FIGURE 2.

Rotational visuomotor adaptation task (rVMA) and initial directional error (IDE) variable. The center dot is the starting home position for each trial. The remaining dots are the targets which appeared every 2 s in one of eight possible locations (45, 90, 135, 180, 225, 270, 315, and 360°) and remained visible during 750 ms. To compute the IDE, two movement trajectories were defined: the ideal trajectory and the real initial trajectory. Ideal trajectory was defined as the linear vector from the center of the test screen to the target. The real initial trajectory was defined as the linear vector from the test screen center to the cursor position 80 ms after the movement onset. IDE stands for the output error before visual feedback was available to correct the cursor trajectory, so IDE was an indirect measure of the motor planning of the movement.