ワーキングメモリ・実行機能 Working Memory and Executive Function
P1-1-177 スパイク時間依存の計算とセルアセンブリによるワーキングメモリ形成 Spike-based computations and cell assemblies as a basis of working memory ○深井朋樹1 ○Tomoki Fukai1, Matthieu Gilson1,2 理化学研究所　脳センター1, 科学技術振興機構　戦略的創造研究推進事業2 RIKEN Brain Science Institute, Wako1, CREST, Japan Science and Technology2 Cortical neurons can retain information about sensory input in their firing activity that may last several minutes to hours after the end of the stimulus presentation. Such a temporary storage of information is necessary for organizing behavior and is referred to as working memory. Several models have been proposed to explain this sustained firing at the level of neurons. For example, short-term facilitation can lead to stimulus-dependent network responses. Here we examine an alternative mechanism, which postulates that stimulus-specific cell assemblies are formed by strong connections within a recurrent network. Schematically, synapses exhibit a bistable property with a low baseline level and a high potentiated level. The transitions between these two states follows from synaptic dynamics that are sensitive to the transient response of neurons to correlated activity. Concretely, we use an inherently bistable spike-timing-dependent (STDP) model, inspired by a recent model of calcium-based plasticity. Our model explains how sustained firing activity in response to stimuli slowly builds up over a learning epoch. Stimulating inputs exhibit coordinated firing at short time scales, which is captured by STDP. The slow build-up arises because neurons belonging to the same assembly share more and more strong synapses, whereas other synapses remain at a baseline level. The emergent structure of strong synaptic weights generates stereotypical activity in the recurrent network, namely sustained correlated firing that has some bearing with attractor networks.	P1-1-178 Measure Cognitive Load Using Electroencephalography Technology ○Ting-Kuang Yeh1, Po-Lei Lee2, Chun-Yen Chang1, Pei-Jung Lin1,3 Institute of Marine Environmental Science and Technology, National Taiwan Normal University, Taipei, Taiwan1, National central University2 This study aims to measure learner's cognitive load using electroencephalography technology. The cognitive load theory, which describes the cognitive processes involved in learning and understanding, has been somewhat limited, in regard to addressing said issues. Cognitive processes are hidden from our observations, how to evaluate cognitive load over time by subjective measurements has been regarded as an important issue. In the current study, participants performed three tasks of different difficulty levels. Event-relation de-synchronization /synchronization (ERD/ERS) and Fourier spectrum will be utilized to measure cognitive load. A significant finding is that increased cognitive load is associated with higher brain wave desynchronization for alpha rhythms. Furthermore, higher brain wave power at 12 Hz for the alpha rhythms is associated with increased cognitive load. These recent and exciting results support the feasibility of using EEG-based methods for monitoring cognitive load during learning process.
P1-1-179 安静時機能的結合はワーキングメモリ成績個人差を予測する Resting state functional connectivity predicts individual differences in working memory performance ○山下真寛1,2, 今水寛1,3 ○Masahiro Yamashita1,2, Hiroshi Imamizu1,3 ATR認知機構研1, 奈良先端大・情報科学2, 情報通信研・脳情報通信融合研究センター3 ATR Cognitive Mechanisms Labs., Kyoto, Japan1, Information Science, NAIST, Japan2, NICT Center for Information & Neural Networks, Osaka, Japan3 Resting state functional connectivity (RS-FC) reflects spontaneous brain activity. Recent studies have suggested that RS-FC predicts an individual's age, perception, and cognitive function. However, it is unknown whether individual differences in working memory (WM) can be predicted from RS-FC that was recorded before first exposure to a WM task. Here, we tested a hypothesis that RS-FC can predict individual differences in WM performance. Nineteen healthy subjects were recruited in the experiment. Five-minute resting state functional magnetic resonance imaging (RS-fMRI) was recorded, and the following day the subjects performed a 3-back task for 25 trials. Using a sparse linear regression model, we predicted a performance index in WM task (A-prime) from RS-FCs among 142 regions of interest that were selected from default, fronto-parietal, cingulo-opercular, sensorimotor, and occipital networks. Leave-one-subject-out cross validation was used to estimate prediction accuracy. Consequently, R2 between the observed mean A-prime and the predicted one for individual subjects was 0.73, which is significantly greater than chance level according to a permutation test (p = 0.002). The sparse model selected RS-FCs within default network regions and between default, cingulo-opercular, and sensorimotor network regions as relevant features. These results suggest that RS-FC holds sufficient information to predict individual differences in WM performance and that RS-FC between multiple networks is critical for efficient working memory.	