Modulation of Fear Extinction Processes Using Transcranial Electrical Stimulation

Research links the processes of fear conditioning and extinction to the treatment of anxiety and stress-related disorders. Moreover, considerable translational research examines the neural correlates of these processes. However, virtually no research in humans manipulates neural correlates of these processes, which limits basic-clinical integration. The present study aimed to use transcranial electrical stimulation (tES) to modulate processes associated with fear extinction in order to assess the potential utility of tES in enhancing exposure-based treatment. To this end, healthy participants underwent a three-day fear conditioning and extinction paradigm. Participants were randomly assigned into 3 groups, differing in terms of tES applied during the extinction learning phase (Day 2) and targeting the medial prefrontal cortex: 1) direct current (DC) stimulation, aimed at enhancing extinction learning; 2) alternate current (AC) stimulation, aimed at interfering with reconsolidation of the fear memory activated during the extinction phase; and 3) sham stimulation. The outcome measures (outlined next) involve the assessment of extinction recall during a test phase (Day 3). Successful modulation of extinction learning by tES would be reflected in enhanced extinction recall.