第17回日本神経科学会 シンポジウム 「大脳連合野研究の新展開」(名古屋)1993.12.7-9

S6-2
FUNCTIONAL COLUMNAR ORGANIZATION IN THE MONKEY INFEROTEMPORAL CORTEX.

Neurosci. Res.Suppl. 18: s13.

ICHIRO FUJITA. PRESTO. Research DeveloDment Corporation of Japan. and Laboratory for
Neural Information Processing, Frontier Research Program, RIKEN, Wako, Saitama 351 -01, Japan


The anterior part of the inferotemporal cortex, cytoarchitectonic area TE, occupies a near-final part of the visual cortical pathway essential to object vision in the monkey. TE cells respond selectively to particular visual features of objects such as shape, color, texture or often a combination of these. Stimulus features critical for activating individual TE neurons are more complex than those for cells at earlier stages of the visual system, although they are still simpler than the complexity of a usual real-world object. TE cells with similar, but not identical, stimulus selectivities cluster vertically across the cortical layers to form columnar organizations. The width of each column is 0.4 mm on average. Multiple separate columns respond to similar stimulus features, while intervening columns prefer quite different object features. Stimuli which activate cells in one column thus do not excite cells in an adjacent column. The border between two adjacent columns is rather discrete: when a recording electrode is moved across the border by 50 gm we see a drastic change of effective stimulus features. Preliminary experiments suggest that the stimulus preference of columns is stable at least over 30 days, because repeated recordings from the same site over this period enable us to find neurons with similar stimulus preferences. The discreteness and temporal stability of columns provide us with rationale to estimate the number of columns
in area TE. One TE is estimated to contain 2000 columns. The number of distinct object features represented in area TE would be smaller than 2000 because of multiplicity of columns for similar features.


サル下側頭葉皮質における機能的コラム構造
新技術事業団さきがけ21,理研フロンティア思考電流研究チーム
藤田一郎

下側頭葉皮質TE野では,似た図形特徴に応じる細胞が平均幅0.4ミリのコ
ラムを形成している.似た図形に応じるコラムは距離をおいて複数存在し,隣り
あうコラムは異なった図形に応じる.予備実験によれば,コラムの性質は,少な
くとも30日にわたり保持されている.コラムが分離しており時間的に安定であ
ることから,コラムの数の算定が意味を持つ.その数は2000と推定された.


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