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野の半球間神経連絡
宮田健二2、川嵜圭祐1、王 全新1、田村 弘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

左右の下側頭葉皮質TE野を結ぶ半球間神経連絡の様式を、順行性標識色素(BDA)および逆行性標識色素(DY,FB)を用いて解析した。順行性色素を一側TE野の微小領域(直径300μm)に注入すると、反対側TEにおいて、200-500μm幅の塊状に分布する軸索終末集団(以下パッチ)が観察された。これらのパッチは対側注入部位と前後軸・背腹軸上で位置的に対応する部位に主に見られたが、対応部位から11mm離れていた例もあった。軸索終末は主に3層に分布し、少数例で1-4層に渡っていた。逆行性標識細胞は対側TEのいくつかの部位に限局し、その中で、一部の標識細胞が軸索終末パッチと同程度の大きさのクラスターを形成していた。ほとんどの標識細胞は3層に分布していた。これらの左右TE野を結ぶパッチ状の半球間連絡は、似た刺激選択性を持つコラム同士を結び付け、左右視野にまたがる受容野内で刺激選択性が保存されていることの基礎となっていると考えられる。


P-105 Interhemispheric projection between area TEs of macaque inferior temporal cortex

Neurosci. Res. Suppl. 24: S72

Kenji Miyata 1, Keisuke Kawasaki 2, Quanxin Wang 2, Hiroshi Tamura 1, Ichiro Fujita 1,2
1Graduate School of Engineering Science. Osaka Uniyersity. Toyonaka Japan, 2Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation (JST), Toyonaka. Japan

We studied the organization of the interhemispheric projections between area TEs of macaque monkeys (Macaca fuscata) by applying small injections (300-700 µ m in diameter, corresponding to the size of an object-feature column) of anterograde (biotinylated dextran amine) or retrograde tracers (diamidino yellow and fast blue) to infer the mechanisms of integration of right and left visual hemifields. Labeled axon terminals of the contralateral TE were distributed in several patches of 200-500 µ m in width. The patches were found mainly in a homotopic locus of the contralateral TE: TEad and TEav injection resulted in contralateral TEad and TEav labeling, respectively. A few ware found in heterotopic loci, such as in the temporal pole of the contralateral hemisphere. Synaptic boutons were found predominantly in layer 3 in most patches, but in some patches they were found in layers 1 through 4. Retrogradely labeled cells of the contralateral TE were also segregated into separate loci and formed clusters, which were similar in size to the anterogradely labeled axonal arbors. Labeled cells were observed mainly in layer 3. Only a small number of retrogradely labeled cells were also found in area TEO. The patchy projections between the right and left TEs may bind similar feature selective column, and may provide a basis for the invariant stimulus selectivity between the two visual hemifields. Supported by CREST.


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