K. Luan Phan from University of Illinois at Chicago professor of psychiatry and colleagues examined alcohol's effects on connectivity between the amygdala and the prefrontal cortex during the processing of emotional stimuli - photographs of happy, fearful and angry faces - using functional magnetic resonance imaging, or fMRI.
Participants were 12 heavy social drinkers with an average age of 23. Their reported average of 7.8 binge drinking episodes per month - defined as consuming five or more drinks for men, and four or more drinks for women -put them at high risk for developing alcohol dependence.
The participants were given a beverage containing either a high dose of alcohol (16 percent) or placebo. They then had an fMRI scan as they tried to match photographs of faces with the same expression.
When participants processed images of angry, fearful and happy faces, alcohol reduced the coupling between the amygdala and the orbitofrontal cortex, an area of the prefrontal cortex implicated in socio-emotional information processing and decision-making.
The researchers also noticed that alcohol reduced the reaction in the amygdala to threat signals - angry or fearful faces.
Phan said that if the amygdala and the prefrontal cortex, which have a dynamic, interactive relationship, 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.
The study was published in the journal of Psychopharmacology.
--ANI (Posted on 30-08-2013)