tACS Entrainment of Cortical Alpha Oscillations

Transcranial alternating current stimulation (tACS) applies a weak sinusoidal electric field through the scalp to nudge the brain's own rhythms. This simulator renders a ring of coupled cortical neural-mass oscillators — a Kuramoto population in the alpha band — driven by an external sinusoidal field, and tracks the phase-locking value R as the population either self-synchronizes through cortical coupling or entrains to the stimulation frequency itself. Tune stimulation frequency, stimulation amplitude, cortical coupling strength and the natural-frequency dispersion of the tissue to explore the Arnold-tongue boundary between "not entrained" and "locked to the driving field", the same mechanism underlying real non-invasive brain-stimulation protocols.