Marinovic Welber, Tresilian James, Chapple Jack L, Riek Stephan, Carroll Timothy J
School of Psychology and Speech Pathology, Curtin University, Australia.
Department of Psychology, University of Warwick, United Kingdom.
Neuroscience. 2017 Apr 21;348:23-32. doi: 10.1016/j.neuroscience.2017.02.016. Epub 2017 Feb 17.
A loud acoustic stimulus (LAS) is often used as a tool to investigate motor preparation in simple reaction time (RT) tasks, where all movement parameters are known in advance. In this report, we used a LAS to examine direction specification in simple and choice RT tasks. This allowed us to investigate how the specification of movement direction unfolds during the preparation period. In two experiments, participants responded to the appearance of an imperative stimulus (IS) with a ballistic wrist force directed toward one of two targets. In probe trials, a LAS (120dBa) was delivered around the time of IS presentation. In Experiment 1, RTs in the simple RT task were faster when the LAS was presented, but the effect on the movement kinematics was negligible. In the Choice RT task, however, movement direction variability increased when the LAS was presented. In Experiment 2, when we primed movements toward one direction, our analyses revealed that the longer participants took to start a movement, the more accurate their responses became. Our results show not only that movement direction reprogramming occurs quickly and continuously, but also that LAS can be a valuable tool to obtain meaningful readouts of the motor system's preparatory state.
强声刺激（LAS）常被用作一种工具，用于研究简单反应时（RT）任务中的运动准备情况，在这类任务中，所有运动参数都是预先已知的。在本报告中，我们使用LAS来研究简单RT任务和选择RT任务中的方向指定。这使我们能够研究运动方向的指定在准备期是如何展开的。在两个实验中，参与者对指令刺激（IS）的出现做出反应，以弹道式腕部力量朝向两个目标之一。在探测试验中，在IS呈现前后施加LAS（120分贝声压级）。在实验1中，当呈现LAS时，简单RT任务中的反应时更快，但对运动运动学的影响可以忽略不计。然而，在选择RT任务中，当呈现LAS时，运动方向变异性增加。在实验2中，当我们启动向一个方向的运动时，我们的分析表明，参与者开始运动的时间越长，他们的反应就越准确。我们的结果不仅表明运动方向重新编程迅速且持续发生，而且LAS可以成为获取运动系统准备状态有意义读数的有价值工具。
