Fig. 1.

Schematic diagram of the stimulus design. During pacing (left side of figure), the timing of movements was guided by auditory stimuli presented at 1.25 Hz. The inset on the bottom left provides a schematic of the two movement patterns required during pacing. The inverted u shaped curves represent finger flexion-extension as typically recorded by the pillow device employed. The solid curve represents the synchronization condition in which movements were made to coincide with the auditory stimuli (circles). During syncopation (dotted curve) movements were made directly in between consecutive stimuli. At the end of pacing the participants continued moving at the same rate in the absence of stimulus pacing after no delay, 3, 6 or 9 s. These delays corresponded to 1, 2 or 3 imaging time steps.