Fig. 2

Experimental paradigm used in this study. Each subject presses a space bar whenever the red circle is presented in the middle of a screen. The red circle is maintained until the subject presses the space bar. “N sec” means different response times between trials. After the task period, the fixation (‘+’) mark is presented to indicate a rest period. The average response time across all subjects was about 690 ± 25 ms for both hands (680 ± 30 ms for right hand and 710 ± 20 ms for left hand)