Vladislav Ayzenberg^1,2, Michael Arcaro¹; ¹University of Pennsylvania, ²Temple University

Understanding the anatomical and functional organization of the visual system at birth provides critical insights into the mechanisms that support early developing perceptual and cognitive abilities. Using resting-state fMRI and diffusion tensor imaging, we examined the cortical and subcortical organization of the visual system in neonates (37-42 weeks gestation). We used an adult probabilistic atlas of retinotopic maps to identify putative visual areas in neonates. Functional correlations between cortical areas revealed that the infant visual system exhibits an adult-like hierarchical organization, with distinct clusters for regions of the occipital cortex, as well as ventral, lateral, and dorsal visual pathways. Direct comparisons between neonates and adults revealed that correlation patterns within occipital and dorsal areas were more adult-like than ventral and lateral areas. We then examined the extent to which this cortical organization was mirrored in the maturity of structural connections between each cortical area and the pulvinar – a subcortical structure that is extensively interconnected with the entire visual cortex in adults and plays a crucial role in visual processing. Probabilistic tractography analyses reliably identified white matter pathways between the pulvinar and each cortical visual area. These connections showed area-level specificity and overlapped with homologous pathways of adults. However, we found developmental differences within the fine-grained connectivity pattern of the pulvinar. Although the coarse connectivity organization for all neonate networks were qualitatively similar to those of adults, the connectivity maps for ventral visual areas were immature and did not show strong specificity within the pulvinar. Altogether, our findings indicate that the large-scale anatomical and functional organization of the visual system is established by birth, but there are developmental differences in the maturity of different pathways with the dorsal pathway maturing earlier than the ventral pathway.