Pre-SMA actively engages in conflict processing in human: A combined study of epicortical ERPs and direct cortical stimulation

► We assigned a conflict task to an epilepsy patient undergoing presurgical evaluation with subdural electrodes. ► Degree of conflict modulated ERPs during the task at a deeper portion of the pre-supplementary motor area. ► Electrical cortical stimulation of this restricted area prolonged reaction time in trials with more conflict. ► The stimulation site was located 1-2 cm rostral to the supplementary negative motor area.