title: Neural time course of conflict adaptation effects on the Stroop task.
abstract: Cognitive control theory suggests conflict effects are reduced following high- relative to low-conflict trials. Such reactive adjustments in control, frequently termed "conflict adaptation effects," indicate a dynamic interplay between regulative and evaluative components of cognitive control necessary for adaptable goal-directed behavior. The current study examined conflict adaptation effects while 36 neurologically-normal participants performed a single-trial color-naming Stroop task. Trials preceded by incongruent (high conflict) and congruent (low conflict) trials were compared for behavioral (response time [RT] and error rate) and electrophysiological (N450 and conflict SP components of the event-related potential [ERP]) concomitants of cognitive control. A conflict adaptation effect was present for RTs that could not be accounted for by associative or negative priming. ERPs revealed a parietal conflict slow potential (conflict SP) that differentiated incongruent from congruent trials and monotonically differentiated current trial congruency on the basis of previous-trial context (i.e., showed conflict adaptation); the fronto-medial N450 was sensitive to current trial congruency but not to previous-trial context. Direct comparison of normalized conflict SP and N450 amplitudes showed the conflict SP was sensitive to the effects of previous-trial context, while the N450 was so to a lesser extent and in a different pattern. Findings provide clarification on the neural time course of conflict adaptation and raise further questions regarding the relative roles of the parietal conflict SP and fronto-medial N450 in conflict detection and processing.
authors.affiliation: Department of Psychology, Brigham Young University, Provo, UT, United States. michael_larson@byu.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Larson
authors.forename: David A S
authors.initials: DA
authors.lastname: Kaufman
authors.forename: William M
authors.initials: WM
authors.lastname: Perlstein
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D003071:Cognition / Q000502:physiology*; D003118:Color Perception / Q000502:physiology; D003220:Conflict, Psychological; D004569:Electroencephalography; D004594:Electrophysiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000502:physiology*; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult