Mapping Early Brain Maturation: Anatomical Substrates of Cortical Connectivity Shifts in Neonates

Understanding the early development of brain connectivity 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 connectivity in infants. We quantified interareal variations in connectivity and identified three distinct global connectopies (GCs) along the rostrocaudal, dorsoventral, and mediolateral axes by using gradient mapping techniques. A pivotal age-dependent shift between the dorsoventral and mediolateral GCs occurred at 40 postmenstrual weeks. This shift was diminished by virtual thalamic fiber lesions, underscoring the critical role of thalamic projections. A longitudinal analysis disclosed a delayed structural connectivity pattern development in preterm infants who failed to exhibit the anticipated shift. This research helps to clarify 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. These findings are essential for understanding typical brain growth and the pathogenesis of neurodevelopmental disorders.