Coleman J, Diamond I T, Winer J A
Brain Res. 1977 Dec 2;137(2):233-52. doi: 10.1016/0006-8993(77)90336-5.
The visual cortex of opossum was studied by injecting horseradish peroxidase into the cortex and identifying labeled neurons in the thalamus. The results show that the lateral geniculate nucleus projects to area 17 in a topographical manner: the rostral lateral geniculate is represented in caudal striate cortex, and the dorsal extremity of the lateral geniculate, which probably corresponds to the zero vertical meridian, is represented along the border of area 18. Small injections in area 17 produced restricted bands of labeled neurons across the medial-lateral extent of the lateral geniculate, suggesting a greater precision in the topography than previously shown by retrograde degeneration studies. Following injections into area 17, labeled cells were also found in the lateral posterior nucleus. Injections of peristriate cortex produced labeled cells in the lateral posterior nucleus, as well as the lateral intermediate, posterior and intralaminar nuclei. Since the lateral posterior nucleus receives visual projections from the superior colliculus, the results show two visual pathways: the geniculo-striate path projecting just to core area or area 17, and a more diffuse parallel path that projects to both the core and belt. Whether or not this overlap is characteristics of the mammalian prototype it seems to be present in widely separated species.
通过将辣根过氧化物酶注入负鼠的视皮层并鉴定丘脑中标注的神经元，对负鼠的视皮层进行了研究。结果表明，外侧膝状体核以拓扑方式投射到17区：嘴侧外侧膝状体在尾侧纹状皮层中有所体现，而外侧膝状体的背侧末端（可能对应于零垂直子午线）则沿着18区的边界有所体现。在17区进行小剂量注射，在外侧膝状体的内侧-外侧范围内产生了有限的标注神经元带，这表明拓扑结构比之前逆行变性研究所显示的更为精确。在向17区注射后，在外侧后核中也发现了标注细胞。向纹周皮层注射后，在外侧后核以及外侧中间核、后核和层内核中产生了标注细胞。由于外侧后核接受来自上丘的视觉投射，结果显示出两条视觉通路：膝状体-纹状通路仅投射到核心区域或17区，以及一条更弥散的平行通路，该通路投射到核心区域和带状区域。这种重叠是否是哺乳动物原型的特征，似乎在广泛分布的物种中都存在。
