Different coupling for the reach and grasp components in bimanual prehension movements

In this study on functional coupling in bimanual grasping movements, nine n ormal subjects had to reach and grasp two different objects simultaneously. Both objects could be either small or large, resulting in four different c onditions of bimanual grasping. The main dependent variables were the coupl ing coefficients calculated either between the hand displacements or betwee n the grip apertures of both hands, serving as variables for the coupling o f the reach and the grasp component respectively. The correlation was signi ficantly higher for the reach component than for the grasp component, with only the latter one changing significantly with variation of object size. T hese findings suggest different temporo-spatial coupling modes for the reac h and the grasp components of bimanual grasping movements. NeuroReport 11:3 787-3791 (C) 2000 Lippincott Williams & Wilkins.