Lasers are fantastic things. Curiosity uses one to interrogate rocks on Mars, they can create a true 3D display, and they can get you into a lot of trouble with the police depending on where you aim your laser pointer. Now it seems, they’ve been put to good use in the field of medicine, and have helped form a new way of tackling drug addiction.
Research carried out at the National Institute on Drug Abuse (NIDA) gave scientists an excuse to use a laser on a rat’s brain. They did have a good reason, though. The prelimbic region of the prefrontal cortex in the human brain is thought to play a key role in drug addiction, and they wanted to see if manipulating cells there had a positive or negative impact on that addiction.
The research involved setting up a test that saw rats supplied with cocaine by pushing a lever and then receiving an electrical shock as a penalty for taking it. Some rats got addicted and kept coming back for more regardless of the pain they’d be subjecting themselves to. It was discovered that in those that did get addicted, there was a change in the activity of the cells in the prefrontal cortex.
The rats were given light sensitive proteins called rhodopsins that were placed in their prefrontal cortex, attaching to the neurons there. By shining a tuned laser light on to the prefrontal cortex, it was possible to activate and deactivate the cells. By turning them on with the laser, the addictive behavior of the rats was removed. Turning them off, even in the non-addicted rats, saw the addictive behavior return or introduced.
For someone with a serious cocaine addiction who wants to break the habit, they may agree to have a laser fired into their brain. But it looks as though they won’t have to. Now that this technique has been proven to work on rats, there’s a non-invasive alternative method that can be tried on humans.
It’s called transcranial magnetic stimulation (TMS) and is already used to help treat depression. All it does is apply an electromagnetic field to the brain externally and is thought/hoped to have the same impact on cells in the prelimbic region as the laser. Having the treatment a few times a week is expected to help drug users cut their habit, and clinical trials are set to start to prove whether this is indeed the case.
If the TMS solution isn’t good enough, maybe we’ll revert back to using the laser method and hope doctors have a good aim.