Spinal sensory neurons project onto the hindbrain to stabilize posture and enhance locomotor speed.
Spinal sensory neurons project onto the hindbrain to stabilize posture and enhance locomotor speed.
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脊髓感觉神经元投射到后脑以稳定姿势并提高运动速度。
DOI：
10.1016/j.cub.2021.05.042
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Wyart,Claire
中科院分区：
文献类型：
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作者：
Wu,Ming-Yue;Carbo-Tano,Martin;Mirat,Olivier;Lejeune,Francois-Xavier;Roussel,Julian;Quan,FengB;Fidelin,Kevin;Wyart,Claire
在脊髓中，脑脊液接触神经元（CSF-cNs）是gaba能内感受性感觉神经元，通过与Reissner纤维的功能偶联来检测脊柱弯曲。这种机械感觉系统最近被发现与脊柱形态发生和姿势控制有关，但其潜在机制尚不完全清楚。在斑马鱼中，CSF-cNs投射出一个上行的同侧轴突，达到2至6节段。Rostralmost CSF-cNs将轴突同侧发送到后脑，后脑是一个包含运动核和网状脊髓神经元（rsn）的大脑区域，后者向脊髓回路发送下行运动指令。到目前为止，仅在脊髓中研究了CSF-cNs的突触连通性，在脊髓中它们与运动神经元和运动前兴奋性中间神经元突触。后脑CSF-cN靶点的身份以及这些从脊髓到后脑的感觉投射的行为相关性尚不清楚。在这里，我们提供了解剖学和分子证据，表明几乎所有的CSF-cNs突触连接到包括Mauthner细胞和V2a神经元在内的大型rsn的轴突上。功能解剖和光遗传学辅助定位显示，吻侧CSF-cNs也与支配鳃下肌肉的颅运动神经元的体和树突相连。在声-前庭诱发的逃逸反应中，前列脑脊液-中枢神经系统的消融导致逃逸反应较弱，伴有c -弯曲幅度降低、速度减慢和姿势控制不足。我们的研究表明，脊髓感觉反馈可以提高速度和稳定姿势，并揭示了一种新的脊髓门控机制，作用于后脑向脊髓发送的下行命令的输出。
In the spinal cord, cerebrospinal fluid-contacting neurons (CSF-cNs) are GABAergic interoceptive sensory neurons that detect spinal curvature via a functional coupling with the Reissner fiber. This mechanosensory system has recently been found to be involved in spine morphogenesis and postural control but the underlying mechanisms are not fully understood. In zebrafish, CSF-cNs project an ascending and ipsilateral axon reaching two to six segments away. Rostralmost CSF-cNs send their axons ipsilaterally into the hindbrain, a brain region containing motor nuclei and reticulospinal neurons (RSNs), which send descending motor commands to spinal circuits. Until now, the synaptic connectivity of CSF-cNs has only been investigated in the spinal cord, where they synapse onto motor neurons and premotor excitatory interneurons. The identity of CSF-cN targets in the hindbrain and the behavioral relevance of these sensory projections from the spinal cord to the hindbrain are unknown. Here, we provide anatomical and molecular evidence that rostralmost CSF-cNs synapse onto the axons of large RSNs including Mauthner cells and V2a neurons. Functional anatomy and optogenetically assisted mapping reveal that rostral CSF-cNs also synapse onto the soma and dendrites of cranial motor neurons innervating hypobranchial muscles. During acousto-vestibular evoked escape responses, ablation of rostralmost CSF-cNs results in a weaker escape response with a decreased C-bend amplitude, lower speed, and deficient postural control. Our study demonstrates that spinal sensory feedback enhances speed and stabilizes posture, and reveals a novel spinal gating mechanism acting on the output of descending commands sent from the hindbrain to the spinal cord.