ANALYSIS OF THE RECURRENT RENSHAW CIRCUIT

这项建议涉及对递归伦肖电路的分析 其目的是帮助我们理解循环的作用 抑制脊髓运动神经元的放电。这个 对这种双突触回路的分析将主要由 一种刺激单个运动神经轴突的技术联合应用 为记录小突触后突触而触发的平均波 脊髓运动神经元中由这种刺激引起的电位。vbl.使用 这些方法将解决一些具体问题。这个 单轴突反复抑制性突触后电位的特点 (RIPSP)以及它们之间的关系 神经元间放电的特征。RIPSP的分布 在同名运动核内将根据 刺激轴突的运动单位类型和大鼠的运动单位类型 运动神经元接受重复性抑制。RIPSP的分布 还将检查是否有RIPSP“分割”的证据，即， 由支配特定肌肉区域的沙子产生的RIPSP是 在支配同一肌肉区域的运动神经元中最大的。 如果找到这样的分区，将分析其对 地形特异性与物种特异性的比较。 这些研究可望有助于我们了解 反复抑制脊髓的组织及其功能意义 运动神经元，此外还提供了一种分析神经元的方法 哺乳动物脊髓中涉及双突触和多突触的回路 关系。这项研究与健康相关的最终目标是 有助于了解节段性运动功能的改变 控制机制，如在痉挛、僵硬等状态下发生 和还押人。

This proposal is concerned with analysis of the recurrent Renshaw circuit with the goal of contributing to our understanding of the role of recurrent inhibition in controlling the discharge of spinal motoneurons. The analysis of this disynaptic circuit will be accomplished primarily by the use of a technique for stimulating single motor axons in conjunction with spike-triggered averaging in order to record the small postsynaptic potentials in spinal motoneurons which result from such stimulation. Using these methods a number of specific issues will be addressed. The characteristics of single-axon recurrent inhibitory postsynaptic potentials (RIPSPs) will be documented as well as the relation of these characteristics to interneuronal discharge. The distribution of RIPSPs within a homonymous motor nucleus will be determined with respect to the motor-unit type of the stimulated axon and the motor-unit type of the motoneuron receiving the recurrent inhibition. The distribution of RIPSPs will also be examined for evidence of a "partitiioning" of RIPSPs, i.e., that RIPSPs produced by asons innervating a particular region of muscle are largest in those motoneurons which innervate that same region of muscle. Such a partitioning, if found, will be analyzed for contributions of topographic specificity in comparison to species specificity. These studies are expected to contribute to our understanding of the organization and functional significance of recurrent inhibition to spinal motoneurons and, in addition, to provide an approach for analyzing neuronal circuits in the mammalian spinal cord which involve di- and polysynaptic connections. The ultimate health-related goal of this study is to contribute to an understanding of altered function of segmental motor control mechanisms, such as occurs in such states as spasticity, rigidity and remor.