Brain criticality predicts individual synchronization levels in humans

Moderate levels of synchronization of neuronal oscillations are essential for healthy brain dynamics. Synchronization levels exhibit large inter-individual variability the origins of which are unknown. Neuronal systems have been postulated to operate near a critical transition point or in an extended regime between disorder (subcritical) and order (supercritical phase) characterized by moderate synchronization and emergent power-law long-range temporal correlations (LRTCs). We investigated whether inter-individual variability in synchronization levels is explained by the individual position along the critical regime by analyzing magnetoencephalography (MEG) and intra-cerebral stereo-electroencephalography (SEEG) human resting-state data. Here we show that variability in synchronization levels exhibits a positive linear and quadratic relationships with LRTCs in healthy participants and brain areas. In the epileptogenic zone this correlation was negative. These results show that variability in synchronization levels is regulated by the individual position along an extended critical-like regime, with healthy brain areas tending to operate in its subcritical and epileptogenic areas in its supercritical side.