Maslovat Dana, Carlsen Anthony N, Franks Ian M
School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada.
Behav Neurosci. 2012 Jun;126(3):499-503. doi: 10.1037/a0028285.
The purpose of the current study was to examine the relationship between movement preparation and excitability of subcortical motor circuits, as measured by the reflexive response to a startling acoustic stimulus. We compared the size and incidence of activation in the sternocleidomastoid (startle indicator) from participants completing either a simple or choice reaction time (RT) task. Consistent with predictions, results indicated that the startle reflex habituated after several presentations of the SAS for the choice RT group but not for the simple RT group, which we attributed to advance motor preparatory processes involved in a simple RT task. Additionally, when participants from the choice RT group were put into a simple RT condition, the startle reflex response returned to nonhabituated levels. We conclude that the increased corticospinal activation associated with advance preparation may also result in increased subcortical activation, accounting for the observed lack of habituation to a startling stimulus in simple RT.
本研究的目的是通过对惊人听觉刺激的反射反应来检验运动准备与皮质下运动回路兴奋性之间的关系。我们比较了完成简单或选择反应时（RT）任务的参与者胸锁乳突肌（惊吓指标）的激活大小和发生率。与预测一致，结果表明，选择反应时组在多次呈现声音惊吓刺激（SAS）后惊吓反射出现习惯化，而简单反应时组则未出现，我们将此归因于简单反应时任务中涉及的提前运动准备过程。此外，当选择反应时组的参与者处于简单反应时条件下时，惊吓反射反应恢复到未习惯化水平。我们得出结论，与提前准备相关的皮质脊髓激活增加也可能导致皮质下激活增加，这解释了在简单反应时中观察到的对惊人刺激缺乏习惯化的现象。
