私立大学情報教育協会主催 平成２８年度FD のための情報技術研究講習会に参加平成29年度 第1回FSD研修にて研修報告

平成28年度ISO新入生対象セミナーの講師を担当

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>Generally applicable qualifications of sleep and principles for achieving better sleep are difficult to design, because sleep quality can depend on individual demographic characteristics and lifestyles. In this study, the static and dynamic features of sleep–wake patterns were analyzed in association with quantitative sleep-related parameters and self-rated sleep quality to serve as a practical selection of sleep–wake patterns fitted to individual conditions. Data obtained over a 2-week period by actigraphy from university students and information technology workers were measured to obtain a daily subjective rating of sleep quality using the Oguri–Shirakawa–Azumi (OSA) sleep inventory. Qualitative sleep quality in terms of OSA score and quantitative sleep-related and chronobiological features were analyzed with regard to their dependency on the demographic characteristics, habitual sleep–wake patterns (HSWP), and distinction of weekdays/weekends. Multi-factor ANOVA was used to further investigate their dependencies regarding multiple ways of interactions between the demographic characteristics, HSWP, and distinction of weekdays/weekends. Subjective sleep quality and quantitative sleep-related parameters depended on the demographic characteristics, and so did their associations. The classification of day-to-day variations in HSWP showed four clusters that were effective factors for understanding their dependencies. Multi-factor analysis revealed demographic characteristics, HSWP, distinction of weekdays/weekends, and their multi-way interactions up to 3rd order as significant effectors of qualitative and quantitative quality of sleep. This study clarified how quantitative sleep-related parameters, subjective sleep quality, and their associations depended on demographic characteristics. Furthermore, their dependency was understood as a combination of multi-way interactions between the demographic characteristics, HSWP, and the distinction of weekdays/weekends. Our findings could provide a basis for the design of individually matched sleep–wake patterns.

DOI： 10.1007/s41105-021-00326-9

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Other Link： https://link.springer.com/article/10.1007/s41105-021-00326-9/fulltext.html

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DOI： 10.1007/s41105-020-00271-z

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DOI： 10.1038/s42003-020-01215-6

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DOI： 10.3389/fnins.2019.00554

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/EMBC.2019.8857083

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Other Link： https://dblp.uni-trier.de/rec/conf/embc/2019

Language：English   Publisher：(一社)日本睡眠学会  

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Language：Japanese   Publisher：Japanese Society for Medical and Biological Engineering  

Appropriate characterization of state-dependent Heart Rate Variability Dynamics (HRVD) has been explored.We analyzed the difference between state-dependent HRVD and the HRVD of Slow Wave Sleep (SWS: the deepest sleep), together with subjective sleep evaluation. The results showed that the subjective sleep evaluation differentiates the relationship between the state-dependent HRVD with reference to those in SWS. A future study will be further investigation of sleep quality and dynamics of cardiovascular control system.

DOI： 10.11239/jsmbe.annual56.s331

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Language：Japanese  

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2015&ichushi_jid=J03969&link_issn=&doc_id=20160405490004&doc_link_id=10.11239%2Fjsmbe.53.328&url=https%3A%2F%2Fdoi.org%2F10.11239%2Fjsmbe.53.328&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

Language：Japanese   Publisher：Japanese Society for Medical and Biological Engineering  

So far, many behavioral and pharmacological experiments on genetically modified mice have been conducted to study the molecular mechanism of the psychiatric or neurological diseases. On the other hand, recent functional MRI studies have revealed close relationship between the psychiatric or neurological diseases and the structure of functional connectivity in the resting-state of the human brain. To make linkage between the human and mouse studies, it is necessary to establish the method to analyze brain-wide spontaneous activity in the mouse. In this study, we simultaneously measured spontaneous cortical EEG and transcranial green-reflected-light (GRL, wavelength of 530 nm) signal to monitor cortical hemodynamics at high-spatial resolution in unanesthetized mice during natural sleep-wake cycle. It is shown that GRF decreases at 3% during theta-dominant period (REM sleep) compared to the delta-dominant periods, suggesting the increase in the blood volume of the cerebral cortex during REM sleep.

DOI： 10.11239/jsmbe.53.S245_01

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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/EMBC.2015.7319827

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Language：Japanese   Publisher：Japanese Society for Medical and Biological Engineering  

It has been reported that therapeutic value of cancer chemotherapy depends on a period of treatment time of the day. This effect, circadian time-dependency of treatment, has been considered to come from interactions between cell cycle and circadian rhythm. In this study, we aimed to clarify a biological background of this effect by means of simulating therapeutic effect based on a model of cell cycle controlled by circadian rhythms. Here we constructed a cell proliferation model using a framework of stochastic automaton. During the cell cycle process, a cell is subject to DNA damage with a certain probability. Then the damaged cell dies or returns to the cell cycle, causing a phase response to the cellular circadian clock system. In the simulations, a cancer cell is characterized by prolonged or shortened duration of G1 phase of the cell cycle. We simulated proliferation of 10,000 cells population treated by a drug that increases death rate of cells in S phase. As a result, we found that morning treatment is most effective to maximize the damage to the cancer cells and minimize the normal cell's death.

DOI： 10.11239/jsmbe.53.S133_01

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Language：Japanese  

DOI： 10.9746/sicetr.50.602

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Other Link： https://www.jstage.jst.go.jp/article/sicetr/50/8/50_602/_article/-char/ja/

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DOI： 10.1109/EMBC.2014.6945196

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Language：English   Publisher：Japanese Society for Medical and Biological Engineering  

MRI-guided surgical ablation has been used as a novel technique to achieve minimally invasive glioma resection. In this surgery, low-power thermal energy is supplied via a laser probe, which is inserted into the patients brain to coagulate the tumor region. To position the laser probe precisely, intraoperative MRI is performed. However, MRI images cannot provide sufficient details regarding the fiber tracts. In order for surgeons to know the spatial distribution of subcortical nerve tracts and improve safety during surgery, we propose the use of subcortical mapping to support MRI-guided surgical ablation. Conventional electrical stimulation using biphasic rectangular pulses has poor selectivity in nerve recruitment, and precise spatial distribution of nerve fibers in the subcortical region is difficult to obtain. In this study, we conducted computer simulations to determine which waveform of stimulation results in better spatial selectivity. We used a multi-layer volume conductor model of the human skull and neocortex, in which a mathematical model of a human myelinated nerve fiber was embedded. We numerically calculated the nerve responses to extracellular stimulation provided by an electrode attached to the laser probe inserted into the white matter. We evaluated the distance and diameter selectivity of a solitary test pulse alone and that of conditioning stimuli consisting of a triangular waveform and burst pulses followed by the test pulse. The results showed that the distance and diameter selectivity are markedly improved when using conditioning stimuli prior to the test pulse. A mechanism for improvement of selectivity can be explained based on the nonlinear dynamic properties at the axonal node. These results suggest that the novel conditioning waveform has the potential to provide detailed information of nerve fiber tracts to surgeons during MRI-guided surgical ablation.

