TOP 活動実績 2007年

(15) Spatiotemporal Brain Activities in Recalling Sentences by Loci Mnemonic System

Takahiro Yamanoi, Hisashi Toyoshima, Hidetomo Ichihashi
2007 IEEE International Conference on Systems, Man and Cybernetics, pp.1878-1883, 2007-10


 To investigate the brain activity during human recalling system of memory, the authors recorded electroencephalograms (EEGs) from one subject in recalling English sentences which had stored by loci mnemonic system. The subject had stored almost three thousands English sentences for seven years by loci mnemonic method. We displayed one number corresponding to one sentence on CRT. These EEGs were summed to get the event related potentials (ERPs), and the ERPs were applied to the equivalent current dipole source localization (ECDL) method, and the results were compared with that of Ichihashi et al. From the analysis of ECDL, the dorsal pathway was confirmed; ECDs were localized to the V1 at 152ms, to the MT at 163ms, to the intraparietal sulcus (IPS) at 186 ms, to the left postcentral gyrus (PstCG) at 255ms, to the left PrCG at 275ms, and the ventral pathway was also confirmed; start from the V1, to the V2 at 178ms, to the left ITG at 248ms. These pathways agree with the result of a moving white circle stimulus and random-dot stereogram's stimulus. Then ECDs were localized to the left IPS at 305ms, to the MTG at 311ms, then to the inferior parietal lobulus (IPL) at 330ms, and again to the PrCG at 361ms. Then ECDs were localized to the right ITG at 415ms, to the right MTG at 433ms, to the right fusiform gyrus (FuG) at 447ms and to the right PrCG at 477ms. After the right PrCG, ECDs were activities in the right and the left frontal lobes were confirmed. After then, ECDs were localized to the left hippocampus (HiC), to the right HiC and to the right ITG to the right MTG. Then ECD were passing through the right AnG and reached to the right HiC again. During latency from 600ms to 800ms and from 1,150 to 1,500ms, ECDs were sequentially localized to the left MFG, the cingulated gyrus (CiG), to the left HiC, to the right HiC then to the right MFG. And between 900ms and 1,100ms, and between 1,500ms and 1600ms, we localized ECDs to the right MFG and to the left MFG, at 1,617ms to the right PrCG. After that no ECD was localized to any special area.

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