Grierson Lawrence E M, Elliott Digby
Department of Kinesiology, McMaster University, 1280 Main St. W. Hamilton, Ontario, Canada L8S 4K1.
Hum Mov Sci. 2008 Dec;27(6):839-56. doi: 10.1016/j.humov.2008.06.001. Epub 2008 Sep 2.
Examination of goal-directed movements has evidenced two processes of visually regulated online control: early trajectory control that operates to make movement adjustments on the basis of limb velocity comparisons to internally generated models of the expected limb velocity, and late trajectory control that uses allocentric information about the limb and target positions. The results of experiments using illusory perturbations suggest that the two systems have an additive influence on movement outcome, and are relatively independent. In this theoretical context, three experiments were conducted in which actual perturbations to the aiming limb dynamics and the tasks demands were introduced. Compressed air expulsed through a stylus, in the direction of, or opposite to, that of the movement was used to impact limb velocity and the target location was moved at movement initiation to impact late evaluation of target and limb position. The results of the compressed air-only and moving target-only conditions replicated the previous evidence of early and late control, respectively. Interestingly, movement accuracy measures yielded an interactive effect of the two perturbations when presented in tandem. It appears that the perturbations prompted parallel operation of the two control processes.
早期轨迹控制，它基于肢体速度与预期肢体速度的内部生成模型的比较来进行运动调整；以及晚期轨迹控制，它使用关于肢体和目标位置的异心信息。使用虚幻扰动的实验结果表明，这两个系统对运动结果具有累加影响，并且相对独立。在这一理论背景下，进行了三项实验，其中对瞄准肢体动力学和任务需求引入了实际扰动。通过笔管沿运动方向或相反方向喷出的压缩空气被用来影响肢体速度，并且在运动开始时移动目标位置以影响对目标和肢体位置的晚期评估。仅压缩空气条件和仅移动目标条件的结果分别重现了早期和晚期控制的先前证据。有趣的是，当同时呈现这两种扰动时，运动准确性测量产生了两种扰动的交互作用。看来这些扰动促使两个控制过程并行运作。
