DECREASES IN THE LATENCY OF SMOOTH-PURSUIT AND SACCADIC EYE-MOVEMENTSPRODUCED BY THE GAP PARADIGM IN THE MONKEY

The initiation of both pursuit and saccades was affected by the presen ce of a temporal gap between the disappearance of a fixated visual tar get and the appearance of a second, eccentric, target. For pursuit, th e gap paradigm produced a modest (20 msec) decrease in latency, For sa ccades, the gap paradigm produced a similar modest decrease in the lat ency of some saccades, but also revealed a population of very short la tency ''express'' saccades. The modest changes in the latency of pursu it and regular saccades displayed a similar dependence on gap duration , with the largest decreases produced by gaps of 200-300 msec. The gap paradigm did not produce ''express'' pursuit, even though express sac cades could be elicited on interleaved trials.