The effects of transcranial direct current stimulation (tDCS) on subjective, autonomic and neuropsychological response in the 7.5% CO 2 experimental model of anxiety

Background: Anxiety is characterized by hypervigilance, distractibility and selective processing of negative information. There is growing evidence that prefrontal function underlies biases in threat processing and attention control in anxiety. We examined the effect of 20 min of 2 mA dorsolateral prefrontal cortex transcranial direct current stimulation (tDCS) (bipolar-balanced montage) on subjective anxiety, autonomic arousal and threat processing in the 7.5% CO 2 experimental medicine model of anxiety. Methods: A between-subjects healthy volunteer double-blind randomized design compared 2 mA tDCS stimulation of the PFC versus sham tDCS on subjective anxiety, autonomic arousal and antisaccade performance during 7.5% CO 2 challenge. Results: tDCS did not moderate subjective and autonomic response to CO 2 challenge. tDCS reduced erroneous eye movements toward threat images relative to neutral images. Conclusion: Twenty minutes of active 2 mA tDCS over the left dorsolateral prefrontal cortex may reduce threat processing biases during experimentally induced anxiety and could help target early positive changes in emotion processing.