MODIFICATIONS IN END POSITIONS OF ARM MOVEMENTS FOLLOWING SHORT-TERM SACCADIC ADAPTATION

WE investigated whether short-term saccadic adaptation modifies hand p ointing. Subjects were presented with double-step targets, the second target jump occurring during the saccade to the first one and bringing the target back to 66% of the first target eccentricity, in order to reduce the gain of their gaze saccades. Before and after this adaptati on phase, they pointed with their hand to single step targets while ke eping their gaze straight ahead. The results show that the hand moveme nts terminated at positions that were significantly less eccentric fol lowing the adaptation phase, resembling the adaptive modification seen in the gaze movements. These results suggest that the motor systems c ontrolling gaze and hand use common information about target position.