Experimental setup and protocol.

<p>(A) Configuration of the experimental apparatus. Participants rested their heads on the chin rest and were required to make reaching movements from the button switch to the target displayed on the monitor while they watched the fixation point. The motion of the reflective marker was recorded by the motion capture system as the kinematics of the reaching movement. (B) Visual stimulus layout. The diameter of the fixation point participants were asked to watch during the trials was 0.85 deg (shown as a green filled circle). Right- or left-pointing prime and mask stimuli were regular triangles whose sides were 1.5 and 6.0 deg, respectively. The centroid of the prime triangle was located at 10 deg above the fixation point in the vertical plane. Possible targets (white filled circle, diameter of 0.6 deg) were located at 6.8 and 9.3 deg horizontally from the centroid on each side, respectively. (C) Time sequence of the visual stimuli (prime-mask combination) in each condition. While the fixation point remained green in the congruent(incongruent)-green and neutral conditions after the button release, the color of the fixation point was switched from green to blue in the incongruent(congruent)-blue conditions at the same timing of prime onset. The outer contour of the prime stimuli fit exactly within the inner contour of the cutout of the mask triangles. Except for trials in the neutral condition, either the right- or left- target point (white filled circle, diameter: 0.6 deg) reappeared according to the direction of the mask stimulus, and feedback about the reaching endpoint (green filled circle, diameter: 0.6 deg) was also provided after the reaching movement (i.e., contact with touch panel).