Infant brain regional cerebral blood flow increases supporting emergence of the default-mode network

Human infancy is characterized by most rapid regional cerebral blood flow (rCBF) increases across lifespan and emergence of a fundamental brain system default-mode network (DMN). However, how infant rCBF changes spatiotemporally across the brain and how the rCBF increase supports emergence of functional networks such as DMN remains unknown. Here, by acquiring cutting-edge multi-modal MRI including pseudo-continuous arterial-spin-labeled perfusion MRI and resting-state functional MRI of 48 infants cross-sectionally, we elucidated unprecedented 4D spatiotemporal infant rCBF framework and region-specific physiology-function coupling across infancy. We found that faster rCBF increases in the DMN than visual and sensorimotor networks. We also found strongly coupled increases of rCBF and network strength specifically in the DMN, suggesting faster local blood flow increase to meet extraneuronal metabolic demands in the DMN maturation. These results offer insights into the physiological mechanism of brain functional network emergence and have important implications in altered network maturation in brain disorders.

Automated summary

Human infancy is characterized by rapid increases in regional cerebral blood flow (rCBF) and the emergence of the default-mode network (DMN). This study used advanced multi-modal MRI techniques to investigate the spatiotemporal changes in infant rCBF and the coupling between physiology and functional networks. The results showed that the DMN exhibited faster rCBF increases compared to visual and sensorimotor networks. Additionally, there was a strong coupling between rCBF and network strength specifically in the DMN, indicating increased local blood flow to support DMN maturation. These findings provide insights into the physiological mechanisms underlying the emergence of functional brain networks and have important implications for understanding altered network maturation in brain disorders.