Neural oscillations and network specialisation in early childhood captured with next-generation magnetoencephalography

Early childhood sees very rapid brain development, reflected in substantial alterations in neural oscillations and reorganisation of functional networks. Yet, these developmental trajectories remain poorly understood, due to a paucity of studies in this age range. Optically pumped magnetometer-based magnetoencephalography provides a unique opportunity to assess neural activity from young children with high spatiotemporal resolution. Here, we use this technology to determine the development of neural oscillations and functional networks in 111 children aged 1–5 years, including both cross-sectional and longitudinal data (163 datasets). We demonstrate that the aperiodic slope and offset increase across this age range, with regional specificity: the greatest changes were shown in temporo-parietal regions. Periodic power shifted towards higher frequencies, such that theta oscillations decreased with age, while alpha and beta increased. Global connectivity decreased from 1–5 years, driven by a broadband bilateral parietal and frontal network, while task-relevant occipital connections increased with age. Our findings establish that oscillatory power and connectivity patterns evolve significantly over early childhood, contributing foundational information for understanding the neural underpinnings of maturing cognitive abilities.