulness at night and her infant's circadian sleep-wake rhythm was examined. The subjects were seven primipara and their infants. Actigraphic recordings for the mothers and their infants were made over three to five continuous days during Weeks 3, 6, 9 and 12. A 24-h peak of autocorrelograms of the infants' movements appeared in two cases at Week 6, in six cases at Week 9, and in seven cases at Week 12. The mothers' night-time movements significantly decreased from Week 3 to Week 12. Mothers' wakefulness during night sleep in the post-partum period is related to their infants' obtaining circadian sleep-wake rhythm.

We have reported the presence of continuous gamma (30-150 Hz) activity in the human medial temporal lobe (MTL). Since the MTL is involved in learning and memory, we speculated that MTL gamma activity is related to such higher brain functions. It is thus of interest to learn how this activity changes during different states of consciousness. In this study, we recorded electrocorticographic (ECoG) activity directly from the surface of the MTL after various doses of sevoflurane anesthesia. Five epileptic patients underwent electrode placement operations in which electrodes were attached to the surfaces of the MTL and the basal temporal robe (BTL). Immediately following the operation ECoG was recorded from each patient under four concentrations of sevoflurane anesthesia (1.5, 2.0, 2.5 and 3.0%). Fast Fourier Transform (FFT) analysis was performed on the MTL ECoGs. Under the lowest sevoflurane concentration, MTL gamma activity was observed in all patients. However, gamma activity was progressively suppressed by increased concentrations of sevoflurane,in a dose-dependent manner. Sevoflurane has been known to reduce neuronal excitability in the rat hippocampus in vitro, probably by changing GABAergic inhibition. The reduction of MTL gamma in the present study may be the result of such a mechanism. Although memory function was not tested in this study, the amount of MTL gamma activity may be related to residual memory function during anesthesia. NeuroReport 11:39-42 (C) 2000 Lippincott Williams & Wilkins.

DURING wakefulness, signals from subdural electrodes attached to the basal and medial temporal lobes of adult human epilepsy patients revealed a rhythmic oscillation in the beta-1 frequency range (10-20 Hz). This activity was more prominent in the medial than in the basal temporal cortex. We also observed simultaneous oscillations in alpha frequency activity in the medial and the basal::temporal cortices. In an eyes-open condition, the alpha oscillation was attenuated, while the beta-1 oscillation in the medial temporal lobe was not. This is the first report that the beta-1 oscillation is present in the human medial temporal lobe. Since we recorded this activity from within the limbic system, beta-1 activity may be an analog of the hippocampal rhythmic slow activity observed in some animals. (C) 1999 Lippincott Williams & Wilkins.

Zero-cross and zero-derivative period amplitude analysis (PAA) data were compared with power spectral analysis (PSA) data obtained with the fast Fourier transform in all-night sleep EEG from 10 subjects. Although PAA zero-cross-integrated amplitude showed good agreement with PSA power in 0.3-2 Hz, zero-cross analysis appears relatively ineffective in measuring 2-4 Hz and above waves. However, PAA zero-derivative measures of peak-trough amplitude correlated well with PSA power in 2-4 Hz. Thus, while PAA appears able to measure the entire EEG spectrum, the analytic technique should be changed from zero cross to zero derivative at about 2 Hz in human sleep EEG. PAA and PSA both demonstrate robust and interrelated across-night oscillations in three frequency bands: delta (0.3-4 Hz); sigma (12-16 Hz); and fast beta (20-40 Hz). The frequencies between delta and sigma, and between sigma and fast beta, did not show clear across-night oscillations using either method, and the two methods showed lower epoch-to-epoch agreement in these intermediate bands. The causes of this reduced agreement are not immediately clear, nor is it obvious which method gives more valid results. We believe that the three strongly oscillating frequency bands represent fundamental properties of the human sleep EEG that provide important clues to underlying physiological mechanisms. These mechanisms are more likely to be understood if their dynamic properties are preserved and measured naturalistically rather than being forced into arbitrary sleep stages or procrustean models. Both PAA and PSA can be employed for such naturalistic studies. PSA has the advantages of applying the same analytic method across the EEG spectrum and rests on more fully developed theory. Combined zero-cross and zero-derivative PAA demonstrates EEG oscillations that closely parallel those observed with spectral power, and the PAA measures do not rely on assumptions about the spectral composition of the signal. In addition, both PAA techniques can measure the relative contributions of wave amplitude and incidence to total power. These waveform characteristics represent different biological processes and respond differentially to a wide range of experimental conditions. (C) 1999 Elsevier Science Inc.

