ACTIVITY OF CELLS IN THE DEEPER LAYERS OF THE SUPERIOR COLLICULUS OF THE
RHESUS MONKEY: EVIDENCE FOR A GAZE DISPLACEMENT COMMAND
Edward G. Freedman and David L. Sparks
Edward G. Freedman, Dept. of Psychology Physiology and Biophysics, Univ. of
Pennsylvania 357290, School of Medicine, 3815 Walnut St. Phila., PA 19104-6196
Phone: (215) 898-0427 Fax: (215) 898-7301, email:
freedman@cattell.psych.upenn.edu, Univ. of Washington, Seattle, WA 98195,
Phone: (206)-543-5978 fax: (206)-685-0305,
email:freedman@bart.rprc.washington.edu
APStracts 4:0078N, 1997.
ABSTRACT
When the head is free to move, microstimulation of the primate superior
colliculus (SC) evokes coordinated movements of the eyes and head. The
similarity between these stimulation-induced movements and visually-guided
movements, indicates that the SC of the primate is involved in re-directing
the line of sight (gaze). To determine how movement commands are represented
by individual collicular neurons, we recorded the activity of single cells in
the deeper layers of the superior colliculus of the rhesus monkey during
coordinated eye-head gaze shifts.
Two alternative hypotheses were tested. The "separate channel" hypothesis
states that two displacement commands are generated by the SC; one signal
specifying the amplitude and direction of eye movements and a second signal
specifying the amplitude and direction of head movements. Alternatively, a
single gaze displacement command could be generated by the SC ("gaze
displacement" hypothesis).
Received 1996 August 13; accepted in final form 1997 May 27.
APS Manuscript Number J638-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 11 June 1997