Descending projections from brainstem and sensorimotor cortex to spinal enlargements in the cat
Descending projections from brainstem and sensorimotor cortex to spinal enlargements in the cat
复制标题
猫从脑干和感觉运动皮层到脊柱增大的下降投射
DOI：
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发表时间：
2004
影响因子：
2
通讯作者：
A. Rustioni
中科院分区：
文献类型：
--
作者：
N. L. Hayes;A. Rustioni
总结在猫中采用单和双逆行示踪技术研究：（1）脊髓上神经元投射到臂膨大或腰骶膨大的位置关系，（2）单个脊髓上神经元以轴突分支方式投射到两个扩大区的分布和相对频率。在肱部或腰骶部的扩张处都有这些实验结果支持了最近关于脑干中枢起源于下行脊髓通路的观察，并为第6区的皮质脊髓神经元群提供了证据。在第二组实验中，HRP被注射到一个扩大区，3 H-apo-HRP（酶活性）被注射到另一个扩大区。在延髓和脑桥网状结构、双侧前庭内侧核和下核、同侧前庭外侧核、Edinger-Westphal核、尾侧中线中缝核和结合臂周围核区中观察到相对大量的神经元与两个放大物（双标记）的侧支投射。在红核、前庭外侧核和感觉运动皮质中，投射到臂膨大的神经元与投射到腰骶膨大的神经元在拓扑学上基本分离。然而，有一些重叠，并始终观察到重叠区域内的双标记神经元。在感觉运动皮层，臂和腰投射神经元之间的重叠是最突出的区域4和3a，沿着交叉沟，但也涉及其他cytoarchitectonic地区的内侧方面的半球。
SummarySingle and double retrograde tracer techniques were employed in cats to investigate: (1) the topographical relationships between supraspinal neurons projecting to either the brachial or lumbosacral enlargement, (2) the distribution and relative frequency of single supraspinal neurons which project to both enlargements by means of axonal branching.In one group of cats large injections of horseradish peroxidase (HRP) were made throughout either the brachial or lumbosacral enlargement. The results from these experiments support recent observations on the multiplicity of brainstem centers giving origin to descending spinal pathways and provide evidence for a population of corticospinal neurons in area 6.In a second set of experiments, HRP was injected in one enlargement, and 3H-apo-HRP (enzymatically inactive) was injected in the other enlargement. Relatively large numbers of neurons with collateral projections to both enlargements (double-labeled) were observed in the medullary and pontine reticular formation, the medial and inferior vestibular nuclei bilaterally, the ipsilateral lateral vestibular nucleus, Edinger-Westphal nucleus, caudal midline raphe nuclei and nuclear regions surrounding the brachium conjunctivum. By contrast, double-labeled neurons were infrequently observed in the red nucleus and sensorimotor cortex, contralateral to the injections.In the red nucleus, lateral vestibular nucleus and sensorimotor cortex, neurons projecting to the brachial enlargement were largely segregated topographically from neurons projecting to the lumbosacral enlargement. However, there was some overlap, and double-labeled neurons were consistently observed within the region of overlap. In the sensorimotor cortex, the overlap between brachial- and lumbar-projecting neurons was most prominent in areas 4 and 3a, along the cruciate sulcus, but also involved other cytoarchitectonic regions in the medial aspect of the hemisphere.