Anticholinergic drug is often used to treat extrapyramidal symptoms. We measured muscarinic cholinergic receptor (mAckR) occupancy by the oral administration of biperiden in eight healthy subjects using positron emission tomography (PET) and [C-11]N-methyl-4-piperidylbenzilate (NMPB). After the baseline scan each subject underwent one or two post-dose PET scans. mAckR occupancy was 10-45% in the frontal cortex three hours after the oral administration of 4mg of biperiden. The occupancy correlated with the plasma concentration of biperiden in a curvilinear manner. (C) 1999 Elsevier Science Inc.

We performed fast Fourier transformation power spectral analysis of the electrocorticogram in human medial temporal lobe during wakeful rest in six epileptic subjects. Compared with the electrocorticogram wave in the basal temporal lobe, which showed monotonic decline of spectral power across the frequency axis, the electrocorticogram wave in the parahippocampal gyrus was enhanced (or did not decline) in the gamma frequency range (30-150 Hz) in all subjects.
Although it has been suggested that electrical oscillations of the hippocampus have functional roles in higher brain functions, namely learning and memory, the knowledge of hippocampal oscillations is largely limited to animal studies. The present results demonstrate that fast frequency oscillation is also present in the human medial temporal lobe, which has been reported in animal hippocampi. They also demonstrate the importance of recording very fast field potentials in human electrocorticograms. This fast oscillation is likely to play important functional roles related to learning and memory, possibly to induce long-term potentiation in the human medial temporal lobe. (C) 1999 IBRO. Published by Elsevier Science Ltd.

The effects of 0.5 mg triazolam (TRI) and 4 mg flunitrazepam (FNZ) on the sleep electroencephalogram (EEG) were studied in eleven (six for TRI, and five for FNZ) healthy young male subjects. C3 EEG channel data of one baseline night, three drug nights and two withdrawal nights were recorded and their analyzed using a fast Fourier transformation (FFT) method. Changes in the 0.5 Hz to 40 Hz power spectrum showed that: 1) both TRI and FNZ increased higher frequency activity and reduced lower frequency activity on the drug nights; 2) on drug nights, NREM sigma frequency power was more strongly enhanced by TRI than FNZ, while the beta power of both NREM and REM was more strongly enhanced by FNZ than TRI; 3) NREM alpha power increased on the second night of withdrawal from both TRI and FNZ; 4) the power spectra for both NREM and REM sleep returned to baseline levels by the fourth night of withdrawal from either TRI or FNZ. These findings suggest that 0.5 mg TRI and 4 mg FNZ have both common and differing pharmacological effects on the central nervous system. Such differences could be caused by differences in the dose, half-life or systemic distribution of these two drugs.

Analysis of electroencephalogram (EEG) is presented for sleep physiology. This analysis is performed by the Instantaneous Maximum Entropy Method (IMEM), which was given by the author. Appearance and continuation of featuristic waves are not steady in EEG. The characteristics of these waves responding to epoch of sleep are analyzed. The behaviours of waves were clarified by this analysis as follows; (a) time dependent frequency of continuous oscillations of alpha rhythm was observed precisely. Sleep spindles were detected clearly within NREM and these parameters of time, frequency, and peak energy were specified, (b) delta waves with very low frequencies and sleep spindles were observed simultaneously. And (c) the relationship of sleep spindles and delta waves was first detected with negative correlation along time-axis. The analysis by the IMEM was found effective comparing conventional analysis method of FFT, bandpass filter bank, etc.

