Synaptic Organization of Connections between the Temporal Cortex and Pulvinar Nucleus of the Tree Shrew
Synaptic Organization of Connections between the Temporal Cortex and Pulvinar Nucleus of the Tree Shrew
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DOI：
10.1093/cercor/bhp162
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发表时间：
2010-04-01
期刊：
影响因子：
3.7
通讯作者：
Bickford, Martha E.
中科院分区：
文献类型：
--
作者：
Chomsung, Ranida D.;Wei, Haiyang;Bickford, Martha E.
我们检查了颞叶皮层与树鼩枕核的背侧（Pd）和中央（Pc）细分（分别受内侧和外侧上丘支配的区域）之间相互连接的突触组织。 Pd 和 Pc 细分都在地形上投射到颞叶皮层的 2 个独立区域；顺行示踪剂的小量注射放置在 Pd 或 Pc 标记的颞叶皮层末端的 2 个焦点中。髓皮质通路支配 I-IV 层，珠状轴突垂直于皮质表面，与不含伽马氨基丁酸 (GABA) 的棘突触，可能位于锥体细胞的顶端树突上。从颞叶皮层到 Pd 和 Pc 的投射源自 VI 层细胞，并形成接触小口径非 GABA 能树突的小终端。这些结果表明，皮质末端位于 Pd 和 Pc 投射细胞的树突轴上顶盖末端的远端，随后与颞皮质中的锥体细胞接触。该电路可以为枕核提供一种机制来激活皮层下视觉运动电路并调节其他视觉皮层区域的活动。讨论了与灵长类动物顶峰皮质通路的潜在关系。
We examined the synaptic organization of reciprocal connections between the temporal cortex and the dorsal (Pd) and central (Pc) subdivisions of the tree shrew pulvinar nucleus, regions innervated by the medial and lateral superior colliculus, respectively. Both Pd and Pc subdivisions project topographically to 2 separate regions of the temporal cortex; small injections of anterograde tracers placed in either Pd or Pc labeled 2 foci of terminals in the temporal cortex. Pulvinocortical pathways innervated layers I-IV, with beaded axons oriented perpendicular to the cortical surface, where they synapsed with spines that did not contain gamma amino butyric acid (GABA), likely located on the apical dendrites of pyramidal cells. Projections from the temporal cortex to the Pd and Pc originate from layer VI cells, and form small terminals that contact small caliber non-GABAergic dendrites. These results suggest that cortical terminals are located distal to tectopulvinar terminals on the dendritic arbors of Pd and Pc projection cells, which subsequently contact pyramidal cells in the temporal cortex. This circuitry could provide a mechanism for the pulvinar nucleus to activate subcortical visuomotor circuits and modulate the activity of other visual cortical areas. The potential relation to primate tecto-pulvino-cortical pathways is discussed.