Maturation of the neonatal cortical-depth-dependent BOLD response measured using ultra-high field fMRI

The human brain undergoes rapid and dramatic development across the perinatal period which is critical for lifelong brain function. In the mature brain, neuronal activity, metabolism, vasculature and neurovascular coupling vary across cortical layers, however, each property follows distinct and complex developmental trajectories in early life. As a result, haemodynamic maturation likely varies with cortical depth, with implications for the physiology supporting emerging patterns of neural activity. To probe this, we developed and applied an ultra-high-field (7 Tesla) MRI platform to acquire high-resolution (sub-millimetre) BOLD-fMRI data from 40 newborns and 4 adults. We identified spatially specific haemodynamic responses across all ages which showed cortical depth-dependent patterns of maturation. This aligns with existing evidence indicating tight coupling and co-development of cortical vascular architecture, neuronal function and haemodynamics. This framework provides a foundation for future studies of emerging cortical function and exploration of how disruption leads to later adverse neurodevelopment.