Brain Circuitry Behind Cigarette Cravings Revealed

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A teenage girl smokes a cigarette.
Scientists have found that brain regions involved in self-control play a role in cigarette cravings. (Image credit: Teen smoking photo via Shutterstock)

Addiction to cigarettes and other drugs may result from abnormal wiring in the brain's frontal cortex, an area critical for self-control, a new study finds.

Drug cravings can be brought on by many factors, such as the sight of drugs, drug availability and lack of self-control. Now, researchers have uncovered some of the neural mechanisms involved in cigarette craving. Two brain areas, the orbitofrontal cortex and the prefrontal cortex, interact to turn cravings on or off depending on whether drugs are available, the study reports today (Jan. 28) in the journal the Proceedings of the National Academy of Sciences.

When participants watched the smoking videos, their brains showed increased activity in the medial orbitofrontal cortex, a brain area that assigns value to a behavior. When the cigarettes were available immediately as opposed to hours later, smokers reported greater cravings and their brains showed more activity in the dorsolateral prefrontal cortex. The researchers hypothesize that this area modulates value. In other words, it can turns up or down the "value level" of cigarettes (or other rewards) in the first area, the medial orbitofrontal cortex. The results show that addiction involves a brain circuit important for self-control and decision-making.

Prior to some of the scans, study participants were exposed to transcranial magnetic stimulation, or TMS. This non-invasive method excites or blocks neural activity by inducing weak electrical currents in a particular region of the brain. When the dorsolateral prefrontal cortex was deactivated using TMS, there was no difference in brain activity between those who watched the smoking clips and those who watched neutral videos; those two groups also reported similarly low cravings for cigarettes.

The blocking of this brain region cut off the link between craving and awareness of cigarette availability, suggesting that suppressing the area could reduce cravings brought on by impending access to the drug.

"This is something that we've all been working on, trying to find the target in the brain that you could hit and cause somebody to stop smoking," study researcher Antoine Bechara, a neuroscientist at the University of Southern California, told LiveScience.

Scientists will quibble over the exact brain areas that are the most important targets, Bechara said, but he thinks transcranial magnetic stimulation is a useful approach. "It gives hope to be able, in a noninvasive manner, to help people quit smoking," Bechara added.

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Tanya Lewis
Tanya Lewis
Staff Writer
Tanya was a staff writer for Live Science from 2013 to 2015, covering a wide array of topics, ranging from neuroscience to robotics to strange/cute animals. She received a graduate certificate in science communication from the University of California, Santa Cruz, and a bachelor of science in biomedical engineering from Brown University. She has previously written for Science News, Wired, The Santa Cruz Sentinel, the radio show Big Picture Science and other places. Tanya has lived on a tropical island, witnessed volcanic eruptions and flown in zero gravity (without losing her lunch!). To find out what her latest project is, you can visit her website.