Mapping Early Brain Maturation: Anatomical Substrates of Cortical Connectivity Shifts in Neonates
Understanding the early development of brain connectivities is essential for unraveling the mechanisms of brain maturation. In this study, we utilized diffusion MRI data from 242 term neonates to chart the developmental trajectory of cortical connectivities in infants. We quantified interareal connectivity variations and identified three distinct global connectopies (GCs) along the rostrocaudal, dorsoventral, and mediolateral axes through gradient mapping techniques. A pivotal age-dependent shift between the dorsoventral and mediolateral GCs occurred at 40 postmenstrual weeks, which was diminished by virtual thalamic fiber lesions, underscoring the critical role of thalamic projections. Longitudinal analysis disclosed delayed structural connectivity pattern development in preterm infants who failed to exhibit the anticipated shift. This research clarifies the topographic principles that shape infant brain organization and emphasizes the influence of thalamic connectivity on early brain development. Our findings elucidate the anatomical underpinnings of early brain development, providing critical insights into the formation of cortical hierarchies and highlighting the influence of thalamic connectivity on developmental trajectories, essential for understanding typical brain growth and the pathogenesis of neurodevelopmental disorders.