Skilled reaching relies on a V2a propriospinal internal copy circuit
Skilled reaching relies on a V2a propriospinal internal copy circuit
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DOI：
10.1038/nature13021
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发表时间：
2014-04-17
期刊：
影响因子：
64.8
通讯作者：
Jessell, Thomas M.
中科院分区：
文献类型：
--
作者：
Azim, Eiman;Jiang, Juan;Jessell, Thomas M.
熟练的前肢运动的精确性长期以来一直被认为依赖于由传出的运动命令的内部定向复制触发的快速反馈校正，但推断的内部复制回路的功能相关性仍然不清楚。一类参与哺乳动物前肢运动控制的脊髓中间神经元，即颈椎固有脊髓神经元（PNs），具有通过支配前肢的运动神经元和外侧网状核的小脑前神经元的双重神经支配来传递运动前信号的内部拷贝的潜力。在这里，我们研究是否PN内部复制途径的功能在控制目标导向的达成。在小鼠中，PN包括颈部V2a中间神经元的遗传可接近的亚群，并且它们的靶向消融干扰到达，同时保持前肢运动的其他元素完整。此外，PN内部复制分支的光遗传学激活募集快速小脑反馈回路，其调节前肢运动神经元活动并严重破坏到达运动学。我们的研究结果牵连V2A PN的内部复制通路分配到快速更新的运动输出达到行为的焦点。
The precision of skilled forelimb movement has long been presumed to rely on rapid feedback corrections triggered by internally directed copies of outgoing motor commands, but the functional relevance of inferred internal copy circuits has remained unclear. One class of spinal interneurons implicated in the control of mammalian forelimb movement, cervical propriospinal neurons (PNs), has the potential to convey an internal copy of premotor signals through dual innervation of forelimb-innervating motor neurons and precerebellar neurons of the lateral reticular nucleus. Here we examine whether the PNinternal copy pathway functions in the control of goal-directed reaching. In mice, PNs include a genetically accessible subpopulation of cervical V2a interneurons, and their targeted ablation perturbs reaching while leaving intact other elements of forelimb movement. Moreover, optogenetic activation of the PN internal copy branch recruits a rapid cerebellar feedback loop that modulates forelimb motor neuron activity and severely disrupts reaching kinematics. Our findings implicate V2a PNs as the focus of an internal copy pathway assigned to the rapid updating of motor output during reaching behaviour.