Wang J, Stelmach G E
Motor Control Laboratory, Arizona State University, Tempe 85287-0404, USA.
Exp Brain Res. 1998 Dec;123(3):346-50. doi: 10.1007/s002210050578.
To understand the internal representations used by the nervous system to coordinate multijoint movements, we examined the coordination among the body segments during reach-to-grasp movements which involve grasping by the hand and reaching by the arm and trunk. Subjects were asked to reach and grasp an object using the arm only, the trunk only, and some combinations of both arm and trunk. Results showed that kinematic parameters related to the transport component of the arm and the trunk, such as peak velocity and time to peak velocity, varied across conditions and that the coordination pattern between the arm and trunk was different across conditions. However, parameters related to the grasp component, such as peak aperture, time to peak aperture, and closing distance, were invariant, regardless of whether the hand was delivered to the target by the arm only, the trunk only, or both. We hypothesize that a hierarchy of motor control processes exists, in which the reach and grasp components are governed by independent neuromotor synergies, which in turn are coordinated temporally and spatially by a higher-level synergy.
为了理解神经系统用于协调多关节运动的内部表征，我们研究了在伸手抓握动作过程中身体各部分之间的协调性，这些动作包括用手抓握以及用手臂和躯干伸展。要求受试者仅用手臂、仅用躯干以及使用手臂和躯干的一些组合来伸手抓握物体。结果表明，与手臂和躯干的运输部分相关的运动学参数，如峰值速度和达到峰值速度的时间，在不同条件下会有所变化，并且手臂和躯干之间的协调模式在不同条件下也不同。然而，与抓握部分相关的参数，如峰值孔径、达到峰值孔径的时间和闭合距离，无论手是仅由手臂、仅由躯干还是由两者送到目标，都是不变的。我们假设存在一个运动控制过程的层次结构，其中伸展和抓握部分由独立的神经运动协同作用控制，而这些协同作用又由一个更高层次的协同作用在时间和空间上进行协调。