DOI： 10.14326/abe.3.139

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Language：English   Publisher：Japanese Society for Medical and Biological Engineering  

MRI-guided surgical ablation has been used as a novel technique to achieve minimally invasive glioma resection. In this surgery, low-power thermal energy is supplied via a laser probe, which is inserted into the patients brain to coagulate the tumor region. To position the laser probe precisely, intraoperative MRI is performed. However, MRI images cannot provide sufficient details regarding the fiber tracts. In order for surgeons to know the spatial distribution of subcortical nerve tracts and improve safety during surgery, we propose the use of subcortical mapping to support MRI-guided surgical ablation. Conventional electrical stimulation using biphasic rectangular pulses has poor selectivity in nerve recruitment, and precise spatial distribution of nerve fibers in the subcortical region is difficult to obtain. In this study, we conducted computer simulations to determine which waveform of stimulation results in better spatial selectivity. We used a multi-layer volume conductor model of the human skull and neocortex, in which a mathematical model of a human myelinated nerve fiber was embedded. We numerically calculated the nerve responses to extracellular stimulation provided by an electrode attached to the laser probe inserted into the white matter. We evaluated the distance and diameter selectivity of a solitary test pulse alone and that of conditioning stimuli consisting of a triangular waveform and burst pulses followed by the test pulse. The results showed that the distance and diameter selectivity are markedly improved when using conditioning stimuli prior to the test pulse. A mechanism for improvement of selectivity can be explained based on the nonlinear dynamic properties at the axonal node. These results suggest that the novel conditioning waveform has the potential to provide detailed information of nerve fiber tracts to surgeons during MRI-guided surgical ablation.

DOI： 10.14326/abe.3.139

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DOI： 10.1109/EMBC.2013.6609891

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DOI： 10.1109/EMBC.2013.6611253

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DOI： 10.14326/abe.1.36

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Language：Japanese   Publisher：(公社)日本生体医工学会  

複素ウェーブレット変換を用いて信号を時間周波数変換し、複素独立成分分析(ICA)を適用してスパイク弁別を行う手法を提案した。本稿では、スパイク弁別に有効なマザーウェーブレットのパラメータについて検討した。また、提案手法を模擬データおよび実データに適用し、実数値ICAに基づく手法と比較した。提案法は、複素ウェーブレット変換により細胞外活動電位信号を瞬時混合化し、そこにICAを適用することによって実数値ICAよりも高精度でスパイク弁別することを可能にした。しかし、耐ノイズ性や過完備条件への対応などの実現が必須であり、ICAをパターン認識法など他の方法と組み合わせたハイブリッド弁別法の開発などを検討する必要がある。

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2012&ichushi_jid=J03969&link_issn=&doc_id=20120501290007&doc_link_id=10.11239%2Fjsmbe.50.52&url=https%3A%2F%2Fdoi.org%2F10.11239%2Fjsmbe.50.52&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

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DOI： 10.1109/EMBC.2012.6345907

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2011&ichushi_jid=J03969&link_issn=&doc_id=20120313450014&doc_link_id=10.11239%2Fjsmbe.49.896&url=https%3A%2F%2Fdoi.org%2F10.11239%2Fjsmbe.49.896&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

Language：English   Publishing type：Part of collection (book)   Publisher：Cambridge University Press  

DOI： 10.1017/CBO9780511921179.045

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DOI： 10.1109/IEMBS.2011.6090204

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DOI： 10.1109/IEMBS.2011.6091094

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Theta waves in the amygdala are known to be synchronized with theta waves in the hippocampus. Synchronization between amygdala and hippocampal theta waves is considered important for neuronal communication between these regions during the memory-retrieval process. These theta waves are also observed during rapid eye movement (REM) sleep. However, few studies have examined the mechanisms and functions of theta waves during REM sleep. This study examined correlations between the dynamics of hippocampal and amygdala theta waves and pontine (P) waves in the subcoeruleus region, which activates many brain areas including the hippocampus and amygdala, during REM sleep in rats. We confirmed that the frequency of hippocampal theta waves increased in association with P wave density, as shown in our previous study. The frequency of amygdala theta waves also increased with in associated with P wave density. In addition, we confirmed synchronization between hippocampal and amygdala theta waves during REM sleep in terms of the cross-correlation function and found that this synchronization was enhanced in association with increased P wave density. We further studied theta wave synchronization associated with P wave density by lesioning the pontine subcoeruleus region. This lesion not only decreased hippocampal and amygdala theta frequency, but also degraded theta wave synchronization. These results indicate that P waves enhance synchronization between regional theta waves. Because hippocampal and amygdala theta waves and P waves are known to be involved in learning and memory processes, these results may help clarify these functions during REM sleep.

DOI： 10.1152/jn.00551.2009

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DOI： 10.1111/j.1479-8425.2009.00414.x

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DOI： 10.1109/IEMBS.2009.5333510

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Multiunit recording with multi-site electrodes in the brain has been widely used in neuroscience studies. After the data recording, neuronal spikes should be sorted according to the pattern of spike waveforms. For the spike sorting, independent component analysis (ICA) has recently been used because ICA has potential for resolving the problem to separate the overlapped multiple neuronal spikes. However the performance of spike sorting by using ICA has not been examined in detail. In this study, we quantitatively evaluate the performance of ICA-based spike sorting method by using simulated multiunit signals. The simulated multiunit signal is constructed by compositing real extracellular action potentials recorded from guinea-pig brain. It is found that the spike sorting by using ICA hardly avoids significant false positive and negative errors due to the cross-talk noise contamination on the separated signals. The cross-talk occurs when the multiunit signal of each recording channel have significant time difference; this situation does not satisfy the assumption of instantaneous source mixture for the major ICA algorithms. Since the channel delay problem is hardly resolved, an ICA algorithm which does not require the instantaneous source mixing assumption would be appropriate for use of spike sorting.

