Sympathetic-somatomotor coupling in human SCI

描述(申请人提供)：不完全脊髓损伤(SCI)患者对肌肉活动时心血管系统的调节知之甚少。过去，躯体运动障碍和交感神经控制障碍在脊髓损伤中被分开研究。我们建议研究交感神经和躯体运动控制的耦合，因为它与旨在改善躯体运动功能或增强身体素质的运动训练范例有关。我们的方法将是在交感神经刺激前后测量肌腱轻击反射、自愿肌肉激活以及膝关节(损伤以下)和肘部(损伤以上)的血流量，包括冷加压测试、心算和一次急性运动。这些数据将提供有关肌肉活动期间交感神经控制血液流动的信息。交感-躯体运动耦合的可塑性也将通过在跑步机训练练习计划之前和之后进行测量来调查。这些实验将使我们能够实现三个目标。目标1将描述低于脊髓损伤水平的交感神经和躯体运动系统的耦合。这个目标将检查脊髓交感神经和运动反射及其相互作用。它还将研究脊柱损伤是如何扰乱下行躯体运动耦合的。在目标2中，我们将确定交感神经和躯体运动系统在脊髓损伤上方相互作用的变化。由于损伤和损伤下发生的变化，交感-躯体运动耦合也很可能在手臂上被破坏。目标3将在运动训练后演示交感-躯体运动偶联的可塑性。将测试三种不同的8周运动训练计划，包括1)上身测功器，2)跑步机训练，其努力水平与上体测功器相匹配，以及3)跑步机训练，其心率与上体测功器的初始测试相匹配。将对运动训练进行测试 这是一项随机交叉研究设计，运动训练范例之间有三个月的时间。我们预计交感-躯体运动偶联将具有可塑性，运动训练的效果将使这些系统的控制正常化。然而，由于受伤，我们预计适应将不同于非受伤的对照。本研究对人类脊髓损伤的运动训练有一定的指导意义。交感神经和躯体运动系统的耦合预计将取决于锻炼的目标是上半身还是下半身。功能的恢复既需要改善运动的控制，也需要改善对活跃肌肉群的血液流动的调节。此外，这项研究对于了解跑步机运动训练对心血管健康的潜在影响非常重要，这是一个越来越受到体力活动限制的人感兴趣的话题。

DESCRIPTION (provided by applicant): The regulation of cardiovascular systems during muscle activity is poorly understood in people with incomplete spinal cord injury (SCI). In the past, disruptions in somatomotor and sympathetic control have been investigated separately in SCI. We propose to investigate the coupling of sympathetic and somatomotor control because it is relevant to exercise training paradigms that are designed to improve somatomotor function or enhance physical fitness. Our approach will be to measure tendon tap reflexes, voluntary muscle activation, and blood flow of the knee (below injury) and elbow (above injury) before and after sympathetic stimuli consisting of cold pressor tests, mental math and an acute bout of exercise. These data will provide information about sympathetic control of blood flow during muscle activity. Plasticity of the sympathetic- somatomotor coupling will also be investigated by making measurements before and after a treadmill training exercise program. These experiments will enable us to address three aims. Aim 1 will be to characterize coupling of sympathetic and somatomotor systems below the level of spinal injury. This aim will examine spinal sympathetic and motor reflexes and their interactions. It will also examine how descending somatomotor coupling is disrupted by the spinal injury. In Aim 2, we will identify changes in the interactions of sympathetic and somatomotor systems above a spinal injury. Because of the injury and the changes that occur below the injury, the sympathetic-somatomotor coupling is also likely to be disrupted in the arm. Aim 3 will then demonstrate plasticity of sympathetic-somatomotor coupling after exercise training. Three different eight week exercise training programs will be tested including 1) upper body ergometry, 2) treadmill training with exertion level matched to the upper body ergometry and 3) treadmill training with heart rate matched to an initial test of upper body ergometry. The exercise training will be tested in a randomized crossover study design with three months between exercise training paradigms. We anticipate that there will be plasticity of sympathetic-somatomotor coupling and that the exercise training effects will normalize control of these systems. However, because of the injury, we anticipate that adaptations will differ from non-injured controls. This study has implications for exercise training in human SCI. The coupling of sympathetic and somatomotor systems is expected to depend on whether exercise targets the upper or lower body. The recovery of function requires both the improvement in the control of movement as well as in the regulation of blood flow to active muscle groups. In addition, this study is important for understanding the potential impact of treadmill exercise training on cardiovascular fitness, a topic of increasing interest in people with limitations to physical activity.