Abstract
Previous experiments have shown that the location of stimuli briefly flashed around the time of the saccade are perceived either as compressed towards the saccade target or as shifted in saccade direction. The mechanisms underlying these misperceptions remain unresolved. It can be assumed that perceiving brief flashes is a challenging task in part because it requires accurate integration of sensory and motor information in time. For example, the task is complicated by the brain's uncertainty about when a saccade is initiated. In the present study we systematically manipulated saccade onset times by presenting saccade targets either at a location that was highly predictable or at a location, on the opposite side, that occurred less frequently. We found that saccade reaction times were more scattered for the unpredictable target location than for the predictable one. Also, our data suggest that the degree of misperception is more pronounced for the unpredictable saccade direction. These results are consistent with the idea that perisaccadic perception of space is a challenging task that is affected by the brain's limited ability to process the timing of sensory and motor signals.