Triazolam (TRZ) 0.5 mg was administered to six healthy young male students for 7 days. Polysomnographic recordings of the two nights of baseline (BLN) drug and the second and fourth withdrawal nights were made, and EEG from the C3 electrode site was analyzed using fast Fourier transformation (FFT). No significant changes in the EEG spectra of NREM or REM sleep were found in comparisons of whole-night recordings of drug nights. However, when corresponding portions of the sleep period were compared, the initial drug night (IDN) showed the strongest drug effects in NREM periods from the second half of the night, whereas the 4th and 7th drug nights (4DN and 7DN) showed the strongest effects in NREM periods from the first half of the night. These findings suggest that the initial effects of TRZ on human sleep differ from those in later nights.

We have reported three sleep electroencephalogram (EEG) frequencies whose fast Fourier transform (FFT) power show rhythmic fluctuations throughout the night; Delta (0.3-3 Hz), sigma (12-16 Hz) and beta (20-28 Hz). We investigated these frequencies using conventional polysomnography (PSG), EEG topography and electrocorticography (ECoG). Polysomnography was useful for extracting the dynamic changes of these three EEG frequencies throughout the night. Topographies revealed different distributions of each frequency on the skull. ECoG was applied to study the sigma frequency, which was not apparent on the temporal cortex. The absence of the sigma frequency may indicate that the temporal cortex does not receive influences from the reticular nucleus of the thalamus, which is considered to be the generator of sigma spindles. These results indicate that multimodal studies of these frequencies can shed light on both our knowledge of sleep and brain structure.

This paper describes the analysis of electroencephalogram (EEG) signal from human brains on sleep. The result of the analysis based on the Instantaneous Maximum Entropy Method (IMEM) clarified multiple effect on the investigation of human sleep, By this analysis, the negative correlation was found out between sleep spindle and delta wave during deep NREM sleep. The fine structure of time dependent behaviour was made clear of alpha wave at sleep onset, sleep spindle and delta ur ave during MREM sleep.

Flunitrazepam (FNZ) is known to enhance the higher EEG frequencies, including sigma (10-15 Hz) and beta (20-28 Hz). Both sigma and beta frequency bands show an inverse relationship with delta (0.3-3 Hz) during NREM periods, as we have previously reported. It is not known whether generation of these two EEG frequencies is mediated by the same or different neuronal mechanisms. In this report, we compare alterations of delta, sigma and beta EEG induced by FNZ (4 mg) orally administered to five healthy male subjects for seven consecutive nights. Sleep EEG on the baseline night (BLN), and the fourth and seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. On drug nights, sigma was enhanced without regard to delta amount, but beta was enhanced only during epochs containing low delta. Thus, sigma and beta EEG were altered differently by the same pharmacological agent. These results suggest that sigma and beta EEG are mediated by different neuronal mechanisms.

Flunitrazepam (FNZ) (4 mg), an intermediate type benzodiazepine (BDZ) hypnotic, was administered orally to five healthy male subjects (Ss) for seven consecutive nights. Sleep EEG from the baseline night (BLN), the initial drug night (IDN), the fourth and seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. During NREM sleep of 4DN and 7DN sigma band (11.0-12.5 Hz) activity was similarly enhanced in every S. In REM of 4DN and 7DN the beta band (23.0-29.0 Hz) was enhanced, but with larger variations among Ss. High Intra-individual consistency of the relative EEG power patterns on 4DN and 7DN was observed. These results suggest that 1) EEG responses to FNZ are different in sleep states; explorations of these differences may provided better understandings of sleep mechanisms, and 2) individual variations in EEG responses may reflect individual variations of the BDZ receptor system. These methods may be useful for exploring receptor changes in neuropsychiatric disorders.

