Scientists have established that two glasses of alcohol alter the functioning of the prefrontal cortex of the brain.
Researchers have used magnetic resonance imaging (MRI) to better understand why people often become aggressive and violent after drinking alcohol. They measured blood flow in the brain.
After only two drinks, the scientists noted changes in the functioning of the prefrontal brain cortex, the part normally involved in alleviating a person's levels of aggression. The study was conducted by Thomas Denson, University of New South Wales, Australia, and published in the journal Cognitive, Affective, & Behavioral Neuroscience.
So far, no substantial evidence has corroborated the theory that alcohol-related aggression was caused by changes in the prefrontal cortex.
For this study, Thomas Denson and his team recruited 50 young men in good health. Participants received either two drinks containing vodka or two non-alcoholic placebo drinks. While lying in an MRI machine, participants had to respond to a verbal provocation triggering their aggression.
Magnetic resonance imaging allowed researchers to see what areas of the brain had been stimulated by verbal provocation. They could also compare the scans of the subjects who had consumed alcohol and the scans of the subjects who had not consumed it. As a result, the activity of the prefrontal cortex of boys who consumed alcohol had decreased. This moderating effect of alcohol has also been observed in areas of the brain involved in the feeling of reward.
"Even following the ingestion of a low dose of alcohol, we found a significant cause-and-effect relationship between prefrontal cortex activity and alcohol-related aggression," says Thomas Denson. These brain regions can trigger different behaviors depending on whether a person is sober or intoxicated. "
The results are largely consistent with a growing body of research on the neuronal basis of aggression and how it is triggered by changes in the prefrontal cortex, limbic system and brain regions related to feeling rewarded. . The results of this study are also consistent with several psychological theories of alcohol-related aggression.
"We are encouraging future large-scale investigations into the neural basis of alcohol-related aggression, with higher doses and clinical samples, which could potentially help address alcohol-related harms," he said. concludes Thomas Denson.