Goffaux Philippe, Phillips Natalie A, Sinai Marco, Pushkar Dolores
Centre for Research in Human Development, Department of Psychology, Concordia University, 7141 Sherbrooke Street West, Montreal, Que., Canada H4B 1R6.
Biol Psychol. 2006 Jun;72(3):278-90. doi: 10.1016/j.biopsycho.2005.11.009. Epub 2006 Jan 18.
In order to understand how the brain prepares for and executes a switch in task demand, we measured reaction time (RT), accuracy, and event-related brain potentials associated with performance in single and mixed-task blocks using a cued design. Our results show that trials which repeat in a mixed-task block (repeat trials) were more demanding than trials which repeated in a single-task block, as reflected by the presence of a RT mixing cost and by the presence of a smaller target-locked positivity (P3b) on repeat trials. Within a mixed-task block, repeat and switch trials also differed, where repeat trials showed evidence of greater preparation (larger cue-locked negativity), more efficient target processing (larger target-locked P3b), and shorter RTs. In addition, the cue-locked negativity difference remained despite equating repeat and switch trials on RT, suggesting that this negativity difference is specific to the switching process. Our results are discussed in light of existing models of task switching.
为了了解大脑如何为任务需求的转换做准备并执行这种转换，我们使用线索提示设计，测量了在单任务和混合任务块中与表现相关的反应时间（RT）、准确性以及事件相关脑电位。我们的结果表明，在混合任务块中重复的试验（重复试验）比在单任务块中重复的试验要求更高，这体现在反应时间的混合成本以及重复试验中较小的目标锁定正波（P3b）的存在上。在混合任务块中，重复试验和转换试验也有所不同，重复试验显示出准备更充分（更大的线索锁定负波）、目标处理更高效（更大的目标锁定P3b）以及反应时间更短的证据。此外，尽管在反应时间上使重复试验和转换试验相等，但线索锁定负波的差异仍然存在，这表明这种负波差异是转换过程所特有的。我们根据现有的任务转换模型对结果进行了讨论。
