Rats addicted to cocaine lost the craving when researchers used laser light to stimulate a specific part of their brains.

The laser technique was also used to trigger new cocaine addictions. The therapy, targeting the prefrontal cortex of the rat brain, could point the way to a new method of treating human addicts.

"When we turn on a laser light in the prelimbic region of the prefrontal cortex, the compulsive cocaine-seeking is gone," said Dr. Antonello Bonci of the University of California, San Francisco.

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Genetic engineering was used to insert light-sensitive proteins called rhodopsins into nerve cells (neurons) in the rats' prefrontal cortex. Activating this brain region with a laser tuned to the rhodopsins turned the neurons on and off.

Turning on the neurons eliminated cocaine addiction while turning them off triggered addiction, said the study, published online Wednesday by the journal Nature. The findings suggest a new therapy that could be tested in humans, though by electromagnetic stimulation outside the scalp, rather than lasers, said the researchers from UCSF and the U.S. National Institute of Drug Abuse. -- HealthDay