Ts'o D Y, Gilbert C D
Laboratory of Neurobiology, Rockefeller University, New York, New York 10021.
J Neurosci. 1988 May;8(5):1712-27. doi: 10.1523/JNEUROSCI.08-05-01712.1988.
The cytochrome oxidase-rich patches or blobs of the monkey striate cortex have been shown to contain cells that have unoriented receptive fields, many of which are color selective. We studied the functional organization of color opponency in the blob regions of the parafoveal representation of the visual cortex. We also examined the patterns of connectivity among blob and nonblob cells by multiple electrode penetrations and cross-correlation analysis. Some of the color-selective cells in the blobs exhibited receptive fields that were similar to those found in the parvocellular layers of the lateral geniculate nucleus (LGN): one type exhibited center-surround spatial and chromatic opponency corresponding to the Type I cell found in the LGN; another had center-only chromatic opponency, corresponding to the Type II cell of the LGN. A blob color-selective cell with no LGN counterpart had center color opponency with a nonchromatically opponent surround antagonism. We termed this cell the "modified Type II" cell. Contrary to previous reports, few true double color-opponent cells were found. Some blob cells previously characterized as double opponent probably belong to our modified Type II category and, unlike true double opponent cells, do not respond well to isoluminant color boundaries. Occasional color-selective oriented cells were either intermixed or in close proximity to blob cells. Neighboring electrode penetrations within the same blob yielded cells of the same color opponency, either red versus green or blue versus yellow, suggesting that individual blobs are dedicated to processing one color opponency. Blobs dedicated to red/green color opponency were 3 times more numerous than blue/yellow blobs. Furthermore, the cells in layer 4C lying beneath blobs of a given color opponency had identical color opponency to the overlying cells in blobs. Cross-correlation analysis of pairs of nonblob, oriented cells in the superficial layers showed interactions between cells with matched orientation and eye preference, at varying horizontal separations. Such interactions are consistent with anatomically demonstrated clustered horizontal connections. Positive cross-correlograms were found between blob cells in the same and in adjacent blobs when the cells' receptive field type, color opponency, and ocular dominance matched. Correlograms also indicated monosynaptic connections from Type II to modified Type II cells of the same color opponency, suggesting that Type II cells may contribute to the construction of the modified Type II fields in the cortex.(ABSTRACT TRUNCATED AT 400 WORDS)
猕猴纹状皮层中富含细胞色素氧化酶的斑块或斑点已被证明含有具有非定向感受野的细胞，其中许多细胞具有颜色选择性。我们研究了视觉皮层中央凹旁代表区斑点区域中颜色拮抗的功能组织。我们还通过多电极穿刺和互相关分析研究了斑点细胞和非斑点细胞之间的连接模式。斑点中的一些颜色选择性细胞表现出与外侧膝状体核（LGN）小细胞层中发现的感受野相似的感受野：一种类型表现出中心-周边空间和颜色拮抗，对应于LGN中发现的I型细胞；另一种只有中心颜色拮抗，对应于LGN的II型细胞。一个没有LGN对应物的斑点颜色选择性细胞具有中心颜色拮抗和非颜色拮抗的周边拮抗。我们将这种细胞称为“改良II型”细胞。与先前的报道相反，发现真正的双色拮抗细胞很少。一些先前被表征为双色拮抗的斑点细胞可能属于我们的改良II型类别，并且与真正的双色拮抗细胞不同，它们对等亮度颜色边界的反应不佳。偶尔出现的颜色选择性定向细胞要么与斑点细胞混合在一起，要么与斑点细胞相邻。在同一斑点内相邻的电极穿刺产生具有相同颜色拮抗的细胞，要么是红对绿，要么是蓝对黄，这表明单个斑点专门用于处理一种颜色拮抗。专门用于红/绿颜色拮抗的斑点比蓝/黄斑点多3倍。此外，位于给定颜色拮抗斑点下方的4C层中的细胞与斑点中上层细胞具有相同的颜色拮抗。对表层中非斑点定向细胞对的互相关分析表明，具有匹配方向和眼优势的细胞之间在不同水平间距处存在相互作用。这种相互作用与解剖学上证明的成簇水平连接一致。当细胞的感受野类型、颜色拮抗和眼优势匹配时，在相同和相邻斑点中的斑点细胞之间发现了正互相关图。相关图还表明从II型细胞到相同颜色拮抗的改良II型细胞存在单突触连接，这表明II型细胞可能有助于在皮层中构建改良II型场。（摘要截断于400字）
