Abstract
Introduction. Ocular dominance - influenced by mutual inhibition between the monocular streams and the weight given to each during binocular combination - exhibits plasticity, where monocular deprivation can bias dominance. Notably, short-term deprivation, counter-intuitively, biases dominance in favor of the deprived eye (as measured by binocular rivalry duty cycles, as well as dichoptic motion coherence, phase, and contrast discrimination thresholds). While these effects have been well-modeled by contrast gain changes, it is not clear whether the trigger to plasticity - the deprivation itself - need be contrast-based; all deprivation studies thus far have used light-tight patches or optical diffusers that obliterate contrast. In this study, monocular deprivation was induced with a 'kaleidoscopic' lens that obliterated coherent form and behavioral relevance, but preserved color, spatial frequency, and contrast. Method. 10 observers underwent short-term (2.5 hour) kaleidoscopic deprivation, and, as a baseline, light-tight deprivation (during a separate visit). Subjects performed a pre- and post-deprivation global motion coherence task dichoptically, with signal and noise dots presented to different eyes using LCD goggles - to measure ocular dominance. Results. Overall, in line with previous studies, light-tight deprivation significantly enhanced motion coherence sensitivity in the deprived eye (7% drop in threshold motion coherence; SE: 0.015; two-tailed t-test: 4.532; p=0.001). Kaleidoscopic deprivation showed similar, but non-significant trends (about a 4% drop), but these overall measures obscure considerable individual differences (with 7 of 10 observers showing enhancement, 1 suppression, and 2 no effect with light-tight deprivation, and 5 of 10 showing enhancement, 3 suppression, and 2 no effect with kaleidoscopic). Conclusions. Kaleidoscopic deprivation is sufficient to trigger ocular dominance plasticity in some observers, similarly to light-tight deprivation, but further tests are required (and ongoing) to determine the ubiquity of the effect and the source of individual differences.
Meeting abstract presented at VSS 2016