Study finds chronic alcohol use shifts brain's control of behavior

August 23, 2013, National Institutes of Health

(Medical Xpress)—Chronic alcohol exposure leads to brain adaptations that shift behavior control away from an area of the brain involved in complex decision-making and toward a region associated with habit formation, according to a new study conducted in mice by scientists at the National Institutes of Health.

The finding provides a that helps to explain compulsive alcohol use and the progression to . A report appears online in the Proceedings of the National Academy of Sciences (PNAS).

The brain's is involved in decision-making and controlling emotion, while the dorsal striatum is thought to play a key role in motivation and . Past studies have shown that alcohol dependent individuals show problems with skills mediated by the prefrontal cortex such as . These same individuals often show exaggerated in the dorsal striatum to alcohol-related cues.

To investigate whether changes in the dorsal striatum might account for these observations, researchers led by Andrew Holmes, Ph.D., in the Laboratory of Laboratory of Behavioral and Genomic Neuroscience at NIAAA, measured changes in the brains of mice that were chronically exposed to alcohol vapors.

He and his colleagues found profound changes in the dorsal striatum of these mice, including the expansion of , the branching projections of the nerve cell that conduct signals. Such changes are also seen with chronic exposure to drugs such as amphetamine. These structural changes were associated with changes in synaptic plasticity, the brain's ability to change in response to experience, and reduced activity of endocannabinoid receptors, which are part of a signaling system that may play a role in sensation, mood, and memory.

"These findings give important insight into how excessive drinking affects learning and behavioral control at the neural level," said Kenneth R. Warren, Ph.D., acting director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA). "The shift to increased striatal control over behavior may be a critical step in the progression of alcoholism."

"The changes we observed suggest that the manner in which the dorsal striatum signaled and adapted to environmental information has been altered by alcohol," said senior author Dr. Andrew Holmes. "The findings imply that chronic drinking may set up a concerted set of adaptions in this key brain region that produce a bias for striatal control over behavior."

Such changes could contribute to the emergence of habitual and compulsive patterns of behavior in alcohol abuse, and suggest that treatments designed to normalize striatal function may be an important approach for alcohol treatment.

Dr. Holmes and his colleagues add that their findings suggest that drug abuse doesn't simply impair brain functions, but instead produces a complex set of adaptations that tamp down the function of some brain regions while dialing up the function of others.

Indeed, the researchers found that chronic alcohol actually improved the ability of mice to learn to make choices on a touchscreen.

"Improved performance on learning tasks that we know depend on the dorsolateral striatum is particularly interesting because it suggests that alcohol could prime the brain to favor other dorsal striatal behaviors – including things like habit formation, which may foster addictive patterns of behavior," said Dr. Holmes.

Explore further: Study identifies brain circuits involved in learning and decision making

More information: DePoy, L. et al. Chronic alcohol produces neuroadaptations to prime dorsal striatal learning, PNAS, 2013 Aug 20. [Epub ahead of print]

Related Stories

Study identifies brain circuits involved in learning and decision making

July 9, 2013
(Medical Xpress)—Research from the National Institutes of Health has identified neural circuits in mice that are involved in the ability to learn and alter behaviors. The findings help to explain the brain processes that ...

Brain patterns may help predict relapse risk for alcoholism

May 2, 2013
(Medical Xpress)—Distinct patterns of brain activity are linked to greater rates of relapse among alcohol dependent patients in early recovery, a study has found. The research, supported by the National Institutes of Health, ...

Heavy drinking rewires brain, increasing susceptibility to anxiety problems

September 2, 2012
Doctors have long recognized a link between alcoholism and anxiety disorders such as post-traumatic stress disorder (PTSD). Those who drink heavily are at increased risk for traumatic events like car accidents and domestic ...

Brain dopamine may serve as a risk marker for alcohol use disorders

August 10, 2013
There are two traits closely associated with the development of alcohol use disorders (AUDs). One is a lower subjective intoxication response, also known as a low level of response to alcohol. The second is a greater propensity ...

Gene combinations help predict treatment success for alcoholism medication

August 5, 2013
An experimental treatment for alcohol dependence works better in individuals who possess specific combinations of genes that regulate the function and binding of serotonin, a brain chemical affected by the treatment, according ...

Switching between habitual and goal-directed actions—a 'two in one' system in our brain

August 6, 2013
To unravel the circuit that underlies this capacity, the capacity to "break habits," was the goal of the study, carried out by Christina Gremel and Rui Costa, at NIAAA, National Institutes of Health, USA and the Champalimaud ...

Recommended for you

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

A 'touching sight': How babies' brains process touch builds foundations for learning

January 16, 2018
Touch is the first of the five senses to develop, yet scientists know far less about the baby's brain response to touch than to, say, the sight of mom's face, or the sound of her voice.

Brain zaps may help curb tics of Tourette syndrome

January 16, 2018
Electric zaps can help rewire the brains of Tourette syndrome patients, effectively reducing their uncontrollable vocal and motor tics, a new study shows.

Researchers identify protein involved in cocaine addiction

January 16, 2018
Mount Sinai researchers have identified a protein produced by the immune system—granulocyte-colony stimulating factor (G-CSF)—that could be responsible for the development of cocaine addiction.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.