Behavioral/Systems/Cognitive Mislocalization of Perceived Saccade Target Position Induced by Perisaccadic Visual Stimulation

The perceptual localization of objects flashed at the time of a saccade often shows large spatial distortions. These perisaccadic mislocal-izations exhibit different spatial patterns depending on the experimental condition. In darkness, when only extraretinal information is available, mislocalization is spatially uniform. In light and when visual references are available, mislocalization is directed toward the saccade target, resembling a compression of visual space. These patterns are derived from measurements of the absolute perceived position of the flashed object in egocentric space. Here, we report that also the perceived location of the saccade target is altered when an object is flashed perisaccadically. The mislocalization of the target depends on the presentation time of the flashed object and is directed toward the position of the flash. The resulting compression of the relative distance between target and flash is similar in darkness and in light and can also be foundduring fixation.When the localizationof the flashedobject is described relative to the perceived locationof the saccade target, spatial compression becomes similar in many experimental conditions. We therefore suggest that perisaccadic compres-sion relies on an encoding of relative spatial locations of objects rather than on localizations in egocentric space. Key words: eye movement; saccade; spatial perception; visual perception; human; spatial localizatio