A new study published Tuesday in journal the Proceedings of the National Academy of Sciences reports that addiction to cigarettes and other drugs may result from abnormal wiring in the brain.
According to researchers in the study, two areas in the brain – the orbitofrontal cortex and the prefrontal cortex – work together to turn cravings for cigarettes and other drugs on or off, depending on the drug’s availability.
The researchers scanned the brains of 10 moderate-to-heavy smokers to measure brain activity while the participants watched video clips of people smoking, as well as other non-smoking videos. Prior to watching the videos, some subjects were told cigarettes would be available immediately after viewing, while others were told they would have to wait four hours before they could smoke.
When participants watched the smoking videos, their brains showed increased activity in the medial orbitofrontal cortex, a part of the brain that assigns value to a behavior. When the cigarettes were available immediately after watching the videos, smokers reported greater cravings – and their brains showed greater activity in the dorsolateral prefrontal cortex. Accordingly, the researchers hypothesize that this area of the brain modulates value, showing that addiction involves a brain circuit that’s important for self-control and decision-making.
Another part of the experiment involved blocking these areas of the brain, cutting off the link between craving and awareness of cigarette availability. As a result, researchers suggest that suppressing those regions of the brain 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," said researcher Antoine Bechara, a neuroscientist at the University of Southern California.