How does the brain coordinate the choice of target between two different motor systems like saccadic and smooth pursuit eye movements? In principle this could be done in parallel – sending a command to choose a target to both systems at once. Or it could be in serial – first choosing a target with the saccadic movement and then sending that command in serial to the pursuit system. In a series of behavioral and physiological studies we have found that the choice of target is sent in serial from the saccadic to the pursuit motor system. The demo above steps you through a series of microstimulation studies that we used to show this.
Gardner, J. L. , and Lisberger, S. G. (2002) Serial linkage of target selection for orienting and tracking eye movements. Nature Neuroscience 5:892-899 DOI <News and Views by Michael N. Shadlen> Abstract pdf