Scientists Find Compulsive Drinking-Linked Brain Circuit in Mice, Hope It Could One Day Be Used to Treat Alcoholism

Scientists have discovered a brain circuit which they say can predict whether an individual will become a compulsive drinker, following a study on mice. In the future, they hope the finding could help to treat and prevent alcoholism in humans.

To find out why some people develop drinking problems and others don't, the authors of the paper, published in the journal Science, gave mice in a lab alcohol for the first time. The animals were then given alcohol at levels mimicking binge-drinking. During this process, some of the animals started to drink compulsively. Over the course of the study, the team imaged brain cells in a part of the brain called the cortical-brainstem circuit.

Next, the team observed brain cells in two parts of the brain which play a role in controlling behavior and responding to adverse events. In the mice who were habitually drawn to drink, these two parts of the brains started to communicate.

What's more, by activating this cortical-brainstem pathway the team were able to reduce drinking in the mice.

Neurobiology expert Professor Kay M. Tye at Salk Institute for Biological Studies and study co-author, told Newsweek: "Importantly, after several days of activating this cortical-brainstem circuit, we were able to see lasting reductions in drinking, even after we had ceased performing any manipulations to the brain."

Tye explained why it wasn't possible to carry out a study charting the drinking of humans using the same methods. "We can't control their living conditions, how their family, friends, and peers behave, and what social pressures they may be exposed to—not to mention that this can take years in many cases.

"We also can't record the activity of neurons in the brains of normal young adults as they develop various alcohol drinking patterns," she said.

Tye said of the discovery: "My mind was blown that there could be anything in the brain that could predict alcohol drinking behavior so accurately, several weeks later! So to me, this is the most ground-breaking finding [from the study]—that a biomarker with such predictive power exists for something so poorly understood as compulsive alcohol drinking. I think we were very lucky to have chosen this circuit to study."

Co-author Cody A. Siciliano, assistant professor at the Vanderbilt Center for Addiction Research, Vanderbilt University, told Newsweek: "This study gives support to the notion that pre-existing differences in the way the brain is wired, independent of heredity, put some at greater risk for alcohol use disorder.

"By identifying a circuit that mediates vulnerability, this study opens the door to identifying at risk-individuals and intervening before significant problems have developed," said Siciliano.

In the future, the team hopes the research will help to create treatments for alcoholism targeting this circuit.

Professor Jianfeng Feng from the University of Warwick's Department of Computer Science, who did not work on the study, told Newsweek he is among researchers who have been searching for such circuits "for some time."

"Until now, we were unable to identify them," Feng said.

However, Feng said the study only involved animals and it's not clear if the results are applicable to humans.

"As it is always the case in science, it opens more questions than it can answer," he said.

"For example, can we identify genetic biomarkers for the circuit which can be more easily used to predict the three types: low drinkers, high drinkers and compulsive drinkers?"

Feng agreed the research brings scientists a step closer to developing potential treatment targets for addictions using drugs, as well as invasive and noninvasive treatments.

In a study published earlier this year, Feng and colleagues found that the medial prefrontal cortex is one of the key regions related to alcohol drinking, independent of the amount a person drank. "Hence their study seems to confirm part of our findings in humans as well," he said.

Next, researchers could look at whether the same circuit could relate to other substances, too, Feng said.