At the time, Bechara was at the University of Iowa studying the effects of certain types of brain damage after strokes or other injury. While Nathan was hospitalized, stroke specialists sent his information to that brain registry. He was 38, had smoked since 14, said he enjoyed it and had had no intention to quit. But his last puff was the night before his stroke. His surprised wife said he never even asked for a smoke while in the hospital.

It's not unusual for a health scare to prompt an attempt at quitting. "That's the quitting that's not as interesting," Bechara said.

Instead, Nathan experienced what Bechara calls a "disruption of smoking addiction," and he wanted to know why.

Bechara and colleagues culled their brain-damage registry for 69 patients who had smoked regularly before their injuries. Nineteen, including Nathan, had damage to the insula. Thirteen of the insula-damaged patients had quit smoking, 12 of them super-easily: They quit within a day of the brain injury, and reported neither smoking nor even feeling the urge since then.

Of the remaining 50 patients with damage in other brain regions, 19 quit smoking but only four met the broken-addiction criteria.

If Bechara's findings are validated, they suggest that developing drugs that target the insula might help smokers quit. There are nicotine receptors in the insula, meaning it should be possible to create a nicotine-specific drug, Bechara said - albeit years from now.

More immediately, NIDA's Volkow wants to try a different experiment: Scientists can temporarily alter function of certain brain regions with pulses of magnetic energy, called "transcranial magnetic stimulation." She wants to see if it's possible to focus such magnetic pulses on the insula, and thus verify its role.

Other neurologic functions are known to be involved with addiction, too, such as the brain's "reward" or pleasure pathways. The insula discovery doesn't contradict that work, but adds another layer to how addiction grips the brain, Bechara said.

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