Visual Target Tracking with Active Head Rotation

Visual target tracking during active head movements is investigated. Transient response and frequency response both indicate that the eye tracking behavior relative to the target is independent of head movement. The explanation of this phenomenon is pursued. It seems most likely that the vestibulo-ocular reflex, the eye movements elicited by head rotation, plays an essential role. Compensation for head motion is accomplished by this reflex at relatively high frequencies, making visual fixation on stationary objects quite easy. The dynamics of head motion are also investigated. Unusual nonlinear responses are found at high frequencies. Namely, the response frequency is slightly lower than that of the target. A model of the whole system is proposed.