How lasers can switch off cocaine addiction
Researchers find that, at least in rats, when they shine a laser light on a region of the brain associated with impulse control and decision-making, they can turn cocaine-seeking behavior off or on.
Researchers who shined a laser light in a certain region of the brain -- stimulating the area associated with decision-making and impulse control -- were able to zap what they call "cocaine seeking" behaviors in addicts.
And while their work was on rats, their hope is that a similar technique called transcranial magnetic stimulation (TMS, currently used to improve symptoms of depression) will work on humans as well.
"When we turn on a laser light in the prelimbic region of the prefrontal cortex, the compulsive cocaine seeking is gone," Antonello Bonci, the scientific director of the intramural research program at the NIH's National Institute on Drug Abuse (NIDA), where the work was done, said in a news release.
Studies on both rats and humans have already shown extremely low activity in the prefrontal cortex in those who are compulsively addicted to cocaine. For this study, published this week in the journal Nature, lead author Billy Chen of NIDA and colleagues tested whether changing the activity in this specific brain region could have a direct impact on addiction.
To do this, they inserted light-sensitive proteins called rhodopsins into the rat's prefrontal cortex and, via a technique called optogenetics, used a laser tuned to the rhodopsins to turn the activity in that region on or off. Turning the cells on removed the compulsive behavior, while turning them off actually turned non-addicted rats into cocaine seekers.
In humans, the TMS techique -- applying an external electromagnetic field to the brain -- has already been shown to switch on and off activity in the prelimbic cortex, so Bonci, Chen, and colleagues are designing clinical trials on humans. By using this technique a few times a week on cocaine addicts, they hope to restore activity to the prelimbic region and help induce greater control and less desire for the drug.
Some 1.4 million Americans are thought to be addicted to cocaine, with 1.5 percent of Americans between the ages of 18 and 25 reporting having used it within the past month. Cocaine is the leading cause of heart attacks and strokes in people under the age of 35. And its toll is not just on human lives, but also results in lost earnings, crime, investigations, incarcerations, treatment programs, and of course stress on friends and families.
The work is funded by the National Institute on Drug Abuse.