Project/Area Number |
08279103
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Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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Allocation Type | Single-year Grants |
Research Institution | The University of Tokyo |
Principal Investigator |
AIHARA Kazuyuki The University of Tokyo Graduate School of frontier Sciences, Professor, 大学院・新領域創世科学研究科, 教授 (40167218)
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Co-Investigator(Kenkyū-buntansha) |
YAMADORI Atsushi Tohoku University Graduate School of Medicine, Professor, 大学院・医学系研究科, 教授 (10030892)
TSUKADA Minoru Tanagawa University Department of Information Communication Engineering, Professor, 工学部, 教授 (80074392)
SAKATA Hideo Nihon University School of Medicine Department of Physiology, Professor, 医学部, 教授 (10073066)
SHINOMOTO Shigeru Kyoto University Department of Physics Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (60187383)
FUJII Hiroshi Kyoto Sangyo University Department of Information & Communication Sciences, Professor, 工学部, 教授 (90065839)
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Project Period (FY) |
1996 – 1999
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Keywords | High spatial resolution MEG / Short-term memory of 3D shape / Spatio temporal learning rule / Episodic memory / Hippocampus / Coincidence detector system / Dynamical cell assembly hypothesis / Spike statistics |
Research Abstract |
Toyama : Simultaneous study of psychophysical and cortical responses recorded by high spatial resolution MEG revealed responses localized in V2/3 that paralleled with perception of contours in various stimulus conditions, and indicated that V2/3 is the primary site for perception of contour from motion. Sakata : l. We found in the anterior intraparietal (AIP) area, visually responsive neurons that discriminated 3D shape of object. Some of them showed sustained discharge during delay period, suggesting to represent immediate memory of 3D shape. 2. We found the surface-orientation-se1ective (SOS) neurons that responded to the surface in the random-dot-stereogram suggesting to compute surface orientation from disparity gradient. 3. Axis orientation selective (AOS) neurons were sensitive to the orientation disparity and/or width disparity. 4. Relative position of the target of manipulation in the objects were also coded in AIP area. Tsukada : We showed that the spatial distribution and amplit
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ude of LTP is highly sensitive to the statistical correlation between successive inter-stimulus intervals. We proposed a spatio-temporal learning rule based on the experimental plastncity induced by various spatio-temporal pattern stimuli in hippocampal CA1 area. The spatio-temporal learning rule can modify the weight space in the network in the most effective way to discriminate different spatio-temporal patterns. Yamadori : We found neural basis for the maintenance of episodic memory and prospective memory using PET scan. Our clinical data stuggested the specific area for the retrieval of people's name or animate objects. Iijima : The entorhinal-hippocampal interactions were studied in cellular and circuit level with the optical recording methods with voltage-sensitive dyes. Exsistence of the reverberation circuit in the entorhinal cortex and its meaning was craimed. Further, the regulation on the information propagation in the system by amygdala inputs was suggested. Aihara : We found the following properties peculiar to neural networks composed of coincidence detector neurons : control of network functions by temporal input, ergodic encoding with spatio-temporal spikes and coincidence detection as a stochastic resonance phenomena with Poisson spike packets. Fujii : We have proposed the Dynamical Cell Assembly Hypothesis as the basic coding mechanism of the cerebral cortex, based on the coincidence detector nature of the pyramidal neurons. Based on the above hypothesis, the binding mechanism of fragmentary information represented in distant brain areas was also investigated. Shinomoto : We found that the standard neuro-spiking models are not able to account for the spiking data recorded from monkey prefrontal cortex. We also attempted to revise the neuro-spiking model so as to make it consistent with the biological data. Less
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