Département de kinésiologie, Université de Montréal, C.P. 6128, Succursale Centre Ville, Montréal, QC H3C 3J7, Canada.
Exp Brain Res. 2011 Feb;208(3):345-58. doi: 10.1007/s00221-010-2487-9. Epub 2010 Nov 17.
We determined whether uncertainty about the location of one's hand in virtual environments limits the efficacy of online control processes. In the Non-aligned and Aligned conditions, the participant's hand was represented by a cursor on a vertical or horizontal display, respectively. In the Natural condition, participants saw their hand. During an acquisition phase, visual feedback was either permitted or not during movement execution. To test the hypothesis (Norris et al. 2001) that reliance on visual feedback increases as the task becomes less natural (Natural < Aligned < Non-aligned), following acquisition, participants performed a transfer phase without visual feedback. During acquisition in both visual feedback conditions, movement endpoint variability increased as the task became less natural. This suggests that the orientation of the display and the representation of one's hand by a cursor introduced uncertainty about its location, which limits the efficacy of online control processes. In contradiction with the hypothesis of Norris et al. (2001), withdrawing visual feedback in transfer had a larger deleterious effect on movement accuracy as the task became less natural. This suggests that the CNS increases the weight attributed to the input that can be processed without first having to be transformed.
我们确定了在虚拟环境中对手部位置的不确定性是否会限制在线控制过程的效果。在非对齐和对齐条件下，参与者的手分别由垂直或水平显示器上的光标表示。在自然条件下，参与者看到自己的手。在获取阶段，在执行运动期间允许或不允许视觉反馈。为了检验假设（Norris 等人，2001 年），即随着任务变得不那么自然（自然<对齐<非对齐），对视觉反馈的依赖程度会增加，在获取之后，参与者在没有视觉反馈的情况下进行转移阶段。在视觉反馈条件下的获取过程中，随着任务变得不那么自然，运动终点的变异性增加。这表明显示器的方向和光标对手部的表示引入了对手部位置的不确定性，从而限制了在线控制过程的效果。与 Norris 等人（2001 年）的假设相反，随着任务变得不那么自然，在转移过程中取消视觉反馈对运动准确性的有害影响更大。这表明中枢神经系统增加了归因于输入的权重，而无需首先进行转换即可处理。
