Transcranial magnetic stimulation (TMS) modulation of stack–frame difference. (A) Early TMS reduced the difference in activity evoked by stack and activity evoked by frame stimuli in comparison with the no TMS condition (t = 2.97, P = 0.01, two-tailed) and the intermediate TMS condition (t = 2.50, P = 0.04, two-tailed). No difference was found between no TMS and TMS applied in the intermediate time window (t = 0.95, P = 0.37, two-tailed). (B) Excluding error trials resulted in an increased (trend) stack–frame difference (collapsed across TMS conditions, correct trials vs. all trials: t = 1.60, P = 0.07, one-tailed). The dashed lines display the increase in the stack–frame difference for each TMS condition after excluding error trials. The stack–frame difference for correct trials is only significant between the no TMS and early TMS conditions (t = 2.62, P = 0.03, two-tailed). Data are means ± SEM.