Department of Physiology and Center for Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
Ann N Y Acad Sci. 2010 Jun;1198:72-84. doi: 10.1111/j.1749-6632.2010.05533.x.
Innovative molecular and genetic techniques have recently led to the identification of genetically defined populations of ipsilaterally projecting excitatory interneurons with probable functions in the rhythm-generating kernel of the central pattern generators (CPGs). The role of interneuronal populations in specific motor function is determined by their synaptic inputs, intrinsic properties, and target neurons. In this review we examine whether Hb9-expressing interneurons (Hb9 INs) fulfill a set of criteria that are the hallmarks of rhythm generators in the locomotor circuitry. Induced locomotor-like activity in this distinct population of ventral interneurons is in phase with bursts of motor activity, raising the possibility that they are part of the locomotor generator. To increase our understanding of the integrative function of Hb9 INs in the locomotor CPG, we investigated the cellular mechanisms underlying their rhythmic activity and examined the properties of synaptic inputs from low-threshold afferents and possible synaptic contacts with segmental motoneurons. Our findings suggest that the rhythmogenic Hb9 INs are integral components of the sensorimotor circuitry that regulate locomotor-like activity in the spinal cord.
创新性的分子和遗传技术最近导致了具有可能在中央模式发生器（CPG）的节律产生核中起作用的同侧投射兴奋性中间神经元的基因定义群体的鉴定。中间神经元群体在特定运动功能中的作用取决于它们的突触输入、内在特性和靶神经元。在这篇综述中，我们检查了 Hb9 表达中间神经元（Hb9 INs）是否符合节律发生器在运动回路中的特征的一组标准。在这个独特的腹侧中间神经元群体中诱导的类似运动的活动与运动活动的爆发同步，这增加了它们是运动发生器的一部分的可能性。为了增加我们对 Hb9 INs 在运动 CPG 中的整合功能的理解，我们研究了它们节律活动的细胞机制，并检查了来自低阈值传入的突触输入的特性和与节段性运动神经元的可能突触接触。我们的研究结果表明，产生节律的 Hb9 INs 是调节脊髓中类似运动活动的感觉运动回路的组成部分。
