Dynamic structure-function coupling in macroscale neonatal brain networks.

The neonatal period is critical for brain development, yet the mechanisms linking structural differentiation to functional reorganization remain poorly understood. Using multi-modal MRI data from 399 neonates (348 term-born, 51 preterm-born), here we characterize the dynamic structure-function coupling (SFC) across macroscale brain networks and examine its associations with cortical microstructure (indexed by the T1w/T2w ratio) and network flexibility. We show that the dynamic SFC varies markedly across the neocortex and increases with postmenstrual age, particularly within the default mode network (DMN). Notably, the dynamic SFC in the posterior DMN mediates the relationship between the T1w/T2w ratio and network flexibility. Preterm infants exhibit a significantly reduced dynamic SFC relative to term-born peers, along with an altered developmental trajectory of DMN linked to premature extra-uterine exposure. These findings establish dynamic SFC, especially within the DMN, as a potential biomarker for neonatal brain maturation, offering insight into the early emergence of internally directed cognition and its vulnerability to early-life adversity.