Abstract
AbstractPrimates move their eyes 2-3 times per second to bring objects of interest to central, high-resolution vision. For moving objects, they use a combination of rapid saccadic eye movements along with smooth following movements to track targets continuously. Eye movements produce perceptual enhancements for the saccade target, called pre-saccadic attention. Recently, we found in humans that saccades to peripheral motion apertures resulted in smooth post-saccadic following of stimulus motion (Kwon et al, 2019). The early phase of post-saccadic following reflects motion integration at the target before the saccade and could provide a behavioral read-out of the target’s motion. Here we examined post-saccadic following in marmoset monkeys. Marmosets performed a saccade foraging task in which they made a saccade to one of three different motion apertures. Immediately upon saccade offset, the marmoset’s eye movements followed the target’s motion with a low (10-20%) gain that was consistent with what has been observed in humans. The motion from other non-target apertures also influenced following responses, though with much weaker gain. The gain was distributed equally across apertures before the saccade but enhanced for the target immediately after the saccade, consistent with a post-saccadic enhancement (Gardner and Lisberger, 2001). This following response provided an estimate of target motion with a median absolute angular error of roughly 40 degrees, half as accurate as explicitly trained reports (Cloherty et. al., 2020). Further, the relative gain for the target motion direction versus other apertures provided an index of attentional selection. Thus smooth eye movements provide a read-out both of pre-saccadic motion integration and attention.New & NoteworthyUsing a saccade foraging paradigm in marmoset monkeys we measured visual motion integration and pre-saccadic attention from smooth following eye movements with minimal animal training.
Publisher
Cold Spring Harbor Laboratory