Is conflict monitoring supramodal? Spatiotemporal dynamics of cognitive control processes in an auditory Stroop task.

The electrophysiological correlates of conflict processing and cognitive control have been well characterized for the visual modality in paradigms such as the Stroop task. Much less is known about corresponding processes in the auditory modality. Here, electroencephalographic recordings of brain activity were measured during an auditory Stroop task, using three different forms of behavioral response (overt verbal, covert verbal, and manual), that closely paralleled our previous visual Stroop study. As was expected, behavioral responses were slower and less accurate for incongruent than for congruent trials. Neurally, incongruent trials showed an enhanced fronto-central negative polarity wave (N(inc)), similar to the N450 in visual Stroop tasks, with similar variations as a function of behavioral response mode, but peaking ~150 ms earlier, followed by an enhanced positive posterior wave. In addition, sequential behavioral and neural effects were observed that supported the conflict-monitoring and cognitive adjustment hypothesis. Thus, while some aspects of the conflict detection processes, such as timing, may be modality dependent, the general mechanisms would appear to be supramodal.