The Neurobiology of Impulsive Aggression

Abstract

This selective review provides a model of the neurobiology of impulsive aggression from a cognitive neuroscience perspective. It is argued that prototypical cases of impulsive aggression, those associated with anger, involve the recruitment of the acute threat response system structures; that is, the amygdala, hypothalamus, and periaqueductal gray. It is argued that whether the recruitment of these structures results in impulsive aggression or not reflects the functional roles of ventromedial frontal cortex and dorsomedial frontal and anterior insula cortex in response selection. It is also argued that impulsive aggression may occur because of impaired decision making. The aggression may not be accompanied by anger, but it will reflect disrupted evaluation of the rewards/benefits of the action.

FIG. 1.

Systems implicated in impulsive aggression. The circuit running from the amygdala to the hypothalamus and from there to the periaqueductal gray is thought to mediate reactive aggression. The probability that activation of this circuit is expressed as reactive aggression is partly determined by systems implicated in reinforcement-based decision making including the ventromedial (vmPFC) and dorsomedial frontal (dmFC) and anterior insula cortices (AIC). The vmPFC is particularly important for representing the value of actions and objects. The dmFC is thought to use this value information to affect response choice (Hare, Camerer, Rangel, 2009), partly implemented through the AIC.