A Flick of a Switch: Study Reveals How Manipulating a Brain Circuit Can Affect Compulsive Drinking
The question of why some people develop an alcohol use disorder (AUD) and others do not may finally have some answers. Researchers have discovered a brain circuit that controls alcohol drinking behavior in mice and can be used as a biomarker for predicting the development of compulsive drinking later on. Follow us as we review the findings of this landmark study, how the flick of a switch in the brain can affect compulsive drinking, and why this research is vital to the future of those affected by AUD.
By The Numbers
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) states the percentage of adults in the United States with AUD is 5.7%. This statistic is a low number compared to how many people have consumed alcohol in their lifetime, which, according to the National Survey on Drug Use and Health (NSDUH), is 87 percent of people ages 26 or older. However, an alcohol use disorder does not happen in one sitting; it happens in stages, which include periods of intoxication and withdrawal symptoms. The National Institutes of Health defines AUD as a “chronic relapsing brain disease characterized by an impaired ability to stop or control alcohol use despite adverse social, occupational, or health consequences.”
What causes this inability to quit drinking even when it causes significant damage to a person’s life? Up until this point in research, most scientists have focused on examining the brain after a drinking disorder develops. However, researchers at the Salk Institute for Biological Studies recently published a landmark study in the journal Science that finally examines the brain before an AUD occurs. The results of the study are a game-changer.
First, the author of the study Cody Siciliano shares, “We initially sought to understand how the brain is altered by binge drinking to drive compulsive alcohol consumption. In the [research] process, we stumbled across a surprising finding where we were actually able to predict which animals would become compulsive based on neural activity during the very first time they drank (Science Daily, 2019).”
During the study, researchers created a test called a binge-induced compulsion task (BICT). The main objective of the test was to see how the mice would react to a tone to get access to alcohol, even when a bitter substance was added (a negative consequence). The BICT allowed scientists to observe which mice would drink large quantities of alcohol despite facing negative effects. Through a series of tests, researchers noticed the mice started showing differences in their responses and could be sorted into three groups:
- Low Drinkers: mice who consumed little to no alcohol with or without the bitter taste.
- High Drinkers: mice who consumed higher quantities of alcohol, but only if it was not bitter. These mice would reduce their drinking when they faced a negative taste.
- Compulsive Drinkers: mice that consumed large quantities of alcohol regardless of facing the negative consequences or not.
A Flick of a Switch
The researchers then used a special imaging technique to monitor key cells and brain regions of the mice before drinking, during drinking, and after drinking alcohol. They looked at specific neuron activity in two areas involved in behavioral control and responding to negative events: the medial prefrontal cortex (mPFC) and the periaqueductal gray matter (PAG). The PAG is involved in the reaction to adverse events and is often associated with how people respond to alcohol withdrawal symptoms. Researchers found that “the formation of compulsive alcohol drinking was related to communication patterns between the two brain regions, and this was a biomarker for predicting future compulsive drinking (Science Daily, 2019).”
Additionally, the researchers used optogenetics (a technique that involves the use of light to manipulate cells in living tissue) to control the activity of the neural pathway. This action brought the study to another level. Through optogenetics, the scientists were able to either increase compulsive alcohol drinking or reduce it by turning the brain circuit on or off – a literal flick of a switch. This landmark study allows scientists to look into the brain and find specific patterns that predict if mice will become compulsive drinkers in the future – before the compulsion develops. Researchers in the study did admit, “We do not know if this brain circuit is specific to alcohol or if the same circuit is involved in multiple compulsive behaviors such as those related to other substances of abuse or natural rewards – that is something we need to investigate.” Scientists sequence these brainstem neurons to identify targets used for therapeutic purposes.
Looking to the Future
This study reinforces the fact that AUD is an impaired ability to stop alcohol use despite adverse consequences. The Mayo Clinic states, alcohol use disorder can be mild, moderate, or severe, based on the number of symptoms you experience. Signs can include:
- Being unable to limit the amount of alcohol you drink
- Wanting to cut down on how much you drink and repeatedly being unable to do so.
- Spending a majority of time drinking, getting alcohol, or recovering from alcohol use
- Feeling an intense craving to drink alcohol
- Continuing to drink alcohol even though you know it’s causing physical, social or interpersonal problems
Hopefully, scientists will continue additional research that will lead to new and advanced treatment and prevention strategies. Until then, if your drinking results in repeated significant problems functioning in your everyday life, you likely have an alcohol use disorder, and early treatment is critical to a healthy and productive life in recovery. Don’t let the past steal your present, contact Silver Lining Recovery today at (866) 448-4563.