MANUO-OCULAR COORDINATION IN TARGET TRACKING .1. A MODEL SIMULATING HUMAN-PERFORMANCE

During eye tracking of a self-moved target, human subjects' performanc e differs from eye-alone tracking of an external target. Typical laten cy between target and eye motion onsets is shorter, ocular smooth purs uit (SP) saturation velocity increases and the maximum target motion f requency at which the SP system functions correctly is higher. Based o n a previous qualitative model, a quantitative model of the coordinati on control between the arm motor system and the SP system is presented and evaluated here. The model structure maintains a high level of par allelism with the physiological system. It contains three main parts: the eye motor control (containing a SP branch and a saccadic branch), the arm motor control and the coordination control, The coordination c ontrol is achieved via an exchange of information between the arm and the eye sensorimotor systems, mediated by sensory signals (vision, pro prioception) and motor command copy. This cross-talk results in improv ed SP system performance. The model has been computer simulated and th e results have been compared with human subjects' behavior observed du ring previous experiments. The model performance is seen to quantitati vely fit data on human subjects.