Royce G J, Ward J P, Harting J K
J Comp Neurol. 1976 Dec 1;170(3):391-413. doi: 10.1002/cne.901700309.
Autoradiographic and anterograde degeneration tracing methods were used to study and compare the organization of retinofugal pathways in two marsupial opossums, Didelphis virginiana and Marmosa mitis. Seven identical retinal targets were demonstrated for each opossum. These include: (1) the suprachiasmatic nucleus of the hypothalamus, (2) the dorsal and (3) ventral lateral geniculate nuclei, (4) the lateral posterior nucleus, (5) the pretectal complex, (6) the superior colliculus and (7) the accessory optic nuclei. While the pattern of retinal input to six of the seven targets was quite similar in the two species, the organization of the retinogeniculate pathways exhibited striking differences. In particular, our autoradiographs reveal no separation of ocular inputs within the lateral geniculate nucleus of Didelphis, i.e. the ipsilateral input is overlapped completely by the more extensive contralateral projection. In contrast, there is considerable separation, as well as overlap, of the occular inputs within the lateral geniculate nucleus of Marmosa. Our autoradiographs reveal several distinct bands of label within each geniculate nucleus, and upon superimposing the nuclei, ipsilateral and contralateral to the placement it is apparent that two of the bands overlap, while five do not (three ipsi, two contra).
利用放射自显影和顺行性变性追踪方法，对两种有袋负鼠——弗吉尼亚负鼠（Didelphis virginiana）和米氏负鼠（Marmosa mitis）的视网膜传出通路的组织结构进行了研究和比较。每种负鼠都显示出七个相同的视网膜靶点。这些靶点包括：（1）下丘脑视交叉上核，（2）背侧和（3）腹侧外侧膝状体核，（4）外侧后核，（5）顶盖前复合体，（6）上丘和（7）附属视核。虽然在这两个物种中，七个靶点中有六个的视网膜输入模式非常相似，但视网膜膝状体通路的组织结构却表现出显著差异。特别是，我们的放射自显影片显示，在弗吉尼亚负鼠的外侧膝状体内，眼的输入没有分离，即同侧输入完全被更广泛的对侧投射重叠。相比之下，在米氏负鼠的外侧膝状体内，眼的输入有相当程度的分离以及重叠。我们的放射自显影片显示每个膝状体内有几条明显的标记带，并且在叠加放置同侧和对侧的核时可以明显看出，其中两条带重叠，而五条不重叠（三条同侧，两条对侧）。
