TRAJECTORY SPECIFICATION IN TARGETED LIMB MOVEMENT

拟议的研究旨在识别和分析感觉运动 中枢神经系统通过其实现准确的 控制针对视觉目标的多关节运动。他们 解决有关位置和位置的信息如何 肢体和目标周围的状态操作以确保准确 对运动进行编程和控制。实验要用来做 正常受试者，患者患有严重的大纤维神经病 以及有局限性小脑病变的患者。一本小说 程序，即定时响应范例，将被用来分析时间 进程的进程和性质，其方向和程度 移动是指定的。据推测，一个根本原因是 感觉神经病和小脑运动障碍都是不准确的 未能考虑到状态依赖和动态交互作用 多关节运动的编程和控制。这 假设是基于初步结果，这些结果表明 方向和范围上的明显错误可归因于 运动学和动力学变换中的简化 目标位置最终被转换为所需的肌肉命令 把手伸向目标。这些系统性的编程错误 在丧失本体感觉的模式中被极大地放大 但可以在运动前通过肢体视觉部分矫正。 然而，这种影响是暂时的，其时间进程将是 下定决心。拟议的研究还将确定 在前期工作中表现出的关节间协调能力的损害 随之而来的是本体感觉丧失。在其后期阶段， 拟议的工作将表征患者所犯的运动错误 有小脑半球内侧和外侧损害。角色 这些结构的短期学习可能会让他们参与 在生成和不断完善内部模型的过程中 四肢。

The proposed studies aim to identify and analyze the sensorimotor transformations by which the central nervous system achieves accurate control of multijoint movements directed at visual targets. They address the specific question of how information about the location and state of the limb and about the target operate to assure the accurate programming and control of movement. Experiments are to be done with normal subjects, with patients affected by severe large-fiber neuropathy and with patients with circumscribed cerebellar lesions. A novel procedure, the timed response paradigm, will be used to analyze the time course and nature of the processes by which the direction and extent of movement are specified. It is hypothesized that a fundamental cause of the inaccuracy of both sensory neuropathy and cerebellar dysmetria is a failure to take state-dependent and dynamic interactions into account in both the programming and control of multijoint movement. This hypothesis is based on preliminary results which indicate that distinctive errors in direction and extent are attributable to simplifications in the kinematic and dynamic transformations by which target location is eventually converted into the muscle commands needed to bring the hand to the target. These systematic programming errors are greatly magnified in patterns deprived of proprioceptive sensation but can be partially corrected by vision of the limb prior to movement. This effect is, however, transitory and its time course will be determined. The proposed studies will also determine the mechanisms of the impairment in interjoint coordination shown in preliminary work to follow the loss of proprioceptive sensation. In its latter phase, the proposed work will characterize the movement errors made by patients with medial and lateral lesions of the cerebellar hemispheres. The role of these structures in short-term learning may allow them to participate in the generation and continual refinement of internal models of the limb.