Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Ave., Chicago, IL 60611, USA.
Brain Res. 2010 Mar 31;1322:38-49. doi: 10.1016/j.brainres.2010.01.076. Epub 2010 Feb 4.
In the present experiment, the temporal predictability of response time was systematically manipulated to examine its effect on the time course of motor pre-programming and release of the intended movement by an acoustic startle stimulus. Participants performed a ballistic right wrist extension task in four different temporal conditions: 1) a variable foreperiod simple RT task, 2) a fixed foreperiod simple RT task, 3) a low resolution countdown anticipation-timing task, and 4) a high resolution anticipation-timing task. For each task, a startling acoustic stimulus (124dB) was presented at several intervals prior to the "go" signal ("go" -150ms, -500ms, and -1500ms). Results from the startle trials showed that the time course of movement pre-programming was affected by the temporal uncertainty of the imperative "go" cue. These findings demonstrate that the resolution of the timing information regarding the response cue has a marked effect on the timing of movement preparation such that under conditions of low temporal resolution, participants plan the movement well in advance in accordance with the anticipated probability of onset of the cue, whereas movement preparation is delayed until less than 500ms prior to response time when continuous temporal information is provided.
在本实验中，系统地操纵反应时间的时间可预测性，以检验其对运动预编程和受声音起始刺激引发的预期运动释放的时程的影响。参与者在四个不同的时间条件下执行了一个弹道式右手腕伸展任务：1）可变预备简单 RT 任务，2）固定预备简单 RT 任务，3）低分辨率倒计时预期计时任务，以及 4）高分辨率预期计时任务。对于每个任务，在“开始”信号（“开始”-150ms、-500ms 和-1500ms）之前，会在几个时间间隔处呈现一个令人惊讶的声音刺激（124dB）。起始试验的结果表明，运动预编程的时程受到强制性“开始”线索的时间不确定性的影响。这些发现表明，关于反应线索的时间信息的分辨率对运动准备的时间有显著影响，即在时间分辨率较低的情况下，参与者根据线索出现的预期概率提前计划好运动，而当提供连续时间信息时，运动准备会延迟到响应时间前不到 500ms 时进行。
