Abstract
The position of a flash presented during a smooth pursuit eye movement is mislocalized in the direction of the pursuit. This has been explained by a temporal mismatch between the slow visual processing of the flash and fast efferent signals for present eye position. Here we tested whether spatial context would also influence the perceived position of the flash. We put various continuously-lit objects (walls) between the veridical flash location and position where the flash would normally be mislocalized. Walls significantly reduced the mislocalization of the flash, largely preventing the flash from being mislocalized beyond the wall. No change in eye movements was observed that would reduce the mislocalization. When the wall was shortened or had a hole in its center, the number of trials in which the flash was mislocalized beyond the wall increased, but in those trials, the flash was vertically shortened as if cut off or funneled by the wall. The wall also induced color interactions - a red wall made a green flash appear yellowish if it was in the path of mislocalization. Finally, the critical time period for the presentation of the wall was found to be after the disappearance of the flash. These results indicate that features of the flash in pursuit-induced mislocalization are postdictively determined using broad spatial and temporal integration windows, which provides a new insight as to why the afferent signals of the flash are so delayed compared to the efferent eye-position signals.