The average time course of the responses of two slices of the brain in the event-related Stroop task. Each image was acquired 1.65 seconds after the previous image, starting at the time of the incongruent word-color pair. Peak activities are apparent in the BOLD response 5–7 seconds after the event. A widespread pattern of activity is seen in both frontal and posterior regions, triggered by the Stroop effect. Adapted from ref. 11.