Shining a Bright Light on Cocaine Addiction

Image of a slice of a brain stained blue with fluorescent green section at the top center

Caption: Optogenetic stimulation using laser pulses lights up the prelimbic cortex
Source: Courtesy of Billy Chen and Antonello Bonci

Wow—there is a lot of exciting brain research in progress, and this week is no exception. A team here at NIH, collaborating with scientists at the University of California in San Francisco, delivered harmless pulses of laser light to the brains of cocaine-addicted rats, blocking their desire for the narcotic.

If that sounds a bit way out, I can assure you the approach is based on some very solid evidence suggesting that people—and rats—are more vulnerable to addiction when a region of their brain in the prefrontal cortex isn’t functioning properly. Brain imaging studies show that rat and human addicts have less activity in the region compared with healthy individuals; and chronic cocaine use makes the problem of low activity even worse. The prefrontal cortex is critical for decision-making, impulse control, and behavior; it helps you weigh the negative consequences of drug use.

Addiction is an enormous public health issue. Currently, 1.4 million Americans are addicted to cocaine—and no treatment has been approved by the U.S. Food and Drug Administration, making it one of the National Institute on Drug Abuse’s top research priorities.

So let me first say that nerve cells, or neurons, don’t typically respond to laser beams. The rats in this experiment were engineered to carry light-activated neurons within a part of their prefrontal cortex called the prelimbic cortex. The rats were then fitted with optic fibers to transmit the laser pulses. This technique, called optogenetics, was actually invented by a recipient of the NIH’s Pioneer Award, and it will likely contribute significantly to the BRAIN initiative just announced by President Obama.

The researchers studied rats that were chronically addicted to cocaine. Their need for the drug was so strong that they would ignore electric shocks in order to get a hit. But when those same rats received the laser light pulses, the light activated the prelimbic cortex, causing electrical activity in that brain region to surge. Remarkably, the rat’s fear of the foot shock reappeared, and assisted in deterring cocaine seeking. On the other hand, when the team used a different optogenetics technique to reduce activity in this same brain region, rats that were previously deterred by the foot shocks became chronic cocaine junkies.

Clearly this same approach wouldn’t be used in humans. But it does suggest that boosting activity in the prefrontal cortex using methods like transcranial magnetic stimulation (TMS), which is already used to treat depression, might help. In fact, clinical trials at the NIH are scheduled to begin soon. The researchers plan on using TMS to bump up activity in the prefrontal cortex and see if it decreases addictive behaviors in people.

Links

Rescuing cocaine-induced prefrontal cortex hypoactivity prevents compulsive cocaine seeking. Chen BT, Yau HJ, Hatch C, Kusumoto-Yoshida I, Cho SL, Hopf FW, Bonci A. Nature. 2013 Apr 3.

Want to learn more? Check out these two resources from the NIH’s National Institute on Drug Abuse.

http://www.drugabuse.gov/drugs-abuse/cocaine

http://www.drugabuse.gov/publications/drugfacts/cocaine

NIH support: National Institute on Drug Abuse

13 thoughts on “Shining a Bright Light on Cocaine Addiction

  1. Go NIH! I am so proud to work for this place and to help in any small way such amazing work of the scientists.

    • Second that! A country’s budget is a reflection of the peoples’ priorities, and scientific knowledge and human health ranks at the top of my list. Like you, I’m also proud and can’t think of more rewarding work!

      Go NIH!

  2. Would this research indicate that other types of drug addiction would be similarly diminished with the same interventions?

    • Good question! It’s possible that similar interventions might work for other addictions. However, further study is needed to test whether the same approach would work for other drugs like heroin or methamphetamines, for example.

  3. I’m so excited to even hear that people are trying to work on a solution instead of writing these individuals off. I’m a parent of a brain injured son first…and a meth addicted son second. Great work you all!

  4. This is wonderful news! My family is interested in the clinical trials. How do I follow up on that?

    • Thanks for your interest, Allison. NIH’s searchable database of clinical trials, http://www.clinicaltrials.gov, has information about many different kinds of studies for cocaine addiction and other substance abuse problems.

      As Dr. Collins noted, the clinical trial mentioned in this blog post isn’t quite yet ready to recruit patients. But you can learn more about the protocol and track its recruitment status by going to http://www.clinicaltrials.gov and searching for its ClinicalTrials.gov Identifier, NCT01222806. You can also search by its title: Pilot Study of Repetitive Transcranial Magnetic Stimulation in Cocaine Craving.

  5. Drugs are a problem for many countries; the study will help many families with loved ones suffering from addiction …

  6. You really make it seem really easy with your presentation, but … it kind of feels too complicated and very vast for me. I look ahead to your subsequent posts; I will attempt to get the drift of them.

  7. Has there been any studies regarding auriculotherapy as a way of stimulating the prefrontal cortex and subsequently reducing the desire for intoxicants

Comments are closed.