Corticospinal Function after Spinal Cord Injury

 描述（由申请人提供）：我们的总体目标是开发新的策略，以促进脊髓损伤（SCI）后上肢功能的恢复。我们建议使用现代电生理学方法来增强残余皮质脊髓连接的有效性。确定皮质脊髓齐射产生肌肉反应的神经基础将提供最大化剩余运动输出所需的关键信息。我们的具体目标是：1）确定皮质脊髓齐射的时间组织和位置 2）开发促进功能恢复的方法。我们专注于伸展和抓握动作，因为它们在日常生活活动中很重要。皮质脊髓束中的多个下行截击产生肌肉反应的多个峰（间接（I）波）。在目标1中，成对经颅磁刺激（TMS）将用于检查在伸手和抓握过程中上肢肌肉的表面肌电图（EMG）记录中的I波。将确定早期和晚期I波的时间组织以及对自愿EMG活动的贡献。在目标2中，上肢肌肉的皮质地图的大小（和位置）将使用TMS在无框架磁共振成像神经导航系统的引导下进行定义。总之，这些在有和没有SCI的个体中的研究将确定在伸手和抓握过程中皮质脊髓重组的机制。在目标3中，我们将使用新的经颅磁刺激范例，通过参与皮质脊髓重组机制，最大限度地提高残余皮质脊髓连接的有效性。重复的配对TMS将在受影响的运动皮层位置处靶向功能相关的I波间期。伸展和抓握动作的训练将与配对TMS范式相结合，以进一步增强行为相关的可塑性和功能恢复。拟议的实验将提供新的知识皮质脊髓重组的机制，涉及达到和把握运动，这将被用来指导功能相关的可塑性诱导协议，以提高恢复。对于SCI和其他影响皮质脊髓通路的CNS疾病后的上肢运动障碍，目前还没有普遍接受的治疗方法。目前的治疗达到和把握功能的结果有限的改善。因此，迫切需要开发新的策略来促进SCI后有意义功能的恢复。

 DESCRIPTION (provided by applicant): Our overall goal is to develop new strategies to enhance the recovery of upper-limb function after spinal cord injury (SCI). We propose to use modern electrophysiological methods to enhance the efficacy of residual corticospinal connections. Defining the neural basis by which corticospinal volleys generate muscle responses will provide crucial information required to maximize residual motor output. Our specific goals are to: 1) determine the temporal organization of corticospinal volleys and location of motor cortical representations of upper-limb muscles after incomplete cervical SCI and 2) develop methodologies to promote recovery of function. We focus on reach and grasp movements because of their importance in daily life activities. Multiple descending volleys in the corticospinal tract generate multiple peaks in muscle responses (indirect (I) - waves). In Aim 1, paired transcranial magnetic stimulation (TMS) will be used to examine I-waves in surface electromyographic (EMG) recordings of upper-limb muscles during reach and grasp. The temporal organization of the early and late I-waves and contribution to voluntary EMG activity will be determined. In Aim 2, the size (and location) of cortical maps of upper-limb muscles will be defined using TMS guided by a frameless magnetic resonance imaging neuronavigation system. Together, these studies in individuals with and without SCI will determine mechanisms of corticospinal reorganization during reach and grasp. In Aim 3, we will use novel TMS paradigms to maximize the effectiveness of residual corticospinal connections by engaging mechanisms of corticospinal reorganization. Repeated paired-TMS will target functionally relevant I- wave intervals at affected motor cortical locations. Training of reach and grasp movements will be combined with paired-TMS-paradigms to further enhance behaviorally relevant plasticity and recovery of function. The proposed experiments will provide new knowledge on mechanisms of corticospinal reorganization involving reach and grasp movements which will be used to guide functionally-relevant plasticity-inducing protocols to enhance recovery. There are no universally accepted treatments for upper-limb motor disability after SCI and other CNS disorders that affect the corticospinal pathway. Current treatments for reach and grasp functions result in limited improvements. Thus, there is a pressing need to develop new strategies to promote recovery of meaningful function after SCI.