fmθ activity separately for each response speed quartile (fastest, faster, slower, slowest). A, RT quartile-dependent MPFC theta power synchronized to response (left) and stimulus onset (right). B, MPFC theta power separately for congruent (red) and incongruent trials (blue) as a function of RT quartile. C, RT quartile-dependent MFC theta power synchronized to response (left) and stimulus onset (right). D, MFC theta power separately for congruent (red) and incongruent trials (blue) as a function of RT quartile. Theta power was extracted from the 200 ms time window ending at the mean trial-subset RT, with theta increases estimated by subtracting mean baseline power in the (−1000 ms to −750 ms) time window before response onset.