Influence of neuromodulatory input on ankle control and spasticity in persons with spinal cord injury.

脊髓损伤(Sci)患者可能具有一定的行走能力，然而，他们经常面临 痉挛步态模式，特征是抬起脚的肌肉(背屈肌)和 控制推力的肌肉痉挛(足底屈肌)。这两种缺陷都会导致能力受损 实现脚-地清空，行走费力且不稳定。两个主要的神经贡献者 痉挛步态包括皮质脊髓束下行(CST)驱动到踝关节背屈肌的紊乱和受损 足底屈肌脊髓反射回路(SRC)的调制。目前还不清楚是否减少了下降 意志力驱动或反射调节功能障碍对痉挛步态的影响更大。传入输入具有很强的 神经调制对CST和SRC兴奋性的影响。全身振动是一种稳健的振动 一种传入输入的形式，为了解痉挛的神经生理机制提供了一种探针 步态。这项研究的长期目标是开发康复策略，以增强步行功能和 通过改善脚踝控制改善脊髓损伤患者的活动能力。这项建议的总体目标是理解 CST和SRC在踝关节意志和反射控制中的作用。这个项目的基本原理是 了解神经生理学对增强意志控制和减少痉挛的作用 脚踝将是开发重要的非侵入性康复策略以改善痉挛的第一步 脊髓损伤和其他上运动神经元病患者的步态。中心假设是，改进 踝关节功能的改变与CST的变化比与SRC的变化有更大的相关性 调节，因为皮质脊髓驱动影响意志控制和反射调节。使用WBV 激活大脑皮层和脊髓回路，将通过两个具体目标检验中心假说：1)确定 背屈肌CST和足底屈肌SRC兴奋性在踝关节意志控制中的作用 2)确定背屈肌CST和足底屈肌SRC兴奋性对踝关节的作用 脊髓损伤患者的痉挛状态。这项拟议的研究是创新的，因为还没有一项研究 研究同时针对CST和SRC的干预措施如何影响不同的 脊髓损伤后痉挛步态的构成因素。了解痉挛步态背后的机制具有重要意义。 因为它为靶向非侵入性治疗的发展提供了基础，从而增加了 受这种步态模式影响的人的功能结果。总体而言，在这一过程中获得的知识 该提案将提供更多关于脚踝控制和痉挛的潜在机制的见解 SCI。

People with spinal cord injury (SCI) may have some walking ability, however, they are often challenged with a spastic gait pattern, characterized by poor voluntary control of the muscles that lift the foot (dorsiflexors) and spasms of the muscles that control push-off (plantar flexors). Both deficits contribute to impaired ability to achieve foot-ground clearance, making walking laborious and unstable. Two major neural contributors to spastic gait include disrupted descending corticospinal tract (CST) drive to the ankle dorsiflexors and impaired modulation of the plantar flexor spinal reflex circuit (SRC). It is still unknown whether diminished descending volitional drive or impairment of reflex modulation contributes more to spastic gait. Afferent input has a strong neuromodulatory effect on the excitability of both the CST and SRC. Whole body vibration (WBV) is a robust form of afferent input that provides a probe to understand the neurophysiologic mechanisms underlying spastic gait. The long-term goal of this research is to develop rehabilitation strategies to enhance walking function and mobility in persons with SCI by improving ankle control. The overall objective of this proposal is to understand the roles of the CST and SRC in volitional and reflex control of the ankle. The rationale for this project is that understanding the neurophysiological contributions to increased volitional control and decreased spasticity in the ankles will be the first step to developing important non-invasive rehabilitation strategies to improve spastic gait in persons with SCI and other upper motor neuron disorders. The central hypothesis is that improvements in ankle function will have a greater association with changes in the CST than with changes in SRC modulation, as corticospinal drive influences both volitional control and reflex modulation. Using WBV to activate cortical and spinal circuits, the central hypothesis will be tested via two specific aims: 1) Determine the contribution of dorsiflexors CST and plantar flexor SRC excitability to ankle volitional control in individuals with SCI; and 2) Determine the contribution of dorsiflexors CST and plantar flexor SRC excitability to ankle spasticity in individuals with SCI. The proposed research is innovative, because there has yet to be a study examining how an intervention that targets the CST and SRC simultaneously, impacts the different components of spastic gait after SCI. Understanding the mechanisms underlying spastic gait is significant because it provides a foundation for the development of targeted non-invasive therapies to increase the functional outcomes of the people impacted by this impaired gait pattern. Overall, the knowledge gained in this proposal will provide more insight in the underlying mechanisms of ankle control and spasticity in persons with SCI.