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Yi Gao, Michael Webster, Fang Jiang; Dynamics of contrast adaptation in central and peripheral vision. Journal of Vision 2018;18(10):579. doi: 10.1167/18.10.579.
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© ARVO (1962-2015); The Authors (2016-present)
Visual adaptation can operate over multiple timescales to adjust sensitivity for different rates and durations of stimulus change. Adaptation has also been found to increase with eccentricity, yet how eccentricity affects the time course of visual adaptation remains largely unknown. In the current study, we examined these dynamics by tracking the time course of contrast adaptation in both the central visual field and periphery (at 10° eccentricity) using a yes/ no detection task to monitor contrast thresholds. Adapters were 1.5 cycle/degree Gabor patches with a diameter of 5°, counterphase flickering at 5Hz. Consistent with previous studies, aftereffects on 4° test stimuli were stronger in the periphery than in the center when adapting to equivalent high contrast (90%) patterns. Peripheral adaptation remained stronger even when contrast was reduced to one-third (30%) the foveal contrast. The time course of the threshold changes was fitted with separate exponential functions to estimate the time constants during the adaptation and post-adapt phases. Compared to the central adaptation, adaptation effects built up and decayed more slowly in the periphery, and surprisingly did not decay completely to the baseline within the monitored post-adapt period (400 s). Similar results were replicated with the tilt aftereffect using a 2AFC orientation discrimination task. Across all the experiments, there was no correlation between maximum adaptation strength and halftime of the decay phase, suggesting that the slower decay rate in the periphery was not due to a larger adaptation magnitude. Our results indicate that the dynamics of contrast adaptation differs qualitatively between central and peripheral vision, with the periphery adapting not only more strongly but also more slowly. EY023268 to Fang Jiang, EY10834 to Michael A. Webster
Meeting abstract presented at VSS 2018
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