The present study has investigated the effect of imposed eye movement on the electromyographic activity of dorsal neck and extraocular muscles and on movements of the contralateral eye, using the electrooculogram, during vestibular stimulation in the decerebrate pigeon. Imposing movements on one eye at saccadic velocities produced large modulations in the activity of dorsal neck and extraocular muscles which were dependent on the parameters of the imposed eye movement. Thus the largest effects on dorsal neck or extraocular muscle activity were seen when movement was imposed on the eye in the opposite direction to that produced by a compensatory vestibuloocular reflex, i.e. when a contracting extraocular muscle was stretched. Slow, sinusoidal imposed eye movements that mimicked the slow phase of the vestibuloocular reflex, but with amplitude and velocity errors, produced systematic changes in neck and eye muscle responses that were closely correlated to the peak eye velocity imposed. Similarly the movement of the contralateral eye was decreased by increasing amplitudes and velocities of this slow imposed eye movement in a manner that appeared to correct for the errors in the imposed eye movement which would tend to maintain the direction of gaze. Section of the ophthalmic branch of the trigeminal nerve, the presumed pathway of extraocular muscle afferent fibres, abolished the effects of imposed eye movement on the activity of dorsal neck and extraocular muscles and on movements of the contralateral eye, strongly suggesting that the effects of imposed eye movement were mediated by extraocular muscle afferent signals. Section of the ophthalmic branch of the trigeminal nerve also disrupted the slow phase of the vestibuloocular reflex of the ipsilateral eye and caused instability of the ipsilateral eye at rest. This was strikingly similar to the effects seen by others in the cat and rabbit following section of the same nerve.