SYSTEM FOR PROJECTION OF A 3-DIMENSIONAL, MOVING VIRTUAL TARGET FOR STUDIES OF EYE-HAND COORDINATION

Eye-hand tracking of moving visual objects in three-dimensional (3D) s pace is common in the behavioral repertoire of primates. However, beha vioral and/or neurophysiological studies of this function are lacking mainly because devices do not exist that allow its investigation. We d escribe a device by which a spot of light can be presented in the imme diate extrapersonal space of a subject and can be moved in various tra jectories in 3D space. The target is a real image;of a circular apertu re produced by a system consisting of a light source, aperture, filter s, several lenses and fold mirrors, and a large concave mirror to focu s the final real image. Rapid, computer-controlled movement of the ima ge is obtained by tilting a gimbal-mounted guide mirror (for x and y m otion) and by translating a lens (for motion in the z direction). A se cond configuration of the system allows movement of a 3D image in the 3D space. Hand motion is monitored by means of a sonic, 3D, position-m easurement system.