Why You Can’t Remember What You Did Last Night

Illustration of the brain, highlighting the hippocampus.There’s a scene in Cheers where lovable mailman Cliff explains his theory on how drinking makes him smarter. He gives a survival-of-the-fittest scenario that alcohol kills off the slowest brain cells, much like the most sluggish buffalo in the herd is the first to be killed. He argues that killing the slowest brain cells makes his brain faster, in the same way that a herd of buffalo is stronger once the weakest members are culled off.

While this might seem like pretty twisted logic for some, the basic tenet of Cliff’s theory—that alcohol kills brain cells—is pretty much taken for granted. However, new research has found that alcohol—even when used to the point of blackout intoxication—isn’t actually killing brain cells. It’s just preventing your brain from forming new memories.   

A new study from the Washington University School of Medicine in St. Louis, published recently in The Journal of Neuroscience, explains the biology of how the brain deals with alcohol, namely how the brain reacts when a person is so intoxicated they cannot recall events during the period commonly referred to as “blackout.”

The research sheds some light into the surreal period of intoxicated time where your body can dance all night, have conversations, possibly rock the karaoke stage, and manage to make it to bed in one piece, and yet the next morning, you might not remember any of what happened.

Alcohol does many different things to the brain besides lower inhibitions and makes you yearn for pizza with ranch dressing. This study shows that large amounts of alcohol interfere with key receptors in the hippocampus, the main center for cognitive functioning in the brain. While it does this, alcohol also releases a steroid that that inhibits the way by which the brain strengthens synapses—or the connections between brain cells.

In essence, researchers believe, large amounts of alcohol don’t kill brain cells, but rather signals compounds that inhibit the brain’s ability to form memories. This “may explain why individuals who get highly intoxicated don’t remember what they did the night before,” senior investigator Charles F. Zorumski, MD, the Samuel B. Guze Professor and head of the Department of Psychiatry said in a press release from Washington University. 

What researchers are sure about is that alcohol doesn’t kill brain cells in the way that is commonly believed.

More good news is that researchers believe that this study could help scientists better understand how memory actually works—and could even lead to developing new ways to improve or maintain memory and cognitive skills.

Now this research doesn’t suggest that you should go on a two-week bender. Even if you are not losing cognitive ability, the negative effects of alcohol on the body still go far beyond a headache in the morning. 

Then again, relaxing with a nice cool cocktail, when done in moderation, can help your health. For some new recipes, check out Healthline’s Healthy Summer Cocktails.