Drinking dulls the brain's response to threats

By Julie Steenhuysen

CHICAGO (Reuters) - Drinking alcohol dulls the brain's ability to detect threats, U.S. researchers said on Tuesday in a study that helps explain why people who are drunk cannot tell when the guy at the end of the bar is angling for a fight.

They said the study is the first to show how alcohol affects the human brain as it responds to threats.

"You see this all of the time. People get into confrontations when they are intoxicated that they probably wouldn't get into when they are sober," said Jodi Gilman of the National Institutes on Alcohol Abuse and Alcoholism, whose study appears in the Journal of Neuroscience.

Gilman studied 12 people who were given intravenous infusions of alcohol and then monitored their brain activity using functional magnetic resonance imaging while they looked at pictures of frightened and neutral faces.

Her team did the same study on these people when they were given a simple saline infusion as a placebo.

As expected, when people were given the placebo, their brains responded to the fearful faces.

"Our brains respond more to fearful stimuli," Gilman said in a telephone interview. "They signal to us that we are in threatening situations."

When these same people were given infusions of alcohol, however, this response was dulled, suggesting that while intoxicated, "our brain can't distinguish between the threatening and nonthreatening stimuli," said Gilman.