Anatomy of a binge: How alcohol affects your brain

Here's what can happen in a "power hour" - that first hour of a 21st birthday celebration in which young adults try to consume 21 drinks between midnight and 1 a.m.

Ethanol, the chemical in alcoholic drinks, depresses parts of the brain, one after the other. First go, those pesky emotional things such as inhibitions that make you cautious and tame. Then it hits your speech centers, making you slur, and the neurons that tell your muscles how to walk, making you stumble.

Finally, when you've drunk enough fast enough, it shuts down the part of the brain that controls your lungs and your heart.

"If they didn't vomit, it...