Control of aperture closure initiation during trunk-assisted reach-to-grasp movements.
Control of aperture closure initiation during trunk-assisted reach-to-grasp movements.
复制标题
在躯干辅助伸手抓握运动期间控制孔径关闭启动。
DOI：
10.1007/s00221-012-3088-6
复制
发表时间：
2012
影响因子：
2
通讯作者：
Stelmach,GeorgeE
中科院分区：
文献类型：
--
作者：
Rand,MiyaK;VanGemmert,ArendWA;Hossain,AbulBMI;Shimansky,YuryP;Stelmach,GeorgeE
本研究探讨了躯干运动的参与和方向在达到抓取运动影响运输和抓取组件之间的协调。坐着的年轻成年人的躯干的参与是多种多样的，躯干不参与，向前移动（屈曲），或向后移动（伸展）在矢状面达到的对象。每个躯干运动与伸展或屈曲运动的手臂在达到相结合。关于手臂运输的躯干和手臂运动之间的关系，手腕运动相对于躯干的起始延迟到更大程度的躯干伸展比躯干屈曲。从腕部速度峰值到躯干速度峰值的时间段的变异性也显著大于躯干伸展与躯干屈曲。这些结果表明，躯干屈曲更好地集成到控制手腕运输比躯干伸展。在腕部运输和抓握孔径之间的时间关系方面，峰值腕部速度的时间和峰值抓握孔径的时间之间的关系在整个条件下没有改变或变得不太稳定。因此，尽管在手臂运输过程中手臂和躯干之间的节段间协调模式发生变化，但腕部运输和抓握孔径之间的时间协调的稳定性得到了保持。运输孔径协调进一步评估的控制律，根据该控制律，当手越过手到目标的距离阈值时，在到达过程中发生孔径关闭，这是峰值孔径，手腕速度和加速度，躯干速度和加速度，以及躯干到目标的距离在孔径关闭启动时的函数。参与者增加了手到目标的距离阈值的条件下，躯干参与相比，躯干不参与的条件下，把握启动。与躯干屈曲时相比，躯干伸展时也会增加。增加的距离阈值意味着当躯干参与时，特别是当躯干伸展时，手到目标距离相关的抓握安全裕度增加。这些结果表明，中枢神经系统显着利用躯干运动的参数与运动参数有关的手臂和手控制掌握启动。
The present study investigated how the involvement and direction of trunk movement during reach-to-grasp movements affect the coordination between the transport and grasping components. Seated young adults made prehensile movements in which the involvement of the trunk was varied; the trunk was not involved, moved forward (flexion), or moved backward (extension) in the sagittal plane during the reach to the object. Each of the trunk movements was combined with an extension or flexion motion of the arm during the reach. Regarding the relationship between the trunk and arm motion for arm transport, the onset of wrist motion relative to that of the trunk was delayed to a greater extent for the trunk extension than for the trunk flexion. The variability of the time period from the peak of wrist velocity to the peak of trunk velocity was also significantly greater for trunk extension compared to trunk flexion. These findings indicate that trunk flexion was better integrated into the control of wrist transport than trunk extension. In terms of the temporal relationship between wrist transport and grip aperture, the relationship between the time of peak wrist velocity and the time of peak grip aperture did not change or become less steady across conditions. Therefore, the stability of temporal coordination between wrist transport and grip aperture was maintained despite the variation of the pattern of intersegmental coordination between the arm and the trunk during arm transport. The transport–aperture coordination was further assessed in terms of the control law according to which the initiation of aperture closure during the reach occurs when the hand crosses a hand-to-target distance threshold for grasp initiation, which is a function of peak aperture, wrist velocity and acceleration, trunk velocity and acceleration, and trunk-to-target distance at the time of aperture closure initiation. The participants increased the hand-to-target distance threshold for grasp initiation in the conditions where the trunk was involved compared to the conditions where the trunk was not involved. An increase also occurred when the trunk was extended compared to when it was flexed. The increased distance threshold implies an increase in the hand-to-target distance-related safety margin for grasping when the trunk is involved, especially when it is extended. These results suggest that the CNS significantly utilizes the parameters of trunk movement together with movement parameters related to the arm and the hand for controlling grasp initiation.