DOI： 10.1109/IEMBS.2009.5333505

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Language：Japanese   Publisher：(公社)日本生体医工学会  

多重電極の性能をスパイク弁別結果に基づいて評価することを提案するともに、適切な電極パラメータを決定するための新しい枠組みを提案した。神経組織と多重電極を3次元モデル化し、多細胞記録の仮想実験を行うためのシステムを構築した。このシステムを用いて仮想実験を行い、得られた模擬細胞外電位信号に実際に解析で用いられるスパイク弁別法を適用することによって、電極の性能を評価した。市販されているシリコン製テトロードをベースにした多重電極を用いて、ラット海馬CA3領域の複数ニューロン活動を記録した。記録点間隔を25μm程度にすると同時記録できるニューロン数が最大になり、またスパイク弁別の誤り率が最小になることが明らかになった。

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2008&ichushi_jid=J03969&link_issn=&doc_id=20090220470014&doc_link_id=10.11239%2Fjsmbe.46.675&url=https%3A%2F%2Fdoi.org%2F10.11239%2Fjsmbe.46.675&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2008&ichushi_jid=J03969&link_issn=&doc_id=20090220470013&doc_link_id=10.11239%2Fjsmbe.46.667&url=https%3A%2F%2Fdoi.org%2F10.11239%2Fjsmbe.46.667&type=J-STAGE&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00007_2.gif

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DOI： 10.1111/j.1479-8425.2008.00363.x

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The mechanical strain of the neural tissue induced by the implant of neuronal electrode is one of the important factors responsible for the quality and performance of extracellular recording of neuronal activities in the brain because the mechanical strain could kill or inactivate the neurons. In order to evaluate the effect of the implant of neural electrode, we propose a method to estimate the three-dimensional distribution of electrophysiologically active neurons near the electrode based on the multi-site multi-unit recording data. The spatial distribution of the active neurons emerges the region in the neural tissue that could be killed or inactivated by the implant of the electrode. The proposed method will be useful for the in situ assessment of the neural electrode implanted in the brain.

DOI： 10.1109/IEMBS.2008.4650341

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Temporal relationships between hippocampal theta waves and pontine waves (P waves) during rapid-eye-movement (REM) sleep were investigated in rats. P waves were phase-locked to the positive theta peak. The phase relationships of P waves elicited by a tone stimulus (P(E) waves) to hippocampal theta waves were also analyzed to qualitatively clarify the mechanism of phase-locking between these two phenomena. P(E) waves occurred at the positive theta peak, as seen for spontaneous P waves. This phase preference of P(E) waves could be understood as that of the response probability to tone stimulus. These data suggest that the P-wave generator receives inputs that mimic theta waves. As hippocampal theta waves and P waves are known to be involved in learning and memory processes during REM sleep, the present studies could help to clarify these functions.

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Language：Japanese   Publisher：The Institute of Electrical Engineers of Japan  

Physiome inherently investigates hierarchical layers of biological system. In the post genome era, the number of layers should increase because possible mechanisms at molecular level are always referred to. However, biological modeling in the post genome era has to face unavoidable uncertainties in biological measurements and explosion of degree of freedom. An exhaustive modeling seems to be necessary to understand possible mechanisms underlying biological phenomena at every hierarchical level. However, simultaneously it looks like an impossible or reckless trial. In order to get rid of them, we propose a novel modeling strategy that integrates the top-down retrospection and bottom-up reduction modeling. Here, our strategy is applied to modeling of biological rhythms which is an appropriate system to study because of the penetration of rhythmic dynamics through all of the hierarchical layers.

DOI： 10.1541/ieejeiss.127.1486

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Other Link： https://jlc.jst.go.jp/DN/JALC/00300215159?from=CiNii

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DOI： 10.1111/j.1479-8425.2007.00319.x

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Physiological knowledge of the neural mechanisms regulating sleep and wakefulness has been advanced by the recent findings concerning sleep/wakefulness-related preoptic/anterior hypothalamic and perifornical (orexin-containing)/posterior hypothalamic neurons. In this paper, we propose a mathematical model of the mechanisms orchestrating a quartet neural system of sleep and wakefulness composed of the following: 1) sleep-active preoptic/anterior hypothalamic neurons (N-R group); 2) wake-active hypothalamic and brain stem neurons exhibiting the highest rate of discharge during wakefulness and the lowest rate of discharge during paradoxical or rapid eye movement (REM) sleep (WA group); 3) brain stem neurons exhibiting the highest rate of discharge during REM sleep (REM group); and 4) basal forebrain, hypothalamic, and brain stem neurons exhibiting a higher rate of discharge during both wakefulness and REM sleep than during nonrapid eye movement (NREM) sleep (W-R group). The WA neurons have mutual inhibitory couplings with the REM and N-R neurons. The W-R neurons have mutual excitatory couplings with the WA and REM neurons. The REM neurons receive unidirectional inhibition from the N-R neurons. In addition, the N-R neurons are activated by two types of sleep-promoting substances (SPS), which play different roles in the homeostatic regulation of sleep and wakefulness. The model well reproduces the actual sleep and wakefulness patterns of rats in addition to the sleep-related neuronal activities across state transitions. In addition, human sleep-wakefulness rhythms can be simulated by manipulating only a few model parameters: inhibitions from the N-R neurons to the REM and WA neurons are enhanced, and circadian regulation of the N-R and WA neurons is exaggerated. Our model could provide a novel framework for the quantitative understanding of the mechanisms regulating sleep and wakefulness.

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Rapid eye movement (REM) sleep is characterized by hippocampal theta waves and phasic spike-like waves originating from the pons, termed ponto-geniculo-occipital (PGO) waves in cats and pontine (P) waves in rats. While the theta wave and PGO/P wave have been suggested to participate in higher-order brain functions, their generation mechanisms and roles in brain functions have been studied independently. Therefore, the present study investigated instantaneous aspects of the relationship between theta waves and PGO/P waves in both cats and rats. Theta wave was instantaneously accelerated several hundred milliseconds before the negative peak of the PGO/P wave in both animals, and was also amplified just before PGO/P wave occurrence. Considering the integrated knowledge provided by studies of both animals, these results suggest that PGO/P wave-related activities in the pons are delivered to the theta wave generator. The activations of the theta wave coincident with PGO/P wave might facilitate cooperative contribution to higher-order brain functions in REM sleep.

