Why Drunk People Take Risks.

New brain imaging research shows that social drinkers have decreased sensitivity in brain regions involved in detecting threats, and increased activity in brain regions involved in reward.

After alcohol exposure, threat-detecting brain circuits can't tell the difference between a threatening and a non-threatening social situation.

Working with 12 healthy participants who drink socially, researchers used functional magnetic resonance imaging (fMRI) to study activity in emotion-processing brain regions during alcohol exposure. When participants received a placebo instead of alcohol, they showed greater activity in the amygdala, insula, and parahippocampal gyrus -- brain regions involved in fear and avoidance -- when shown a picture of a fearful facial expression.

Alcohol, meanwhile, activated striatal areas of the brain that are important components of the reward system, but did not increase brain activity in areas involved in fear.
Sources:

The Journal of Neuroscience April 30, 2008

What this study really highlights is the fact that if you’ve been drinking, you’re likely to take dangerous risks because you won’t realize if you’re in a threatening situation. And this happens to everyone -- even those of you who think, “Alcohol doesn’t impact me.”