The first study of the effects of alcohol by magnetic resonance imaging reveals that its consumption reduces sensitivity in areas of the brain that detect threats and increases the activity of those involved in reward.
To reach this conclusion, Marina Wolf and her colleagues from Rosalind Franklin University (USA) studied the brains of twelve healthy subjects who were social drinkers. For periods of more than 45 minutes, the participants received alcohol or intravenous saline (placebo) while being shown images of fearful and neutral facial expressions. By comparing brain activity in both circumstances, the researchers found that when participants received placebo, facial expressions of fear triggered increased activity in the amygdala, insula, and parahippocampal gyrus. However, these same areas of the brain barely reacted to the terrified faces when the subjects had consumed alcohol. In addition, alcohol increased the response of the striated areas of the brain, which are important components of the reward system .
According to Franklin, the results explain why alcohol consumption "allows us to get close to a stranger at a party," but also makes us more vulnerable to getting into an argument or a fight .