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Sleep is involved in the development and maintenance of neural networks. We investigated how somatosensory deprivation affects EEG dynamics of adult rats during sleep, which might be a result of changes in neural organization. Rats' whiskers were clipped unilaterally daily and the resulting changes in the balance of EEG spectral powers between the intact and sensory deprived barrel cortices were recorded for a month. Both delta and theta band spectral powers in the deprived cortex initially decreased in terms of their ratio to the intact cortex. Subsequently, the ratio was restored to control levels. This non-monotonic change in EEG activity might reflect the re-organization process of the cortical circuit.

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Language：Japanese   Publisher：(公社)日本生体医工学会  

海馬リズム活動の発生・消滅過程において,リズム活動が空間的に同期していく過程を明らかにするために,カルバコールを負荷した海馬スライス標本のCA3領域において,局所脳波とニューロン活動を2点同時記録し,振動現象の時空間特性を解析した.生後3週齢のモルモットを用いた.CA3b領域においてγ〜θリズムが発生から消滅まで位相差ゼロで空間同期しているのに対し,高周波バースト波においては,空間同期は見られるものの,発生から消滅の過程において位相が変化していくことが明らかになった

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The present study examined the correlations between the dynamics of hippocampal theta waves and pontine waves (P waves) and rapid eye movements (REMs) densities during REM sleep. Theta wave peak frequency and theta amplitude were estimated as the parameters of theta wave dynamics in each 3s segment. The peak frequency and theta amplitude were positively correlated with P wave and REMs densities, however their detailed correlation properties were distinct from each other. Dependency of peak frequency on P wave/REMs density did not change significantly from that on REMs/P wave density. On the other hand, dependency of the theta amplitude on P wave/REMs density significantly increased with an increased REMs/P wave density. Because hippocampal theta waves and P waves are involved in learning and memory functions during REM sleep, the correlation between theta parameters and P wave density might help to clarify these functions.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Tokyo  

DOI： 10.1046/j.1446-9235.2003.00030.x

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We investigated the temporal relationship between hippocampal theta waves and ponto-geniculo-occipital waves (PGO) during rapid eye movement sleep (REM sleep) in cats. In addition, we analyzed the relationship between hippocampal theta waves and PGO as elicited by tone stimulus (PGO(E)) in order to quantitively characterize the PGO wave generator mechanism. The results showed that a spontaneous PGO tended to be phase-locked to the theta wave, which was more clearly observed in the single PGO than in the cluster. However, cluster PGO(E) tended to be phase-locked as well as single PGO(E). It was therefore suggested that the generator of PGO is activated in relation to the hippocampal theta wave. An acceleration of the theta wave associated with PGO occurrence was found, and was more markedly observed than with the cluster PGO. Although the magnitude of it was less than in the spontaneous case, an acceleration around the PGO(E) was also observed. These results suggest that the generators of theta and PGO receive some common activations, especially when a cluster PGO is generated. The interaction between PGO and hippocampal theta waves is expected to be involved in the possible functions of REM sleep.

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The study demonstrated that ponto-geniculo-occipital (PGO) waves are phase-locked with hippocampal theta-waves during rapid eye movement (REM) sleep. A possible mechanism for influencing a PGO wave generator by hippocampal theta-waves was hypothesized. The generator is known to receive afferent inputs such as auditory input. To test this hypothesis, the temporal relationship between hippocampal theta-waves and elicited PGO waves (PGO(E)) by auditory stimuli was analysed. The analysis showed that PGO(E) were synchronized with theta-waves, but did not reset the phase of a theta-wave. Because the occurrence of PGO(E) and spontaneous PGO waves shared the same phase-dependency on theta-waves, the results strongly suggest that the PGO wave generator was driven by theta-waves, as originally hypothesized.

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1046/j.1440-1819.2001.00820.x

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Recently, many sleep researchers are interested in the relationship between sleep and synaptic plasticity. In this study, we trained rats in skilled reaching, and measured sleep EEG in the motor cortex after the training. We found that i) slow wave EEG, whose frequency is 0.5-4.5Hz, was increased for 4h after the training in both sides of the motor cortex, ii) the progressive increment of the delta power of the trained side relative to the untrained side was found, but this asymmetry was no longer present after 4h of sleep. These results suggest that the training of skilled reaching, which presumably induces synaptic potentiation, results in slow wave EEG increases during subsequent sleep, and sleep returns the synaptic weight to a baseline level.

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Other Link： http://search.jamas.or.jp/link/ui/2015261141

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

We have been developing a virtual reality (VR) system that is applicable to behavioral testing of mouse. Because it is expected to improve efficiency and reproducibility of the behavioral testing. However it has been a problem that a mouse sometimes shows unnatural behaviors probably due to imperfect recognition of virtual environment (VE). To ensure recognition of VE, we develop an equipment providing somatosensory feedback to the mouse, i.e. a mouse is applied an air-puff stimulation from an appropriate direction when the mouse is touching a virtual wall. When the somatosensory feedback is activated, the mouse tends to avoid touching virtual walls. As a result, trajectory of movement in the VE becomes similar to that in the real world. Therefore it is suggested that the developed somatosensory feedback would improve the sense of reality of the VR system for mice.

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Language：English   Publishing type：Research paper, summary (international conference)  

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Language：Japanese   Publisher：Japan Soc. of Med. Electronics and Biol. Engineering  

DOI： 10.11239/jsmbe.52.O-381

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Language：Japanese   Publisher：Japan Soc. of Med. Electronics and Biol. Engineering  

DOI： 10.11239/jsmbe.52.O-369

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Language：Japanese   Publisher：Japan Soc. of Med. Electronics and Biol. Engineering  

DOI： 10.11239/jsmbe.52.OS-69

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When a rodent is running, learning and having REM sleep, a rhythmic EEG activity at 6-9 Hz, called the hippocampal theta rhythm, is observed in the hippocampus of the rodent. It is well known that the frequency and the amplitude of the theta rhythm are modulated by the several types of modality of sensation including the vestibular sensation, which is one of the most effective to the rhythm. In this study, we simultaneously recorded the head acceleration and the hippocampal EEG of mice during a passive periodic movement to analyze the effect of frequency and power of the passive movement on the hippocampal EEG. When a periodic movement at 1-4 Hz is loaded to the mouse, the power of hippocampal theta EEG (6-9 Hz) increased with an increase of the frequency. In addition, the power of the hippocampal EEG at the moving frequency also increase during the passive movement. These results suggest the strong influence of the vestibular sensation to the hippocampal EEG activity.

