This award to Dr. A. Georgopoulos will investigate the coordination of movements and forces when the arm is steered in space. Human subjects will operate a handle that can be moved in space, or can locked in place, so that it becomes an isometric force device. Perturbations of the movement will be delivered using two torque motors. The experiment wuill determine how the three-dimensional motor trajectory is steered on-line when such perturbations are applied. This on-line steering of the motor trajectory is embedded in cetain organizational principles; for example, the slowing of the speed when the trajectory is curved and the segmentation of the trajectory in planes. The research will elucidate the interactions between these principles and the steering of the trajectory in the presence of perturbations. This work will contribute basic knowledge to understanding human motor function.
