The spinal cord is home to the intrinsic networks for locomotion. An animal in which the spinal cord has been fully severed from the brain can still produce rhythmic, patterned locomotor movements as long as some excitatory drive is provided, such as physical, pharmacological, or electrical stimuli. Yet it remains a challenge to define the underlying circuitry that produces these movements because the spinal cord contains a wide variety of neuron classes whose patterns of interconnectivity are still poorly understood. Computational models of locomotion accordingly rely on untested assumptions about spinal neuron network element identity and connectivity. In this review, we consider the classes of spinal neurons, their interconnectivity, and the significance of their circuit connections along the long axis of the spinal cord. We suggest several lines of analysis to move toward a definitive understanding of the spinal network.

中文翻译：

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脊髓中间神经元：运动控制的多样性和连通性

脊髓是运动内在网络的所在地。只要提供一些兴奋性驱动，例如物理、药理或电刺激，脊髓已与大脑完全切断的动物仍然可以产生有节奏的、有模式的运动。然而，定义产生这些运动的底层电路仍然是一个挑战，因为脊髓包含各种各样的神经元类别，其互连模式仍然知之甚少。因此，运动的计算模型依赖于关于脊髓神经元网络元件身份和连接性的未经测试的假设。在这篇综述中，我们考虑了脊髓神经元的类别、它们的互连性以及它们沿脊髓长轴的电路连接的重要性。我们建议进行几条分析，以明确了解脊柱网络。