Poster E22, Monday, March 26, 2:30-4:30 pm, Exhibit Hall C
Transcranial direct current stimulation modulate fear extinction-processes
Martin Herrmann1, Natalie Dittert1, Thomas Polak1; 1Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital Wuerzburg, Germany
Although anxiety disorders are a widely spread mental disorder the effectiveness of their therapy is still unsatisfying. Transcranial direct current stimulation (tDCS) has already been used to improve psychotherapy but the underlying mechanisms have not been properly investigated yet. We hypothesized that tDCS could improve extinction processes, which happen to be the main functional factor of exposure based therapy for anxiety disorders. To examine our hypothesis, we used a fear conditioning paradigm with female faces as conditioned stimuli and a 95-dB female scream as unconditioned stimuli. We aimed to stimulate the ventromedial prefrontal cortex with tDCS because this region is involved in extinction learning. For tDCS we applied two 4 x 4 cm electrodes approximately at the electrode positions F7 and F8 (anode right, cathode left) with a current of 1.5 mA. 84 healthy subjects were randomly and double blinded assigned into a sham-stimulation and two real-stimulation group. To measure the fear reactions, we used skin conductance responses (SCR). The results showed a significant interaction between stimulus (Cs+, Cs-)* Phase (acquisition, extinction)* tDCS (verum, sham), p < 0.01). Post-hoc tests revealed higher CS+/CS- discrimination loss in real-stimulation vs. sham-stimulation groups (t(82) = -2.39, p = .019). The study shows that tDCS of the vmPFC modulates the early extinction-processes.
Topic Area: EMOTION & SOCIAL: Other