(21)ランダムドットステレオグラム観察時における時空間的脳活動のモデリング
北海学園大学工学部研究報告，第34号，pp.129-142，2007-2
Binocular disparity is one of the most important cues for depth perception in humans. Previously, some of the authors performed electroencephalogram (EEG) measurement in subjects viewing random dot stereograms (RDSs) with 3 binocular disparities: no, small or large disparity, and estimated the brain sites where the visual information was processed for human stereopsis, using equivalent current dipole source localization (ECDL) method. The results showed that: 1) the postcentral gyrus (PstCG) is involved in visual processing of stereopsis; and 2) all-channel average EEGs converge and the convergence time for larger RDS disparity is longer than that for smaller one. Application of the ECDL method to the average data for small and large disparities revealed that the visual processing before the PstCG localization consists of two pathways: one is from V1 to V4 and then to the TE field; and the other from V1 to the MT field and then to the PstCG. This result did not depend on the amount of disparity. After the PstCG localization, ECDs were localized to the left intraparietal sulcus (IPS). At the interval between the left IPS localization and the EEGs convergence, ECDs were located at both sides of the inferior frontal gyrus (IFG) and both sides of the middle frontal gyrus (MFG). For RDSs with large disparities, the IFG and MFG ECDs were estimated earlier than those for small disparities, while for large disparities the convergence time and the time when ECDs were localized to the IFG just before the convergence time were later than those for small disparities.
>>