Adjustment of saccade characteristics during head movements

Eye-head coordination was investigated by recording from the neck and eye muscles in monkeys. The results show that (i) during eye-head turning, neural activity reaches the neck muscles before the eye muscles, and (ii) all agonist neck muscles are activated simultaneously regardless of the initial head position. Since overt movement of the eyes precedes that of the head, it was concluded that the central neural command initiates the eye-head sequence but does not specify its serial order. Furthermore, it was determined that the compensatory eye movement is not initiated centrally but instead is dependent upon reflex activation arising from movement of the head. Show more

Simultaneous recordings of both eye and head movements in response to a peripheral signal indicated that the backward compensatory eye movement was initiated during the constant velocity of the head rotation. This compensatory movement began before the eyes had actually reached the peripheral signal.