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PSYCHOPATHIC BRAINS: MRIs SHOW MORE ABNORMALITIES
Adding to evidence that the brains of psychopaths are
abnormal, Adrian Raine and colleagues have published new
data revealing anomalies of the corpus callosum in
psychopathic subjects.
The corpus callosum, a thick band of nerve fibers,
connects the two cerebral hemispheres, and routes
communications between them. Abnormalities of the corpus
callosum are linked to a number of brain disorders, ranging
from schizophrenia to Fetal Alcohol Syndrome.
Raine and colleagues used structural magnetic resonance
imaging to measure the volume of the corpus callosum in 15
men with antisocial personality disorder and high scores on
scales of psychopathy, and in 25 controls. The researchers
report that compared to controls, the psychopaths showed
an increase in callosal white matter volume, an increase in
callosal length, a reduction in callosal thickness, and
increased connectivity between brain hemispheres.
Moreover, Raine et al. report, larger callosal volume was
associated with greater affective and interpersonal deficits,
lower autonomic stress reactivity (a phenomenon often seen
in psychopaths), and low spatial ability.
The researchers theorize that "corpus callosum
abnormalities in psychopathic antisocial individuals may
reflect atypical neurodevelopmental processes involving an
arrest of early axonal pruning or increased white matter
myelination."
In an earlier study
(see Crime Times, 2000, Vol. 6, No. 2, Page 1),
Raine et al. used MRI scans to study the
prefrontal area of the cerebral hemispheres in men with
antisocial personality disorder. The researchers found that
antisocial subjects exhibited an 11 percent reduction in
prefrontal gray matter volume when compared with normal
controls, a reduction that could not be accounted for by
substance abuse or mental illness.
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"Corpus callosum abnormalities in psychopathic antisocial
individuals," A. Raine, T. Lencz, K. Taylor, J. B. Hellige, S.
Bihrle, L. Lacasse, M. Lee, S. Ishikawa, and P. Colletti,
Archives of General Psychiatry, Vol. 60, No. 11,
November 2003, 1134-42. Address: Adrian Raine,
Department of Psychology, University of Southern California,
Los Angeles, CA 90089-1061, raine@usc.edu.
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