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Archive for September, 2009

Besides the uncinate fasciculus, a small white matter tract stretching from the amygdala to the orbiotfrontal cortex (see August 9, 2009 post and also Science Daily article Here) new research also show that psychopaths have deformations within the amygdala and an abnormal hippocampal shape. Concerning Raine, Yang et.al. latest research, Localization of deformations within the amygdala in individuals with psychopathy (Sep., 2009) Here showed  “Individuals with psychopathy showed significant bilateral volume reductions in the amygdala compared with controls (left, 17.1%; right, 18.9%). Surface deformations were localized in regions in the approximate vicinity of the basolateral, lateral, cortical, and central nuclei of the amygdala. Significant correlations were found between reduced amygdala volumes and increased total and facet psychopathy scores, with correlations strongest for the affective and interpersonal facets of psychopathy. CONCLUSIONS: Results provide the first evidence, to our knowledge, of focal amygdala abnormalities in psychopathic individuals and corroborate findings from previous lesion studies. Findings support prior hypotheses of amygdala deficits in individuals with psychopathy and indicate that amygdala abnormalities contribute to emotional and behavioral symptoms of psychopathy.”

In regard to the study; Abnormal hippocampal shape in offenders with psychopathy, (online Aug. 2009)  Here  Laakso et.al. found that although the offenders with psychopathy and the controls had similar hippocampal volume and asymmetry ratios, “local analysis showed that the high psychopathy group had a significant depression along the longitudinal hippocampal axis, on both the dorsal and ventral aspects, when compared with the healthy controls and the medium psychopathy group.”  Moreover, “The opposite comparison revealed abnormal enlargement of the lateral borders in both the right and left hippocampi of both high and medium psychopathy groups versus controls, throughout CA1, CA2-3 and the subicular regions. These enlargement and reduction effects survived statistical correction for multiple comparisons in the main contrast (26 offenders vs. 25 controls) and in most subgroup comparisons. A statistical check excluded a possible confounding effect from amphetamine and polysubstance abuse. These results indicate that habitually violent offenders exhibit a specific abnormal hippocampal morphology, in the absence of total gray matter volume changes, that may relate to different autonomic modulation and abnormal fear-conditioning.”

Also of interest;

Structural brain abnormalities in psychopaths-a review. (March, 2008)  Here 
Functional neuroanatomy of psychopathy. (2008) Here
Brain Scans Show Abnormalities In Psychopaths (March, 2004) Here

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Psychopathy and aggression

Lots of new research of interest concerning psychopathy and aggression;

“In the study of aggression, psychopathy represents a disorder that is of particular interest because it often involves aggression which is premeditated, emotionless, and instrumental in nature; this is especially true for more serious types of offenses. Such instrumental aggression is aimed at achieving a goal (e.g., to obtain resources such as money, or to gain status). Unlike the primarily reactive aggression observed in other disorders, psychopaths appear to engage in aggressive acts for the purpose of benefiting themselves. This is especially interesting in light of arguments that psychopathy may represent an alternative life-history strategy that is evolutionarily adaptive; behaviors such as aggression, risk-taking, manipulation, and promiscuous sexual behavior observed in psychopathy may be means by which psychopaths gain advantage over others. Recent neurobiological research supports the idea that abnormalities in brain regions key to emotion and morality may allow psychopaths to pursue such a strategy—psychopaths may not experience the social emotions such as empathy, guilt, and remorse that typically discourage instrumentally aggressive acts, and may even experience pleasure when committing these acts. Findings from brain imaging studies of psychopaths may have important implications for the law.” Psychopathy and instrumental aggression: Evolutionary, neurobiological, and legal perspectives. Here

“In the future we hope that brain imaging can be used to map biological deviations in different offenders in order to try to learn more about the different mechanisms behind violent behaviors.” Aggression, psychopathy and brain imaging – Review and future recommendations. Here

Psychopathy and Instrumental Violence: Facet Level Relationships Here

Distinct characteristics of psychopathy relate to different subtypes of aggression. Here

“Emotional deficits in psychopathy and sexual sadism” –  A Cumulative Scale of Severe Sexual Sadism Here Earlier study (2007) on the topic; Emotional deficits in psychopathy and sexual sadism: implications for violent and sadistic behavior. Here

Psychopathy, aggression, and emotion processing of violent imagery in women Here
Psychopathic traits, victim distress and aggression in children Here
Continuity of aggressive antisocial behavior from childhood to adulthood: The question of phenotype definition. Here
Relationship between psychopathy and indirect aggression use in a noncriminal population Here

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