Increased BOLD variability is accompanied by changes in tissue microstructure and upregulation of gliogenesis in the preterm infant cortex

Motivation: BOLD signal variability structural and biological correlates during early brain development remain largely unknown. Goal(s): Investigate how BOLD variability changes during preterm infants' early development, its alignment with cortical microstructural maturation, gene expression patterns, and the impact of preterm birth. Approach: MRI was acquired longitudinally in 54 very preterm infants at 33- and 40-weeks, and in 19 full-term newborns. Regional BOLD variability and cortical diffusivities were calculated. Gene expression was evaluated using BrainSpan dataset. Results: Increased BOLD variability during preterm development is associated with cortical maturation and upregulation of genes involved in gliogenesis, with preterm birth negatively impacting maturation compared to full-term birth. Impact: Preterm birth disrupts cortical BOLD variability and microstructure by term-equivalent-age. During preterm infants' neurodevelopment, an increase in cortical BOLD variability reflects ongoing changes to tissue microstructure and an upregulation of genes mediating gliogenesis, identifying putative mechanisms for preterm brain injury.