Stabilizing stretch reflexes are modulated independently from the rapid release of perturbation-triggered motor plans
Stabilizing stretch reflexes are modulated independently from the rapid release of perturbation-triggered motor plans
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DOI：
10.1038/s41598-019-50460-1
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发表时间：
2019-09-26
影响因子：
4.6
通讯作者：
Perreault, Eric J.
中科院分区：
文献类型：
--
作者：
Lee, Hyunglae;Perreault, Eric J.
在最短潜伏期脊髓反射之后但在自主活动开始之前引发的反应可以表现出超出刻板反射的复杂性。已经确定了这些快速运动反应的两种不同行为，通常称为长潜伏反射。首先是通过抵抗外部扰动来维持肢体稳定性。第二个是快速释放在干扰之前计划的运动动作，通常称为触发反应。这项研究调查了当运动任务涉及肢体稳定和运动计划时它们的相互作用。我们使用机器人操纵器来改变 2D 手臂到达任务期间触觉环境的稳定性，并应用可以引发快速运动响应的扰动。稳定反射是由触觉环境的方向（场效应）调节的，而触发反应是由受试者被指示到达的目标（目标效应）调节的。我们观察到，在长潜伏反射的早期（50-75 ms）部分，目标和场效应之间没有显着的相互作用，这表明快速运动反应的这些组成部分最初是独立控制的。在反射反应的后期（75-100 毫秒），六块相关肌肉中的两块存在微小但显着的相互作用。此外，目标效应还受到用于引发运动反应的扰动方向的影响，这表明除了触发反应的早期部分之外，还存在后期的反馈校正。总之，这些结果证明了长潜伏反射的不同组成部分如何独立工作和协同工作，以产生复杂的快速运动反应，将计划与对不确定条件的反应结合起来。
Responses elicited after the shortest latency spinal reflexes but prior to the onset of voluntary activity can display sophistication beyond a stereotypical reflex. Two distinct behaviors have been identified for these rapid motor responses, often called long-latency reflexes. The first is to maintain limb stability by opposing external perturbations. The second is to quickly release motor actions planned prior to the disturbance, often called a triggered reaction. This study investigated their interaction when motor tasks involve both limb stabilization and motor planning. We used a robotic manipulator to change the stability of the haptic environment during 2D arm reaching tasks, and to apply perturbations that could elicit rapid motor responses. Stabilizing reflexes were modulated by the orientation of the haptic environment (field effect) whereas triggered reactions were modulated by the target to which subjects were instructed to reach (target effect). We observed that there were no significant interactions between the target and field effects in the early (50-75 ms) portion of the long-latency reflex, indicating that these components of the rapid motor response are initially controlled independently. There were small but significant interactions for two of the six relevant muscles in the later portion (75-100 ms) of the reflex response. In addition, the target effect was influenced by the direction of the perturbation used to elicit the motor response, indicating a later feedback correction in addition to the early component of the triggered reaction. Together, these results demonstrate how distinct components of the long-latency reflex can work independently and together to generate sophisticated rapid motor responses that integrate planning with reaction to uncertain conditions.