Scientists at the University of Iowa have identified a part of the brain that plays an important role in addiction and offers a tantalizing clue about breaking a bad habit. Nasir Naqvi is a medical student in the Medical Scientist Training Program, a combined M.D. and PhD program.
His team was interested in why people smoke, and what parts of the brain are involved in the craving. In particular, they studied a part of the brain called the insula. It’s linked to other regions that are known to process emotion, craving and sensory signals from the body. To test what happens when that part of the brain is damaged, they studied people who had suffered strokes.
"People who smoke tend to have strokes," Naqvi observes, "kind of one of the reasons people shouldn’t smoke, actually." They took the smokers who’d suffered strokes that damaged that particular part of the brain, and looked to see how it had changed their smoking behavior. He says what they found was a striking change in some of their "appetites."
When questioned, the patients say they didn’t lose their desire for food or sensation of hunger, but they lost their desire to smoke. One man whose case is described in their paper said "I forgot I was a smoker."
"We think this part of the brain may have something to do with urges — and particularly ‘learned ‘urges’ like cigarette smoking. Because not everybody starts off wanting to smoke, but it’s something that a lot of people certainly learn to do." The part of the brain they studied is associated with the sense of taste, and with moods and emotion, and he says it would not be advisable to damage it in an effort to erase an addiction.
But he says stimulating it with magnetic fields or drugs might affect how it functions. Their research is published in today’s edition of the journal " Science ."