Fig. 3.

Mean differences and time courses of beta-band total power. (A−H, top panels) Mean power differences at slow RAS (auditory stimulation at 1, 1.5 and 2 Hz) and fast RAS (auditory stimulation at 4, 4.5 and 5 Hz). Unmasked regions in the plots show significantly different z-score clusters (A−H, bottom panels). Time courses of beta-band power at slow and fast RAS. Arrowheads indicate the pre-stimulus beta power increase (−70–0 ms) observed in controls. Gray shaded areas in the bottom panels show significantly different beta-band changes. The “fast RAS” group contains auditory pacing frequencies up to 5 Hz, i.e., with an inter-stimulus interval (ISI) interval of 200 ms. Note that the epochs plotted here are longer than ISIs for the “fast RAS” condition and thus contain responses to more than one stimulus. The peri-stimulus frames marked in the panels represent the time interval used for statistical testing of differences of event-related power changes for the entire considered frequency range (3–80 Hz; upper panels) and for beta-power time courses (for details see methods section). Testing was confined to this time interval to avoid overlapping with preceding or successive stimulus events. All time–frequency plots and power time courses display signal change (in %) relative to the average across the entire data epoch.