Cucchiaro J B
Committee on Neurobiology, University of Chicago, Illinois 60637.
J Comp Neurol. 1991 Oct 8;312(2):193-206. doi: 10.1002/cne.903120203.
This work describes the retinal origin of the crossed and uncrossed projections in newborn, 9-day-old and adult normally pigmented and albino ferrets. Horseradish peroxidase (HRP) was injected unilaterally into the thalamic and midbrain visual centers of ferrets to label retinal ganglion cells retrogradely. In normally pigmented adults, the retinal line of decussation was sharp and passed through the area centralis. Ganglion cells with uncrossed axons occupied the entire temporal retina. In albino adults, ganglion cells with uncrossed axons were distributed in the periphery of the temporal retina away from the area centralis. In the normally pigmented adults, about 11% of the retinal ganglion cells had uncrossed axons compared to about 4% in the albinos. At birth, normally pigmented ferrets had a sharp line of decussation with most (about 98%) uncrossed ganglion cells found in the temporal retina. In the newborn albinos, most uncrossed ganglion cells were in the temporal retina (about 89%), but there were many fewer than in the normal neonates and, as in the albino adults, the uncrossed ganglion cells were distributed along the temporal most margin of the retina. In the normal neonates, about 11% of the ganglion cells had uncrossed axons, compared to about 3% in the albino neonates. The area centralis and visual streak were not evident until 9 days after birth. From these results we conclude that the retinal line of decussation is essentially mature by birth in the ferret, and the degree of the albino's abnormality is as extreme in neonates as in adults. The retinal decussation is virtually mature at a stage of development when the crossed and uncrossed retinal afferent axons are completely intermingled in their target nuclei and prior to the onset of significant retinal ganglion cell loss.
这项研究描述了新生、9日龄以及成年的正常色素沉着和白化雪貂中交叉和不交叉投射的视网膜起源。将辣根过氧化物酶（HRP）单侧注入雪貂的丘脑和中脑视觉中枢，以逆行标记视网膜神经节细胞。在正常色素沉着的成年雪貂中，视网膜交叉线清晰，穿过中央凹区域。具有不交叉轴突的神经节细胞占据整个颞侧视网膜。在白化成年雪貂中，具有不交叉轴突的神经节细胞分布在颞侧视网膜远离中央凹区域的周边。在正常色素沉着的成年雪貂中，约11%的视网膜神经节细胞具有不交叉轴突，而白化雪貂中这一比例约为4%。出生时，正常色素沉着的雪貂有一条清晰的交叉线，大多数（约98%）不交叉的神经节细胞位于颞侧视网膜。在新生白化雪貂中，大多数不交叉的神经节细胞位于颞侧视网膜（约89%），但比正常新生儿少得多，并且与白化成年雪貂一样，不交叉的神经节细胞沿视网膜最颞侧边缘分布。在正常新生儿中，约11%的神经节细胞具有不交叉轴突，而白化新生儿中这一比例约为3%。中央凹区域和视条纹在出生后9天之前不明显。从这些结果我们得出结论，雪貂出生时视网膜交叉线基本成熟，白化雪貂的异常程度在新生儿和成年期一样极端。在视网膜交叉和不交叉传入轴突在其靶核中完全混合且在显著的视网膜神经节细胞丢失开始之前的发育阶段，视网膜交叉实际上已经成熟。
