Coordination deficits after peripheral nerve injury

这个项目的长期目标是了解在运动和定向到达过程中失去短潜伏期本体感觉反馈对运动协调的影响。神经切断后肌肉的自我神经再支配可能会导致有效的本体感觉反馈的永久性丧失。周围神经损伤也可能导致长期的灵巧性或运动协调性中断，即使在神经再生后也是如此。这个项目的中心假设是，来自肌肉前受体的感觉反馈提供了对协调和自愿运动行为的持续调节，并且这种反馈的丧失会导致运动协调的永久性缺陷。这一假说将通过使用自我神经再支配的方法来验证，方法是从猫的选定肌肉中移除有效的反馈，并评估这些动物在恢复运动能力后的运动表现。首先将确定来自肌梭受体和高尔基肌腱器官的本体感觉反馈的肌肉间分布。这些通路的作用将通过拉伸单独的肌肉或扰乱去大脑动物的前肢，然后测量所产生的力或肌电反应来测量。这些数据将被用来确定最重要的感觉反馈来源。由于失去这种反馈而导致的运动缺陷将通过导致选定肌肉的自我神经再支配来评估其他完好的动物，这些肌肉向前肢的其他肌肉提供关键的反馈。动物在坡道表面移动或在有针对性的到达运动期间将被拍摄下来。基于对后肢的类似研究，去除有效的反馈预计会导致关节间在坡道上失去协调性，并难以终止前肢的运动。这些动物弥补这些缺陷的能力将通过长期的行为任务经验进行评估。该项目将对肌肉的感觉反馈在协调自愿运动方面的作用以及周围神经损伤后失去协调的机制进行评估。

The long-term goal of this project is to understand the consequences of the loss of short-latency proprioceptive feedback for motor coordination during locomotion and targeted reaching. Self-reinnervation of muscle following transection of the nerve can lead to a permanent loss of effective proprioceptive feedback. Peripheral nerve injury can also lead to a long-term disruption of dexterity or motor coordination, even after regrowth of the nerve. The central hypothesis for this project is that sensory feedback from muscle prioprioceptors provides ongoing regulation of coordination and during voluntary motor behavior, and that the loss of this feedback leads to permanent deficits in motor coordination. This hypothesis will be tested by using the method of self- reinnervation to remove effective feedback from selected muscles in the cat and evaluating the motor performance of these animals following the restoration of motor power. The intermuscular distribution of proprioceptive feedback from muscle spindle receptors and Golgi tendon organs will first be determined. Actions of these pathways will be measured by stretching individual muscles or perturbing the forelimb in decerebrate animals and then measuring the resulting force or electromyographic responses. These data will be used to determine the most important sources of sensory feedback. Motor deficits resulting from loss of this feedback will be evaluated in otherwise intact animals by causing the self-reinnervation of selected muscles that supply critical feedback to other muscles in the forelimb. Animals will be filmed during locomotion on ramp surfaces or during targeted reaching movements. Based on similar studies using the hindlimb, the removal of effective feedback is expected to produce a loss of interjoint coordination down a ramp and difficulty in terminating movements of the forelimb. The ability of these animals to compensate for these deficits will be evaluated by long-term experience on the behavioral task. This project will constitute an evaluation of the role of sensory feedback from muscles on the coordination of voluntary movements and of the mechanisms underlying the loss of coordination following peripheral nerve injury.