Brain Dysfunction

Differents parts of the brain have different functions. Stimulation of the amygdala or the hypothalamus elicits aggression whereas the prefrontal cortex appears to act as a brake for aggressive behaviour via the communication with the amygdala.

Charles Whitman, an engineering student kills his wife, his mother, 13 people on the street and an unborn child even though he never showed aggressive behaviour before and was a very intelligent person. The doctors supposed this was due to a brain tumour that may have been pressed against the nearby amygdala regions of the brain.

Raine, Buchsbaum and LaCasse tried to find out if violent criminals have a higher glucose metabolism in the parts of the brain that are associated with aggression so he tested the brains of 41 murderers, including six schizophrenics who didn't take any medication 2 weeks prior to the experiment, who were being assessed to support NGRI pleas. The control group was matched in age, gender and also six schizophrenics. They found out that murderers had a decreased glucose metabolism in frontal lobes and parietal lobes and also in the corpus callosum and the left amygdala. There was an increased glucose metabolism in the occipital lobes and the right amygdala and the right thalamic regions. They concluded, that murderers pleading NGRI have a brain function different from normal. Reduces activity in prefrontal areas might explain impulsive behaviour, immaturity and the loss of self-control, which would all contribute to an increased likelihood of violence.

The reduced activity in the parietal cortex explains a reduced verbal ability that leads to a failure at school and might lead to crime.

The disrupted activity in the limbic system might explain fearlessness, the lack of inhibition of aggression and the failure to learn negative effects of violence and when they are not able to control their temper they are more likely to assault people and lead to criminal behaviour.