TRAJECTORY SPECIFICATION IN TARGETED LIMB MOVEMENT

我们的长远目标是进一步了解 使我们能够快速移动四肢的神经过程 准确地指向我们周围的目标并解释混乱 感觉障碍和小脑患者的准确性 难治性心律失常。我们也希望设计出有效的方法来改进 这类患者的运动表现。我们的方法是分析 详细说明要揭示的简单运动任务的执行情况 神经系统控制的基本原则 肌肉骨骼系统。本提案延长了工作时间 在本期内完成的，完全集中在 产生简单的等距反应。首先，我们计划 确定目标响应的幅度和方向如何 使用从目标派生的信息指定。问题是 使用一种新的实验程序解决了这一问题 从刺激到反应的时间间隔可以有系统地变化。 第二，我们计划确定控制策略的差异 用于在以下情况下的作用力和位置轨迹 受试者面临不同的加载条件。特例 注意减速惯性载荷的问题。 使用精确计时的命令来对付对手。第三，我们计划 慢性阻塞性肺疾病患者眼球轨迹形成障碍分析 严重的感觉神经病。两个阶段的初步观察 患者表示，性能不准确的原因是 对弹道参数进行编程的能力也受到了损害 因为无法有效地利用内部反馈 修正初始弹道误差的机构。建议 实验将使用听觉提示来代替迷路的人 本体感知信息，以提高准确性和 正在更新。第四，我们将启动对小脑运动障碍的研究。 以确定造成不准确和 这类患者表现出运动启动延迟。

Our long term objectives are to gain further understanding of the neural processes that enable us to move our limbs rapidly and accurately to targets around us and to explain the disordered accuracy of patients with sensory impairment and cerebellar dysmetria. We also hope to devise effective methods for improving motor performance in such patients. Our approach is to analyze in detail the performance of a simple motor task to uncover fundamental principles by which the nervous system controls the musculoskeletal system. The present proposal extends work accomplished in the current period that was focused exclusively on the production of simple isometric responses. First, we plan to determine how the amplitude and direction of an aimed response are specified using information derived from a target. The problem is addressed using a new experimental procedure by which the time interval from stimulus to response can be varied systematically. Second, we plan to determine the differences in control strategies used for the producing force and position trajectories when subjects are faced with different loading conditions. Particular attention is given to the problem of decelerating inertial loads using accurately timed commands to antagonists. Third, we plan to analyze the disorders in trajectory formation of patients with severe sensory neuropathies. Preliminary observations in two patients indicate that inaccurate performance results from impairment in the ability to program trajectory parameters as well as from an inability to make effective use of internal feedback mechanisms to correct initial trajectory errors. Proposed experiments will use auditory cues to substitute for the lost proprioceptive information in order to improve accuracy and updating. Fourth, we will initiate a study of cerebellar dysmetria to determine the mechanisms responsible for the inaccuracy and the delays in movement initiation shown by such patients.