State anger and prefrontal brain activity: evidence that insult-related relative left-prefrontal activation is associated with experienced anger and aggression.

Research has demonstrated that left-prefrontal cortical activity is associated with positive affect, or approach motivation, and that right-prefrontal cortical activity is associated with negative affect, or withdrawal motivation. In past research, emotional valence (positive-negative) has been confounded with motivational direction (approach-withdrawal), such that, for instance, the only emotions examined were both positive and approach related. Recent research has demonstrated that trait anger, a negative but approach-related emotion, is associated with increased left-prefrontal and decreased right-prefrontal activity, suggesting that prefrontal asymmetrical activity is associated with motivational direction and not emotional valence. The present experiment tested whether state-induced anger is associated with relative left-prefrontal activity and whether this prefrontal activity is also associated with aggression. Results supported these hypotheses.