Smokers: Seeing someone light up is brain trigger

A big temptation for smokers is watching others smoke. Now, scientists are getting a deeper understanding of what goes on in the brain during those kinds of cravings.

A new study in the Journal of Neuroscience shows that watching people in a movie smoke triggers the same brain activity involved in planning to actually smoke a cigarette.

"This is one potential cue out there that can influence whether or not you’ll engage in smoking," said Dylan Wagner, lead study author and researcher at Dartmouth College.

Researchers showed clips of the film "Matchstick Men" in which characters smoked during several scenes. Participants were 17 smokers and 17 nonsmokers, which is a relatively small group of subjects, but significant for a brain scanning study.

They looked at brain activity through functional magnetic resonance imaging (fMRI) to see which areas would respond most to watching smoking on the screen.

Like previous experiments, this one found a connection to the brain's reward system. But this study also adds that a brain region involved in planning, observing, and carrying out hand-based actions also seems to play a role, Wagner said.

A major limitation of the study is that researchers did not follow participants out of the laboratory to see whether they actually lit up after viewing the film clips.

The next step in this research is to try to link the findings to whether watching films with smoking will actually increase a person's frequency of smoking.

"Smokers should be informed that these are potential influences that might lead to increased cravings," Wagner said.