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Other Link： http://search.jamas.or.jp/link/ui/2014120863

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Other Link： http://search.jamas.or.jp/link/ui/2014120864

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Recently, many sleep researchers are interested in the relationship between sleep-wake rhythm and synaptic plasticity. In this study, we performed whole-cell patch-clamp recordings from layer II/III pyramidal neurons of somatosensory cortex in acute slices of the rats that had been awake or asleep to investigate the effect of wake on excitatory synaptic transmission. We found that i) current-voltage relationship of EPSCs showed inward rectification, and ii) eEPSCs were depressed by Philanthotoxin 74, which is antagonist of Ca^<2+> -permeable AMPA receptors, in slices of waking animals. Both results show that Ca^<2+> permeable AMPA receptors levels are high during wakefulness and periods of wakefulness are associated with an increase in cortical synaptic strength.

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Other Link： http://search.jamas.or.jp/link/ui/2014120862

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We have developed an immersive virtual reality system for mice. By using this system, we recorded locomotion activity of free-moving mice in an infinite wide virtual world. It was found that shape of trajectory of locomotion was strongly dependent on the kinematic parameters of a spherical treadmill that was used to measure the locomotion activity. After adjusting the kinematic parameters of the treadmill properly, locomotion and hippocampal EEG were simultaneously recorded. It was confirmed that the power spectral density of EEG changed strongly dependent on behavior of the mice which was similar to that observed in mice freely behaving in real world. In addition, we found that the frequency of hippocampal theta EEG was correlated with the locomotion speed in the virtual world.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

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There is a large number of studies showing that REM sleep contributes memory consolidation. The mechanism of the memory consolidation during REM sleep is not clear, but hippocampal theta waves and PGO waves are suggested to be involved in the memory processes. In this study, we have recorded the theta waves and PGO waves during REM sleep in fear-conditioned rats to clarify the mechanism. We found that frequency of hippocampal theta waves and PGO wave densities were increased just after the fear learning. These results suggest that PGO and theta waves contribute cooperatively to the REM sleep dependent memory consolidation.

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Other Link： http://search.jamas.or.jp/link/ui/2013202691

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

We investigated the relationship between sleepiness and amplitude of amplitude-modulation following response (AMFR) to find the best tone to raise awareness of sleepy drivers. In this study, auditory responses which were evoked by amplitude modulated tones whose carrier frequencies were 500, 1000, 4000, and 8000Hz were recorded in 16 subjects. Performance level was divided into three stages by using reaction time of psychomotor vigilance test, and the amplitude of AMFR was found to be decreased as the decrement of the performance in all frequency range. The high performance stages were further divided into two stages, those with alpha wave and without alpha wave. We found that auditory responses evoked by 500Hz AM tone in alpha wave state were smaller those in no-alpha state, but those evoked by the other AM tone were consistent. These results suggest that the high frequency tone could make drivers aware of their sleepiness.

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Other Link： http://search.jamas.or.jp/link/ui/2013202690

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We developed a system for recording of multi-channel neural activity and local field potential in freely moving rats. This system is composed of four 8-wire electrodes (octrodes), four microdrives, 32-channel high impedance DC amplifiers, band-pass filters (0.8 Hz-5000 Hz), 32:1 multiplexer, single channel A/D converter and custom-made data acquisition software.

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Other Link： http://search.jamas.or.jp/link/ui/2012099236

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

It has been suggested that the electrode-to-axonal distance selective recruitment of relatively thick myelinated axons can be achieved by the down staircase-shape electrical nerve stimulation delivered from an extracellular electrode. However, the response of thin axons such as stimulus pulse duration dependency has not clarified. In this research, we investigated the pulse duration-dependency of the response of a thin myelinated axon model to square pulse stimulation by the numerical simulation. It was shown that short pulse stimulus (duration = 50 μs) activated only axons close to the electrode. In contrast, the stimulus with longer duration (e.g. 200 μs) activated more distant axons without activating near axons. However, stimulus with much longer duration (e.g. 500 μs) did not show distance-selective recruitment of axons due to occurrence of anodal break excitation of axons in the neighborhood of the electrode. In addition, thin axons (&lne;1 μm) at more than 300 μm far from the electrode could not be activated by the square pulse stimulation.

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Other Link： http://search.jamas.or.jp/link/ui/2012099235

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2011&ichushi_jid=J04991&link_issn=&doc_id=20110117080002&doc_link_id=%2Fai5slepd%2F2010%2F000404%2F003%2F0469-0475%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fai5slepd%2F2010%2F000404%2F003%2F0469-0475%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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Although auditory evoked response (ABR) was considered to be insensitive to physiological sleep, we found that amplitude of the ABR increases during NREM sleep. In this study, effect of carbachol, which activates muscarinic receptor, on amplitude of the ABR was examined to show the role of acetylcholine in the sleep-wake state dependency of ABR amplitude. Amplitude of ABR wave IV was found to decrease just after the injection of carbachol into the lateral ventricle. Because acetylcholine concentration is high during wakefulness, these results suggest that acetylcholine plays a crucial role in the attenuation of ABR during wakefulness.

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Other Link： http://search.jamas.or.jp/link/ui/2011101851

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

In extracellular action potential (spike) recording of neurons, information about the location of neuron is useful for neuronal spike sorting, optimization of position of the recording electrode and so on. In this study, the accuracy of position estimation methods of neuron based on the multi-site neuronal spike recording is compared by using the computer simulation of extracellular action potential generated from a compartmental model of neuron. In addition, performance characteristics of multi-site electrodes with different shape and layout of recording sites are evaluated in terms of the accuracy of position estimation of neuron.

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Other Link： http://search.jamas.or.jp/link/ui/2011101850

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

We recorded Auditory Brainstem Responses (ABR) in humans and investigated the relationship of sleepiness to ABR amplitude to know whether the ABR can measure sleepiness or not. Objective sleepiness is measured by reaction time, which is defined as a reaction latency on button-press action, and facial expression scale. The amplitude of ABR, especially wave IV-V complex, was found to be significantly increased with an increase in sleepiness measured by both reaction time and facial expression scale (p<0.05), suggesting that sleepiness could be measured by ABR amplitude.

