Lifespan development of EEG alpha and aperiodic component sources is shaped by the connectome and axonal delays

We introduce [Formula: see text]-[Formula: see text]NET, a model of cortical activity that represents EEG aperiodic ([Formula: see text]) and [Formula: see text]-rhythm ([Formula: see text]) components as Hida-Matérn processes constrained by anatomical connectivity and interareal conduction delays. This approach integrates the decomposition of spectral Granger causality and quantifies the lifespan trajectories of spectral processes. Using Bayesian inversion on cross-spectral rsEEG data from 1965 participants aged 5-100 (HarMNqEEG dataset), the model estimates cortical activity with high test-retest reliability, effective connectivity patterns and conduction delays. Given the approximate cortical hierarchy inferred from the inverted T1w/T2w myelination map, used as a proxy for feedforward and feedback organization, the aperiodic and [Formula: see text] components reveal opposite directional networks across the lifespan: the aperiodic component is localized in the frontal cortex, whereas the [Formula: see text] component is localized in the posterior cortex, with feedforward and feedback-directed connections, respectively. For both processes, the spectral parameters follow a nonlinear inverted U-shape lifespan trajectory. Finally, the model uniquely estimates global conduction delays, which are negatively correlated with [Formula: see text] frequency and with independent cortical myelination (T1w/T2w) measures, consistent with a mechanistic link between conduction delays and [Formula: see text]-rhythm modulation.