Neural Gain Modulation Propagates from Posterior to Anterior Brain Regions to Optimize Orientation Perception in Chronic Astigmatism

While visual impairments commonly occur daily, many individuals fail to recognize these distortions. Yet, the brains role in adapting to distorted sensory inputs remains largely unknown. In this study, we focused on how the brain recalibrates physical orientation-specific blur after chronic exposure to astigmatism. By reconstructing the population orientation tuning response from electroencephalogram activity patterns and estimating neural gain modulation using an optics-based computational model (data from 42 participants, including 15 females), we found enhanced neural gain for underrepresented orientations and reduced gain for overrepresented ones, especially in individuals with long-term astigmatism. The strength of the gain modulation correlated with the optimization of orientation perception in these participants. Furthermore, this push-pull neural gain modulation dynamically propagated from the posterior brain regions to others, and the strength of the propagation correlated with the degree of perceptual optimization. In contrast, short-term exposure resulted in transient and short-lived neural optimization, characterized by a relatively stronger anterior-to-posterior transference pattern. These results show how feature-specific information is modified across the entire brain in response to systematic visual distortion, revealing duration-dependent strategies the brain employs to handle sensory impairments.