Psychopaths are deceitful and manipulative and often engage in antisocial behaviour. They lack empathy with other people and find it hard to recognise the emotional significance of social events. Some scientists think that a part of the brain called the amygdala might be involved in these patterns of thinking and behaviour as the amygdala is involved in fear (which psychopaths feel much less of), social interaction and moral emotion and reasoning. Researchers from the University of California, Los Angeles compared the brains of 27 psychopaths and 32 normal people to see if there were any differences in the amygdalas of the psychopaths. They found that the psychopaths showed significant reductions in the volumes of their amygdalas. There were deformities in the basolateral, lateral, cortical and central nuclei of the amygdala in the psychopaths. There were significant correlations between reduced amygdala volumes and scores for psychopathy - links that were particularly strong to the affective (mood) and interpersonal aspects of psychopathy.
Yang, Yailing ... [et al] - Localization of deformations within the amygdala in individuals with psychopathy Archives of General Psychiatry September 2009, 66(9), 986-994