Resting-state magnetoencephalography (MEG) has uncovered changes in brain functional connectivity after mild traumatic brain injury (mTBI). In NeuroImage: Clinical, Dimitriadis et al. reported a reduction in the strength of local connections and an increase in the strength of long-range connections in the brains of individuals with mTBI compared with healthy controls. The researchers suggest that MEG-based functional connectivity could provide a diagnostic and therapeutic biomarker for mTBI.