Differences in Prefrontal Glucose Metabolism
and the Violence of the Serial Killers
In attempting to relate the violence of serial murders
with a physiological brain mechanism, researchers in the past did electroencephalogram
(EEG) studies. These studies concluded that the physiological
brain structure linked with violence was the prefrontal cortex. However,
because these findings conflicted with the neuropsychological variables
found in other studies, this hypothesis could not be confidently confirmed.
With the advancement in diagnostic equipment, there is now a way to measure
the direct quantification of glucose metabolism in selected brain areas.
This is determined by using positron emission topography (PET).
Five Studies Using Positron Emission Topography Support
Prefrontal Abnormalities In Serial Killers:
Researchers reported reduced glucose metabolism and blood flow in the frontal
and left temporal cortexes of violent
Study #2 and #3:
Sexual offenders were found to have reduced regional cerebral blood flow
This study found that within a sample of personality disordered patients,
indications of high aggression (using an aggression scale) were correlated with lower
glucose metabolism, specifically in the anterior
frontal brain regions.
A cortical peel analysis of PET scan images of murderers indicated widespread
particularly when compared to the occipital cortex. The group that represented
the abnormal prefrontal
activity was controlled for differences in age, gender, schizophrenia, handedness,
ethnicity, motivation, and any history
of head injury. (They concluded there were no outside factors that contributed
to the prefrontal abnormalities.)