School of Psychology, University of Nottingham, UK.
Brain Res. 2011 Sep 21;1413:51-9. doi: 10.1016/j.brainres.2011.07.017. Epub 2011 Jul 14.
Conflict detection and resolution is crucial in a cognitive task like the Stroop task. Previous studies have identified an early negativity component (N(inc)) as a prominent marker of Stroop conflict in event-related potentials (ERPs). However, to what extent this ERP component reflects conflict detection and/or resolution is still unclear. Here, we report a Stroop task in which the stimulus onset asynchrony (SOA) of color and word stimuli presentation was manipulated in order to disentangle the roles of conflict detection and conflict resolution in generating Stroop-related ERP components. Separating the word from the color information gives us precise control over the timing of conflict. If the N(inc) is related with conflict resolution it should be absent when the word appears during response preparation, as in a long-latency positive SOA. Our data shows that the N(inc) occurs in all SOAs, even after a response has been made, supporting its role in the detection of stimulus conflict rather than conflict resolution. The use of SOA manipulation therefore allows for the examination of a wider temporal spectrum of interference in order to specify the functions of this conflict-related component. These results provide insight into the neural signatures of conflict processes, and have implications for models of cognitive control mechanisms in the brain.
冲突检测和解决在认知任务（如 Stroop 任务）中至关重要。先前的研究已经确定了早期负向成分（N(inc)）作为事件相关电位（ERPs）中 Stroop 冲突的一个显著标志物。然而，这个 ERP 成分在多大程度上反映了冲突检测和/或解决仍然不清楚。在这里，我们报告了一个 Stroop 任务，其中颜色和单词刺激呈现的刺激起始时距（SOA）被操纵，以便在生成 Stroop 相关 ERP 成分时分离冲突检测和冲突解决的作用。将单词与颜色信息分离，使我们能够精确控制冲突的时间。如果 N(inc)与冲突解决有关，那么当单词在反应准备期间出现时，它应该不存在，就像长潜伏期正 SOA 一样。我们的数据表明，即使在做出反应之后，N(inc)也会出现在所有 SOA 中，这支持了它在检测刺激冲突而不是冲突解决中的作用。因此，使用 SOA 操纵可以检查更广泛的干扰时间谱，以确定这个与冲突相关的成分的功能。这些结果提供了对冲突过程的神经特征的深入了解，并对大脑中的认知控制机制模型具有启示意义。
