Wang J, Stelmach G E
Motor Control Laboratory, Arizona State University, Tempe 85287-0404, USA.
Exp Brain Res. 2001 Jan;136(2):231-40. doi: 10.1007/s002210000572.
The present study utilized a trunk-assisted prehension task to examine the hypothesis that there is spatial regularity between the grasp and transport components. To test this hypothesis, we varied movement amplitude, reach speed, and object size. When examining the opening and closure phases of aperture formation, it was found that the distance to peak aperture increased systematically with hand-path trajectory length, while the distance from peak aperture to the object remained constant, which supports the notion of state-space control. Regarding the relationship among the body segments involved, temporal measures such as relative time to peak aperture, and peak velocity of the arm and trunk were altered by the changes in both object size and reach speed. It was also found that the time to peak trunk velocity was coupled with the time to peak arm velocity as well as with the time to peak aperture. Based on these results, it appears that the trunk is closely linked not only to the arm motion, but also to the aperture formation. Collectively, these findings suggest that, during trunk-assisted prehension, the arm and the trunk are coordinated by neuromotor synergies that appear to position grip aperture for a stable closure to grasp the object.
本研究采用躯干辅助抓握任务来检验抓握和运输组件之间存在空间规律性这一假设。为了验证这一假设，我们改变了运动幅度、伸手速度和物体大小。在检查孔径形成的张开和闭合阶段时，发现到峰值孔径的距离随着手部路径轨迹长度而系统性增加，而从峰值孔径到物体的距离保持不变，这支持了状态空间控制的概念。关于所涉及身体节段之间的关系，诸如到峰值孔径的相对时间以及手臂和躯干的峰值速度等时间测量值会因物体大小和伸手速度的变化而改变。还发现，躯干峰值速度出现的时间与手臂峰值速度出现的时间以及峰值孔径出现的时间相关联。基于这些结果，似乎躯干不仅与手臂运动密切相关，而且与孔径形成也密切相关。总体而言，这些发现表明，在躯干辅助抓握过程中，手臂和躯干通过神经运动协同作用进行协调，这些协同作用似乎会定位抓握孔径以实现稳定闭合来抓取物体。
