The role of V3 neurons in speed-dependent interlimb coordination during locomotion in mice.
The role of V3 neurons in speed-dependent interlimb coordination during locomotion in mice.
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DOI：
10.7554/elife.73424
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发表时间：
2022-04-27
期刊：
影响因子：
7.7
通讯作者：
Rybak, Ilya A.
中科院分区：
文献类型：
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作者：
Zhang, Han;Shevtsova, Natalia A.;Deska-Gauthier, Dylan;Mackay, Colin;Dougherty, Kimberly J.;Danner, Simon M.;Zhang, Ying;Rybak, Ilya A.
关键词：
速度依赖性的肢体间协调使动物在不同的环境下保持稳定的运动。已知V3神经元参与肢体间协调。我们先前对控制肢体间协调的运动脊髓回路进行了建模（Danner等人，2017年）。该模型包括介导左右节律发生器（RG）之间相互兴奋的局部V3神经元。在这里，我们的重点是V3神经元参与上行长propriospinal相互作用（aLPNs）。使用逆行追踪，我们发现了一个亚群的腰椎V3 aLPNs与对侧颈部的预测。V3OFF小鼠，其中所有V3神经元被沉默，具有显著降低的最大运动速度，不能使用稳定的小跑，疾驰，或绑定移动，并主要使用横向序列步行。为了重现这些数据并理解V3 aLPN的功能作用，我们通过将对角V3 aLPN介导从每个腰椎RG到对侧颈椎RG的输入来扩展我们先前的模型。扩展模型再现了我们的实验结果，并表明，局部投射V3神经元，介导左，右腰和颈髓内的相互作用，促进左，右同步必要的奔马和绑定，而V3 aLPNs促进同步之间的对角线向前和向后的RG必要的小跑。该模型提出了组织脊髓电路可用于未来的实验测试。
Speed-dependent interlimb coordination allows animals to maintain stable locomotion under different circumstances. The V3 neurons are known to be involved in interlimb coordination. We previously modeled the locomotor spinal circuitry controlling interlimb coordination (Danner et al., 2017). This model included the local V3 neurons that mediate mutual excitation between left and right rhythm generators (RGs). Here, our focus was on V3 neurons involved in ascending long propriospinal interactions (aLPNs). Using retrograde tracing, we revealed a subpopulation of lumbar V3 aLPNs with contralateral cervical projections. V3OFF mice, in which all V3 neurons were silenced, had a significantly reduced maximal locomotor speed, were unable to move using stable trot, gallop, or bound, and predominantly used a lateral-sequence walk. To reproduce this data and understand the functional roles of V3 aLPNs, we extended our previous model by incorporating diagonal V3 aLPNs mediating inputs from each lumbar RG to the contralateral cervical RG. The extended model reproduces our experimental results and suggests that locally projecting V3 neurons, mediating left–right interactions within lumbar and cervical cords, promote left–right synchronization necessary for gallop and bound, whereas the V3 aLPNs promote synchronization between diagonal fore and hind RGs necessary for trot. The model proposes the organization of spinal circuits available for future experimental testing.