Heavy alcohol consumption causes long -term brain damage

Summary: For the first time, scientists have shown how heavy alcohol use leads to long -term cognitive deficiencies by damaging brain circuits responsible for decision making. In a rat model, animals exposed to high levels of alcohol worked significantly worse in a complex and changing task, even after almost three months of sobriety.

These decision -making deficits were linked to the weakened neuronal activity in the dorsomedial striatum, a crucial brain region to evaluate the options. The findings suggest that alcohol -induced brain changes can be the basis of a bad judgment and relapse on people with alcohol consumption disorder.

Key facts:

Persistent damage: rats exposed to alcohol showed deteriorated decision making months after retreat. Oral brain impact: damage to the dorsomedial striatum, a decision center was found. Sex differences observed: the effects were observed in male rats but not in female, which suggests a variability based on sex.

Source: Ju

For the first time, researchers demonstrate in an animal how heavy alcohol use leads to long -term behavioral problems by damaging critical brain circuits for decision making.

Rats exposed to high amounts of alcohol exhibited a bad decision making during a complex task even after a period of retirement of months. The key areas of their brains had suffered dramatic functional changes compared to healthy rats.

The findings, published today in Science Advances, provide a new explanation of the long -term effects of alcohol on cognition.

“Now we have a new model for the unfortunate cognitive changes that humans show with alcohol consumption disorder,” said author Patricia Janak, neuroscientific from Johns Hopkins University that studies the biology of addiction.

“We know that humans who are addicted to alcohol can show deficits in learning and decision making that can contribute to their bad decisions related to alcohol consumption. We need an animal model to better understand how chronic alcohol abuse affects the brain.

“Knowing what is happening in an animal’s brain when they have these decision -making difficulties will tell us what is happening in humans.”

In experiments led by the first author Yifeng Cheng, a research scientist in the janak laboratory who studies the effects of alcohol in the brain, rats received a very high exposure of alcohol for a month. Then, after a withdrawal period of almost three months, the rats received a decision -making test based on rewards along with a rating control group that had not been exposed to alcohol.

To obtain a reward, the rats were given a two levers option. Pressing a lever led to a greater probability of reward than to press the other lever. Rats easily learn which lever results in the greatest reward, so researchers complicated things every few minutes changing which lever had the most likely reward.

To obtain the greatest reward, a rat should quickly change your behavior every time you discover that the probability of reward has changed.

It was a difficult task that required memory and strategy. Rats exposed to alcohol worked considerably worse.

The previous experiments in animals were not comparable to humans with alcohol consumption disorder because animals did not demonstrate deficits in rapid decision making. The team believes this was because the tasks in previous experiments were too easy.

“Our experiment was quite challenging and rats exposed to alcohol simply could not do it too,” said Janak.

“When the correct answer constantly changed, the control rats made the best decisions faster. They were more strategic. And when we looked at their brains, neuronal signals related to the decision of the control rats were stronger.”

The team linked behavioral difficulties with dramatic functional transformations in dorsomedial striatum, a part of the critical brain for decision making. The alcohol had damaged the neuronal circuits that caused the rats exposed to alcohol to process the information less effectively.

A surprise was how long the dependence of alcohol harms cognition and neuronal function, even after abstinence.

“This can give us an idea of ​​why relapse rates for alcohol addicts are so high,” said Janak. “Alcohol -induced neuronal deficits can contribute to drinking decisions even after going to rehabilitation. We can clearly demonstrate that these deficits can be durable.”

The team only found behavioral and neural impediments only in male rats. The team does not believe that this suggests that female rats are immune to the effects of alcohol, but that there could be sensibilities related to sex in the effects of long -term alcohol on brain function.

Then, researchers hope to explore how alcoholism affects other areas of the brain that interact with the dorsomedial striated body and what could be causing the differences between men and women.

Additional authors include Robin Magnard, a postdoctoral fellow in Johns Hopkins; Angela J. Langdon of the National Health Institutes; and Daeyeol Lee, a distinguished professor of neuroscience and psychological and brain sciences in Johns Hopkins.

About this auditor and cognition research news

Author: Jill Rosen
Source: Ju
Contact: Jill Rosen – Jhu
Image: The image is accredited to Neuroscience News

Original research: open access.
“Chronic ethanol exposure produces sex -dependent alterations in value calculations in the striated body” by Patricia Janak et al. Scientific advances

Abstract

Chronic ethanol exposure produces sex -dependent impediments in value calculations in the striated body

Decision making based on value is based on the striated body, where neural plasticity can be altered by exposure to chronic ethanol (ETOH), but the effects of such plasticity on stiatal neuronal dynamics during decision making are still not clear.

This study investigated ETOH’s long -term impacts on decision -making promoted by rewards and striatal neurocomputations on male and female rats that use a dynamic probabilistic reversal learning task.

After a prolonged withdrawal period, male rats exposed to ETOH exhibited deficits in adaptability and exploratory behavior, with an aberrant value update based on the result that increased the preference for the chosen action.

These behavioral changes were linked to the altered neuronal activity in the dorsomedial striated body (DMS), where ETOH increased coding related to the result and decreased coding related to the choice. In contrast, female rats showed minimal behavior changes with different alterations of neuronal activity, revealing significant sex differences in the impact of chronic etoh.

Our findings underline the impact of chronic exposure to ETOH on adaptive decision making, revealing lasting changes in neurocomputational processes in the striated body underlying cognitive deficits that differ according to sex.