Unraveling the mesoscale functional connectivity of the human primary visual cortex using high-resolution functional MRI.

UNLABELLED

Despite their importance in shaping visual perception, functional connectivity between ocular dominance columns (ODCs), the building blocks of neuronal processing within the human primary visual cortex (V1), remains largely unknown. Using high-resolution functional MRI (fMRI), we localized ODCs and assessed their resting-state functional connectivity (rs-FC) in 11 human adults (3 females). Consistent with anatomical studies in animals, we found stronger rs-FC in the middle compared to deep and superficial cortical depths and selectively stronger rs-FC between ODCs with alike compared to unalike ocular polarity. Beyond what was known from animal models, and consistent with human perceptual biases, we found stronger intra- and interhemispheric rs-FC in peripheral (compared to central) and in dorsal (compared to ventral) V1 subregions. Lastly, we found a significant correlation between rs-FC patterns and ODC maps, supporting the hypothesis that ODC maps can be predicted from rs-FC patterns within V1. These results highlight the heterogeneity in functional connectivity between ODCs across cortical depths and V1 subfields, underscoring their likely association with human perceptual biases.

SIGNIFICANCE STATEMENT

Our findings provide evidence for selective mesoscale rs-FC between ODCs, aligning with prior anatomical findings in animals.Beyond what is known from animal studies, we demonstrate that the mesoscale rs-FC pattern varies across V1 subregions, aligning with the expected heterogeneity in global visual processing across visual subfields.We provide evidence for the predictability of ODC maps from the rs-FC pattern, establishing one of the first steps toward leveraging rs-FC for segmentation of the visual cortex at mesoscale levels.