After a Hangover: The Invisible Effects of Alcohol on Your Brain

Researchers have found that chronic alcohol consumption can impair the brain’s ability to make good decisions, especially in uncertain situations. In tests on rats, males showed more difficulty adapting and exploring new options after exposure to alcohol, while females were less affected. These changes in behavior are linked to changes in the activity of an area of ​​the brain called the striatum, which is important for evaluating rewards and planning actions.

Decision-making, especially when we choose the best among several options, is a very important process for our daily lives and depends on specific areas of the brain, such as the striatum. This region helps to evaluate rewards and define the value of each choice.

However, when the brain is exposed to alcohol for long periods, as happens in cases of alcoholism, these functions can be impaired, both in humans and in laboratory animals, such as rats.

Previous research has shown that alcohol can alter the functioning of brain cells and weaken the neural connections needed for thinking and decision-making, particularly in a part of the striatum called the dorsomedial striatum (DMS).

This region is essential for learning from rewards and planning goal-directed actions. Despite this, little is known about exactly how alcohol alters these decision-making processes.

Another important factor is that alcohol does not affect men and women in the same way. Studies show that there are differences in alcohol consumption, in the risk of developing dependence and even in the way the brain reacts to alcohol between the sexes.

In addition, men and women also behave differently in tasks that involve learning to obtain rewards.

Therefore, understanding how alcohol alters brain function differently in males and females is essential to developing more effective treatments for alcohol-related problems.

To investigate these questions, scientists at Johns Hopkins University in the United States trained male and female rats that had been exposed to alcohol for a long period of time in a task called “dynamic probabilistic reversal learning” (dynaPRL).

In this task, the rats had to constantly adapt to changes in the chances of receiving a reward, in an environment that simulated uncertainty, similar to real-life situations where conditions change without warning.

Compared to simpler tasks, dynaPRL increases the level of unpredictability, requiring greater mental flexibility from the animals.

Dynamic Probabilistic Reversal Learning: Scientists used a touchscreen to train mice in choice-learning tests. First, they associated images on the screen with food. Then, the mice had to touch the images to get the reward. Then, they had to learn to choose between two different images, one that gave food and the other that didn’t. Eventually, the rules changed: the image that previously didn’t give food became the correct one. During all of this, the positions of the images on the screen changed so as not to create easy-to-follow patterns. Source: Jonathan L Brigman, DOI: 10.3389/neuro.01.013.2010

The results showed that alcohol affected the behavior of the mice, but in different ways between males and females.

Male mice exposed to alcohol had greater difficulty adapting to changes in rewards and showed altered exploratory behavior, that is, they had more difficulty trying new options to try to find better results. Females, on the other hand, showed much less impact on behavior, even after exposure to alcohol.

When the researchers analyzed the animals' brains, focusing on the activity of neurons in the dorsomedial striatum, they observed significant changes. In male rats that had consumed alcohol, neural activity related to making choices and calculating the value of different options was reduced, while the brain's response to received rewards was increased.

This means that in males, alcohol caused the brain to overreact when they received a reward, but left the decision-making system more “blind” to the best strategies to follow. On the other hand, in females, the changes in neural activity were different and less damaging, suggesting that the female brain may be more resistant to these specific effects of alcohol.

These findings show that chronic alcohol consumption throughout life profoundly alters the way the brain processes information to make reward-based decisions. Furthermore, these changes are not the same in males and females, reinforcing the need to consider sex differences in research on the impact of alcohol on the brain.

Understanding these changes may help in the future to develop more targeted treatments to restore cognitive functions affected by alcohol abuse.

READ MORE:

Chronic ethanol exposure produces sex-dependent impairments in value computations in the striatum

Yifeng Cheng, Robin Magnard, Angela J. Langdon, Daeyeol Lee and Patricia H. Janak

Science Advances. 2 Apr 2025 Vol 11, Issue 14

DOI: 10.1126/sciadv.adt0200

Abstract:

Value-based decision-making relies on the striatum, where neural plasticity can be altered by chronic ethanol (EtOH) exposure, but the effects of such plasticity on striatal neural dynamics during decision-making remain unclear. This study investigated the long-term impacts of EtOH on reward-driven decision-making and striatal neurocomputations in male and female rats using a dynamic probabilistic reversal learning task. Following a prolonged withdrawal period, EtOH-exposed male rats exhibited deficits in adaptability and exploratory behavior, with aberrant outcome-driven value updating that heightened preference for chosen action. These behavioral changes were linked to altered neural activity in the dorsomedial striatum (DMS), where EtOH increased outcome-related encoding and decreased choice-related encoding. In contrast, female rats showed minimal behavioral changes with distinct EtOH-evoked alterations of neural activity, revealing significant sex differences in the impact of chronic EtOH. Our findings underscore the impact of chronic EtOH exposure on adaptive decision-making, revealing enduring changes in neurocomputational processes in the striatum underlying cognitive deficits that differ by sex.