1998 Fiscal Year Final Research Report Summary
The study of the brain mechanism of working memory : event related potential (ERP) analysis on verbal and visuo-spatial stimuli
| Project/Area Number |
09610079
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
実験系心理学
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| Research Institution | Osaka University of Foreign Studies |
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Principal Investigator |
OSAKA Mariko Osaka University of Foreign Studies, Faculty of Foreign Studie, 外国語学部, 助教授 (70144300)
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| Project Period (FY) |
1997 – 1998
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| Keywords | working memory / event related potential / P300 / kana / dot |
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| Research Abstract |
The purpose of this research was to investigate the brain mechanism of working memory on the event related potential (ERP) as to the processing of verbal and visuo-spatial stimuli Event related potential (ERP) and reaction time (RT) were recorded in a memory search experiment, In the verbal experiment, the stimuli were Japanese kana, and the visuo-spatial experiment the stimuli were dots. In the both experiments, the target stimulus was presented after the stimulus set was disappeared, and a subject was requested to decide the target was in the memory set (inset) or was not in the memory set (outset). There were two kinds of memory set size of three (small) and eight (large), and each set sizes, the stimulus presentation duration were 1 and 2 seconds each.
Individual differences of working memory were measured with use of reading span test (RST). Subjects were divided into two groups ; high score of RST (high span group) and low score of RST (low span group).
The RT increased when the memory set size was large both in the kana and dot stimulus conditions. The ERP showed a typical component of P300. P300 amplitude decreased in the large memory set size condition. The differences between small and large memory set size on P300 components were large in the kana condition. This is probably because a parallel processing was done in dot condition, on the contrary a serial search processing was done in the kana condition.
The differences between the kana and dot stimulus and the effect of memory set size were measured between the group. The P300 amplitude was larger in the high span groups as compared with low span groups. Moreover. for high span subjects, P300 amplitude localized in the frontal areas , which is suggested to be a locus of working memory.
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