BIRTH DATES OF RETINAL GANGLION-CELLS GIVING RISE TO THE CROSSED AND UNCROSSED OPTIC PROJECTIONS IN THE MOUSE
BIRTH DATES OF RETINAL GANGLION-CELLS GIVING RISE TO THE CROSSED AND UNCROSSED OPTIC PROJECTIONS IN THE MOUSE
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DOI：
10.1098/rspb.1985.0021
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发表时间：
1985-01-01
期刊：
影响因子：
--
通讯作者：
DRAGER, UC
中科院分区：
文献类型：
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作者：
DRAGER, UC
与大多数哺乳动物一样，在小鼠中，交叉的视神经投射起源于整个视网膜范围，而产生非交叉（同侧）投射的神经节细胞仅限于颞侧和腹侧视网膜。在视网膜中的这个双侧突出区域的鼻边界对应于视野的中线。在这里，同侧和对侧突出的神经节细胞的出生日期相结合的氚标记的胸苷标记在胚胎中的辣根过氧化物酶示踪在成人的视束。从胚胎第E11天至约10天产生向两侧突出的神经节细胞。E19以粗糙的同心方式与最老的细胞在中央和最年轻的在周边视网膜。同侧，从E11-E16产生突起细胞，即，在对侧投射诞生的早期阶段。在神经节细胞产生的最早期（E11-12），同侧和对侧投射细胞在不同的视网膜区域内产生，未来的中线代表形成了2个区域之间的边界。E13后，当同侧和对侧投射细胞都出生在双侧投射区域时，这种区别就消失了。因此，在E11-12时，视网膜具有二分组织，这可能允许指定具有相反拓扑极性的2个图，其中交叉和非交叉投影被组织。由于在成年视网膜中，这种二分组织仅保留在投射到外侧膝状体核的大神经节细胞中，并且由于已知大神经节细胞是小鼠中形成的最早的神经节细胞，因此这些细胞可能是建立视网膜的早期和双侧投射的细胞。视网膜中的双侧投射系统反映了早期发育程序，而不是在后期阶段两只眼睛之间竞争的结果，这一结论通过观察小鼠的同侧投射的实际正常视网膜起源而得到加强，所述小鼠从眼睛发育的最早阶段只有一只正常眼睛。
In the mouse, as in most mammals, the crossed optic projections originate from the entire extent of the retina, whereas ganglion cells giving rise to the uncrossed (ipsilateral) projection are restricted to the temporal and ventral retina. The nasal border of this bilaterally projecting region in the retina corresponds to the midline of the visual field. Here the birth dates of ipsilaterally and contralaterally projecting ganglion cells were determined by combining tritiated thymidine labeling in the embryo with horseradish peroxidase tracings from the optic tract in the adult. Contralaterally projecting ganglion cells were generated from embryonic day E11 to .apprx. E19 in a crude concentric fashion with the oldest cells in central and youngest ones in peripheral retina. Ipsilaterally, projecting cells were born from E11-E16, i.e., during the earlier part of the period in which the contralateral projection was born. At the earliest time of ganglion cell generation (E11-12) ipsi- and contralaterally projecting cells were born within separate retinal regions, with the future midline representation forming the border between the 2 zones. This distinction became lost after E13, when both ipsi- and contralaterally projecting cells were born in the bilaterally projecting region. Hence at E11-12 the retina had a bipartite organization that may allow the specification of the 2 maps of opposite topographical polarity in which the crossed and uncrossed projections are organized. Since in the adult retina this bipartite organization is preserved only in the large ganglion cells that project to the lateral geniculate nucleus, and since large ganglion cells are known to be the earliest ones formed in the mouse, these cells may be the ones that establish the early and bilateral projections of the retina. The conclusion that the bilateral projection system in the retina reflects an early developmental program, and not the result of competition between the 2 eyes at later stages, was reinforced by observing a practically normal retinal origin of ipsilateral projections in mice which had only 1 normal eye from the earliest stages of eye development.