James Fallon, a neuroscientist at the University of California-Irvine studies the brains of psychopaths in order to tease apart the biological basis for behavior. He compares the brains of killers to "normal" brains.
While talking with his 88 year old mother, Fallon got the idea to look into his own family who, in the past, had some very violent members. So he decided to look at his family to see if anyone possessed the brain of a serial killers. There are no current problems in any of this current family members and Fallon had 10 members submit a PET brain scan and a blood sample as part of a project to see whether his family had a risk for developing Alzheimer's disease. He found that his wife, mother, siblings, and children's scans were normal. His scan? Not so much. Put simply, Fallon states that the orbital cortex puts a brake on the amygdala, which is involved in aggression and appetites, and an imbalance of one affects the other. His own scan showed that his orbital cortex appears inactive. Yep, killer brain.
He also tested DNA for 12 genes associated with aggression and violence, zeroing in on the MAO-A gene (monoamine oxidase A) also called the "warrior gene due to its regulation of serotonin in the brain. Everyone in the family was normal. Once again, he was not, in fact he got a 100%.
Should his family, friends, and anyone he ever met be worried? Probably not. Generally, scientists believe that brain patterns and genetic makeup are not enough to make someone a psychopath. You need a third, important ingredient: abuse or violence during childhood. But even then, we can't legally say "their brains made them do it" or "their genes made them do it." But it is further evidence as to why people do the things they do.
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