Number of electrodes with statistically significant changes in the frequency bands. Number of electrodes (out of 64 electrodes for S01, S03, S04 and 20 electrodes for S02) with S1 activity in any frequency band, as determined by a cluster-mass based permutation test. Forty-eight of the 60 electrodes (80.0%) over S1 had activity in one of the bands. Beta activity was the most frequent (90% of those electrodes with activity), followed by gamma. S02 had no statistically significant activity in high gamma, and S03 had no activity in the alpha band