The brain function of people addicted to cocaine is different from that of people who are not addicted, according to a new study.
The new research also found that the variations in the way the different regions of the brain connect, communicate, and function in people addicted to cocaine are often linked to highly impulsive behavior.
The study, conducted by a collaborative research team led by the University of Texas Medical Branch at Galveston and Virginia Commonwealth University, was recently published in NeuroImage: Clinical.
Cocaine addiction affects an estimated 800,000 people in the U.S. alone, but despite decades of attempts, an FDA-approved medication to combat the addiction remains elusive, according to the researchers.
People who are addicted to cocaine are often highly impulsive and are prone to acting quickly, without regard to negative consequences, researchers noted. This impulsivity is linked with increased relapse to cocaine abuse, which has led researchers to look at impulsivity as an important behavioral target for the development of relapse prevention medications.
To measure impulsivity, scientists often use the Go/NoGo task, which monitors a person’s ability to thwart an impulsive response. In this task, participants are instructed to make a certain response, or “Go,” when presented with a particular image and withhold their responses or “NoGo” when presented with different images.
The new study sought to determine whether people with cocaine addiction display impaired task performance and altered patterns of brain activity compared to non-cocaine users.
Researchers traditionally study differences in regional brain activity using functional magnetic resonance imaging. The researchers in this study took fMRI analysis one step further to decipher the connections and direction of information flow between brain regions in both cocaine and non-cocaine users, using an fMRI-based technique called Dynamic Causal Modeling.
The technique provides a new tool to study brain connectivity, according to researchers, who hope to design and develop new medications.
For the study, the researchers recruited 13 cocaine users and 10 non-cocaine users to evaluate brain connectivity during performance of the Go/NoGo task within an fMRI scanner. Both groups performed the task equally well, suggesting that the average ability to inhibit a response was the same in the two groups, the researchers found.
However, they say there were intriguing differences between the cocaine users and non-users in the strength of communication between key brain structures.
The left caudate, a brain structure known to control motor function, was activated in both groups during NoGo response inhibition. However, the cortical brain structures that regulate left caudate activity differed between cocaine users and non-cocaine users during harder questions of the Go/NoGo task, the study found.
“These findings suggest that, while some cortical brain regions show altered activity in cocaine users, other regions may compensate for cocaine-associated deficits in function,” said University of Texas Medical Branch lead author Kathryn A. Cunningham, Ph.D., a professor of pharmacology and director of the Center for Addiction Research.
“Targeting altered brain connections in cocaine use disorder for therapeutic development is a fresh idea, offering a whole new arena for research and the potential to promote abstinence and prevent relapse in these vulnerable individuals.”
The study was supported by the National Institutes of Health.