Frequency-specific maturation of cortical organization and social-cognitive links from childhood to adolescence

The human brain unfolds its functional architecture over multiple timescales during childhood and adolescence, yet we know little about how these developmental trajectories vary between individuals. Slow brain signals at different frequencies are thought to support distinct functional processes, but their contribution to shaping large-scale cortical organization across development remains unclear. Here, we map the maturation of cortical organization by decomposing spontaneous slow brain activity into multiple frequency bands in participants aged 6-19 years. We identify a reproducible three-stage progression - child-like, transitional, and adult-like configurations - whose timing depends on frequency: faster dynamics mature earliest, intermediate frequencies develop gradually, and lower-frequency dynamics reorganize abruptly around puberty. Individual cognitive and social traits modulate these trajectories: children with higher social anxiety or higher IQ reach adult-like configurations earlier in specific frequency bands, whereas lower-IQ children show generalized delays. These results reveal that cortical organization matures along multiple, frequency-specific timescales and that intellectual and socio-emotional factors shape its pace. Our multi-frequency framework provides a new perspective on hierarchical brain development and may inform biomarkers for atypical neurodevelopment.