Abstract
Primates use prior experiences to facilitate their responses to a target stimulus. Research on oculomotor control has demonstrated that inhibition of return (IOR) and repetitive priming (RP) play a role in this process. Recent studies showed that neural activity at the supplementary eye field (SEF) of monkeys is predictive the onset of a target for eye movements and microstimulation here alters saccade latency. To examine whether the effect of saccade history is mediated by the SEF, monkeys were trained to execute saccades toward a target appearing at one of two horizontal locations with equal or unequal frequency while microstimulation was applied to SEF sites that facilitated or delayed visually-guided saccades toward one of the two target locations. Results show that a saccade preceded by another with the same metric (direction and amplitude) had a shortened latency only when a temporal gap was present before target onset, and had a longer latency without a gap. Target frequency exacerbated these effects by increasing the frequency of consecutive saccades with the same metric. Stimulating SEF facilitation site resulted in shortened saccade latency only when the preceding saccade had the opposite metric, and stimulating delay sites resulted in increased saccade latency only when the preceding saccade had the opposite metric and without a gap. These results implicate the SEF in exerting the influence of saccade history, and likely underscore phenomena such as IOR and RP in affecting oculomotor readiness.