Spatial frequency-specific visual adaptation may cause paradoxical transient improvements in visual acuity: computer simulation and confirmatory experiments

In the visual cortex of monkeys and humans, several types of processing are conducted, such as orientation-selective edge detection. It was also reported by Campbell and associates that the cerebral visual cortex conducts processing consisting of spatial-frequency-and-orientation-specific multiple narrow-band channels. It has also been reported that spatial-frequency-and-orientation-specific visual stimuli cause adaptations in the corresponding channels, resulting in reductions of the visual sensitivity around some frequency ranges. In the course of simulation studies using Landolt rings to measure visual acuity, we found that spatial-frequency-specific adaptations would cause paradoxical transient improvements in visual acuity. We therefore conducted perceptual experiments to see if these improvements in visual acuity take place after spatial-frequency-specific visual adaptation, with positive results. These findings may be significant in designing road information boards for car drivers, because such an adaptation often occurs while driving a car.