Although results of these cross-trial averaging analyses generally link medial frontal theta to response conflict, the single-trial regression analyses provide more behaviorally relevant insights into the theta dynamics that may support cognitive control. Indeed, several findings emerged only in the single-trial analyses (discussed in more detail below): (1) single-trial regression demonstrated that pre-response theta is involved in conflict-modulated response selection over a longer time period than is apparent in trial-averaged theta; (2) single-trial “weighted” phase modulation demonstrated that pre-response theta phase predicted endogenous conflict as reflected by reaction time, whereas trial-averaged phase coherence showed only a low-frequency general phase alignment; (3) single-trial phase synchrony modulation demonstrated that medial–lateral prefrontal phase synchronization was significantly modulated by upcoming reaction time in situations of high response conflict, whereas trial-averaged phase synchronization suggested that connectivity was unrelated to conflict.
