Interaction of visually guided saccades with saccades induced by electrical stimulation of the posterior parietal cortex in the monkey.
The properties of the neural code specifying the parameters of trained, visually guided saccades were examined by applying micro-stimulation of area PG in monkeys while they generated saccades to receive reward. It was hypothesized that electrical stimulation would alter the spatial pattern of cells being activated, and thereby predictably alter the characteristics of the resultant saccade. Instead, the two mechanisms of saccade generation, one initiated by electrical stimulation, the other initiated internally, were mutually exclusive, and resulted in either the cancellation of saccades, or the delay (up to 640 msec) of the visually guided saccade. Visually guided saccades accurately fixated visual targets (no longer visible at the start of saccades) whether or not the eyes were previously perturbated by the electrical stimulation. Unlike stimulation applied to the frontal eye fields or the superior colliculus, the end position of visually guided saccades cannot be modified by altering activity in area PG during saccade generation.
Kurylo
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DD
Department of Psychology, Northeastern University, Boston, MA 02115.
D000818:Animals; D004558:Electric Stimulation; D008254:Macaca nemestrina; D009039:Motion Perception / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D013997:Time Factors