The present study investigated the impact of auditory-induced mood on brain processing of cognitive control using a Stroop color-word interference task. A total of 135 positive, negative, and neutral sounds (45 of each) were presented in separate blocks for a mood induction procedure, which was then followed by a Stroop color-word task in each trial. Event-related potentials (ERPs) were recorded for color-word congruent, incongruent and neutral (color-word irrelevant) words and subjects named the printed colors of the words by pressing the appropriate key (irrespective of word meaning). Response latency was delayed during incongruent vs. neutral trials, and this cost did not interact significantly with mood states. ERP data showed prolonged peak latencies in the P200 component and more negative deflections in the Late Positive Component (LPC, 450-550 ms) during incongruent vs. neutral conditions, regardless of mood states. Moreover, the negative deflections (N450) in the 450-550 ms interval of the incongruent- neutral difference waves, which index cognitive control effect in brain potentials, was more pronounced in the pleasant, but not in the unpleasant, mood state when compared with the neutral mood state. These data suggest that, pleasant mood intensifies brain processing of cognitive control, in a situation requiring effective inhibition of task-irrelevant distracting information. In addition, N450 component serves as an affective marker, embodying not only cognitive control effect in the brain but also its interaction with mood states.
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