Crain B J, Hall W C
J Comp Neurol. 1980 Sep 15;193(2):351-70. doi: 10.1002/cne.901930204.
As a first step in analyzing the influence of various afferent projections on the development of the hamster lateral posterior nucleus, its normal organization was studied using both light and electron microscopic techniques. Rostrolateral, rostromedial, and caudal subdivisions were identified. The rostrolateral subdivision receives dense projections from the ipsilateral superior colliculus and posterior neocortex, as well as sparser, more restricted projections from the contralateral colliculus and retina. The ipsilateral colliculus is by far the major source of medium-sized (M)terminals with round vesicles. These terminals synapse around the shafts of large central dendrites to form distinctive synaptic clusters. The contralateral colliculus and retina contribute a few M-terminals to the clusters. In contrast, axons from the posterior neocortex form very large (RL-)terminals with round vesicles from the posterior neocortex form very large (RL)terminals with round vesicles which synapse onto numerous appendages of single proximal dendrite, are surrounded by glial lamellae, and rarely participate in the clusters. Axons from all four sources also form small (RS)terminals with round vesicles which synapse on the shafts of small dendrites. Finally, F-terminals with flat or pleomorphic vesicles form symmetric synaptic contacts both within and outside the clusters. The only identified projection to the rostromedial subdivision is from the ipsilateral posterior neocortex, which contributes RL- and RS-terminals. F-terminals are also found, but neither M-terminals nor synaptic clusters are present. The caudal subdivision also receives RL- and RS-terminals from the ipsilateral posterior neocortex. Small inputs from the ipsilateral and contralateral colliculi are present, but their axons form only RS-terminals. No M-terminals or synaptic clusters are found. These results indicate that a large neonatal superior colliculus lesion would eliminate the vast majority of the M-terminals in the synaptic clusters of the ipsilateral lateral posterior nucleus. In subsequent studies (Crain and Hall, '80 a,b,c), we will examine how the remaining inputs from the retina, contralateral superior colliculus, and posterior neocortex contribute to the synaptic organization when it develops after such a lesion.
作为分析各种传入投射对仓鼠外侧后核发育影响的第一步，利用光学显微镜和电子显微镜技术研究了其正常组织结构。确定了嘴侧外侧、嘴侧内侧和尾侧亚区。嘴侧外侧亚区接受来自同侧上丘和后新皮层的密集投射，以及来自对侧上丘和视网膜的较稀疏、更局限的投射。同侧上丘是中等大小（M）圆形囊泡终末的主要来源。这些终末围绕大型中央树突的轴突形成独特的突触簇。对侧上丘和视网膜为这些突触簇贡献了少量M终末。相比之下，来自后新皮层的轴突形成非常大的（RL-）圆形囊泡终末，这些终末与单个近端树突的许多附属物形成突触，被胶质板包围，很少参与突触簇的形成。来自所有四个来源的轴突也形成带有圆形囊泡的小（RS）终末，这些终末与小树突的轴突形成突触。最后，带有扁平或多形囊泡的F终末在突触簇内外形成对称的突触接触。唯一确定的投射到嘴侧内侧亚区的是来自同侧后新皮层的投射，它贡献了RL-和RS-终末。也发现了F终末，但没有M终末或突触簇。尾侧亚区也接受来自同侧后新皮层的RL-和RS-终末。存在来自同侧和对侧上丘的少量输入，但其轴突仅形成RS终末。未发现M终末或突触簇。这些结果表明，新生儿期上丘的大面积损伤将消除同侧外侧后核突触簇中绝大多数的M终末。在随后的研究中（Crain和Hall，1980年a、b、c），我们将研究在这种损伤后发育时，来自视网膜、对侧上丘和后新皮层的剩余输入如何对突触组织产生影响。
