Spatial and Temporal Control of Targeted Limb Movements

该项目的长期目标是确定人类中枢神经系统（CNS）如何协调自主运动，并最终利用这些信息开发运动障碍（如中风）的治疗方法。 本申请中提出的研究目标是确定受体水平上的本体感受（在本例中是肌梭）如何导致感知。 要研究的中心假设是，在主动运动中，本体感受输入的主要来源是延长的“拮抗”肌肉中的肌梭，而不是收缩的“激动”肌肉中的肌梭。 具体目标1是对比激动剂和拮抗剂肌梭发出的信息，以确定这些人群中的哪一个为CNS提供关于肢体位置和运动的最准确信息。 与激动肌梭不同，拮抗肌梭对主动关节旋转的反应知之甚少。 我们将描述激动剂和拮抗剂肌梭如何发出关节位置和运动信号，以检验CNS使用来自两个群体的输入的假设，但拮抗剂肌梭提供的信息是最准确的。具体目标2是研究拮抗肌梭如何编码位置和运动变量，以告知中枢神经系统的位置和运动的四肢在空间。 拟议的实验旨在测试的假设，在运动过程中，拮抗肌梭信号的CNS信息的起始位置，运动速度，肢体位置在运动过程中的三个不同的功能内的发射模式。具体目标3是表征梭运动输入对拮抗肌梭的影响。 过去对激动剂肌梭的研究未能解释为什么中枢神经系统在随意运动中激活梭运动系统。 所提出的实验的目的是测试这一假设，即fusimotor输入增加的精确度，拮抗肌梭信号肢体的位置和运动在精确的运动和电机学习过程中，但fusimotor输入不降低的精确度信号从拮抗肌梭在加载运动。

The long-range goal of this project is to determine how the human central nervous system (CNS) coordinates voluntary movement and ultimately to use this information to develop treatments for motor disorders, such as stroke. The goal of the research proposed in this application is to determine how proprioception at the receptor level-in this case, the muscle spindle-leads to perception. The central hypothesis to be investigated is that, in active movement, the primary source of proprioceptive input is muscle spindles in the lengthening, "antagonist" muscles, rather than muscle spindles in the contracting, "agonist" muscles. Three specific aims are addressed: Specific Aim 1 is to contrast the information signaled by agonist and antagonist muscle spindles to determine which of these populations provides the CNS with the most accurate information about limb position and movement. Unlike agonist muscle spindles, little is known about how antagonist muscle spindles respond to active joint rotation. We will characterize how agonist and antagonist muscle spindles signal joint position and movement to test the hypothesis that the CNS uses the input from both populations, but that the information provided by antagonist muscle spindles is the most accurate. Specific Aim 2 is to investigate how antagonist muscle spindles encode position and movement variables, to inform the CNS of the location and movement of the limbs in space. The proposed experiments are designed to test the hypothesis that, during a movement, antagonist muscle spindles signal the CNS information about the starting position, movement velocity, and limb position during movement by three distinctive features within the firing pattern. Specific Aim 3 is to characterize the influence of fusimotor input on antagonist muscle spindles. Past research on agonist muscle spindles has failed to explain why the CNS activates the fusimotor system during voluntary movement. The proposed experiments are designed to test the hypothesis that fusimotor input increases the precision with which antagonist muscle spindles signal limb position and movement during precise movements and during motor learning, but that fusimotor input does not decrease the precision of signaling from antagonist muscle spindles during loaded movements.