Localisation of increased prefrontal white matter in pathological liars.

We examined white matter volumes in four prefrontal subregions using structural magnetic resonance imaging in 10 pathological liars, 14 antisocial controls, and 20 normal controls. Liars showed a relatively widespread increase in white matter (23-36%) in orbitofrontal, middle and inferior, but not superior, frontal gyri compared with antisocial and normal controls. This white matter increase may predispose some individuals to pathological lying.

Prefrontal white matter in pathological liars.

BACKGROUND: Studies have shown increased bilateral activation in the prefrontal cortex when normal individuals lie, but there have been no structural imaging studies of deceitful individuals. AIMS: To assess whether deceitful individuals show structural abnormalities in prefrontal grey and white matter volume. METHOD: Prefrontal grey and white matter volumes were assessed using structural magnetic resonance imaging in 12 individuals who pathologically lie, cheat and deceive ('liars'),16 antisocial controls and 21 normal controls. RESULTS: Liars showed a 22-26% increase in prefrontal white matter and a 36-42% reduction in prefrontal grey/white ratios compared with both antisocial controls and normal controls. CONCLUSIONS: These findings provide the first evidence of a structural brain deficitinliars, they implicate the prefrontal cortex as an important (but not sole) component in the neural circuitry underlying lying and provide an initial neurobiological correlate of a deceitful personality.

Volume reduction in prefrontal gray matter in unsuccessful criminal psychopaths.

BACKGROUND: Although studies of neurologic patients have suggested that prefrontal structural impairments may predispose to sociopathy, it is unknown whether there is a relationship between psychopathy and prefrontal volume in individuals from the community and whether any prefrontal structural impairment is specific to "unsuccessful" (caught) psychopaths as opposed to "successful" (uncaught) psychopaths. This study tests the hypothesis that psychopathy is associated with a reduction in prefrontal gray volume but that this abnormality is specific to unsuccessful psychopaths. METHOD: Prefrontal gray and white matter volumes were assessed using structural magnetic resonance imaging (MRI) in 16 unsuccessful psychopaths, 13 successful psychopaths, and 23 control subjects. RESULTS: Higher total as well as subfactor psychopathy scores (arrogant/deceptive, affective, and impulsive/unstable) were all associated with low prefrontal gray volume. Unsuccessful psychopaths, but not successful psychopaths, had a 22.3% reduction in prefrontal gray matter volume compared with control subjects. CONCLUSIONS: These results demonstrating for the first time a prefrontal structural deficit in community psychopaths provide partial support for a prefrontal theory of psychopathy but highlight an important difference between successful and unsuccessful psychopaths.

Hippocampal structural asymmetry in unsuccessful psychopaths.

BACKGROUND: Structural and functional hippocampal abnormalities have been previously reported in institutionalized psychopathic and aggressive populations. This study assessed whether prior findings of a right greater than left (R > L) functional asymmetry in caught violent offenders generalize to the structural domain in unsuccessful, caught psychopaths. METHODS: Left and right hippocampal volumes were assessed using structural magnetic resonance imaging (MRI) in 23 control subjects, 16 unsuccessful psychopaths, and 12 successful (uncaught) community psychopaths and transformed into standardized space. RESULTS: Unsuccessful psychopaths showed an exaggerated structural hippocampal asymmetry (R > L) relative both to successful psychopaths and control subjects (p <.007) that was localized to the anterior region. This effect could not be explained by environmental and diagnostic confounds and constitutes the first brain imaging analysis of successful and unsuccessful psychopaths. CONCLUSIONS: Atypical anterior hippocampal asymmetries in unsuccessful psychopaths may reflect an underlying neurodevelopmental abnormality that disrupts hippocampal-prefrontal circuitry, resulting in affect dysregulation, poor contextual fear conditioning, and insensitivity to cues predicting capture.

Corpus callosum abnormalities in psychopathic antisocial individuals.

CONTEXT: Psychopathic antisocial individuals have previously been characterized by abnormal interhemispheric processing and callosal functioning, but there have been no studies on the structural characteristics of the corpus callosum in this group. OBJECTIVES: To assess whether (1) psychopathic individuals with antisocial personality disorder show structural and functional impairments in the corpus callosum, (2) group differences are mirrored by correlations between dimensional measures of callosal structure and psychopathy, (3) callosal abnormalities are associated with affective deficits, and (4) callosal abnormalities are independent of psychosocial deficits. DESIGN: Case-control study. SETTING: Community sample. PARTICIPANTS: Fifteen men with antisocial personality disorder and high psychopathy scores and 25 matched controls, all from a larger sample of 83 community volunteers. MAIN OUTCOME MEASURES: Structural magnetic resonance imaging measures of the corpus callosum (volume estimate of callosal white matter, thickness, length, and genu and splenium area), functional callosal measures (2 divided visual field tasks), electrodermal and cardiovascular activity during a social stressor, personality measures of affective and interpersonal deficits, and verbal and spatial ability. RESULTS: Psychopathic antisocial individuals compared with controls showed a 22.6% increase in estimated callosal white matter volume (P<.001), a 6.9% increase in callosal length (P =.002), a 15.3% reduction in callosal thickness (P =.04), and increased functional interhemispheric connectivity (P =.02). Correlational analyses in the larger unselected sample confirmed the association between antisocial personality and callosal structural abnormalities. Larger callosal volumes were associated with affective and interpersonal deficits, low autonomic stress reactivity, and low spatial ability. Callosal abnormalities were independent of psychosocial deficits. CONCLUSIONS: Corpus callosum abnormalities in psychopathic antisocial individuals may reflect atypical neurodevelopmental processes involving an arrest of early axonal pruning or increased white matter myelination. These findings may help explain affective deficits and previous findings of abnormal interhemispheric transfer in psychopathic individuals.

Prefrontal structural and functional deficits in schizotypal personality disorder.

Structural prefrontal deficits have been reported in patients with schizophrenia, but it is unclear if they are also found in patients with schizophrenia spectrum personality disorders. The hypothesis that a spectrum group will be characterized by prefrontal structural deficits was tested by assessing prefrontal gray and white volumes using magnetic resonance imaging in a community sample of 16 individuals with schizotypal/paranoid personality disorder, 27 comparisons, and 26 psychiatric controls. Frontal neurocognitive functioning was also assessed using the Wisconsin Card Sorting Test and the Continuous Performance Test. The spectrum group showed reduced prefrontal gray volumes and poorer frontal functioning compared to both other groups. Structural deficits were independent of functional deficits and together correctly classified 84.2 percent of subjects. Structural but not functional deficits were abolished after a strict control for antisocial personality was made. Results support the notion that frontal deficits may be centrally involved in the etiology of schizophrenia but also suggest that comorbid antisocial behavior may be one factor accounting for differences in prefrontal structural findings across studies.