Poster C30, Sunday, March 25, 1:00-3:00 pm, Exhibit Hall C
Conflict-related ERPs in the Temporal Flanker Task: N2 under conditions of perceptual mismatch and response conflict
Kerstin Jost1, Mike Wendt2, Aquiles Luna-Rodriguez3, Andreas Löw3, Thomas Jacobsen3; 1Brandenburg Medical School, 2Medical School Hamburg, 3Helmut-Schmidt-University/ University of the Federal Armed Forces Hamburg
Processing of conflicting distractor-target conjunctions is frequently associated with a pronounced N2 component of the event-related potential, assumed to reflect control processes like conflict/error detection or response inhibition. We here investigated processing of distractor-target conflict in a Temporal Flanker Task in which a target stimulus is preceded by a congruent or an incongruent distractor presented in the same location. As indicated by behavioral congruency effects and the distractor-related lateralized readiness potential, incongruent distractors yield response conflict, particularly when the proportion of incongruent trials is low. The analysis of target-locked brain waves revealed a broadly distributed negative component around 270 ms in incongruent trials. When the proportion of incongruent trials was low, this negativity was much larger than typical N2 effects in conflict or oddball tasks, suggesting that it was driven by both cognitive conflict and unexpected perceptual mismatch. Distractor-target mismatch also elicited an earlier component at posterior electrodes, resembling the P150 observed in letter priming studies. This component was, however, unaffected by the congruent/incongruent ratio. Together, the results suggest a series of processes, involving stimulus-related mismatch detection and context-dependent conflict evaluation or regulation.
Topic Area: EXECUTIVE PROCESSES: Monitoring & inhibitory control