FREE ESSAY ON BRAIN SCANS SHOW PATTERN IN VIOLENT BEHAVIOR

BRAIN SCANS SHOW PATTERN IN VIOLENT BEHAVIOR

Murderers and other people prone to violence have distinct brain patterns that can be
scanned and that might be changed with drugs and other therapies, researchers said. Most
people's brain can rein in overreaction to emotions such as fear or anger. But in
pathologically violent people, this control system gets short-circuited. Several studies
have shown this rewiring can be seen in images such as PET(positron emission tomography)
scans. Impulsive,affective aggression may be the product of a failure of emotion
regulation, University of Wisconsin-Madison psychologist Richard Davidson and colleagues
wrote in their report, published in journal science.
They said normal people can control their emotions,and can respond to cues from other
people, such facial expressions of fear. We suggest that individuals predisposed to
aggression and violence have an abnormality in the central circuitry responsible for
these adaptive behavioral strategies, they wrote.
Davidson and his team reviewed studies, including some of their own, involving 500
violent people with aggressive personality disorder,childhood brain injuries and
convicted murderers. They compared their brain function to nonviolent people. 
They found dysfunction in the same brain regions in 41 murderers, in a group suffering
from aggressive impulsive personality disorder and in some people diagnosed with
antisocial personality disorder. And they found that the same brain regions were involved
again and again. The evidence we have reviewed indicates that the orbitofrontal cortex
and the structures with which it is interconnected, including other prefrontal
territories, the anterior cingulate cortex ,and the amygdala, constitute core elements of
a circuit that underlies emotion regulation,they wrote. The orbital frontal cortex is
important in h olding back impulsive outbursts, while the anterior cingulate cortex
recruits other brain regions in the response to conflict.
The amydala, the almond-shaped structure linked with fear and emotion ,is also and
important player. In violent people, its activity essentially ran out of control, while
other brain regions could calm it down in normal people. Abnormalities in serotonin
function in regions of the prefrontal cortex may be especially important, the researchers
added. Serotonin is an important message-carrying hormone, known as a neurotransmitter,
linked with mood and emotion. It is targeted by antidepressant drugs. Davidson said
genetics and environment are probably both involved and it may be possible to rewire
these faulty circuits with drugs or psychological therapy. Given what we know about brain
plasticity and the fact that the brain really can change in response to experience, we
have good reason to expect that these treatments may, in fact, have beneficial
consequences, he said in a statement. 
Meanwhile, a second report in Science suggested that aggression is not always bad. Frans
de Waal of the yerkes Regional Primate Research Center in Atlanta said sometimes conflict
led to closer relationships by letting peole literally kiss and make-up. For example,
chimpanzees kiss and embrace after fight, and other nonhuman primates engage in similar
reconciliations,he wrote.