Vasopressin modulates neural responses during human reactive aggression.

The neuropeptide arginine vasopressin (AVP) is known to modulate aggressive behavior in mammals, but the neural mechanisms underlying this modulation are not clear yet. In the present study, we administered 20 IU AVP nasally in a randomized, placebo-controlled, double-blind manner to 36 healthy men using a between-subjects design. After drug administration, participants performed a competitive reaction time task (Taylor Aggression Paradigm, TAP) to elicit reactive aggressive behavior while functional magnetic resonance imaging was recorded. Under AVP treatment, we found increased activations in the right superior temporal sulcus in the decision phase during trials in which participants could get punished after losing the reaction time competition. At the behavioral level, no differences could be found between AVP treatment and placebo condition. The lack of AVP-related behavioral effects is discussed in terms of the general aggression model (GAM).