Abstract
Saccades rapidly reposition the most sensitive portion of the retina, the fovea, to interesting locations. However, they represent a challenge for the construction of a spatiotopic visual representation over time. It is currently unclear whether visual information is accumulated across eye movements or starts anew after each separate fixation. We investigated this issue using a visual motion illusion ("high phi"; Wexler et al. 2013) in which a random texture (inducer), slowly rotating clockwise or counter-clockwise, is replaced with a rapid succession of different textures (transient). With sufficiently long inducer durations, participants report the transient as a large rotational jump in the direction opposite to inducer direction (backward jumps). Crucially, the stability of the perceived jump depends on the inducer duration, eventually settling with consistent perceptions of backward jumps for longer inducer durations. This allowed us to compare the benefit of spatiotopic representations on the speed of perceptual processing. We measured the influence of inducer duration in the high phi illusion in different experimental conditions, varying the reference frame of the transient with respect to the inducer (spatiotopic or retinotopic). When the pre-saccadic inducer and the post-saccadic transient were presented in spatiotopic coordinates we observed a faster buildup of a bias in perceived jump direction, as compared to the same condition without eye movements. In control conditions we confirmed that the observed spatiotopic effect is not the result of a long-range effect, but it is tied to saccade execution. Together, these findings (I) provide strong evidence for the existence of spatiotopic storage of visual information, and (II) indicate that pre-saccadic visual input affects post-saccadic input by facilitating the spatiotopic interpretation of the visual information in the new fixation.
Meeting abstract presented at VSS 2016