Preclinical and clinical neurophysiological and neurorehabilitation research has generated rather surprising levels of recovery of volitional sensory-motor function in persons with chronic motor paralysis following a spinal cord injury. The key factor in this recovery is largely activity-dependent plasticity of spinal and supraspinal networks. This key factor can be triggered by neuromodulation of these networks with electrical and pharmacological interventions. This review addresses some of the systems-level physiological mechanisms that might explain the effects of electrical modulation and how repetitive training facilitates the recovery of volitional motor control. In particular, we substantiate the hypotheses that: (1) in the majority of spinal lesions, a critical number and type of neurons in the region of the injury survive, but cannot conduct action potentials, and thus are electrically non-responsive; (2) these neuronal networks within the lesioned area can be neuromodulated to a transformed state of electrical competency; (3) these two factors enable the potential for extensive activity-dependent reorganization of neuronal networks in the spinal cord and brain, and (4) propriospinal networks play a critical role in driving this activity-dependent reorganization after injury. Real-time proprioceptive input to spinal networks provides the template for reorganization of spinal networks that play a leading role in the level of coordination of motor pools required to perform a given functional task. Repetitive exposure of multi-segmental sensory-motor networks to the dynamics of task-specific sensory input as occurs with repetitive training can functionally reshape spinal and supraspinal connectivity thus re-enabling one to perform complex motor tasks, even years post injury.

临床前和临床神经生理学和神经康复研究已使脊髓损伤后的慢性运动麻痹患者的感觉运动功能恢复水平达到了令人惊讶的水平。这种恢复的关键因素主要是脊柱和棘上神经网络的活动依赖性可塑性。该关键因素可以通过用电学和药理学干预对这些网络进行神经调节来触发。这篇综述讨论了一些系统级的生理机制，这些机制可能解释了电调制的影响以及重复训练如何促进自愿运动控制的恢复。特别是，我们证实了以下假设：（1）在大多数脊柱病变中，损伤区域中的关键数量和类型的神经元得以幸存，但不能传导动作电位，因此在电学上无响应；（2）病变区域内的这些神经元网络可以被神经调节到电能力的转变状态；（3）这两个因素使脊髓和大脑中神经元网络具有广泛的依赖于活动的重组的潜力，并且（4）脊椎神经网络在驱动损伤后这种依赖于活动的重组中起着关键作用。脊椎网络的实时本体感受输入提供了重组脊椎网络的模板，这些模板在执行给定功能任务所需的运动池协调水平中起着主导作用。