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If a person loses control in a fit of anger, makes the wrong decision, or becomes addicted to drugs, can they blame it on their genes? If not genes, how about the very structure of their brain?
The brain is the last real frontier of medical research. Scientists are just barely unraveling the puzzle, but what they're seeing so far, in very early studies, presents some bizarre possibilities.
In an outburst, University of Utah student actor Aaron Anderson portrays losing control. He screams, he yells, and then - if we carried this scene to the real world - does something that threatens both his life and the lives of others.
Dr. Deborah Yurgelun-Todd, with the University of Utah's Brain Institute, said, "It may be true that the structural development of certain individuals' brains actually predispose them to not be able to inhibit these bad behaviors."
Yurgelun-Todd and her colleagues at the University of Utah are using magnetic resonance imaging to map the brains of teenagers. Their focus is the frontal cortex. "The frontal cortex has to keep information online, in sort of an available state, continually while you're making a decision. And it has to be able to play out the consequences," Yurgelun-Todd said.
The structure of the brain in the frontal cortex area is not fully developed in a teenager and may not have reached maturity even in some normal adults. In those cases, it may not be able to inhibit inappropriate or wrong decisions. "They can have many skills that appear to be adult or appear to be mature and still have an absence of this appreciation of consequences. So, we're in a new neuroscientific territory, "Yurgelun-Todd explained.
In actor Gwen De Ver's portrayal, she's calm, cool, thinking things through. She makes a decision that threatens neither her nor anybody else. But for others, Yurgelun-Todd says, "The feeling or risk is actually an engaging one for many people, even if they know their behavior is going to be dangerous. If it's going to be high risk, they still want to do it."
In addition to the actual structure of the brain, what about genes? Dr. Glen Hanson and his colleagues at the U have already identified genetic variations that affect nicotine receptors in yet another area of the brain.
A person born with this variation who begins smoking before age 17 has a 1.6- to a five-fold increased risk of becoming a heavy smoker as an adult.
In animal studies, adolescent rats will skip food, preferring to press the nicotine bar.
Other genes may also play a role in alcoholism. Actor Ruth Jones portrays the social, low-end drinker while her fellow actor Gwen portrays the heavy side. If Gwen is the alcoholic, did genes make her more susceptible?
And what about other behaviors? There are lots of possibilities, but researchers still have a long way to go in search of answers.
Dr. Yurgelun-Todd says while they can measure structure, the environment plays a major role in molding the plasticity of the brain. We don't have a defined pattern, she adds, with a label saying the brain is now mature and able to make appropriate decisions.
E-mail: eyeates@ksl.com
