Microstructural cortical maturation underlies longitudinal BOLD signal variability of emerging resting-state networks in preterm infants

Motivation: BOLD signal variability (BOLD-SD) has emerged as a measure for assessing brain function, but little is known regarding its biological significance. Goal(s): Demonstrate that cortical BOLD-SD modifications are accompanied by structural intracortical maturational changes. Elucidate brain networks undergoing the most important maturational changes during early development. Approach: Longitudinal brain MRI acquisition in preterm infants at 33 and 40 weeks’ gestational age. Assessment of cortical BOLD-SD and NODDI indices longitudinal modifications per brain network. Results: A significant longitudinal cortical BOLD-SD increase is observed in primary sensory networks and Default-Mode-Network, accompanied by a decreased NDI (neurite-density-index) and/or increased ODI (orientation-dispersion-index), reflecting concomitant structural intracortical maturation. Impact: During early brain development, the BOLD signal variability increase in resting-state networks was associated to underlying structural intracortical maturational changes and thus it can be considered as a marker of cortical maturation.