Ferrera V P, Nealey T A, Maunsell J H
Department of Physiology, University of Rochester, New York 14642-8642.
Nature. 1992 Aug 27;358(6389):756-61. doi: 10.1038/358756a0.
Visual information from the retina is transmitted to the cerebral cortex by way of the lateral geniculate nucleus (LGN) in the thalamus. In primates, most of the retinal ganglion cells that project to the LGN belong to one of two classes, P and M, whose axons terminate in the parvocellular or magnocellular subdivisions of the LGN. These cell classes give rise to two channels that have been distinguished anatomically, physiologically and behaviourally. The visual cortex also can be subdivided into two pathways, one specialized for motion processing and the other for colour and form information. Several lines of indirect evidence have suggested a close correspondence between the subcortical and cortical pathways, such that the M channel provides input to the motion pathway and the P channel drives the colour/form pathway. This hypothesis was tested directly by selectively inactivating either the magnocellular or parvocellular subdivision of the LGN and recording the effects on visual responses in the cortex. We have previously reported that, in accordance with the hypothesis, responses in the motion pathway in the cortex depend primarily on magnocellular LGN. We now report that in the colour/form pathway, visual responses depend on both P and M input. These results argue against a simple correspondence between the subcortical and cortical pathways.
来自视网膜的视觉信息通过丘脑的外侧膝状体核（LGN）传输到大脑皮层。在灵长类动物中，投射到LGN的大多数视网膜神经节细胞属于P和M两类中的一类，其轴突终止于LGN的小细胞或大细胞亚区。这些细胞类别产生了在解剖学、生理学和行为学上已被区分的两个通道。视觉皮层也可细分为两条通路，一条专门用于运动处理，另一条用于颜色和形状信息。几条间接证据表明皮层下通路和皮层通路之间存在密切对应关系，即M通道为运动通路提供输入，P通道驱动颜色/形状通路。通过选择性地使LGN的大细胞或小细胞亚区失活并记录对皮层视觉反应的影响，直接对这一假设进行了检验。我们之前曾报道，按照这一假设，皮层中运动通路的反应主要依赖于LGN的大细胞。我们现在报道，在颜色/形状通路中，视觉反应依赖于P和M两者的输入。这些结果与皮层下通路和皮层通路之间的简单对应关系相悖。
