NEWS: News-medical.net - 4/2/08 'Subconscious signals can trigger drug craving'

Subconscious signals can trigger drug craving
Medical Studies/Trials
Published: Monday, 4-Feb-2008

Using a brain imaging technology called functional magnetic resonance imaging (fMRI), scientists have discovered that cocaine-related images trigger the emotional centers of the brains of patients addicted to drugs even when the subjects are unaware they've seen anything.

The study, published Jan. 30 in the journal PLoS ONE, was funded by the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health (NIH).

A team of researchers at the University of Pennsylvania, led by Dr. Anna Rose Childress and Dr. Charles O'Brien, showed cocaine patients photos of drug-related cues like crack pipes and chunks of cocaine. The images flashed by in just 33 milliseconds -- so quickly that the patients were not consciously aware of seeing them. Nonetheless, the unseen images stimulated activity in the limbic system, a brain network involved in emotion and reward, which has been implicated in drug-seeking and craving.

"This is the first evidence that cues outside one's awareness can trigger rapid activation of the circuits driving drug-seeking behavior," said NIDA director Dr. Nora Volkow. "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."

To verify that the patterns of brain activity triggered by the subconscious cues reflected the patients' feelings about drugs, Childress and her colleagues gave the patients a different test two days later, allowing them to look longer at the drug images. The patients who demonstrated the strongest brain response to unseen cues in the fMRI experiment also felt the strongest positive association with visible drug cues. Childress notes, "It's striking that the way people feel about these drug-related images is accurately predicted by how strongly their brains respond within just 33 milliseconds."

Childress and her colleagues also found that the regions of the brain activated by drug images overlapped substantially with those activated by sexual images. This finding supports the scientific consensus that addictive drugs usurp brain regions that recognize natural rewards needed for survival, like food and sex.

According to Childress, these results could improve drug treatment strategies. "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 and would give patients a fighting chance to manage their urges."

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jude101 said:

Pavlov's dogs anybody?

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time traveler said:

Great find. I have always suspected a subconscious pathway was responsible for triggering the more subtle and sinister behaviour to "get a fix"

If it is purely subconcious, you just cant controll it. Its beyond you. This is why goverments do not like drugs. This is why i dont like them too.

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Our findings clearly demonstrate that intense sweetness can surpass cocaine reward, even in drug-sensitized and -addicted individuals. We speculate that the addictive potential of intense sweetness results from an inborn hypersensitivity to sweet tastants. In most mammals, including rats and humans, sweet receptors evolved in ancestral environments poor in sugars and are thus not adapted to high concentrations of sweet tastants. The supranormal stimulation of these receptors by sugar-rich diets, such as those now widely available in modern societies, would generate a supranormal reward signal in the brain, with the potential to override self-control mechanisms and thus to lead to addiction.

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Slateroz said:

But the dog doesn't have a mind. It doesn't have the ability to separate mental and physical cravings from what is best for it. We do...and yet the brain can come up with an ingenious idea such as making one relive past pain; pain and situations you know damn well are behind you, just to get its fix.
I'm not complaining...I'm marveling at it.

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