Cellular-level changes relevant to substance abuse | Addiction Treatment Strategies

For Release January 18, 2011

Time-lapse technique can show cellular changes related to problems like  addiction and brain tumors.

Changes within deep regions of the brain can now be visualized at the  cellular level, based on research on mice, which was funded by the National Institutes of Health. Published Sunday in Nature Medicine, the study used a  groundbreaking technique to explore cellular-level changes over a period of weeks within deep brain regions, providing a level of detail not possible with  previously available methods.

The study was supported by the National Institute on Drug Abuse (NIDA), the National Cancer Institute, and the National Institute  of  Neurological Disorders and Stroke.

Researchers at Stanford University used time-lapse fluorescence  microendoscopy, a technique that uses miniature probes to directly visualize specific cells over a period of time, to explore structural changes that occur  in neurons as a result of tumor formation and increased stimulation in the mouse brain.

This could lead to greater information on how the brain adapts to  changing situations, including repeated drug exposure. “Continued drug use leads to changes in neuronal circuits that are evident  well after a person stops taking an addictive substance,” said Dr. Nora D. Volkow, director of NIDA. “This study demonstrates an innovative technique that  allows for a glimpse of these cellular changes within the brain regions implicated in drug reward, providing an important tool in our understanding and  treatment of addiction.”

Investigators focused on two brain regions within the study, the hippocampus  and striatum. The striatum, a brain region important for motor function and habit formation, is also a major target for abused drugs. Some researchers  believe that a shift in activity within the striatum is at least partly responsible for the progression from voluntary drug-taking to addiction.

This  new technique could allow a better understanding of how these processes occur at the cellular level, leading to insights into mechanisms underlying addictive  behaviors. “The results should now allow neuroscientists to track longitudinally in the  living brain the effects of drugs of abuse at the levels of neural circuitry, the individual neuron, and neuronal dendrites,” said Dr. Mark Schnitzer,  corresponding author for the article. “For example, our imaging methods work well in the dorsal striatum, which we have followed with microscopic resolution  over weeks in the live brain. This should permit researchers interested in the reward system to address a range of issues that were previously out of  reach.”

The study can be found online at http://dx.doi.org/10.1038/nm.2292.