Researchers at Johns Hopkins University have unveiled seminal findings on how heavy alcohol consumption causes lasting damage to brain circuits involved in decision-making.
In a pioneering study published in Science Advances, researchers at Johns Hopkins University have demonstrated the lasting effects of heavy alcohol consumption on decision-making and brain function utilizing animal models. This innovative research offers new insights into the persistent cognitive deficits seen in individuals with alcohol use disorder (AUD) and highlights the importance of addressing chronic alcohol abuse.
For the first time, scientists detailed how extensive alcohol exposure causes long-term changes in the brain circuits critical for decision-making.
In the study, rats that were exposed to high levels of alcohol exhibited significant impairments in decision-making tasks even after an extended withdrawal period of nearly three months.
“We now have a new model for the unfortunate cognitive changes that humans with alcohol use disorder show,” co-corresponding author Patricia Janak, a Johns Hopkins University neuroscientist, said in a news release. “We know that humans who are addicted to alcohol can show deficits in learning and decision-making that may contribute to their poor decisions related to alcohol use. We needed an animal model to better understand how chronic alcohol abuse affects the brain. Knowing what is happening in the brain of an animal when they are having these decision-making difficulties will tell us what is happening in humans.”
The experiments, led by first author Yifeng Cheng, a research scientist in Janak’s lab, involved subjecting rats to a month-long period of heavy alcohol exposure. Following a withdrawal period, the rats were tested alongside a control group in a complex decision-making task, which required memory and strategic thinking. The task involved choosing between two levers, where the reward likelihood frequently changed, compelling the rats to adapt their choices rapidly.
As hypothesized, the alcohol-exposed rats struggled significantly more than their healthy counterparts. The findings indicated that the task, designed to be more challenging than previous experiments, effectively mirrored the rapid decision-making deficits observed in humans with AUD.
“Our experiment was quite challenging and the alcohol-exposed rats just couldn’t do it as well,” Janak added. “When the right answer was constantly changing, the control rats made the best decisions faster. They were more strategic. And when we looked at their brains, the control rats’ decision-related neural signals were stronger.”
The study linked these behavioral impairments to dramatic functional changes in the dorsomedial striatum, a part of the brain imperative for decision-making. The alcohol-exposed rats displayed weakened neural signals, highlighting their reduced capacity to process information efficiently.
One of the most striking revelations was the prolonged impact of alcohol dependence on cognitive and neural function. This aspect of the study offers critical insights into the high relapse rates seen in individuals recovering from alcohol addiction.
“This may give us insight into why relapse rates for people addicted to alcohol are so high,” added Janak. “Alcohol-induced neural deficits may contribute to decisions to drink even after going to rehab. We can clearly demonstrate these deficits can be long-lasting.”
The study noted that the observed impairments were exclusive to male rats, raising questions about potential sex-related sensitivities in long-term alcohol effects on brain function.
The researchers plan to further investigate how alcohol affects other areas of the brain and the underlying reasons for the differences between males and females in subsequent studies.
Source: Johns Hopkins University