WEDNESDAY, Jan. 30, 2008 (HealthDay News) -- Cocaine-related images can trigger the brain's emotional centers in drug addicts, even if they're unaware that they've actually seen such an image, says a study funded by the U.S. National Institute on Drug Abuse (NIDA).
University of Pennsylvania researchers used functional MRI to monitor brain activity in cocaine-addicted patients while drug-related photos, such as crack pipes and chunks of cocaine, were flashed in front of them for just 33 milliseconds -- so quickly that the patients weren't consciously aware that they were seeing the photos.
The images triggered activity in the limbic system, a brain network involved in emotion and reward that's been implicated in drug seeking and craving. Patients with the strongest brain response to the flashed images also had the strongest response when shown drug-related images for a longer period of time.
The study also found substantial overlap between regions of the brain activated by drug images and areas activated by sexual images. This supports the common scientific belief that addictive drugs hijack brain regions that recognize natural rewards, such as food and sex, the researchers said.
These findings could help lead to improved treatments for drug addiction, said study co-leader Dr. Anna Rose Childress.
"We have a brain hard-wired to appreciate rewards, and cocaine and other drugs of abuse latch onto this system. We are looking at the potential for new medications that reduce the brain's sensitivity to these conditioned drug cues that would give patients a fighting chance to manage their urges," Childress said in a prepared statement.
The study is published in the Jan. 30 issue of the journal PLoS One.
"This is the first evidence that cues outside one's awareness can trigger rapid activation of the circuits driving drug-seeking behavior," NIDA Director Dr. Nora Volkow said in a prepared statement. "Patients often can't pinpoint when or why they start craving drugs. Understanding how the brain initiates that overwhelming desire for drugs is essential to treating addiction."
The U.S. National Institute on Drug Abuse has more about treatments for drug addiction.