Submitted on January 8, 2007
Accepted on August 22, 2007
Coordination of Smooth Pursuit and Saccade Target Selection in Monkeys
Gilbert R Case1 and Vincent P Ferrera2*
1 Biological Sciences, Florida State University, Tallahassee, Florida, United States
2 Psychiatry, Columbia University, New York, New York, United States
* To whom correspondence should be addressed. E-mail: vpf3{at}columbia.edu.
The coordination of saccadic and smooth pursuit eye movements in macaque monkeys was investigated using a target selection paradigm with two moving targets crossing at a center fixation point. A task in which monkeys selected a target based on its color was used to test the hypothesis that common neural signals underlie target selection for pursuit and saccades, as well as testing whether target selection signals are available to the saccade and pursuit systems simultaneously or sequentially. Several combinations of target color, speed and direction were used. In all cases, smooth pursuit was highly selective for the rewarded target before any saccade occurred. On over 80% of the trials, the saccade was directed toward the same target as both pre- and post-saccadic pursuit. The results favor a model in which a shared target selection signal is simultaneously available to both the saccade and pursuit systems, rather than a sequential model.