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Other Link： http://search.jamas.or.jp/link/ui/2011101849

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Multi-unit recording methods with multi-channel electrodes have been widely used for brain-machine interface system. For sorting neuronal spikes recorded by this method, the independent component analysis (ICA) is very useful because this analysis can separate neuronal spikes even if the spikes are overlapped. However the accuracy of the spike sorting was insufficient. We have proposed an efficient spike sorting method combined with continuous wavelet transform and complex-valued ICA (WICA method). In this study, we developed a real-time system composed of a DOS PC and a Windows PC. It was confirmed that this system is capable of hard real-time detection and sorting of neuronal spikes within 1.5-milli-seconds.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

The rodent's whisker sensory information is transmitted to barrel cortex via ventral posteromedian nucleus (VPM) and posterior medial nucleus (POm) of thalamus. It is suggested that POm transmit whiskering sensation, and VPM transmit both whiskering and steady sensation. In this study, we investigate the spatio-temporal dynamics of barrel cortex in response to VPM stimulation using thalamocortical slice preparation of mice, in which thalamus, neocortex and thalamocortecal synaptic connections are kept alive. It is found that the successive two electical stimulation (paired pulse stimulation) to VPM with interval of less than 300-ms showed paired-pulse depression (PPD) of the response in the barrel cortex. The current source-density analysis suggests that the PPD occurrs at the synaptic transmission from VPM to layer 4 neuron in the barrel cortex.

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Other Link： http://search.jamas.or.jp/link/ui/2010152580

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

There is a hypothesis that the thalamus is the primary structure involved in closing the sensory gate during sleep. Recent findings which shows amplitude of auditory evoked potential during NREM sleep tends to be larger than that during wakefulness conflicts with the hypothesis. In this study, somatosensory evoked potential in the somatosensory cortex was recorded during different sleep-wake state to examine whether there is a common tendency in the other sensory modality. We found that the somatosensory evoked potentials during NREM sleep were larger than those during wakefulness. On the other hand, the evoked potentials during REM sleep were low amplitude as well as those during wakefulness. Taken together, these results suggest that there is a common mechanism involved in state dependency of sensory evoked potentials and the sensory input is not disrupted at the thalamus level during NREM sleep.

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Other Link： http://search.jamas.or.jp/link/ui/2010152581

Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

Sleepiness at the wheel is one of the causes of fatal crashes and highway accidents by car drivers. Since the EEG alpha activity occurs in association with the subjective sleepiness, and the alpha activities are observed in a mixed signal, aureate decomposition method has been required. In this study, we propose a method to decompose the time-delayed mixture of alpha source signals by using the time-frequency domain analysis and complex-valued independent component analysis. The method is applied to the human scalp EEG data to decompose the alpha activities occur associated with the subjective sleepiness during a driving simulation task. It is shown that this method provide information about not only the spatial distribution of alpha power (power map) generated by each source but also the phase difference among the recording site (phase map). The alpha power map and the phase map would be useful for the investigation of the mechanism of cortical alpha rhythms such as dipole estimation in the brain

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Other Link： http://search.jamas.or.jp/link/ui/2010152586

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Single-ICA can be very useful method to extract independent components from signal observed by single channel. But there is still a problem in the accuracy of separation and a lot to work on. We propose a simple single-ICA algorithm using blind source separation with references, and investigate the changes in the accuracy of separation and time gap between extracted signal and source signal, by altering the dimension and the lag time of the multi-dimensional embedded matrix. Then the result is that each extracted signal shows different change characteristics for the increase of dimension and lag time. Considering the property that causes these change characteristics, we are expecting these results to be helpful for optimal design of dimension and lag time.

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Language：Japanese   Publisher：日本時間生物学会  

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Language：Japanese   Publisher：(公財)金原一郎記念医学医療振興財団  

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2009&ichushi_jid=J00731&link_issn=&doc_id=20090810090005&doc_link_id=10.11477%2Fmf.2425100857&url=https%3A%2F%2Fdoi.org%2F10.11477%2Fmf.2425100857&type=%88%E3%8F%91.jp_%83I%81%5B%83%8B%83A%83N%83Z%83X&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00024_2.gif

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The mechanical distortion of neural tissue caused by the implant of neuronal electrodes is an important factor affecting the performance of neuronal spike recording in the brain because the mechanical distortion could kill or inactivate the neurons. In this study, we propose a method to obtain the information about the mechanical distortion near the electrode based on the extracellular potential waveforms recorded by the multiple-site electrode. First, the three-dimensional position of each neuron is estimated making use of the spatial profile of action potential. Second, the shift of the neuron in the neural tissue with a movement of the electrode is estimated to visualize the effect of mechanical strain induced by the electrode. Our method will provide useful information for the assessment of the implant of neural electrode in the brain.

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Other Link： http://search.jamas.or.jp/link/ui/2009175124

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Multi-unit recordings with multi-site electrodes have been widely used in the field of neuroscience and neuroengineering, for such as brain-machine interface. This method requires sorting of neuronal spikes according to the pattern of spike waveforms. For this purpose, the independent component analysis (ICA) is known to be useful. However the accuracy of the sorting result is not sufficient in many cases. We have proposed an efficient spike sorting method combined with the wavelet transform and the complex-valued ICA (WICA method) which achieves higher sorting accuracy than the conventional ones. In this study, we explore the parameter dependency of the WICA method on the accuracy of sorting results by using the simulated multi-unit data. In addition, we propose three methods to automatically determine the threshold level for neuronal spike detection from the unmixed signals obtained by the WICA method..

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Circadian and cell cycles are suggested to be linked at molecular level. In order to elucidate the mechanism of interactions, we first established a model for cell cycle in eukaryotes, which involves Cyclin: CDK, CDC25, Wee1, Cyclin: CDK: CKI, SKP2, APC and CDC20. Because Wee1 is suggested to be a candidate to establish the link, phase responsiveness was investigated by applying a perturbation on Wee1 transcription in the model. We found that the growth curve of cell mass has a critical role in the responsiveness. The model with a power law growth curve exhibited a PRC with only a delay response, which will be used to study circadian regulations on cell cycle.

