A system for the study of visuomotor coordination during reaching for moving targets

Prehensile behavior is a popular task in current research on human motor co ntrol. Most studies on reaching used stationary target objects and, therefo re, most models do not address the challenges the motor system must respond to when reaching for moving objects. The machines used in earlier studies to produce object motion offered a limited range of trajectories and restri cted control over various movement parameters. We have developed a device t hat allows a great variety of object trajectories along a Rat-table surface and gives the experimenter full control over all movement parameters. A li near positioning system is used to move a sled beneath the table surface. M agnetic coupling transfers the sled's movement to the target object on the tabletop. This arrangement allows fast movements of the object (up to 5 m/s ) and at the same time protects subjects from any harm due to the moving pa rts. The system is connected to LC shutter glasses, a 3-D movement registra tion device, and a switch that detects the onset of hand motion. This allow s the selective withdrawal of vision during the reaching task or the introd uction of changes in the object motion depending on the subject's reactions . (C) 2000 Elsevier Science B.V. All rights reserved.