Aberrant social and cerebral responding in a competitive reaction time paradigm in criminal psychopaths.

In a previous study (Lotze et al., 2007) we described dorsal medial prefrontal cortex (mPFC) activation in healthy subjects during retaliation in a competitive reaction time task. Interestingly, the less callous the subjects were, the more they responded with ventral mPFC-activation when watching the opponent suffering. In this study we used this paradigm to investigate behavioral and neural responding of ten criminal psychopathic individuals from a forensic psychiatric institution. In contrast to healthy subjects, who show reactive aggressive behavior of inflicting punishment with increasing intensity after experiencing an increasing amount of punishment from a yoked opponent, psychopathic participants did not react with comparable retaliation. However, when psychopaths punished with a high amount they showed increased activation in the hypothalamus, the lateral prefrontal cortex, the posterior cingulate cortex and the amygdala. The trait "physical aggression" showed a positive correlation with hypothalamic activation. Medial prefrontal areas, associated with emotional control and conflict management in healthy subjects performing this paradigm, were inactive in psychopathic subjects during retaliation. When psychopaths observed the yoked opponent being punished they showed increased activation in the dorsal and ventral medial prefrontal cortex, which was positively associated by impulsivity and antisocial behavior of Hare's psychopathy construct. This finding supports the notion that reactive aggression is more related to antisocial behavior and anger management than with emotional and interpersonal characteristics of psychopathy and suggests that two separate brain activation patterns seem to account for these two behavioral dispositions.