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Other Link： http://search.jamas.or.jp/link/ui/2008171591

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Multi-neuronal activity was recorded by using multi-electrode in the raphe and the tegmental nuclei. In these nuclei, there are "sleep regulating neurons" that are believed to be involved in regulation of sleep-wake rhythm. Cross-correlation analysis of spike trains suggested that (i) there are the functional connections between the adjacent neurons; (ii) there are the connections not only between sleep-regulating neurons, but between state-unrelated neurons and sleep-regulating neurons. These will provide a novel framework for the understanding of the mechanisms regulating sleep and wakefulness.

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Other Link： http://search.jamas.or.jp/link/ui/2008171592

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Blind source separation using reference signals (BSSR) is very useful especially when target signals have distinctive features, where the performance of separation is known to have robustness against uncertainties of the reference signals. Here, detail properties of the robustness were investigated by diluting spike waves composed of the reference signal, widening the spikes, and altering the order of evaluation function. Increased dilution rate and wider spikes were found to deteriorate the performance of BSSR; the 4th order of correlation evaluation was shown to be optimal. These results are expected to be helpful for optimal design of reference signals.

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In order to obtain good signal-to-noise ratio recording of neuronal activities in the brain, adjustments of parameters of neural electrode such as the shape of electrode, number of recording channel and arrangement of recording points are essential. However these parameters have been empirically decided so far because of the high cost to test the electrode by using experiment animals. In this study, we develop a simulation system, which is composed of three-dimensional model neural tissue of the hippocampal CA3 region and the model of extracellular action potential recording system. By combining experimental data and simulation results, we characterize the extracellular electrodes. This system would be useful for the design and test of the neural electrode..

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Multi-site multi-unit recording method using multi-channel electrodes have been widely used for brain-machine interface system. Independent component analysis (ICA) is useful for sorting neuronal spikes recorded by this method because this analysis can separate neuronal spikes even if the spikes are overlapped. However the sufficient result would not be obtained if only this analysis was simply applied to the experimental data. We have proposed an efficient spike sorting method combined with continuous wavelet transform and complex-valued ICA. In this study, we show that our method has a better efficiency for sorting noisy data than the conventional method. In addition, we implement this method in a digital signal processor system. This system can process neuronal spike sorting within 2-milli-seconds in real-time.

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Language：English   Publishing type：Book review, literature introduction, etc.  

DOI： 10.1007/s00018-007-6534-z

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2007&ichushi_jid=J00060&link_issn=&doc_id=20070126200006&doc_link_id=%2Faa7ayuma%2F2007%2F022004%2F007%2F0303-0307%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Faa7ayuma%2F2007%2F022004%2F007%2F0303-0307%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

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DOI： 10.1152/jn.z9k-7840-corr.2006

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Multi-site multi-unit recording using a multi-channel electrode is an powerful method for investigating cooperative activity of numerous neurons that interact with each other in the network. In this method, each spike waveform should be sorted into spike-generating neuron by means of pattern matching. However the conventional spike-sorting methods can not correctly resolve overlapping spikes that are caused by synchronized firing of neurons. Recently several methods utilizing the independent component analysis (ICA) have been proposed to overcome this problem, but their performance is insufficient. In this study, an improved spike-sorting method combining continuous wavelet transform and complex-valued ICA is proposed. Computer simulation shows that the new method more accurately resolves overlapping spikes than the conventional ICA-based method.

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Other Link： http://search.jamas.or.jp/link/ui/2007231030

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In the somite, the segmental unit for the metametric structure such as skeletal muscles, vertebrate, and ribs, are sequentially generated in a head-to-tail order by segmentation of the mesenchymal tissue called presomitic mesoderm (PSM). The segmentation occurs periodically at the anterior end of the PSM, and this periodic segmentation has been suggested to be regulated by a molecular clock. In mouse PSM, Notch signaling molecules such as Hes and Lfng alternate their expression every 120 minutes, and this cyclic expression is essential for regular somite segmentation. In this paper, according to recently accumulated knowledge, a molecular network model of segmentation clock mechanisms is constructed. Through simulations, it is clarified how the dynamics of gene expressions are regulated by interactions between molecules.

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Other Link： http://search.jamas.or.jp/link/ui/2007231031

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Recent neuroscience research has revealed that sleep is controlled by complicated interactions among many "sleep regulating neurons"' in the hypothalamus and brainstem. Here, we propose a neural network model consisting of these neurons on the basis of the new physiological findings. As a result, this model reproduces many physiological phenomena, such as 90-minute (NREM-REM) ultradian cycles as well as 24-hour sleep-wake cycles. Furthermore, activities of the model neurons mimic rough profiles of the actual neuronal discharge across sleep stage transition. This model will provide a novel framework for the quantitative understanding of the mechanisms regulating sleep and wakefulness.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Cross-correlation histogram (CCH) of simultaneously recorded multiple neuronal activities has widely been used to decide whether a synaptic connection between two neurons exists or not. In this report, we point out problems in accuracy of statistical testing using conventional shuffling-corrected CCH method when the contribution of shared inputs for the neurons on the CCH is strongly dependent on the lag-time of the correlation function. We propose an improved testing method utilizing the characteristics of shuffling CCH, which has only been used to cancel the effect of the shared input to the raw CCH so far. In addition, we develop a method to evaluate the intensity of the neuronal connectivity utilizing the CCH based on a simple input-output relationship of a neuron and characteristics of common driver.

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Language：Japanese   Publisher：(株)メディカルレビュー社  

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Language：English   Publishing type：Book review, literature introduction, etc.  

DOI： 10.1111/j.1479-8425.2006.00206.x

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Fetal electrocardiogram (fECG) has been expected to play an important role in monitoring condition of fetal heart. A blind source separation (BSS) has been employed to extract the fECG. However, extracted fECG is not so reliable for clinical application. Distortion or nonlinearity of the fECG signal is one of the main reasons of this difficulty. We have developed a new filtering method to extract nonlinear signals from the noisy mixed observation. In this paper, the result of extraction is shown together with the filtering method.

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Other Link： http://search.jamas.or.jp/link/ui/2006069539

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Sleep-wake rhythms are considered to be controlled by the mutually interacting two oscillators, one for suprachiasmatic(SCN) oscillator, and the other for non SCN oscillator. We have developed two different mathematical model of human sleep-wake rhythms : one is the phase dynamics model of human circadian rhythms, and the other is the thermoregulatory model of sleep control. A phase dynamics model and thermoregulatory model are mutually complementary. The former cannot provide amplitude information such as temperature and sleepiness, and the latter can work only under the externally entrained conditions. We try to integrate them by mapping the phase dynamics onto the oscillators of the thermoregulatory model. The behavior of integrated model is shown in this paper.

