第17回日本神経科学会(名古屋)1993.12.7-9

COLUMNAR AND HORIZONTAL CONNECTIONS IN THE MONKEY INFEROTEMPORAL CORTEX: ANALYSIS OF ANTEROGRADE LABELING AFTER BIOCYTIN INJECTION.

Neurosci. Res.Suppl. 18: s181.

     In area TE of the monkey inferotemporal cortex, neurons with similar stimulus selectivities are clustered in multiple columns separated by those with distict selectivities.  To advance our understanding of the anatomical substrate and the functioning of this organization, we studied intrinsic connections of area TE by analyzing anterograde labeling after extracellular injections of biocytin.  Biocytin (4%) was injected into single or restricted layers (1-2,2-3, 3, 3-4, 4, 5 or 6) in area TE of seven Japanese monkeys.  Labeling appeared most strongly in a vertical alignment of the injection site.  Axons from the superficial layers ran in bundle towards the white matter.  They made a prominent arborization in layer 5 on their way.  Axons from the deeper layers towards the pia were present but obscured by massive apical dendrites of labeled cells.  In addition to these vertically running axons, there were axons running roughly parallel to the cortical layers.  These horizontal axons, particularly those in layers 2-4, produced patches of terminal arborizations 0.5±0.2 mm in size at a center-to-center interval of 0.7±0.3 mm.  These patches often spanned layers 1 to 4.  Single axon tracing confirmed that these terminal arbors belonged to horizontal axons from the injection site, and were not recurrent collaterals of the retrogradely labeled cells.  A single injection could label more than 15 patches which were distributed in an elongated way parallel to the superior temporal sulcus.  We suggest that the radial connections across layers and the patchy horizontal connections may provide an anatomical basis for the functional columnar system in area TE.


サル下側頭葉皮質におけるコラム状および水平方向神経結合

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、藤田多恵子

下側殖葉皮質TE野内の局所神経結合を,バイオサイチン順行性標識法により解析した.特定層に行なった注入部位の上下に,垂直方向に標識が強く現われた.加えて,水平軸索が2-6層を走っていたが,特に2-4層の軸索は顕著なパッチ状終末集団を形成した.このパッチはしばしば1-4層をまたがる円筒状の様相を呈した.これらの構造はTE野の機能的コラムの基盤の一つと考えられる.


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