In the auditory (A)-visual (V) condition, an auditory stimulus specifying the effector (right hand, left hand, right face or left face) was presented first. After a variable delay period (12~20 s), subjects moved the specified body part or imagined it moving in response to a green (G) or red (R) visual stimulus, respectively. In the visual-auditory condition, a green or red color stimulus was presented first. After a delay period, an auditory stimulus prompted subjects to move the instructed body part or imagine it moving. For example, right hand movement (RH move) should occur in response to the visual stimulus (G) in the auditory-visual condition and to the auditory stimulus (right hand) in the visual-auditory condition.