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THE PSYCHOPATHIC BRAIN: NEW FINDINGS
Crime Times recently reported evidence, from a study by Adrian Raine, that
abnormalities in the prefrontal cortex of the brain may be linked to violent crime
(See Crime Times, Vol. 1, No. 1/2, Page 1).
Now a Canadian study suggests that psychopathic
behavior also may be linked to deficits in this region of the brain.
Dominique LaPierre et al. compared 30 psychopaths to 30 non-psychopathic criminals,
using tests that measure the functioning of two different areas of the prefrontal cortex
(the orbitofrontal and frontal ventromedial areas). Their data, the researchers say,
revealed that "the psychopaths were significantly impaired on all the orbitofrontal-
ventromedial tasks" in comparison to the non-psychopathic criminal controls. No
differences were seen when tests measured the function of other areas of the frontal
cortex.
One particularly interesting discovery was that psychopathic subjects were quite
impaired on a test requiring them to select the verbal label for an odor. (The test was
selected because patients known to have orbitofrontal damage do poorly at this task.)
"This... finding is particularly important," the researchers say, "in the sense that it
cannot readily be explained socioculturally, thus presenting a new and convincing
argument for brain-based etiology of this disorder."
LaPierre and colleagues note that their findings are not surprising in light of the striking
similarities between psychopaths and patients with prefrontal cortex damage. "Both the
psychopath and the orbitofrontal or ventromedial frontal patient show an exaggerated
preoccupation with sexual matters, acting in a promiscuous and impersonal
maladaptive way," they say. "Both are remarkable for their lack of social and ethical
judgment. Both neglect long-term consequences of their actions, choosing immediate
gratification over careful planning."
The researchers caution, however, that the deficits they discovered may not, in and of
themselves, explain psychopathic behavior. They note that a number of brain regions
are involved in inhibiting inappropriate behavior, and that a disruption in any part of
this "behavior inhibition circuit" could cause the disinhibition, distractibility, and
sensation-seeking behaviors characteristic of psychopaths.
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"Ventral frontal deficits in psychopathy: neuropsychological test findings," Dominique
LaPierre, Claude M. J. Braun, and Sheilagh Hodgins, Neuropsychologia, Vol. 33,
No. 2,
1995. Address: Claude M. J. Braun, Psychologie (LNC) UQAM, C.P. 8888, Succ.
"Centreville" Montreal, P.Q., Canada H3C 3P8.
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