Effects of Theta Transcranial Alternating Current Stimulation Over the Frontal Cortex on Reversal Learning

Theta oscillations in the electroencephalogram (EEG) are associated with learning and behavioral adaptation.To investigate the effects of theta transcranial alternating current stimulation (tACS) applied to the frontal cortex on reversal learning.Healthy volunteers participated in a sham-controlled between subjects design. TACS at 1 mA peak-to-peak was administered during a reward-punishment reversal learning task. Resting state EEG was measured before and after tACS and the task.Active tACS improved learning ability, but at the same time interfered with applying the rule to optimize behavior. Furthermore, a significant decrease in frontal theta-beta EEG ratios was observed following active tACS.Results provide behavioral and electrophysiological evidence for influencing reversal learning with exogenous oscillatory electric field potentials applied to the frontal cortex.