第23回日本神経科学大会・第10回日本神経回路学会合同大会
2000.9.4-9.6 (横浜)

サル下側頭葉皮質TE野細胞の両側性受容野の定量的解析
川嵜圭祐1、田村 弘2、宮田健二2、藤田一郎1,2
1
科学技術振興事業団CREST, 2大阪大学 基礎工 認知脳科学

下側頭葉皮質TE野では一部の細胞の受容野が視野の垂直経線を越え同側視野に及び、腹側視覚経路において初めて広く左右視野が統合されている。今回我々はこの受容野の生成メカニズムを知るために両側性受容野を持つTE野細胞の64枚の刺激セットに対する応答特性を定量的に検討した。麻酔・不動化したニホンザル3頭を用いて515個の細胞から記録した。10Hz以上の有意な視覚応答を示した細胞(103個)の約半数が、左右視野11°以上に広がる両側性受容野を持っていた。視覚刺激を同側視野11°に呈示した時と対側視野11°に呈示した時の応答は似ており、応答の相関係数は高い値を示した(r=0.76ア0.30, n=54)。しかし同側視野に呈示した時の法が応答強度は小さく応答潜時も長かった。これらの結果は左右20°以上離れた視野上でも刺激選択性が保存されていること、刺激選択性の似た細胞同士が半球間連絡によって統合されて両側性受容野の形成されることを示唆する。



P-112 Quantitative comparison of intrahemispheric and interhemispheric responses of neurons in macaque area TE

Neurosci. Res. Suppl. 24: S73

Keisuke Kawasaki 1, Hiroshi Tamura 2, Kenji Miyata 2. Ichiro Fujita 1.2
1CREST, JST, 2Grad. Sch. of Engn. Sci., Osaka Univ.

The responses of TE neurons to the contralateral and ipsilateral visual hemifields depend on the intra- and interhemispheric information flow, respectively. In the present study, we quantitatively analyzed the responses of TE neurons to stimuli located far-off the two visual hemifields to determine whether the stimulus selectivity was preserved between intra- and interhemispheric responses. Single unit activities were recorded in three anesthetized monkeys (Macaca fuscata). Visual stimuli (4° ) were presented at one of nine positions spaced 11°horizontally and 7.5° vertically within 15° x 22° of a visual field centered on the fovea. A tota] of 515 neurons were recorded from TE.. In about one-half (54) of well activated neurons ( 103/515), the RFs covered laterally more than 22° and extended well into the ipsilateral hemifield (>11° ). In these neurons with a bilateral RF, stimulus selectivity was preserved between the responses at 11° ipsilateral and those at 11° contralateral, as evidenced by a high correlation coefficient (r=0.76±0.30,n=54) between the responses at the two sites. The magnitude of interhemispheric responses was, however, smaller than that of intrahemispheric responses. The onset latency of interhemispheric responses was longer than that of intrahemispheric ones. Thus, the translational invariance of stimulus selectivity of TE neurons, which has previously been reported for central or contralateral visual fields, is observed between the two hemifields separated by more than 20°. Supported by CREST


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