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Other Link： http://search.jamas.or.jp/link/ui/2006069538

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

The synaptic plasticity dependent on the order and time interval of pre- and postsynaptic spikes (spike timing-dependent-plasticity, STDP) is observed in the hippocampus and cerebral cortex. STDP is believed to play an important role in self-organization of network structure in the brain. In this study, we explored self-organizing process of network in a model of neural circuit incorporating STDP rule and time delay for signal transmission among neurons, which is an extended version of a model proposed by Kitano et al. It is shown that the self-organizing process and resultant network structure are strongly dependent on the time delay.

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Other Link： http://search.jamas.or.jp/link/ui/2006032004

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Other Link： https://projects.repo.nii.ac.jp/?action=repository_uri&item_id=309961

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Gamma frequency (20-80Hz) oscillation of electroencephalogram observed in the hippocampus and cerebral cortex is expected to be used as neural clock for parallel distributed information processing. Recently, it has been shown that the gamma oscillation is mainly generated by the synchronous activities of the interneuron network. In this study, we explore topological conditions for generation of spatially coherent gamma oscillation by the computer simulations. It reveals that the boundary line for coherent gamma oscillation in the parameter space agree well with isogram of the product of average number of synaptic contacts par neuron and clustering coefficient of the network, which measures the cliquishness of neighborhood.

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

We have examined EEG power spectra during transition of sleep stages in rats, which discloses characteristic EEG dynamics associated with the transitions. In this study, we analyzed a relationship between EEG dynamics and neuronal activities in the hypothalamus and the brainstem. These neurons are known to have something to do with sleep-wake regulation. As a result, we found these neuronal activities were correlated with EEG theta (5-10Hz) and alpha (10-16Hz) band power spectra. Additionally, neuronal activities started to change at or prior to the transition. These results suggest that these neurons play different roles in switching and maintaining sleep stages.

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Other Link： http://search.jamas.or.jp/link/ui/2005048896

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Gamma frequency (20-80Hz) oscillation observed in the cerebral cortex and hippocampus thought to be supported by the synchronous activities in the interneuron network. In this study, a model of interneuron network proposed by Wang & Buzsaki is extended to study the effect of spatial network structure and time delay for synaptic interaction on the γ-range synchronous neural activities. It is shown that 'Small-World'-like structure is useful for generation of synchronous activities. In addition synaptic delay also gives increase of γ-range synchronization.

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Other Link： http://search.jamas.or.jp/link/ui/2005048895

J-GLOBAL

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Language：English   Publishing type：Research paper, summary (international conference)  

Web of Science

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Sensory deprivation is known to alter the neural organizations involved for processing the deprived neural information especially in developmental process. However, long-term effects of the sensory deprivation have not yet been well-understood. In order to investigate this effect on the post-mature neural organizations and possible contribution of sleep to them, cortical EEG dynamics during sleep in adult rats were measured during up to a month, while somatosensory inputs were constantly deprived by cutting whiskers unilaterally. Keeping rat's whiskers cut unilaterally, the resulting change in balance between EEG spectral powers in the intact and the sense-deprived barrel cortices was traced. Spectral powers of EEG in the sense-deprived barrel cortex decreased in terms of their ratio to the intact during initial 10 days. Subsequently, the ratio was gradually restored to the control level. The resulting change in EEG dynamics is expected to be caused by a certain re-organization of neural circuits associated with the long-term sensory deprivation. The results here suggest the possibility of alternation in neural circuit even after maturation.

CiNii Research

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Other Link： http://search.jamas.or.jp/link/ui/2004126293

J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

The spike potentials called rapid eye movements anticipatory phasic potentials(RAPPs), discovered in our laboratory, have been suggested that its source is located in the brain stem. In order to verify the hypothesis, a human head model consisting of an actual human skull was constructed. In addition, the potential distribution produced by the artificial current dipole located at the sites corresponding to the brain stem was measured on the surface of the head model. The potential distribution fairly mimicked the RAPPs. This result suggests that the RAPPs would correspond to the potential electronically spread from the brain stem through the optic canal and the superior orbital fissure.

CiNii Research

J-GLOBAL

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Other Link： http://search.jamas.or.jp/link/ui/2002155400

J-GLOBAL

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J-GLOBAL

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Spontaneous single-unit activities during sleep were recorede from neurons of the cat's cerebellar cortex. The activities showed a white noise-like spectrum in the low frequency range, 0.04-1.0Hz, during steadystate non-REM sleep (slow-wave sleep), and the 1/f-noise-like during REM sleep. These results were consistent with our previous reports regarding the thalamic ventrobasal complex neurons as well as the hippocampal theta and pyramidal neurons, the neurons of the mesencephalic reticular formation, the primary somatosensory cortex, areas 6 and 18 of the cortex, the lateral geniculate nucleus, supporting the generality of the neuronal dynamics-alternation during sleep in the processor system which is tentatively called by us.

CiNii Research

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Other Link： http://search.jamas.or.jp/link/ui/2001131287

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

We investigated the temporal relationship between hippocampal theta waves and PGO waves during REM sleep which presumablely relates to the higher-order brain functions. We found that the PGO waves phaselocked to the hippocampal theta waves. In order to clarify the phase-locking mechanism, auditory stimuli were employed to elicit PGO waves (PGO_E) at an arbitray phase in reference to the theta wave. As a result, the occurrence probability of PGO_E in response to the stimulus was found to depend on the hippocampal theta wave rhythm. These results suggest the mechanism that the potine tegmentum neurons, generator of PGO waves, are driven by the hippocampal theta wave rhythm and auditory afferent inputs.

CiNii Research

J-GLOBAL

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Other Link： http://search.jamas.or.jp/link/ui/2001127180

Event date： 2024.10

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2024.7

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Event date： 2024.3

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Venue：愛知県名古屋市  

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Venue：山形県山形市  

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Venue：福岡県福岡市  

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Event date： 2022.3

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Event date： 2022.2

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Venue：オンライン  

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Event date： 2021.6

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Event date： 2020.5

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Venue：オンライン開催  

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Venue：福島県郡山市  

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Venue：長野県長野市  

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Award type：Award from Japanese society, conference, symposium, etc. 

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Award type：Award from Japanese society, conference, symposium, etc. 

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