Long-term alcohol exposure hampers social communication, according to a new study conducted by researchers at the University of Illinois at Chicago College of Medicine.
The results were published in the September issue of journal Psychopharmacology.
Previous research showed that alcohol reduces activity in the amygdala, the area of the brain in charge for indentifying social cues such as facial expressions.
"Because emotional processing involves both the amygdala and areas of the brain located in the prefrontal cortex responsible for cognition and modulation of behavior, we wanted to see if there were any alterations in the functional connectivity or communication between these two brain regions that might underlie alcohol's effects," said K. Luan Phan, UIC professor of psychiatry.
Researchers arrived at the conclusion after examining 12 participants with history of heavy social drinking.
They closely observed the participants brains, using functional magnetic resonance imaging or fMRI, while the subjects were shown photographs of happy, scared and angry faces. While they looked at the pictures, the participants were given drinks that either contained a placebo or alcohol.
Each participant was shown three pictures on a screen- one on top and two at the bottom. Participants had to select the picture from the bottom that resembled the one on top.
Researchers found those respondents that were given alcohol, revealed lower levels of activity between anygdala and the orbitofrontal cortex, which is responsible for social cues and decision-making.
They also found that alcohol also decreased the brain's reaction to threats.
"The amygdala and the prefrontal cortex have a dynamic, interactive relationship. How the amygdala and prefrontal cortex interact enables us to accurately appraise our environment and modulate our reactions to it," Phan said. "If these two areas are uncoupled, as they are during acute alcohol intoxication, then our ability to assess and appropriately respond to the non-verbal message conveyed on the faces of others may be impaired. This research gives us a much better idea of what is going on in the brain that leads to some of the maladaptive behaviors we see in alcohol intoxication including social disinhibition, aggression and social withdrawal."
