The mammalian spinal commissural system: properties and functions.
The mammalian spinal commissural system: properties and functions.
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哺乳动物脊柱连合系统：特性和功能。
DOI：
10.1152/jn.00347.2019
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发表时间：
2020
影响因子：
2.5
通讯作者：
Maxwell DJ
中科院分区：
文献类型：
--
作者：
Maxwell DJ
连合系统是协调骨骼肌系统左右活动的运动回路的重要组成部分。连合系统存在于神经轴的许多层面，包括皮质、脑干和脊髓。在这篇综述中，我们将讨论哺乳动物脊髓连合系统的各个方面。我们将专注于连合中间神经元，它们从脊髓的一侧投射到另一侧，形成局限于脊髓本身的轴突终末。连合中间神经元形成异质群体，影响多种脊髓环路。它们可以根据各种标准来定义，包括脊髓灰质中的位置、轴突投射和靶点、神经递质表型、激活特性和胚胎学起源。目前，我们还没有对这些细胞进行全面的分类，但很明显，位于灰质不同区域的细胞具有特征属性，对运动神经回路有特殊的贡献。连合中间神经元对运动功能和姿势的贡献已得到很好的证实和简要讨论。然而，它们在其他以目标为导向的行为中的作用还不是很清楚，如抓取、伸手和双手任务。这在一定程度上是因为我们对包括人类在内的灵长类动物颈脊髓中连合中间神经元的组织和功能特性的信息有限。在这次审查中，我们将讨论这些不同的问题。首先，我们将考虑连合中间神经元的特性，并随后检查关于它们的功能的已知情况。然后我们讨论它们如何有助于脊柱损伤和中风后功能的恢复。
Commissural systems are essential components of motor circuits that coordinate left–right activity of the skeletomuscular system. Commissural systems are found at many levels of the neuraxis including the cortex, brainstem, and spinal cord. In this review we will discuss aspects of the mammalian spinal commissural system. We will focus on commissural interneurons, which project from one side of the cord to the other and form axonal terminations that are confined to the cord itself. Commissural interneurons form heterogeneous populations and influence a variety of spinal circuits. They can be defined according to a variety of criteria including, location in the spinal gray matter, axonal projections and targets, neurotransmitter phenotype, activation properties, and embryological origin. At present, we do not have a comprehensive classification of these cells, but it is clear that cells located within different areas of the gray matter have characteristic properties and make particular contributions to motor circuits. The contribution of commissural interneurons to locomotor function and posture is well established and briefly discussed. However, their role in other goal-orientated behaviors such as grasping, reaching, and bimanual tasks is less clear. This is partly because we only have limited information about the organization and functional properties of commissural interneurons in the cervical spinal cord of primates, including humans. In this review we shall discuss these various issues. First, we will consider the properties of commissural interneurons and subsequently examine what is known about their functions. We then discuss how they may contribute to restoration of function following spinal injury and stroke.