Many things can trigger a craving for cigarettes in smokers, and Nicolas Cage apparently is one of them. Watching an actor light up onscreen activates the part of the brain that plans hand movements in smokers, a new study finds, just as if the smokers were about to light a cigarette themselves.
Regular smokers have a well-trod motor pathway for getting out a cigarette, lighting it, and bringing it to their lips. Previous research has shown that reminders of any addictive drug can prompt cravings in addicts, but Dartmouth College researcher Todd Heatherton and graduate student Dylan Wagner wanted to know if the effect went even deeper than that. Would watching someone else smoke trigger the parts of the brain responsible for the physical smoking routine?
To find out, the researchers asked 17 smokers and 17 nonsmokers to watch the first 30 minutes of the move "Matchstick Men," starring Nicolas Cage. They chose this movie because it features lots of smoking without alcohol use, sex or violence, which could have skewed the results. The volunteers did not know the experiment was about smoking.
Planning to puff
The volunteers viewed the film while in a functional magnetic resonance imaging machine (fMRI), which measures blood flow to different areas of the brain as a way to pinpoint brain activity.
The researchers found that during smoking scenes, smokers showed increased brain activity in two areas compared to non-smoking viewers. The first cluster of activity showed up in the orbitofrontal corex, dorsolateral prefrontal cortex and anterior cingulate cortex. These areas are in the front of the brain. They're responsible for processing rewards. The anterior cingulated cortex has been associated with cigarette cravings.
Smokers also showed increased activity in the intraparietal sulcus, an area on the surface of the brain above and behind the ear associated with the perception of movement and motor control. Two other motor-control regions, the dorsal premotor cortex and the lateral prefrontal cortex, lit up with activity as well. The activity matched the hand each smoker used to smoke.
"What is particularly novel about these findings is that viewing movie smoking activated regions involved in understanding and planning actions," Heatherton wrote in an e-mail to LiveScience.
These regions have been relatively unstudied in addiction research, Heatherton said.
Cigarettes and cool kids
The U.S. Centers for Disease Control and Prevention reported in 2010 that about half of 2009 movies contained tobacco imagery. This held true for PG-13 movies easily accessible to teenagers, 54 percent of which included smoking.
"The main thing we have noticed is that in movies that appeal to teens, many of the popular characters smoke," Heatherton said. "They have characteristics that appeal to teens, such as being cool and attractive."
The researchers don't know if their volunteers went directly from the lab to a smoke break, but prior research has shown that smokers who watch movies containing lots of smoking report more cravings than those who watch movies without cigarettes in them, Heatherton said. So it's not surprising that a visual cue like Nicolas Cage puffing a cigarette would trigger cravings, said Scott Huettel, a Duke University neuroscientist who was not involved in the study.
"This finding builds upon the growing body of evidence that addiction may be reinforced not just by drugs themselves, but by images and other experiences associated with those drugs," Huettel said in a statement.