Weller R E, Kaas J H
Department of Psychology, University of Alabama, Birmingham 35294.
Vis Neurosci. 1989 Oct;3(4):327-49. doi: 10.1017/s0952523800005514.
Partial lesions of striate cortex were made in newborn and adolescent or young adult macaque monkeys, one newborn squirrel monkey, and adult squirrel and owl monkeys. After survival times ranging from 3 1/2 weeks to 8 years, the retinas were examined for transneuronal retrograde ganglion cell loss and retinal projections to the dorsal lateral geniculate nucleus, and other targets were examined for changes. After lesions in infant macaque monkeys and long postoperative survivals, nearly 80% of the ganglion cells were lost in the altered portions of the retinas. The degeneration appeared to be exclusively of ganglion cells projecting to the parvocellular layers of the lateral geniculate nucleus, and the loss of this class of cell appeared to be complete or nearly complete for the affected portions of the retina. Cases with shorter survivals showed that nine-tenths of the potential loss occurred within 6 months, and about half of the potential loss took place within one month. In cases where lesions were placed in adolescent and young adult macaque monkeys, the loss also was of ganglion cells projecting to the parvocellular layers. However, the rate of cell loss was slower so that little or no cell loss was apparent after six months, and only one-third to three-fourths of the potential loss occurred within 12-14 months. A cell loss of 22% was measured in the altered portions of the retina of a squirrel monkey lesioned as an infant and surviving for 6 months, but no regions of ganglion cell loss were apparent in the retinas of owl and squirrel monkeys lesioned as adults and surviving as long as two or more years. We conclude that nearly 80% of the ganglion cells project to the parvocellular layers in macaque monkeys, and that the ultimate survival of these ganglion cells depends on the presence of target neurons in the parvocellular layers. Age is important in that the loss of ganglion cells proceeds rapidly in infant macaque monkeys, but slowly in older animals. Infant New World monkeys, judging from one squirrel monkey, are also susceptible to ganglion cell loss, although apparently at a rate comparable to older macaque monkeys. Finally, adult New World monkeys do not appear to be susceptible to ganglion cell loss. These age and species differences in rates of loss and susceptibility to loss challenge a "sustaining collateral" hypothesis proposed earlier (Weller et al., 1979), and suggest alternatives and modifications.
在新生、青少年或成年猕猴、一只新生松鼠猴以及成年松鼠猴和猫头鹰猴身上制造了纹状皮质的部分损伤。在存活3.5周至8年不等的时间后，检查视网膜是否存在跨神经元逆行性神经节细胞丢失以及视网膜向背外侧膝状核的投射，并检查其他靶点是否有变化。在幼年猕猴受损且术后存活时间较长后，视网膜改变部位近80%的神经节细胞丢失。这种变性似乎仅发生在投射到外侧膝状核小细胞层的神经节细胞中，对于视网膜的受影响部分，这类细胞的丢失似乎已完全或几乎完全。存活时间较短的病例显示，十分之九的潜在丢失发生在6个月内，约一半的潜在丢失发生在1个月内。在青少年和成年猕猴身上制造损伤的病例中，丢失的也是投射到小细胞层的神经节细胞。然而，细胞丢失的速度较慢，因此6个月后几乎没有明显的细胞丢失，在12 - 14个月内仅发生三分之一到四分之三的潜在丢失。一只幼年时受损并存活6个月的松鼠猴，其视网膜改变部位测量到细胞丢失率为22%，但成年时受损并存活长达两年或更长时间的猫头鹰猴和松鼠猴的视网膜中，未发现神经节细胞丢失区域。我们得出结论，猕猴中近80%的神经节细胞投射到小细胞层，这些神经节细胞的最终存活取决于小细胞层中靶神经元的存在。年龄很重要，因为幼年猕猴的神经节细胞丢失迅速，而老年动物则缓慢。从一只松鼠猴判断，幼年新大陆猴也易发生神经节细胞丢失，尽管其发生率显然与老年猕猴相当。最后，成年新大陆猴似乎不易发生神经节细胞丢失。这些在丢失率和易感性方面的年龄和物种差异对早期提出的“维持侧支”假说（Weller等人，1979年）提出了挑战，并提出了替代方案和修正意见。
