EFFECT OF EARLY VISUAL EXPERIENCE ON SPONTANEOUS NEURAL VARIABILITY ACROSS THE VISUAL HIERARCHY

Perception relies on intrinsic cortical priors that help inference under uncertainty. Interactions between spontaneous activity and sensory input during early development are thought to shape these intrinsic dynamics. Visual deprivation from birth provides a critical opportunity to test how early input shapes neural priors.

We examined intrinsic neural variability and neural timescales in individuals born with dense bilateral congenital cataracts (CC) who later underwent sight-restoration surgery. Resting-state fMRI data were acquired during eyes-open (EO) and eyes-closed (EC) conditions from presurgery (CC-Pre) and postsurgery (CC-Post) CC individuals, along with age-matched sighted controls (SC) (Fig.1a). Variance-based BOLD fluctuations were quantified using the standard deviation of the BOLD signal across the visual hierarchy (V1–V4). A hierarchical Bayesian model integrated data across scanners, cohorts, regions, and conditions to obtain robust group-level estimates (Fig.1b).

All groups exhibited a systematic increase in BOLD variability from V1 to V4 (Fig.1c,d). However, CC-Pre individuals showed significantly higher variability across the visual hierarchy compared to sighted controls. Crucially, restoration of visual input (CC-Post individuals) was associated with reduced variability after surgery, but the variability in CC- Post remained higher than in SC individuals across the hierarchy, especially in EO condition.

To assess whether altered variability was accompanied by changes in neural timescales, BOLD autocorrelation decays were computed (Fig.1e,f). While SC individuals showed slower autocorrelation decay from V1 to V4, CC individuals exhibited faster decay, suggesting shorter intrinsic timescales. Together, these findings demonstrate the crucial role of early visual input in shaping the spatiotemporal organization of intrinsic cortical dynamics.