Influence of Static Eye and Head Position on Tone-Evoked Gaze Shifts - Contribution of head to gaze shifts

To program eye-head gaze shifts to sounds, the orientation of eyes and head should be incorporated to specify the target relative to the eyes, and only head orientation should be incorporated to specify the target relative to the head. Here we test whether the eye and head motor systems employ different reference frames for gaze shifts evoked by broadband sounds and pure tones. The head-movement component of the gaze shift was modulated by initial head-orientation and sound frequency, but not by eye position. This demonstrates that eye and head are controlled separately by signals in an eyecentered and head-centered reference frame, respectively.