Cressman Erin K, Franks Ian M, Enns James T, Chua Romeo
School of Human Kinetics, University of British Columbia, 210-6081 University Boulevard, V6T 1Z1, Vancouver, BC, Canada.
Exp Brain Res. 2006 May;171(2):174-83. doi: 10.1007/s00221-005-0260-2. Epub 2005 Nov 24.
It has been claimed that visually guided limb movements are automatically corrected in response to a change in target location but not when the same change in target is cued through a colour switch (Pisella et al. 2000). These findings were based solely on limb endpoint data. Here we examine the kinematic trajectory of the hand during the entire movement. Participants pointed rapidly to a target object that could change position either by changing spatial location, or by switching colour with a second object. Participants performed in two instructional conditions: a "go" condition to index intentional movements and a "stop" condition in which failures to stop pointing indexed automatic limb guidance. Kinematic analysis indicated efficient intentional pointing in both location and colour change conditions. However, only targets that changed spatial location elicited involuntary limb modifications and these occurred within 150 ms of the change. This conclusion held even after baseline differences in the efficiency of processing colour-defined targets were taken into account, thereby strengthening the claim of a strongly automatic pilot for visually guided limb movements.
有人声称，视觉引导的肢体动作会根据目标位置的变化自动进行校正，但当目标的相同变化通过颜色切换来提示时则不会（皮塞拉等人，2000年）。这些发现仅基于肢体端点数据。在此，我们研究了整个运动过程中手部的运动轨迹。参与者迅速指向一个目标物体，该目标物体可能通过改变空间位置或与第二个物体切换颜色来改变位置。参与者在两种指导条件下进行操作：一种是“进行”条件，以指示有意的动作；另一种是“停止”条件，在该条件下未能停止指向则指示自动肢体引导。运动学分析表明，在位置和颜色变化条件下都有高效的有意指向。然而，只有改变空间位置的目标才会引起肢体的非自愿调整，并且这些调整发生在变化后的150毫秒内。即使考虑了处理颜色定义目标的效率的基线差异，这一结论仍然成立，从而强化了视觉引导肢体动作存在强大自动引导机制的说法。
