As little as one alcoholic drink may be enough to impair your ability to read emotions and modulate along social contexts, a new study concludes. Using brain imaging technology, researchers at the University of Illinois and Chicago have determined that a single drink at 16 percent alcohol per volume is enough to disrupt the chemical interaction between the amygdala and the orbitofrontal cortex – two brain centers responsible complex cognitive behavior, personality expression, and social aptitude. This immediate communicative breakdown may help explain why even social drinkers experience erratic moods and loss of inhibition.
According to study author Dr. Luan Phan, our ability to read social cues and facial expression is not restricted to a single cerebral center. Instead, these emotional processes depend on complex interactions involving several parts of the brain. For this reason, the researchers theorized that social impairment is not strictly the product of discrete cerebral damage, but may also result from inhibited connectivity and communication.
“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,” Phan said, speaking to PsychCentral.
To investigate, the research team enrolled 12 heavy social drinkers in an experiment. After consuming either a non-alcoholic placebo or an alcoholic beverage comparable to a strong glass of wine (16% alc/vol), subjects were presented with photographs of faces and asked to match them with happiness, anger, fear, and other basic emotional profiles. While they performed this task, the researchers used functional magnetic resonance imaging (fMRI) scans to determine which cerebral centers were active.
The team found that subjects who had been given an alcoholic drink exhibited reduced connectivity and communication between the amygdala and the orbitofrontal cortex. They also noticed a reduction in the brain area’s responsive capacity.
“This suggests that during acute alcohol intoxication, emotional cues that signal threat are not being processed in the brain normally because the amygdala is not responding as it should be,” Phan explained, adding that the findings improve our understanding of the cerebral processes underpinning “the maladaptive behaviors we see in alcohol intoxication, including social disinhibition, aggression and social withdrawal.”
So, if you’re planning on reading facial expressions and assessing social cues, any amount of alcohol may be unwise.
Source: Gorka SM, Fitzgerald DA, King AC, Phan KL. Alcohol attenuates amygdala-frontal connectivity during processing social signals in heavy social drinkers : A preliminary pharmaco-fMRI study. Psychopharmacology (Berl). 2013 Sep;229(1):141-54. doi: 10.1007/s00213-013-3090-0. Epub 2013 Apr 13.