This article critically reviews 8 computer implementations of Fujimori's method for EEG waveform recognition, with methodological considerations for the application of this method to the analysis of all-night sleep EEG. Fujimori's method has been considered one of the most appropriate waveform analyses for EEG. This kind of analysis is advantageous for measuring frequency and amplitude of each EEG wave separately. However, current implementations have drawbacks which must be resolved before they can be used on all-night sleep EEG. An optimal sampling rate should be determined which is appropriate to the purpose of analysis. Amplitude thresholds for wave recognition, which are now set arbitrarily, should also be improved. Measurement of waves in higher orders of superimposition is also necessary, although existing systems are limited to the second order. Additional algorithms, such as for the separate detection of sleep slow waves, may be useful. Further applications for Fujimori's method are suggested.

All night sleep EEG from ten normal students were subjected to FFT spectral analyses. Delta (0.3-3 Hz), sigma (12-16 Hz) and beta (20-28 Hz) EEG showed strongly oscillating patterns across the night. The scattergram of sigma versus beta revealed two separate clusters. One cluster demonstrated a positive linear correlation between sigma and beta. The second cluster showed a range of beta, but a stable, low level of sigma activity. Points in the former cluster consisted of those from NREM epochs, and in the latter, from REM epochs. The present results suggest that REM and NREM EEG are composed of two sets of EEG frequency components, perhaps reflecting different neuronal pools.

All-night sleep EEGs from 7 normal young male adults were analyzed by a waveform recognition method using FFT-IFFT band pass filters. The total durations of sleep spindles and sleep delta waves in each 20-s epoch were measured and plotted on an X-Y graph with lines connecting the points in time sequence (dynamic two-component plot). The relationship between these two measures within a single NREM period showed three dynamic phases and one stationary period. In the first phase, spindles increased while delta remained at a low level or increased slightly. In the second phase, delta increased greatly while spindles decreased. In the third phase, delta decreased while spindles remained at a low level. There was a stationary period between the second and third phases, when delta maintained a higher level and spindles maintained a lower level. These dynamic descriptions reflect the underlying physiological mechanisms more directly than static sleep stages. They should also permit finer analyses of sleep in psychiatric and neurological disorders.

In order to study effects of daytime activities on sleep, eleven healthy male university students (aged 19-25) spent three different activities days; the mentally and physically relaxation day, the mental active day, and the physical active day. Their sleep were recorded in the nights after these three different days.
The large amount of slow wave sleep (SWS) concentrated on the first sleep cycle in the night after the physically active day. The individual differences in body temperature curve during a night became large in the order of the night after the physical active day, the night after the mental active day, and the night after the mentally and physically relaxation day.
These results suggest that an active day not only leads to a good quality of sleep, but also stabilizes the circadian body temperature curve.

Across-night oscillations of beta (20-28 Hz) and delta (0.3-3 Hz) electroencephalograms (EEGs) were examined with spectral analysis in 10 normal young adult subjects (Ss). In each S, power densities of beta were found to oscillate reciprocally with delta power density across both nonrapid eye movement (NREM) and rapid eye movement (REM) sleep. Linear correlation coefficients between log power density of delta vs. beta were significant (p &lt; 0.0001) for each S. An incidental observation was that beta power within REM was reliably lower in epochs with more eye movement activity. The reciprocal relationship between beta and delta holds implications for sleep physiology and supplements our earlier finding that sigma (12-15 Hz) oscillates reciprocally with delta within NREM sleep. These descriptions of the continuously varying EEG across sleep provide information not available when EEG measures are tabulated by discrete NREM periods and REM periods.

Sleep EEG in the sigma and delta frequency bands was subjected to spectral analysis in 8 normal young adults. In each subject, power density of sigma and delta oscillated reciprocally during NREM sleep, confirming an observation made initially with period/amplitude analysis. In REM sleep, power density for both frequency bands was at its lowest levels. Correlation coefficients between power density of delta vs. 1/sigma for all artifact-free 20-s epochs of NREM sleep/night were highly significant for each subject. These results show that cyclic oscillation of EEG within sleep is not limited to delta frequencies. The reciprocal relation of sigma to delta holds implications for the EEG mechanisms of NREM sleep. This dynamic pattern may also prove useful for sleep stage scoring and for a finer empirical analysis of sleep in psychiatric and neurological disorders.