Individualized Theta Transcranial Alternating Current Stimulation Modulates Mnemonic Discrimination and ERP Responses to Positive Information in Individuals With Elevated Depressive Symptoms

Individuals with elevated depressive symptoms often show impairments in positive memory processing. This randomized, double-blind study investigated whether individualized theta-frequency transcranial alternating current stimulation (tACS) using an OFC-oriented montage modulates mnemonic discrimination and ERP responses to positive information. Sixty-one individuals with elevated depressive symptoms received either real or sham stimulation before completing an emotional mnemonic discrimination task. Behavioral results showed that lure discrimination increased following real stimulation but not sham stimulation. EEG results showed that real stimulation modulated ERP responses during positive memory encoding and retrieval, as reflected by increased late positive potential (LPP) amplitudes during encoding and altered early retrieval-related ERP amplitudes. These findings suggest that individualized theta-tACS may influence both mnemonic discrimination performance and neural responses to positive information.