The On-Off Switch for Cocaine Addiction
A fascinating research paper was published this week in the journal Nature. Researchers found that they could create or extinguish cocaine addiction in rats by stimulating different areas of the brain with laser light.
Called “prefrontal cortex hypoactivity,” the pattern of nerve firings has been linked to cocaine use, but until now the direct link to addiction hadn’t been shown. By stimulating neurons directly with laser light, the researchers literally switched cocaine addiction off in habituated rats and conversely created an addiction by stimulating other neurons. Or, as the researchers put it, “optogenetic prelimbic cortex inhibition significantly increased compulsive cocaine seeking.”
The “optogenectic” refers to laser light shining on an area of the brain - not a treatment that would work in humans, at least not without piercing the skull. But there may be an alternative readily available.
Transcranial Magnetic Stimulation
Transcranial magnetic stimulation (TMS) of the brain is already being explored by researchers. This technique uses high power magnets to influence electrical signaling in the brain. You can see how it works by bringing a magnet close to an older style (non-LCD) television screen. As the magnet comes close, the electrons “painting” the screen are warped by the magnetic field – without contacting the screen directly. In a similar manner, magnets can be used to stimulate the brain without having to open the skull. It isn’t as accurate as using surgery and a laser, but with the right target, it may work.
The rat model of addiction is well understood and accepted as a good parallel for human addiction, so the findings are considered very significant. To get the data, researchers bound a dye to certain neurons in the rat brain. The dye allowed laser light to be absorbed and trigger just those neurons that had the dye attached. The difficulty in adapting the therapy to humans will be at least partly because TMS is not as well targeted as the technique used in this study.
The laser on-off switch doesn’t do anything to prevent withdrawal or the physical symptoms of addiction, but for cocaine users the most difficult thing to overcome is the craving for the drug, and this was what scientists were measuring. In effect, this “brain switch” would restore a cocaine addict’s ability to choose not to use, an ability addiction destroys.