Figure 5.

Motor-related processing is topographically distinct from that of timing-error brain-behavior dynamics. A, Time-frequency power of oscillations during tapping is plotted relative to the power during eyes-open rest for a left central channel. B, Beta oscillations showed a clear modulation at around the 1 Hz tapping rate, whereas alpha/mu showed a sustained depression in power compared with eyes-open rest. C, Unlike the mu depression (Fig. 2H), the 1 Hz beta modulation was lateralized toward the contralateral motor areas (top). Alpha/mu showed no 1 Hz modulation on any scalp location (bottom). D, A subset of signals showed large ERP variation. Scalp topographies are shown for the three time points with largest RMS deviation across leads, the positions of leads included in the ERP plot are shown as diamonds. The largest RMS deviation appears 125 ms after finger press with a strong frontal positivity. Note that the large variation reappears 1 s before and after the event—the approximate tapping interval—but is much reduced because of jitter. The other time points with relatively large scalp potential variation showed reversed potentials with positivity over occipital areas and negativity over frontal. None of the scalp maps resembled those observed in Figure 2.