Electrical Stimulation of the Supplementary Eye Fields in the Head-Free Macaque Evokes Kinematically Normal Gaze Shifts

Abstract

Crawford. Electrical stimulation of the supplementary eye fields in the head-free macaque evokes kinematically normal gaze shifts. J Neurophysiol 89: 2961–2974, 2003. First published February 5, 2003; 10.1152/jn.01065.2002. The supplementary eye fields (SEFs), located on the dorsomedial surface of the frontal cortex, are involved in high-level aspects of saccade generation. Some reports suggest that the same area could also be involved in the generation of motor commands for the head. If so, it is important to establish whether this structure encodes eye and head commands separately or gaze com-mands that give rise to coordinated eye-head movements. Here we systematically stimulated (50 A, 300 Hz, 200 ms) the SEF of two head-free (head unrestrained) macaques while recording three-dimen-sional eye and head rotations. A total of 55 sites were found to consistently elicit saccade-like gaze movements, always in the con-tralateral direction with variable vertical components, and ranging i