ERD/ERS produced by repetitive motor task. Panels A and B are computed from data recorded prior to training and Panels C and D are from after training. The lower panels show averaged ERD/ERS values in the 26–30 Hz band (Panel E) and in the 27–32 Hz band (Panel F) for comparison between pre- and post-training conditions. The left column (Panels A, C, and E) and the right column (Panels B, D, and F) represent the data recorded from around C3 (left hemisphere) and C4 (right hemisphere), respectively. Statistically non-significant areas are shown as blank in Panels A–D. The significance level is set to P < 0.01.