Motor pre-programming in the control of disparity vergence eye movements

Disparity vergence eye movements are oppositely directed eye rotations in response to target depth changes. This oculomotor system has been thought to be controlled by a simple feedback mechanism; however, results presented here of finding multiple or biphasic waveforms during open-loop vergence responses and the dynamic similarity of vergence responses (P <; 0.18) evoked by briefly presented step stimuli, indicate an initial component which is under pre-programmed control.