Thalamocortical projection from the ventral posteromedial nucleus sends its collaterals to layer I of the primary somatosensory cortex in rat
Thalamocortical projection from the ventral posteromedial nucleus sends its collaterals to layer I of the primary somatosensory cortex in rat
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DOI：
10.1016/j.neulet.2004.06.042
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发表时间：
2004-09-09
影响因子：
2.5
通讯作者：
Kuroda, M
中科院分区：
文献类型：
--
作者：
Oda, S;Kishi, K;Kuroda, M
在这里，我们通过细胞外和细胞内注射生物细胞素作为顺行示踪剂，定量地检测了从腹侧丘脑后内侧核（VPM）到初级体感皮层（SI）第一层的轴突投射。细胞外注射后，观察到两种不同树突模式的VPM传入。I型垂直延伸，在第IV层和第VI层形成密集的神经丛，向第I层投射侧枝。II型在SI层很少分支，在第I型形成的神经丛中收敛，向球髓上层不投射侧枝。第一层标记纤维平行于脑表面，平均长度为339.7±87.5 mm。细胞内注射到携带两种传入信号的VPM神经元中，显示丘脑网状核（Rt）和SI的轴突完全树突化。1型神经元轴突总长度为86,968.8 mm， SI第1层轴突侧枝长度为433.1 mm。携带II型的神经元的总轴突长度非常小。本研究首次证明了从VPM到SI第一层的大量投影，并提供了单个VPM神经元丘脑皮质轴突投影的整个范围的定量数据。2004爱思唯尔爱尔兰有限公司版权所有。
Here we examined quantitatively axonal projections originating from the ventral posteromedial thalamic nucleus (VPM) to layer I of the primary somatosensory cortex (SI) by extracellular and intracellular injections of biocytin as an anterograde tracer. Following the extracellular injections, two types of VPM afferents with different arborization patterns in SI were observed. The type I extended vertically, forming dense plexus in layers IV and VI, and projected collaterals to layer I. The type II rarely branched in SI, converged in the plexus formed by the type I, and projected no collaterals to the supragranular layers. The labeled fibers in layer I derived from the first type ran parallel to the brain surface, and their mean length was 339.7 +/- 87.5 mum. Intracellular injection into VPM neurons bearing both types of afferent demonstrated the full axonal arborization in both the reticular thalamic nucleus (Rt) and SI. The total length of the axon of a neuron bearing the type I was 86,968.8 mum, and the length of axonal collaterals in layer I of SI was 433.1 mum. The total axonal length of a neuron bearing the type II was very small. The present study is the first to demonstrate substantial projections from VPM to layer I of SI, and provide quantitative data on the entire extent of the axonal arborization of thalamocortical projections from single VPM neurons. (C) 2004 Elsevier Ireland Ltd. All rights reserved.