title: Amygdala dysfunction attenuates frustration-induced aggression in psychopathic individuals in a non-criminal population.
abstract: BACKGROUND
  Individuals with psychopathy have an increased tendency toward certain types of aggression. We hypothesized that successful psychopaths, who have no criminal convictions but can be diagnosed with psychopathy in terms of personality characteristics, are skilled at regulating aggressive impulses, compared to incarcerated unsuccessful psychopaths.
  
  
  METHODS
  In this block-designed functional magnetic resonance imaging (fMRI) study, we sought to clarify the neural mechanisms underlying differences in frustration-induced aggression as a function of psychopathy in non-criminal populations. Twenty male undergraduate students who completed a self-report psychopathy questionnaire were scanned while they completed a task in which they either could or could not punish other individuals who made unfair offers of monetary distribution.
  
  
  RESULTS
  Individuals with high psychopathic tendencies were less likely to make a decision to inflict costly punishment on people proposing unfair offers. During this decision-making, psychopathy was associated with less amygdala activity in response to the unfairness of offers. Moreover, the amygdala dysfunction in psychopathic individuals was associated with reduced functional connectivity with dopaminergic-related areas, including the striatum, when punishment was available compared to when it was unavailable.
  
  
  CONCLUSIONS
  The possibility that levels of psychopathic traits in a regular population were milder than in incarcerated populations cannot be ruled out.
  
  
  CONCLUSIONS
  The findings indicate that amygdala dysfunction underlies affective deficits of psychopathy. We propose that the insensitivity of the amygdala to the affective significance of social stimuli contributes to an increased risk of violation of social norms, but enhances the ability to attenuate impulses toward maladaptive aggression in successful psychopaths.
authors: Department of Psychology, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan. osumi@flet.keio.ac.jp
authors: Takahiro
authors: T
authors: Osumi
authors: Takashi
authors: T
authors: Nakao
authors: Yukinori
authors: Y
authors: Kasuya
authors: Jun
authors: J
authors: Shinoda
authors: Jitsuhiro
authors: J
authors: Yamada
authors: Hideki
authors: H
authors: Ohira
mesh_terms: D000293:Adolescent; D000328:Adult; D000374:Aggression / Q000502:physiology*; D000679:Amygdala / Q000503:physiopathology*; D000987:Antisocial Personality Disorder / Q000175:diagnosis / Q000503:physiopathology*; D003342:Corpus Striatum / Q000473:pathology / Q000503:physiopathology; D057237:Criminals; D005639:Frustration; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011678:Punishment; D011795:Surveys and Questionnaires; D055815:Young Adult