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

Jiaxin Cindy Tu, Chenyan Lu, Trevor K. M. Day, Robert Hermosillo, Lucille A. Moore, Anxu Wang, Xintian Wang, Donna Dierker, Aidan Latham, Jeanette K. Kenley, Damien A. Fair, Jed T. Elison, Chad M. Sylvester, Barbara B. Warner, Joan L. Luby, Cynthia E. Rogers, Deanna M. Barch, Christopher D. Smyser, Timothy O. Laumann, Evan M. Gordon et al. (2 additional authors not shown)

Abstract: h3>Abstract</h3> <p>Functional brain networks support human cognition, yet how individualized network architecture emerges in early childhood remains poorly understood. Averaging across participants can obscure age-specific organization and person-to-person differences, particularly in slowly developing association cortices. We developed an age-appropriate functional reference that captured common structure across toddlers without averaging away individual variability, enabling estimation of each child’s networks from resting-state fMRI.</p><p>Across cohorts of 8–60-month-old children, we found individualized network organization—including finer-scale subdivisions and emerging language lateralization—well before age five. Network layouts showed longitudinal stability, with greater consistency in sensory than association regions. Within-network connectivity was stronger and explained age-related variance when networks were defined using individualized rather than group-consensus topography. Left-lateralization of language networks tracked age-normalized verbal ability, linking early functional architecture to emerging cognition. These findings show that behaviorally relevant brain networks arise far earlier than previously recognized, providing a foundation for studying typical development and early biomarkers.</p>

External IDs:doi:10.1101/2025.09.12.675913