Right ventrolateral prefrontal cortex involvement in proactive and reactive aggression: a transcranial direct current stimulation study.

To investigate whether modulation of the excitability of the right ventrolateral prefrontal cortex (rVLPFC) using transcranial direct current stimulation (tDCS) would alter proactive aggression, reactive aggression, or both. The Taylor Aggression Paradigm, considered to provide measures indicative of the two types of aggression, was presented with delivery of either anodal tDCS or sham tDCS over rVLPFC. Participants were required to select levels of negative feedback to delivery should they win on a competitive reaction-time task and the levels selected on initial trials (with no feedback from the opponent) were taken as measures of proactive aggression, whereas levels on subsequent trials (with feedback from the opponent) were indicators of reactive aggression. The 'opponent' throughout was actually computer controlled. tDCS delivered over rVLPFC was associated with significantly lower levels of negative feedback being selected for both types of trials, suggesting reduction of proactive and reactive aggression. The results are consistent with rVLPFC playing a general role in the regulation of aggressive behavior. Further work to evaluate the site-related specificity of this would be beneficial.