HAGERTY: What he didn’t want to reveal was that his orbital cortex looks inactive.
Dr. FALLON: If you look at the PET scan, I look just like one of those killers.
HAGERTY: Fallon cautions that this is a young field. Scientists are just beginning to understand this area of the brain. Still, he says, the evidence is accumulating that some people’s brains predispose them toward violence, and that psychopathic tendencies may be passed down from one generation to another.
Which brings us to the next part of this family experiment. Along with brain scans, Fallon also tested each family member’s DNA for genes that are associated with violence and impulsivity. He looked at 12 genes and zeroed in on something called the MAOA gene. It’s also known as the warrior gene because it regulates serotonin in the brain.
Serotonin affects your mood, and many scientists believe that if you have a certain version of the warrior gene, your brain won’t respond to the calming effects of serotonin.
Dr. FALLON: So this is the MAO gene. And we can see here my daughter, son, daughter, daughter, brother, brother, wife, brother.
HAGERTY: Everyone in his family has the low aggression variant, except…
Dr. FALLON: I’m like 100 percent here. I have the pattern, a risky pattern. In a sense, I’m a born killer.
( http://thesituationist.wordpress.com/category/neuroscience/ )