Spinal sensory neurons project onto hindbrain to stabilize posture and enhance locomotor speed
Spinal sensory neurons project onto hindbrain to stabilize posture and enhance locomotor speed
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DOI：
10.1101/2021.03.16.435696
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发表时间：
2021-03
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通讯作者：
Ming-Yue Wu;Martin Carbó-Tano;Olivier Mirat;François-Xavier Lejeune;Julian Roussel;Feng Quan;Kevin Fidelin;Claire Wyart
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作者：
Ming-Yue Wu;Martin Carbó-Tano;Olivier Mirat;François-Xavier Lejeune;Julian Roussel;Feng Quan;Kevin Fidelin;Claire Wyart
在脊髓中，脑脊液接触神经元 (CSF-cN) 是 GABA 能内感受感觉神经元，可通过与赖斯纳纤维的功能耦合来检测脊柱弯曲。最近发现这种机械感觉系统参与脊柱形态发生和姿势控制，但其潜在机制尚不完全清楚。在斑马鱼中，CSF-cNs投射出一个上升的同侧轴突，延伸到两到六个节段之外。头端 CSF-cN 将其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，后脑向脊髓回路发送下行运动命令。到目前为止，CSF-cN 的突触连接仅在脊髓中进行了研究，它们突触到运动神经元和运动前兴奋性中间神经元。后脑中 CSF-cN 目标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，表明最前端的 CSF-cN 突触到大 RSN 的轴突上，包括 Mauthner 细胞和早期出生的 chx10+ 神经元。功能解剖学和光遗传学辅助绘图表明，头侧 CSF-cN 也突触到支配下臂肌的颅运动神经元的体细胞和树突上。在声前庭诱发逃避反应期间，头端 CSF-cN 的消融会导致逃避反应较弱，C 弯曲幅度降低、速度降低和姿势控制不足。我们的研究表明，脊髓感觉反馈可以提高速度并稳定姿势，并揭示了一种新颖的脊髓门控机制，作用于从后脑发送到脊髓的下行命令的输出。 eTOC 脑脊液接触神经元是检测脊柱弯曲的机械感觉细胞。吴等人。这里显示后脑中最前部的 CSF-cNs 突触连接到颅运动神经元和网状脊髓神经元的下降轴突，并增强主动运动过程中的速度和力量以及姿势控制。亮点 脊髓头端的脑脊液接触神经元 (CSF-cN) 在颅运动神经元上形成抑制性突触 头端 CSF-cN 与网状脊髓神经元的下降轴突形成突触 脊髓头端的 CSF-cN 感觉反馈增强运动的速度和力量 投射到后脑的头端 CSF-cN 有助于姿势控制
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 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 spinal cord to hindbrain are unknown. Here, we provide anatomical and molecular evidence that rostralmost CSF-cNs synapse onto the axons of large RSNs including the Mauthner cells and early born chx10+ neurons. Functional anatomy and optogenetic-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 a 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. eTOC Cerebrospinal fluid-contacting neurons are mechanosensory cells that detect spinal curvature. Wu et al. show here that rostralmost CSF-cNs synapse in the hindbrain onto cranial motor neurons and the descending axons of reticulospinal neurons, and enhance speed and power as well as postural control during active locomotion. Highlights Cerebrospinal fluid-contacting neurons (CSF-cNs) in rostral spinal cord form inhibitory synapses onto cranial motor neurons Rostral CSF-cNs synapse onto descending axons of reticulospinal neurons CSF-cN sensory feedback in the rostral spinal cord enhance speed and power of locomotion Rostral CSF-cNs projecting to the hindbrain contribute to postural control