Fiber length distribution characterizes the brain network maturation during early school-age

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Brain Imaging

Background:

• Early school age involves significant environmental and social changes impacting brain development.
• Understanding white matter adjustments in the developing brain is crucial for optimizing network topology.
• Novel metrics are needed to capture continuous brain maturation during this period.

Purpose of the Study:

• To investigate how white matter networks in typically developing children mature during early school age.
• To introduce and utilize fiber length distribution as a novel nodal metric for brain network analysis.
• To explore the relationship between fiber length distribution changes and functional network organization.

Main Methods:

• Acquired diffusion MRI (dMRI) data from 30 typically developing children (ages 7-8) with a one-year follow-up.
• Assessed longitudinal changes in fiber length distribution, defined by the median length of connected fibers per brain region.
• Employed meta-analytic decoding and simulation tests on healthy adults to interpret findings.

Main Results:

• Fiber length median changes correlated with network topology metrics (degree, betweenness, clustering coefficient, local efficiency).
• Significant decreases in length median observed in temporal, parietal, and prefrontal cortices from ages 7 to 8.
• Decreases in long-range connections and increases in short-range connections were associated with enhanced network segregation and integration.

Conclusions:

• The maturation of white matter networks during early school age involves a dual process of altering short- and long-range connections.
• This developmental strategy optimizes brain network organization in a cost-efficient manner.
• Findings provide insights into the neural basis of cognitive development during a critical period.