The ramification and connections of retinal fibres in layer 7 of the domestic chick optic tectum: a Golgi impregnation, anterograde tracer and GABA‐immunogold study
The ramification and connections of retinal fibres in layer 7 of the domestic chick optic tectum: a Golgi impregnation, anterograde tracer and GABA‐immunogold study
复制标题
家鸡视顶盖第 7 层视网膜纤维的分支和连接：高尔基体浸渍、顺行示踪剂和 GABA 免疫金研究
DOI：
10.1046/j.0021-8782.2001.00012.x
复制
发表时间：
2002
影响因子：
2.4
通讯作者：
T. Tömböl
中科院分区：
文献类型：
--
作者：
T. Sebestény;D. Davies;N. Zayats;A. Németh;T. Tömböl
第7层是鸟类视顶盖的视网膜受体层之一。然而，关于这一层的神经元组织及其对视觉功能的影响的信息很少。高尔基体浸渍用于研究视网膜输入和小鸡视顶盖第7层的神经元结构，其在两个细胞致密层6和8之间形成窄带。顺行示踪剂也被用来调查的传入和传出连接的第7层，在光镜和电镜下，与GABA免疫金标记。根据神经元轴突的来源和走行，将放射状神经元分为三种类型。这些神经元的胞体位于顶盖第10 ~ 11层。这些放射状神经元的主树突上升到顶盖表面，并在第7层产生树突侧支。这些树突侧支接受来自视网膜纤维分支末端的不对称突触。2型放射状神经元，其轴突来自核周体的深极或偶尔来自基底树突，被证明投射到峡部核大细胞部，其先前已被证明是GABA能的，并投射到顶盖层4-5中的肾小球样复合体。在这些层中，投射到圆核的第13层神经元的树突分支先前已被证明接收视网膜纤维输入。因此，通过涉及峡部大细胞核的顶盖的第4-5层的反馈回路，到第7层的视网膜输入可能能够调节到视觉丘脑的信息传输。
Layer 7 is one of the retinorecipient layers of the avian optic tectum. However, little information is available about the neuronal organization of this layer and its implications for visual function. Golgi impregnation was used to investigate the retinal input to and the neuronal architecture of layer 7 of the chick optic tectum, which forms a narrow band between the two cell‐dense layers 6 and 8. Anterograde tracers were also used to investigate the afferent and efferent connections of layer 7, in both the light and the electron microscope, together with GABA immunogold labelling. Three types of radial neuron were defined according to the origin and course of their axons. The perikarya of these neurons were situated in tectal layers 10–11. The principal dendrites of these radial neurons ascended to the tectal surface and gave rise to dendritic side‐branches in layer 7. These dendritic side‐branches received asymmetric synapses from the terminations of retinal fibre arborisations. Type 2 radial neurons, whose axons arose from the deep pole of the perikaryon or occasionally from a basal dendrite, were shown to project to the nucleus isthmi pars magnocellularis, which has previously been demonstrated to be GABAergic and to project to glomerulus‐like complexes in tectal layers 4–5. In these layers, the dendritic branches of layer 13 neurons that project to the nucleus rotundus have previously been shown to receive retinal fibre input. Therefore, the retinal input to layer 7 may be able to modulate the transmission of information to the visual thalamus, by way of a feedback loop to layers 4–5 of the tectum involving the nucleus isthmi pars magnocellularis.