Giving mice a specific drug before anesthesia helps them remember scary situations better after waking up.

Mice given a common anesthesia for 6 hours remember scary situations worse for at least a week after, showing they’re less fearful when they should be — a sign their memory is temporarily impaired.

In mice, a drug called fenofibrate helps protect the brain after anesthesia, but only if the brain can burn fat for energy — when another drug blocks fat burning, the protection goes away.