The ERSP images of the left motor cluster with five cases. (a) The ERSP images of the left motor cluster with five cases. The right column shows the onset sequences of the two tasks. Color bars indicate the magnitude of the ERSPs. Red solid lines show the onset of math. Red dashed lines show the mean response time for math task. Blue solid lines show the onset of deviation task. Blue dashed lines show the mean response time for deviation task. The red circle pointed out by a red arrow in case 2 means the red solid line and blue solid line are on the same position. Latencies calculated from (a) are shown in (b) by calculating from the deviation task onset to the first occurrence of power suppressions. The open bars represent the latencies in the alpha (8 ~ 14 Hz) band. The gray blue bars represent these latencies in the beta band (16 ~ 20 Hz). (c) shows the comparison of total power in cross-subject (11 subjects) averaged ERSP images in the left motor cluster between cases. The amount of total power is calculated by adding all the power suppressions in the same temporal period and the same frequency band. The open bars represent the total power in the alpha band. The gray bars represent the total power in the beta band.