Regional BOLD variability reflects microstructural maturation and neuronal ensheathment in the preterm infant cortex

Area of Science:

• Neuroscience
• Developmental Biology
• Medical Imaging

Background:

• Blood Oxygen Level Dependent (BOLD) variability is a marker of brain activity.
• Its developmental trajectory and biological underpinnings in early life are not well understood.
• Understanding these factors is crucial for identifying impacts of preterm birth on brain development.

Purpose of the Study:

• To investigate the evolution of BOLD variability in very preterm infants.
• To examine the relationship between BOLD variability, cortical microstructure, and gene expression.
• To compare BOLD variability in preterm infants with full-term newborns at term-equivalent age.

Main Methods:

• Longitudinal resting-state functional MRI (fMRI) and multi-shell diffusion imaging were used.
• Data were acquired from 54 very preterm infants and 24 full-term newborns.
• Gene expression data from the BrainSpan dataset were analyzed.

Main Results:

• BOLD variability increased in sensory and proto-Default-Mode-Network regions during preterm development, with decreased cortical diffusivity.
• Gene expression analysis showed increased gliogenesis and neuronal ensheathment.
• At term-equivalent age, preterm infants had lower BOLD variability and higher cortical diffusivity than full-term infants.

Conclusions:

• BOLD variability reflects cortical microstructural maturation, influenced by gliogenesis and neuronal ensheathment.
• Preterm birth appears to interrupt these developmental processes.
• This interruption offers potential mechanisms for preterm brain injury.