Bilateral Theta Transcranial Alternating Current Stimulation (tACS) Modulates EEG Activity: When tACS Works Awake It Also Works Asleep.

Subjects who show the expected changes during wake after the stimulation also had a consistent pattern of changes during sleep. The enhancement of cortical synchronization by θ-tACS during wakefulness actually corresponds to increased sleep pressure, but it occurs only in some individuals. Thus, θ-tACS can enhance sleep, although individual factors to be further investigated affect the actual responsiveness to this treatment.