Wilmut Kate, Wann John
Department of Psychology, Oxford Brookes University, Oxford, United Kingdom.
J Mot Behav. 2008 Nov;40(6):558-67. doi: 10.3200/JMBR.40.6.558-567.
The accuracy of reaching movements improves when active gaze can be used to fixate on targets. The advantage of free gaze has been attributed to the use of ocular proprioception or efference signals for online control. The time course of this process, however, is not established, and it is unclear how far in advance gaze can move and still be used to parameterize subsequent movements. In this experiment, the authors considered the advantage of prescanning targets for both pointing and reaching movements. The authors manipulated the visual information and examined the extent to which prescanning of targets could compensate for a reduction in online visual feedback. In comparison with a conventional reaching/pointing condition, the error in pointing was reduced, the eye-hand lead decreased, and both the hand-closure time and the size of the maximum grip aperture in reaching were modulated when prescanning was allowed. These results indicate that briefly prescanning multiple targets just prior to the movement allows the refinement of subsequent hand movements that yields an improvement in accuracy. This study therefore provides additional evidence that the coordinate information arising from efference or ocular-proprioceptive signals can, for a limited period, be buffered and later used to generate a sequence of movements.
当可以使用主动注视来固定目标时，伸手动作的准确性会提高。自由注视的优势归因于利用眼本体感觉或传出信号进行在线控制。然而，这个过程的时间进程尚未确定，并且不清楚注视可以提前移动多远并仍然用于为后续动作设置参数。在本实验中，作者考虑了预扫描目标对指向和伸手动作的优势。作者操纵视觉信息，并研究了目标预扫描能够补偿在线视觉反馈减少的程度。与传统的伸手/指向条件相比，当允许预扫描时，指向误差减小，眼手超前量减小，伸手时的手部闭合时间和最大抓握孔径大小均受到调节。这些结果表明，在动作之前短暂预扫描多个目标可以优化后续手部动作，从而提高准确性。因此，本研究提供了额外的证据，表明来自传出或眼本体感觉信号的坐标信息可以在有限的时间内被缓冲，并随后用于生成一系列动作。
