CEREBELLAR DYSFUNCTION AND REACH TO GRASP MOVEMENTS

这些实验旨在比较REACH-to-TO的几个功能 正常受试者和小脑患者的运动掌握 获得对小脑在调节这个井中的作用的见解- 有组织的、高度整合的行为。总的假设是 测试表明，小脑对大脑的 手腕运输和握力之间一致的、刻板的关系 光圈，这种结构是保持这种一致性所必需的 模式一旦建立，则它是优化 获取和执行预先计划的伸手抓握动作 直接指向移动目标，并且它对于获取 进行在线校正所需的自适应策略 一旦启动了这些运动的扰动。这些实验是 基于对人类受试者的一系列初步研究 从PI的实验室获得的相关实验的见解， 采用了小脑功能障碍的动物模型。 将开展五个具体项目。第一个特征将是 伸手抓握运动的组织特征是 作为小脑病理的结果而修改。第二个项目 将探讨小脑功能障碍与 视觉线索在REACH的两个阶段整合，早期 制定握法前的运输阶段和之后的握法阶段 在接近目标时发生的。第三项研究将评估 小脑患者对两种不同类型药物的反应能力 目标位置的可预测变化，其中一个是位置的阶跃变化 第二个是连续成比例的位置变化 受试者在伸展过程中的手腕速度。第四个实验 将评估小脑患者的能力以改善他们的 当目标位置的这些相同类型的变化是 在连续的试验中被提出。在第五个项目中， 小脑患者获得对弹性负荷的适应策略 在河段的运输和抓握阶段施加的扰动- 将对抓握动作进行探索。除了测试特定的 这些实验设计背后的假设，数据将 让我们深入了解关于小脑在脑内的作用 调控目标定向肢体的习得和操作 运动，也将有助于理解电机 在小脑患者中观察到的异常。

These experiments are designed to compare several features of reach-to- grasp movements in normal subjects and cerebellar patients in order to obtain insights into the role of the cerebellum in regulating this well- organized, highly integrated behavior. The general hypotheses to be tested are that the cerebellum contributes significantly to the consistent, stereotypic relationship between wrist transport and grip aperture, that this structure is necessary to maintain this consistent pattern once it is established, that it is required for optimizing the acquisition and performance of pre-planned reach-to-grasp movements directed toward moving targets, and that it is essential for acquiring adaptive strategies necessary for making on-line corrections for perturbations of these movements once initiated. The experiments are based on a series of preliminary studies in human subjects as well as insights obtained from related experiments from the PI's laboratory that employed animal models of cerebellar dysfunction. Five specific projects will be undertaken. The first will characterize the organizational features of the reach-to-grasp movement that are modified as a consequence of cerebellar pathology. The second project will explore the relationship between cerebellar dysfunction and the integration of visual cues during two phases of the reach, the early transport phase before the grip is formulated and the later grip phase occurring as the target is approached. The third study will evaluate the capacity of cerebellar patients to respond to two different types of predictable changes in target position, one a step change in position and the second a change in position that is continuously proportional to the subjects' wrist velocity during the reach. The fourth experiment will assess the capacity of cerebellar patients to improve their performance when these same types of changes in target position are presented in successive trials. In the fifth project, the capacity of cerebellar patients to acquire adaptive strategies to elastic load perturbations applied during the transport and grip phases of the reach- to-grasp movement will be explored. In addition to testing specific hypotheses underlying the design of these experiments, the data will lend insights into general concepts regarding the cerebellum's role in regulating the acquisition and performance of goal-directed limb movements and also will contribute to the understanding of the motor abnormalities observed in cerebellar patients.