Asymmetry in the dorsolateral prefrontal cortex and aggressive behavior: A continuous theta-burst magnetic stimulation study

Aggressive behavior is aimed at causing damage or pain to another individual. Aggression has been associated with structural and functional deficits in numerous brain areas, including the dorsolateral region of the prefrontal cortex (DLPFC), typically related to inhibition and impulse control. In this study, we used inhibitory continuous theta-burst magnetic stimulation (cTBS) to explore the role of the right and left DLPFC in aggression. Sixteen healthy right-handed volunteers underwent two sessions involving random, real and sham, right and left DLPFC stimulations. These sessions were followed by the Social Orientation Paradigm (SOP), a monetary task that was specially designed to assess participants' aggressive tendencies by measuring the patterns of their reactive aggression (a response to a perceived provocation) and proactive aggression (an aggressive act with goal-oriented purposes). Results indicate that using cTBS to target the left DLPFC was associated with a greater increase in aggressive responses than right DLPFC stimulation. This pattern of results was found for both reactive and proactive types of aggressive reactions. It is concluded that DLPFC asymmetry is involved in modulating reactive and proactive aggression. Our results are in line with recent studies suggesting that the left DLPFC plays a major role in aggressive behavior.