Measurement of Eye Movements during Reaching and Grasping Based on a Double Step Paradigm using Virtual Objects

Abstract

Using a virtual reality technique, a double step experiment was undertaken to investigate the human performance of reaching and grasping. Subjects were asked to reach and grasp a computer-generated 3D target image in a stereo-display. During reaching movement, the target suddenly changed its position when the subject's hand comes within a certain distance from the starting position (double-step-paradigm). The reaction of reaching and grasping movements and saccadic eye movements were studied. The results showed that the velocity peak of reaching is the time until which altering action is possible. Also, the latency of saccadic eye movements to foveate the second target became shorter when it was accompanied with reaching motion. The experimental system has proven to be useful for the quantitative study of human visual perception and cognition that accompanies motor control of arms and fingers.