Structuro-Functional Differentiation and Coupling of Gyri and Sulci in the Neonatal Cortex.

Brain structure and function undergo rapid development during the neonatal period. Investigating neonatal brain structure, function, and their relationship is therefore crucial for understanding how the brain matures into a complex structuro-functional system. As fundamental anatomical units of the cerebral cortex, gyri and sulci provide novel and valuable insights for such investigations. However, gyro-sulcal differentiation and their structuro-functional developmental relationship in neonates remain poorly explored. To address this gap, we used multi-modal MRI data (structural T2w, diffusion-weighted, and resting state functional MRI) from 438 neonatal brains in the public dHCP dataset. We systematically examined differences in functional connectivity (FC) and structural connectivity (SC) between gyri and sulci from 38 to 44 weeks postmenstrual age, as well as their FC-SC coupling characteristics. From 38 to 44 weeks, both FC and SC were consistently strongest between gyro-gyral regions and weakest between sulco-sulcal regions, demonstrating that gyri act as global information processing hubs while sulci serve as local functional units in the neonatal brain. FC-SC coupling exhibited distinct patterns across cortical lobes and over time, with a characteristic shift from coupling to decoupling around 41 weeks in most regions. This study provides a foundation for understanding early developmental mechanisms of brain structure-function relationships and establishes a normative reference of gyro-sulcal differentiation as well as FC-SC coupling in the neonatal period. These findings may inform future investigations of atypical neurodevelopment and contribute to the identification of early biomarkers for neurodevelopmental disorders.