Illustration of measurement protocol for combined posturography and EEG recordings. A: Setup of force platform and visual feedback. B: Experimental protocol. Each trial consists of a sequence of 20 s quiet stance, 100 s rhythmic tracking, and 20 s quiet stance. During quiet stance only a stationary target is shown. The rhythmic task will be carried out under four different visual feedback conditions: no feedback, real-time feedback, delayed feedback at 250 ms and delayed feedback at 500 ms. See text for further details.