Working memory supports cognitive control by orchestrating dimension-specific modulation during late conflict resolution.

Abstract

Working memory plays a central role in cognitive control, yet how it shapes target- and distractor-related processing over time remains unclear. Here, we combined a working memory load manipulation with a modified Stroop task in which distractors preceded targets. Behaviorally, we found that pre-exposure to the distractor eliminated the congruency effect, but this benefit was absent under high load. This pattern suggests that the benefit of advance distractor presentation is sensitive to concurrent working-memory demands. Electrophysiologically, the distractor-locked lateralized readiness potential (LRP) indicated that working-memory load altered distractor-related response activation before target onset. After target onset, load-related modulation emerged during late conflict resolution, as indexed by the sustained potential (SP), whereas earlier intervals associated with attentional selection (posterior N2) and conflict monitoring (N450) did not show load-dependent modulation. Time-frequency decoding and representational similarity analysis further revealed distinct spectro-temporal profiles of target- and distractor-related processing: target-related coding emerged earlier in the theta band (540-780 ms), consistent with stimulus-response mapping, whereas distractor-related coding emerged later in the mu-beta band (870-1180 ms), consistent with response-related regulation. These findings highlight dimension- and stage-specific patterns of working-memory modulation during conflict resolution.