Abstract
A feature of visuomotor behavior is the stable visual percept that the brain generates despite the volatile input provided by the retinas. One mechanism of visual stability invokes neurons that presaccadically shift their receptive fields. These neurons seem to sample the same region of space twice, permitting a comparison between the presaccadic and postsaccadic samples. We found previously that frontal eye field neurons perform such a comparison operation in the context of intrasaccadic translations. Moreover, the neurons are more sensitive to translations that occur perpendicular to the saccade than parallel to it. Here we extend our physiological findings to the behavioral level. Our aim was to characterize the ability of monkeys to report intrasaccadic translations to visual stimuli. We trained monkeys to perform a scan task in which they made repetitive saccades between two visual targets. After a random number of saccades, a third visual stimulus present on the screen was translated intrasaccadically by a small distance. Upon detecting the change, the monkey was tasked to report his percept by immediately saccading to the translated stimulus. We included two conditions: one in which the stimulus translated parallel to the scanning saccades, and another in which the stimulus translated perpendicular to the saccades. Based on the physiological findings, we made two predictions: that the monkeys' performance would increase with greater translation amount, and that a greater proportion of hits would occur for perpendicular than for parallel translations. The data confirmed both predictions. First, monkeys performed at chance level for small translations, attained ∼50% levels for translations around 2 degrees, and achieved 90% performance at translations greater than 5 degrees. Second, the monkeys had a higher percentage of hits for perpendicular translations. Taken together with our physiological data, these results suggest that monkeys rely on FEF activity for performing intrasaccadic change detection.