Synergistic control of joint angle variability: Influence of target shape
Synergistic control of joint angle variability: Influence of target shape
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DOI：
10.1016/j.humov.2011.12.002
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发表时间：
2012-10-01
影响因子：
2.1
通讯作者：
Straube, A.
中科院分区：
文献类型：
--
作者：
Krueger, M.;Borbely, B.;Straube, A.
到达运动通常用于研究相对于手臂和手的最终位置的运动控制过程的有效性。经验证据表明，不同的目标可以抓住类似的最终位置精度。然而，在其最终位置处实现类似精度的移动仍然可以被不同地控制。特别是，控制策略可能会有所不同，在控制丰富的自由度相对于特定任务的成本。本研究的目的是调查是否适用的控制策略的形状被抓住的目标的影响。它被调查是否机械约束，施加在最终的手的方向或最终的手的位置的形状的目标，影响的协同协调的运动自由度的arm.Subjects被要求抓住一个圆柱形或球形的目标，施加不同的约束最终的手的方向和位置。除了时间运动方面，手臂的关节角度的变化，以及手的方向和手的位置的变化进行了分析，在整个时间过程中的运动执行，使用不受控制的流形方法。由于减速持续时间的差异，圆柱形和球形目标条件之间的整体运动持续时间不同。达到运动的圆柱形目标，这是更多的约束，在最终的手的方向和位置，需要更长的时间比运动的球形目标。分析进一步表明，手臂的自由度协同协调，以稳定手的方向和手的位置，当抓住球形或圆柱形的目标。这表明，在自然达到运动中应用的控制策略可以同时考虑多个任务约束。分析进一步表明，手的方向稳定性更强，当达到一个圆柱形的目标，这对最终的手的方向施加更多的限制。相比之下，手的位置更强烈地稳定在球形目标形状的条件下，其中施加更强的约束，最终的手的位置。这表明，不同的目标形状的影响，即使在运动结束时的可变性不受影响的控制策略达到运动。(C)2011 Elsevier B.V.保留所有权利。
Reaching movements are often used to study the effectiveness of motor control processes with respect to the final position of arm and hand. Empirical evidence shows that different targets can be grasped with similar final position accuracy. However, movements that achieve similar accuracy at their final position may nevertheless be controlled differently. In particular, control strategies may differ in the control of the abundant degrees of freedom with respect to the task-specific costs. The objective of the present study was to investigate whether the applied control strategy was influenced by the shape of the target to be grasped. It was investigated whether mechanical constraints, imposed on final hand orientation or final hand position by the shape of the targets, affected the synergistic coordination of the kinematic degrees of freedom of the arm. Subjects were asked to grasp either a cylindrical or a spherical target, which imposed different constraints on final hand orientation and position. Besides temporal movement aspects, variability of the joint angles of the arm, as well as variability of hand orientation and hand position was analyzed over the whole time course of movement execution, using the uncontrolled manifold method. Overall movement duration differed between cylindrical and spherical target condition, due to differences in deceleration duration. Reaching movements towards the cylindrical target, which was more constraint in final hand orientation and position, took longer than movements towards the spherical target. Analysis further revealed that the degrees of freedom of the arm were synergistically coordinated to stabilize both hand orientation and hand position, when grasping either the spherical or the cylindrical target. This suggests that the applied control strategy in natural reaching movements can simultaneously account for multiple task constraints. The analysis further revealed that stabilization of hand orientation was stronger when reaching towards a cylindrical target, which imposed more constraints on final hand orientation. In contrast, hand position was more strongly stabilized in the spherical target shape condition, where stronger constraints on final hand position were applied. This suggests that different target shapes do influence the control strategy of reaching movements even though variability at movement end was not affected. (C) 2011 Elsevier B.V. All rights reserved.