機能的MRIを用いた視覚性ワーキングメモリ課題における脳活動の検討  [in Japanese] A study on brain activity during visual working memory task using functional MRI  [in Japanese]

Abstract

能動的な短期記憶であるワーキングメモリ(WM)のうち,特に視空間性WMに着目し,言語性記憶の干渉が少ないと考えられる正弦波縞を視覚刺激として用いて,機能的MRIによりその神経基盤を明らかにすることを目的とした実験をおこなった.健常右利き男性7名の実験参加者を対象として,2-back課題遂行中の脳活動を計測した.課題正答率は,低空間周波数の正弦波縞を視覚刺激として用いた結果が,高空間周波数の正弦波縞を視覚刺激として用いた結果よりも有意に高い値となった.脳活動は,前頭葉-頭頂葉ネットワークの賦活が確認され,両課題とも右側の賦活領域が左側より広かったが,賦活強度については低空間周波数では左側が,高周波数では右側の方が強かった.一方,正答率の高かった低空間周波数の正弦波縞を刺激に用いた場合には,左前頭前野腹外側部の強い活動が認められた.実験後の内観で,低周波数縞では縞の本数を記憶し,高周波数縞では縞の間隔の広さを記憶するようにしたという報告が多くあり,低周波数縞の場合に刺激パターンの言語化によるカテゴリー化がおこなわれていることが示唆された.

A functional magnetic resonance imaging study on visuo-spatial working memory task using sinusoidal luminance grating inferred to have little influence on verbal working memory was presented. Seven right-handed healthy male participants wearing a head mount display were scanned while performing two 2-back tasks using the different spatial frequency stimuli. As results, the accuracy of the task using low spatial frequency stimuli was significantly-higher than that of the task using high spatial frequency stimuli. Moreover, both tasks activated the neural network between the prefrontal cortex and the parietal cortex. The activated areas on the right hemisphere were larger than those on left hemisphere. The intensity level of the frontal cortex activation was also asymmetric. The high spatial frequency task activated the right hemisphere higher than the left hemisphere. On the contrary, the low spatial frequency task activated the left hemisphere higher than the other one. Moreover, the activation in the ventrolateral region of left prefrontal cortex during the low spatial frequency task was salient. The activation was found to be caused by the verbalization changing the low spatial stimuli into the numbers.

Journal

Journal of Biomedical Fuzzy Systems Association   [List of Volumes]

Journal of Biomedical Fuzzy Systems Association 11(2), 87-91, 2009-10-02  [Table of Contents]

Biomedical Fuzzy Systems Association

References:  15

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Codes

  • NII Article ID (NAID) :
    110007386475
  • NII NACSIS-CAT ID (NCID) :
    AA1145146X
  • Text Lang :
    JPN
  • Article Type :
    ART
  • ISSN :
    13451537
  • NDL Article ID :
    10471352
  • NDL Source Classification :
    ZS7(科学技術--医学) // ZM2(科学技術--科学技術一般--大学・研究所・学会紀要)
  • NDL Call No. :
    Z74-B741
  • Databases :
    CJP  NDL  NII-ELS 

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