Adaptations to the loss of Proprioceptive Feedback After Peripheral Nerve Injury

摘要 在猫的肌肉神经的处理和手术修复后，运动和感觉 在6 - 9个月的过程中，轴突逐渐重新支配肌肉，但感觉神经元在肌肉中的位置逐渐改变。 信息被永久地阻止进入母体肌肉。中已经显示 患者认为，这种神经损伤导致永久性丧失灵活性，这表明一个重要的 肌肉的感觉反馈在运动协调中的作用。在本计划的前几个周期中， 研究表明，动物接受神经横断和修复后一年， 动物小腿三头肌表现出踝关节僵硬的丧失， 当动物走下斜坡而不是走上斜坡时，踝关节明显屈服。这些 结果是一致的长度反馈的方向特性。在上一个赠款周期， 发现，明显的产量后，再神经支配是不存在或大大减少，如果 即使在横切和修复后，动物也接受了12个月的跑步机训练， 但牵张反射仍然缺失我们现在提出三项新的调查。第一 是为了阐明动物能够补偿损失的方式， 定向反馈其次，我们计划调查系统性的 坡道行走训练本身可能提供一种恢复肌肉局部反馈的方法。 第三，我们希望了解第二个受体的作用，高尔基体腱器官， 为肢体的肌肉提供与力相关的反馈。我们将使用 实验和计算机模拟相结合。在猫身上的实验将用于 解决适应肌肉力量和感觉丧失的机制 反馈计算机模拟将用于了解周围神经损伤和 对这种损伤的适应导致肢体关节整体协调性的变化。最后， 我们将使用斜坡训练来尝试恢复局部感觉反馈。这些实验将 测试动物在多大程度上可以使用替代的肌肉招募模式， 弥补周围神经损伤的缺陷，并提供额外的洞察力， 来自肌梭和高尔基体腱器官的感觉信息的特定作用。最后我们 将尝试采用一种疗法来恢复运动协调的正常机制。

Abstract Following transaction and surgical repair of a muscle nerve in the cat, motor and sensory axons gradually reinnervate the muscle over the course of 6-9 months, but the sensory information is permanently blocked from accessing the parent muscle. It has been shown in patients that such nerve injuries result in permanent loss of dexterity, suggesting an important role for sensory feedback from muscles in motor coordination. In previous cycles of this program project, it was shown that one year after animals received transection and repair of the nerves to the triceps surae muscles the animals exhibited a loss of ankle joint stiffness that resulted in a pronounced ankle joint yield when the animals walked down a ramp but not up the ramp. These findings are consistent with the directional properties of length feedback. In the last grant cycle, it was found that the pronounced yield following reinnervation was absent or much reduced if the animals underwent treadmill training for 12 months following the transection and repair, even though the stretch reflex remained absent. We now propose three new investigations. The first is to elucidate the manner in which the animal was able to compensate for the loss of directionally-specific feedback. Second, we plan to investigate the possibility that systematic training on ramp walking itself might provide a means of restoring local feedback to muscles. Third, we wish to understand the contributions of a second receptor, the Golgi tendon organ that provides force-related feedback to muscles in the limb. We will address these questions using a combination of experiments and computer simulations. Experiments in the cat will be used to address the mechanisms underlying adaptations to the loss of muscle force and sensory feedback. Computer simulations will be used to understand how peripheral nerve injury and adaptations to this injury result in changes in global coordination of the joints of the limb. Finally, we will use ramp training in an attempt to restore local sensory feedback. These experiments will test the extent to which an animal can use an alternative pattern of muscle recruitment to compensate for the deficits from peripheral nerve injuries and provide additional insight into the specific roles of sensory information from muscle spindles and Golgi tendon organs. Finally, we will attempt to employ a therapy to restore the normal mechanisms of motor coordination.