Abstract
Visual system plasticity stabilizes perception for disrupted vision, e.g. due to distortions accompanying artificial image magnifications (Adams, Banks, & van Ee, 2001; Meister & Fisher, 2008). Here, we demonstrate that the visual system recalibrates its response stimulus independently for image skews, which comprise magnifications in oblique directions, in dynamic natural scenes. Moreover, previous exposure to such distortions facilitates future fast recalibration performance of the visual system. This robust plasticity of visual system was inspected after alternate adaptations to two groups of natural image sequences, one skewed at +25° and the other at -25° in both horizontal and vertical directions. The perceived undistorted skew angle (PUA) of a subjective square checkerboard was used to quantify the aftereffect using the method of adjustment. First, PUA was measured with 23 participants after alternate adaptations to the oppositely skewed natural image sequences each lasting 15 minutes. The resulting PUAs shifted from the baseline in the direction of the adapting skew and were found to be significantly different from one another. After four weeks, PUA was measured after brief alternate exposure, 40 second, to the same distortions with 20 participants. Ten of them participated in the previous experiment (experienced) and the other ten never had prolonged exposure to these specific distortions (novice). Significantly different PUAs, shifted in the direction of the adapting skew, were observed only in the experienced subjects. Accordingly, long-term memory of the two skew distortions that affects future adaptation performance was revealed. Similar to the aspect ratio computation in cardinal axis (Regan and Hamstra, 1992), we hypothesize that special neural mechanisms might exist to compute dimensional asymmetry of orthogonal pairs in all directions and their recalibration performance might be facilitated by previous prolonged exposure of asymmetry in the specific directions.
Meeting abstract presented at VSS 2016