Commonality and Variability in Functional Networks in Children Under 5 Years Old

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• Human cognition relies on functional brain networks, but their early developmental trajectory and individual differences are not well understood.
• Traditional methods averaging data across participants can mask crucial age-specific organization and individual variability, especially in developing brain regions.

Purpose of the Study:

• To develop an age-appropriate functional reference for estimating individualized brain networks in young children from resting-state fMRI data.
• To investigate the emergence and stability of individualized functional brain network architecture in early childhood.
• To explore the relationship between early brain network organization and cognitive abilities.

Main Methods:

• Developed a novel age-appropriate functional reference to capture common structure across toddlers while preserving individual variability.
• Utilized resting-state functional magnetic resonance imaging (fMRI) data from cohorts of 8-60-month-old children.
• Analyzed network topography, longitudinal stability, within-network connectivity, and language lateralization in relation to verbal ability.

Main Results:

• Individualized functional brain networks, including finer subdivisions and emerging language lateralization, were identified in children as young as 8 months old, well before age five.
• Network organization demonstrated longitudinal stability, with greater consistency observed in sensory regions compared to association cortices.
• Stronger within-network connectivity, when defined by individualized topography, explained age-related variance and linked left-lateralized language networks to age-normalized verbal ability.

Conclusions:

• Behaviorally relevant functional brain networks emerge much earlier in development than previously recognized.
• Individualized network analysis provides a more sensitive approach to studying early brain development and its link to cognition.
• These findings establish a foundation for investigating typical early neurodevelopment and identifying potential early biomarkers.