Murphy E H, Grigonis A M, Hayden T E, Tashayyod D, Wilkes M
Department of Anatomy, Medical College of Pennsylvania, Philadelphia 19129.
Brain Res. 1988 Jan 1;466(1):27-35. doi: 10.1016/0165-3806(88)90083-1.
Primary visual cortex was ablated unilaterally in neonatal rabbits. Following a survival of 2-4 months, retrograde degeneration of the dorsal lateral geniculate nucleus (LGd) was assessed, and reorganization of retinofugal pathways was studied using methods of anretrograde transport of [3H]proline or of horseradish peroxidase. A complete lesion of primary visual cortex resulted in complete retrograde degeneration of the LGd with no sparing of any class of neurons. The terminations of retinofugal axons in the pretectum and thalamus were compared with those observed in normal animals. No major reorganization of ipsilateral retinofugal projections was observed in either the thalamus and pretectum ipsilateral to the ablated cortex, or in the thalamus and pretectum contralateral to the ablated cortex. However, contralateral retinofugal projections to the thalamus and to the pretectum ipsilateral to the ablated cortex were significantly different from normal. In the thalamus, the projections to the lateral posterior nucleus were expanded in area and increased in density. In the pretectum, the projections to the rostral pretectal areas were greatly increased in area, especially in the region of the olivary pretectal nucleus and posterior pretectal nucleus. However, the density of these projections was not increased relative to normal. Consideration of these results in relation to other published data on the anatomical consequences of neonatal visual cortex lesions, both in mammals which show behavioral sparing following neonatal visual cortex lesions and in mammals which, like the rabbit, show no behavioral sparing, suggests that: (1) behavioral sparing may correlate with patterns of survival or death of neurons in the thalamus and retina; and (2) reorganization of retinofugal pathways is not necessarily associated with behavioral sparing.
在新生兔中单侧切除初级视皮层。在存活2 - 4个月后，评估背外侧膝状核（LGd）的逆行性变性，并使用[3H]脯氨酸或辣根过氧化物酶的逆行转运方法研究视网膜神经通路的重组。初级视皮层的完全损伤导致LGd完全逆行性变性，任何一类神经元均未幸免。将视网膜神经轴突在前顶盖和丘脑的终末与正常动物中观察到的终末进行比较。在切除皮层同侧的丘脑和前顶盖，以及切除皮层对侧的丘脑和前顶盖中，均未观察到同侧视网膜神经投射的主要重组。然而，切除皮层对侧投射到丘脑和切除皮层同侧前顶盖的视网膜神经投射与正常情况有显著差异。在丘脑中，投射到外侧后核的区域扩大且密度增加。在前顶盖中，投射到嘴侧前顶盖区域的面积大幅增加，尤其是在橄榄前顶盖核和后前顶盖核区域。然而，这些投射的密度相对于正常情况并未增加。结合其他已发表的关于新生视皮层损伤解剖学后果的数据来考虑这些结果，无论是在新生视皮层损伤后表现出行为保留的哺乳动物中，还是在像兔子一样不表现出行为保留的哺乳动物中，都表明：（1）行为保留可能与丘脑和视网膜中神经元的存活或死亡模式相关；（2）视网膜神经通路的重组不一定与行为保留相关。
