Sherk H
J Comp Neurol. 1986 Nov 1;253(1):105-20. doi: 10.1002/cne.902530109.
Pathways from a variety of structures to the largest of the cat's suprasylvian visual areas, the Clare-Bishop area, were found to patchy. These inputs arose from the lateral geniculate complex, from area 18, from area 19, and, as noted by Montero (Brain Behav. Evol. 18:194-218, '81), from area 17. The Clare-Bishop area was previously delineated on the basis of its uniform pattern of connections with cortex and thalamus (Sherk: J. Comp. Neurol. 247:1-31, '86) and found to incorporate pieces of several retinotopically defined areas (Tusa, Palmer, Rosenquist: Cortical Sensory Organization. Vol 2. Multiple Visual Areas. Clifton, NJ: Humana Press, pp. 1-31, '81). However, since individual patches did not correspond to particular retinotopically defined areas, other explanations of afferent patchiness were sought. An obvious question is whether the patches originating from different sources are systematically related to each other. Two hypotheses were considered. First, different inputs--for example, from the lateral geniculate nucleus (LGN) and from area 17--might terminate in intermingled but mutually exclusive zones in the Clare-Bishop area. Second, multiple patches of input might reflect duplicate representations of the corresponding visual field segment in the Clare-Bishop area. Both hypotheses were tested by injecting the lateral geniculate complex and either area 17 or area 19 with different anterograde tracers. In each case the two injections involved regions of the visual field that coincided to some degree, ranging from near-total overlap to almost complete exclusion. The first hypothesis predicted that the different labels in the Clare-Bishop area would never be found to overlap, while the second hypothesis predicted that when injections were closely matched retinotopically, there would be extensive overlap between patches. The results supported the second hypothesis: the better the retinotopic match between injections, the greater the overlap found between labeled geniculate and cortical input in the Clare-Bishop area. However, the multiplicity of patches seen in some experiments, and the close spacing between some patches, suggested that an additional, nonretinotopic mechanism also contributes to patchiness in the projections to the Clare-Bishop area.
研究发现，从各种结构到猫最大的上薛氏视觉区即克莱尔 - 毕晓普区的神经通路是不连续的。这些输入来自外侧膝状体复合体、18区、19区，并且，如蒙特罗所指出的（《脑行为与进化》18:194 - 218, '81），还来自17区。克莱尔 - 毕晓普区先前是根据其与皮层和丘脑的连接模式一致而划定的（谢尔克：《比较神经学杂志》247:1 - 31, '86），并发现它包含了几个视网膜拓扑定义区域的部分（图萨、帕尔默、罗森奎斯特：《皮层感觉组织》。第2卷。多个视觉区域。新泽西州克利夫顿：人类出版社，第1 - 31页，'81）。然而，由于单个斑块并不对应于特定的视网膜拓扑定义区域，所以人们寻求对传入不连续性的其他解释。一个明显的问题是，来自不同来源的斑块是否彼此系统相关。考虑了两种假设。第一，不同的输入——例如，来自外侧膝状体核（LGN）和来自17区——可能在克莱尔 - 毕晓普区终止于相互交织但相互排斥的区域。第二，多个输入斑块可能反映了克莱尔 - 毕晓普区中相应视野段的重复表征。通过向外侧膝状体复合体以及17区或19区注射不同的顺行示踪剂来检验这两种假设。在每种情况下，两次注射涉及的视野区域在某种程度上是重合的，范围从几乎完全重叠到几乎完全不重叠。第一种假设预测，在克莱尔 - 毕晓普区永远不会发现不同的标记有重叠，而第二种假设预测，当注射在视网膜拓扑上紧密匹配时，斑块之间会有广泛的重叠。结果支持了第二种假设：注射之间的视网膜拓扑匹配越好，在克莱尔 - 毕晓普区标记的膝状体和皮层输入之间发现的重叠就越大。然而，在一些实验中看到的斑块的多样性，以及一些斑块之间的紧密间距，表明一种额外的、非视网膜拓扑的机制也导致了投射到克莱尔 - 毕晓普区的不连续性。
