INTERLIMB DIFFERENCES IN CONTROL OF MULTIJOINT DYNAMICS

描述：(来自应用程序的逐字)惯用手，手部不对称 以一只手倾向于熟练的表现为特征的 单手任务，是人类运动表现的一个显著特征，即 据信是由于每条肢体的神经控制不同造成的。 然而，造成惯用手的确切机制仍然存在。 有争议的。拟议的研究以我们目前的发现为基础，这些发现 显示节段间动力学控制中的肢体间差异。 以前的研究表明，伸展运动最初计划在 任务术语相关变量，如手部运动方向和幅度 (Krakauer和Ghez，1999)，这个计划必须转化为肌肉 为了运动的发生而激活。这一转变依赖于 肌肉骨骼和特定任务动力学的内部表征 (Gandolfo et at，1996；Goodbody and Wolpert，1998；Jordan and Rumelhart，1992； Lackner和Dizio，1994；Sainburg，et al，1999；Shadmehr和Mussa-Ivaldi， (1994年)。我们假设占主导地位的ARM控制器专用于 开发和更新这种神经表示法。为了检验这一假设， 我们采用了一种独特的实验范式，这是我们之前开发的 研究具有优势臂的新型节段间动力学学习 (Sainburg等人，1999年)。我们将分析下面的移动策略 对改变的惯性动力学的适应，通过将质量附加到 前臂内侧或外侧的外伸支腿。因为这种操控 具体地说，改变了作用于 节段，我们可以调查中枢神经系统在多大程度上 (CNS)表示这些动态，并反过来利用这些表示来 计划和执行后续的动作。我们会比较四肢间 对新的视觉-运动转换和小说的适应差异 惯性动力学，以确定电机控制过程的水平 左撇子是用手表达的。我们将调查这两种预期的差异 基于视觉和体感的纠错机制 机械装置。通过具体地操纵运动的特征 目标，我们将确定是否更大的学习迁移 相互作用力矩或净力矩保持不变的运动。 然后，我们将研究肢体间的差异在学习的程度上 传递相关扭矩的变化。这些研究将提供一个 对利手的神经机制有更透彻的理解， 这对于解决运动的临床康复应用是至关重要的 单侧运动障碍患者的学习能力。

DESCRIPTION: (Verbatim from application) Handedness, the manual asymmetry characterized by the tendency to favor one hand for performance of skilled unimanual tasks, is a prominent feature of human motor performance that is believed to result from differences in the neural control of each limb. However, the precise mechanisms responsible for handedness remain controversial. The proposed studies build on our current findings, which indicate interlimb disparities in the control of intersegmental dynamics. Previous research indicates that reaching movements are initially planned in terms of task relevant variables, such as hand movement direction and amplitude (Krakauer and Ghez, 1999), and that this plan must be transformed into muscle activations in order for movement to take place. This transformation relies on internal representations of musculoskeletal and task specific dynamics (Gandolfo, et at, 1996; Goodbody and Wolpert, 1998; Jordan and Rumelhart, 1992; Lackner and Dizio, 1994; Sainburg, et al, 1999; Shadmehr and Mussa-Ivaldi, 1994). We hypothesize that the dominant arm controller is specialized for developing and updating such neural representations. To test this hypothesis, we employ a unique experimental paradigm that we previously developed to investigate learning of novel intersegmental dynamics with the dominant arm (Sainburg et al., 1999). We will analyze movement strategies following adaptation to altered inertial dynamics, imposed by attaching a mass to an outrigger, either medial or lateral to the forearm. Because this manipulation specifically alters the amplitude of interaction torques acting between the segments, we can investigate the extent to which the Central Nervous System (CNS) represents these dynamics and, in turn, utilizes such representations for planning and executing subsequent movements. We will compare interlimb differences in adaptation to novel visual-motor transformations and to novel inertial dynamics, to determine the level of the motor control process at which handedness is expressed. We will investigate differences in both anticipatory mechanisms, as well as, visual and somatosensory based error correction mechanisms. By specifically manipulating the characteristics of movement targets, we will determine whether transfer of learning is greater for movements in which either interaction torques or net torques remain constant. We will then examine interlimb differences in the extent to which learning transfers across changes in the relevant torque. These studies will provide a more thorough understanding of the neural mechanisms underlying handedness, which is critical for clinical rehabilitation applications that address motor learning in patients with unilateral movement deficits.