IS 43. tDCS-from resting state network modulation to enhancing psychotherapy

Abstract

Introduction Anodal tDCS of the dorsolateral prefrontal cortex (DLPFC) has been associated with improvement of cognitive performance and suggested as therapeutic intervention for several neurological and psychiatric disorders. Most recently, anodal tDCS has been shown to improve deficient cognitive control in major depression. Based on previous behavioral findings and preclinical data of tDCS inducing long-term NMDA receptor and/or BDNF-dependent plasticity, anodal tDCS of the DLPFC may be theoretically suitable for enhancing the effects of psychotherapeutic interventions similar to pharmacological strategies like d-cycloserine. Objectives To investigate whether anodal tDCS of the DLPFC applied as group intervention enhances the effect of a behavioral group therapy program for nicotine dependency. Material and methods Following the investigation of tDCS mediated effects in resting state EEG activity and event related potentials, these effects were further characterized using resting state fMRI in healthy subjects who underwent real and sham tDCS in a randomized cross-over design. tDCS was applied for 20 min at 2 mA with the anode positioned over the left DLPFC and the cathode over the right supra-orbital region. Resting state brain activity was measured before and after tDCS with 3T fMRI. Subsequently, the same tDCS protocol was used in subjects who underwent a behavioral psychotherapy group program for nicotine dependency. tDCS is applied in a placebo-controlled, double-blind pilot study in 36 subjects who want to quit smoking. This study is still ongoing (ClinicalTrials.gov: NCT01729507). Results In healthy subjects, significant changes of regional brain activity were found for the default mode network (DMN) and both frontal-parietal networks (FPN) close to the primary stimulation site and in connected brain regions after real and compared to sham tDCS. The tDCS group intervention in nicotine dependency was feasible and well tolerated so far. The study is still ongoing and preliminary findings will be presented. Conclusion These findings show that prefrontal tDCS modulates connectivity in resting state networks. Such modulation may theoretically allow facilitating the effects of learning in psychotherapy. Moreover, a tDCS group intervention appears to be feasible in adjunction to a behavioral therapy program and final results of this pilot study in nicotine dependency will allow a first evaluation of its therapeutic efficacy.