University of the West of Scotland, Paisley, UK; University of Exeter, Exeter, UK.
University of Exeter, Exeter, UK.
Neuropsychologia. 2021 Sep 17;160:107984. doi: 10.1016/j.neuropsychologia.2021.107984. Epub 2021 Jul 30.
Among the issues examined by studies of cognitive control in multitasking is whether processes underlying performance in the different tasks occur serially or in parallel. Here we ask a similar question about processes that pro-actively control task-set. In task-switching experiments, several indices of task-set preparation have been extensively documented, including anticipatory orientation of gaze to the task-relevant location (an unambiguous marker of reorientation of attention), and a positive polarity brain potential over the posterior cortex (whose functional significance is less well understood). We examine whether these markers of preparation occur in parallel or serially, and in what order. On each trial a cue required participants to make a semantic classification of one of three digits presented simultaneously, with the location of each digit consistently associated with one of three classification tasks (e.g., if the task was odd/even, the digit at the top of the display was relevant). The EEG positivity emerged following, and appeared time-locked to, the anticipatory fixation on the task-relevant location, which might suggest serial organisation. However, the fixation-locked positivity was not better defined than the cue-locked positivity; in fact, for the trials with the earliest fixations the positivity was better time-locked to the cue onset. This is more consistent with (re)orientation of spatial attention occurring in parallel with, but slightly before, the reconfiguration of other task-set components indexed by the EEG positivity.
在多任务认知控制研究中，研究人员考察了以下问题：不同任务的表现所基于的过程是串行发生的，还是并行发生的。在主动控制任务集的过程中，我们也会提出类似的问题。在任务转换实验中，已经广泛记录了任务集准备过程的几个指标，包括对任务相关位置的预期性注视定向（注意力重新定向的明确标志）和后皮质的正脑电位（其功能意义不太清楚）。我们研究了这些准备标记是否是并行发生的，以及它们的发生顺序。在每次试验中，线索要求参与者对同时呈现的三个数字中的一个进行语义分类，每个数字的位置始终与三个分类任务之一相关联（例如，如果任务是奇数/偶数，那么显示在顶部的数字是相关的）。正脑电位出现在对任务相关位置的预期性注视之后，并且与该注视锁定时间同步，这可能表明存在序列组织。然而，与线索锁定正电位相比，注视锁定正电位的定义并不明确；事实上，对于最早出现注视的试验，正电位与线索起始的时间锁定更好。这更符合空间注意力的（重新）定向与 EEG 正电位所标记的其他任务集组件的重新配置并行发生，但略微提前。
