Leibniz Research Centre for Working Environment and Human Factors, WHO Collaborating Research Centre Dortmund, Germany.
Brain Res. 2011 Sep 9;1411:87-97. doi: 10.1016/j.brainres.2011.07.010. Epub 2011 Jul 12.
Electrophysiological studies investigating task switching usually reveal results of the parietal P3. In this study we investigated the frontal and parietal P3 after cues, targets and responses in a combined go/no-go task switch paradigm. We confirm behavioral findings showing reduction of switch costs after no-go trials. This was accompanied by a number of P3 findings: first, the cue-locked parietal P3 was increased after a switch relative to a repetition, regardless whether a go or no-go was previously required but the frontal counterpart was less positive after inhibited responses. Secondly, in the target-locked ERPs task-set switching decreased the P3 at parietal sites, while persisting inhibition from no-go in n-1 was associated with an attenuation of the frontal P3 relative to go in n-1. No impact of task set on the frontal P3 and response mode in n-1 on the parietal P3 was found, suggesting functional dissociation between task set switch and response mode in n-1. Thirdly, exactly the same pattern was observed in the response locked frontal and parietal P3. Fourthly, the task switch related parietal P3 attenuation after targets was also observed in current no-go trials, indicating task and response selection without response execution. No task switch effect on the frontal "no-go P3" was found. In sum, these results suggest that the cue-locked long-lasting P3 reflects task-set updating, whereas the post-target frontal P3 is associated with persisting response inhibition and parietal P3 is related to an after-effect of task-set activation in terms of response selection as it appears both in the target- as well as response-locked ERPs. Furthermore, the post-target parietal P3 effects are most likely due to N2 effects as a more pronounced N2 in switch trials the smaller the P3. A fronto-parietal network for an adaptive control of response requirements and task sets is proposed.
电生理研究通常揭示顶叶 P3 在任务转换中的作用。本研究采用结合 Go/No-Go 任务转换范式，探讨了线索、目标和反应后的额顶叶 P3。我们证实了行为学发现，即无 Go 试次后转换代价降低。这伴随着一系列 P3 发现：首先，与重复相比，无论先前是否要求进行 Go 或 No-Go，转换后额顶 P3 增加，但抑制反应后额 P3 不那么积极。其次，在目标锁定 ERPs 中，任务转换减少了顶叶 P3，而 n-1 中的抑制持续与 n-1 中相对于 Go 的额 P3 衰减相关。在 n-1 中，任务集对额 P3 和反应模式没有影响，提示任务集转换和 n-1 中反应模式之间存在功能分离。第三，在额顶 P3 中也观察到了相同的模式。第四，在目标后，即使当前为 No-Go 试次，也观察到与任务转换相关的顶叶 P3 衰减，表明没有执行反应，就已经进行了任务和反应选择。额“无 Go P3”没有任务转换效应。总之，这些结果表明，线索锁定的长时 P3 反映了任务集更新，而目标后的额 P3 与持续的反应抑制有关，顶叶 P3 与任务集激活的后效有关，因为它出现在目标和反应锁定 ERPs 中。此外，目标后顶叶 P3 效应很可能是由于 N2 效应引起的，即转换试次中 N2 越大，P3 越小。提出了一个用于自适应控制反应要求和任务集的额顶网络。
