State-of-the-art brain imaging shows that changes in the brain’s reward circuitry caused by substance abuse likely remain even after drug and alcohol use stop, according to a Jan. 18 National Institute on Drug Abuse (NIDA) press release.

A team of investigators led by Robert P. J. Barretto of Stanford University’s Clark Center for Biomedical Engineering & Sciences used fluorescence microendoscopy — a process in which tiny probes record images of cellular-level brain changes over time — to measure the effect of increased stimulation, specifically tumor formation, on the hippocampus and striatum in mice. Both regions of the brain are known to be altered by substances of abuse.

They found that progressive deformations in brain circuitry occurred as the tumor grew: while vessels surrounding the tumor increased in diameter over time, blood flow to the affected brain area actually decreased.

The ability to track neural activity at the cellular level can provide valuable insight into how chemical addiction takes root in the brain, according to NIDA director Nora D. Volkow, M.D.

“Continued drug use leads to changes in neuronal circuits that are evident well after a person stops taking an addictive substance,” she said.

“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,” Volkow concluded.

The study was published online Jan. 16 in the journal Nature Medicine. Funding for the study was provided jointly by NIDA, the National Cancer Institute, and the National Institute of Neurological Disorders and Stroke.