P1-1-180 歯磨き行為における大脳前頭前野活性化についての検討 The evaluation of the effect of tooth brushing on the activity of prefrontal cortex in young adult subjects ○大倉義文1, 力丸哲也2, 粟生修司3, 栢豪洋2, 山川烈4 ○Yoshifumi Okura1, Tetsuya Rikimaru2, Shuji Aou3, Hidehiro Kaya2, Takeshi Yamakawa4 福岡医療短期大学 保健福祉学科1, 福岡医療短期大学 歯科衛生学科2, 九州工業大学大学院 生命体工学研究科脳情報専攻3, 一般財団法人　ファジィシステム研究所4 Department of Welfare System and Health Sciences, Fukuoka College of Health Sciences, Fukuoka1, Department of Dental Hygiene, Fukuoka College of Health Sciences, Fukuoka2, Department of Brain Science and Engineering, Graduate School of Life Science and Systems Engineering (LSSE), Kyushu Institute of Technology, Kitakyushu3, Fuzzy Logic Systems Institute, Kitakyushu4 The oral care has been focused on as one of the method of prevention from bedridden situation and rehabilitation in the elderly persons. Although some previous reports have demonstrated the association of the cerebral activation with oral care including tooth brushing, the effect of tooth brushing stimulation on the prefrontal cerebral cortex activation has remained uncertain. In the present study, we examined the effect of intra-oral brushing on the cerebral prefrontal cortex activation using near-infrared spectrography in 11 male young adult subjects (aged 20-47 years, mean age 28.1 ± 9.6 years). Brushing on the gingiva for 60 sec significantly increased blood flow levels in bilateral prefrontal cortex (PFC), compared to the control condition and brushing on the tooth surface. In addition, the increase in PFC blood flow with gingival brushing remarked in bilateral visceral lateral region of PFC (VL-PFC) and working memory regions corresponded to the activated regions after learning task such as simple calculation. However, the increase of blood flow in these PFC regions with gingival brushing (task) showed lower level compared to those with learning task as positive control. These findings suggest that the gingival brushing as an oral care may lead to an increase in blood flow in PFC and may indicate that the intra-oral stimulation may be applied as a useful method for enhanced neurocognitive function in the elderly rehabilitation program and the prevention from bedridden situation via the neuronal activities in PFC.
P1-1-181 日本人の成人自閉症スペクトラム障害患者におけるWCSTを用いた認知の柔軟性の障害の検討 Impaired cognitive flexibility in Japanese patients with Autism Spectrum Disorders in the Wisconsin Card Sorting Test ○安田由華1, 橋本亮太1,2, 大井一高1,2, 山森英長1,3, 福本素己1, 藤本美智子1, 武田雅俊1 ○Yuka Yasuda1, Ryota Hashimoto1,2, Kazutaka Ohi1,2, Hidenaga Yamamori1,3, Motoyuki Fukumoto1, Michiko Fujimoto1, Masatoshi Takeda1 大阪大学大学院医学系研究科　精神医学1, 大阪大学大学院大阪大学, 連合小児, 子どものこころの分子統御機構研究センター2, 分子精神神経学（大日本住友製薬）寄附講座3 Dept Psychiatry, Univ of Osaka, Osaka, Japan1, Mol Res Cent for Children's Ment Develop, United Graduate School of Child Develop, Univ of Osaka, Osaka, Japan2, Dept Mol Neuropsych, Univ of Osaka, Osaka, Japan3 Background: Executive dysfunction is one of the core symptoms in Autism Spectrum Disorders (ASDs). The purpose of the present study was to compare executive performance in adolescents and adults with ASDs to that in controls in Japanese. Methods: Twenty four individuals with ASDs and 42 controls were participated. The ASD and the control groups' demographic variables were matched for age (mean±SD; ASD: 26.9±12.1, Control: 27.0±5.2), gender (Men/Female; ASD: 15/9, Control: 24/18), Full-Scale IQ (ASD: 99.8±13.0, Control: 100.1±7.8), Performance IQ (ASD: 93.7±12.4, Control: 94.4±10.1), and Verbal IQ (ASD: 104.5±13.7, Control: 104.6±8.8). All participants were Japanese and they completed the Wisconsin Card Sorting Test (WCST), an assessment of several executive processes concerned with problem solving and cognitive flexibility. Scores for the five indices of this test, including numbers of category achieved(CA), numbers of response cards until the first category achieved (NUCA), total errors (TE), perseverative errors of Milner (PEM), and perseverative errors of Nelson (PEN), were analyzed using Mann-Whitney's U test. Results: Performances of TE and PEM in ASD group were significantly poorer than those in control group (TE; ASD: 18.5±7.8, Control: 14.6±4.5, p<0.05; PEM; ASD: 3.4±4.2, Control: 1.8±2.5, p<0.05). However, there were no significant differences in the other scores between the groups. Conclusion: PEM reflects cognitive flexibility to adapt to the new situation. In this study, we could measure cognitive inflexibility in patients with ASD without mental disabilities on the WCST. To the best of our knowledge, this is the first report on the WCST performance in adolescents and adults with ASD in Japanese. This may suggests that the WCST could become an attractive endophenotype measurement in ASD in Japanese. Using larger scale studies will lend robustness to these data.

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