How brain networks transform from birth to childhood

The brain's grey matter is involved in higher-order functions like memory, attention, language, and conscious perception. It contains the brain cells and the synapses that process and interpret incoming signals. 

Networks in the gray matter undergo complex transformations from neonatal age to childhood. The transformation supports the rapid cognitive development during very early childhood.

Functional magnetic resonance imaging, or fMRI, has long been a cornerstone in studying brain function, and researchers have long studied the function of the gray matter of the brain.

The brain's white matter contains nerve fibers insulated with fat (making it look white). The nerve fibers ensure efficient communication between areas of grey matter through optimizing signal transmission across the central nervous system.

However, until recently, the development of white matter networks was difficult to study due to their weaker fMRI signals.

New research methods have now allowed scientists to explore these networks in greater detail, revealing how white matter contributes to cognitive growth from infancy into childhood.

White matter in brain development
In a recent study, researchers compared the white matter functional networks in neonates and 8-year-old children.

Using the same imaging protocols and fMRI techniques across groups, they analyzed how these networks function and change with age.

The measures included intra-network connectivity, which captures connections within a single network, inter-network connectivity, the communication between different networks, and finally, a measure of brain activity energy.

The study revealed significant developmental changes in white matter networks between these two age groups. White matter connectivity within certain regions, like the optic radiations (vision) and corticospinal tracts (movements), decreased in 8-year-olds compared to neonates.

This suggests that as the brain matures, some connections within individual networks are more broad and multipurpose in neonates, to become more refined or specialized in older children.

In contrast, inter-network connectivity was higher in older children, indicating that the communication between distinct brain networks becomes stronger with age.

Additionally, brain activity energy was more distributed across higher frequencies in 8-year-olds, suggesting a shift in brain processing patterns as children grow.

Linking white and gray matter in development
The researchers also studied gray matter networks in the same children, finding similar patterns of increased inter-network connectivity and decreased intra-network connectivity with age.

This supports earlier studies showing that as children grow, their brains develop not just by strengthening the specific networks but also by integrating all the brain networks into more efficient communication systems.

These findings reveal that white matter functional networks undergo similar transformations, suggesting that white matter plays a vital role in cognitive development alongside gray matter.

Implications for understanding brain growth
By observing how white matter networks evolve, this study provides a broader picture of brain development.

White matter connectivity changes reflect the brain’s increasing capacity for complex processing and integration, the key to the rapid cognitive growth seen in childhood.

These findings may help inform future research into developmental disorders, where differences in white matter connectivity may play a role in symptoms or cognitive challenges.

About the scientific paper:

First author: Yali Huang, USA
Published: Frontiers in Neuroscience. October 2024 Link to paper: https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2024.1467446/full