Weiler Jeffrey, Hassall Cameron D, Krigolson Olave E, Heath Matthew
School of Kinesiology, The University of Western Ontario, London, ON, Canada.
School of Exercise Science, Physical, and Health Education, University of Victoria, Victoria, BC, Canada.
Behav Brain Res. 2015 Feb 1;278:323-9. doi: 10.1016/j.bbr.2014.10.012. Epub 2014 Oct 22.
The execution of an antisaccade selectively increases the reaction time (RT) of a subsequent prosaccade (the unidirectional prosaccade switch-cost). To explain this finding, the task-set inertia hypothesis asserts that an antisaccade requires a cognitively mediated non-standard task-set that persists inertially and delays the planning of a subsequent prosaccade. The present study sought to directly test the theoretical tenets of the task-set inertia hypothesis by examining the concurrent behavioural and the event-related brain potential (ERP) data associated with the unidirectional prosaccade switch-cost. Participants pseudo-randomly alternated between pro- and antisaccades while electroencephalography (EEG) data were recorded. As expected, the completion of an antisaccade selectively increased the RT of a subsequent prosaccade, whereas the converse switch did not influence RTs. Thus, the behavioural results demonstrated the unidirectional prosaccade switch-cost. In terms of the ERP findings, we observed a reliable change in the amplitude of the P3 - time-locked to task-instructions - when trials were switched from a prosaccade to an antisaccade; however, no reliable change was observed when switching from an antisaccade to a prosaccade. This is a salient finding because extensive work has shown that the P3 provides a neural index of the task-set required to execute a to-be-completed response. As such, results showing that prosaccades completed after antisaccades exhibited increased RTs in combination with a P3 amplitude comparable to antisaccades provides convergent evidence that the unidirectional prosaccade switch-cost is attributed to the persistent activation of a non-standard antisaccade task-set.
执行反扫视任务会选择性地增加随后顺向扫视的反应时间（RT）（单向顺向扫视切换成本）。为了解释这一发现，任务集惯性假说认为，反扫视需要一种认知介导的非标准任务集，该任务集惯性地持续存在并延迟随后顺向扫视的计划。本研究旨在通过检查与单向顺向扫视切换成本相关的同时行为和事件相关脑电位（ERP）数据，直接检验任务集惯性假说的理论原则。参与者在进行脑电图（EEG）数据记录时，在顺向和反扫视之间伪随机交替。正如预期的那样，反扫视的完成选择性地增加了随后顺向扫视的反应时间，而相反的切换则不影响反应时间。因此，行为结果证明了单向顺向扫视切换成本。就ERP结果而言，当试验从顺向扫视切换到反扫视时（与任务指令时间锁定），我们观察到P3波幅有可靠变化；然而，从反扫视切换到顺向扫视时未观察到可靠变化。这是一个显著的发现，因为大量研究表明，P3提供了执行待完成反应所需任务集的神经指标。因此，结果表明，在反扫视后完成的顺向扫视表现出反应时间增加，同时P3波幅与反扫视相当，这提供了趋同证据，表明单向顺向扫视切换成本归因于非标准反扫视任务集的持续激活。
