A 'face-book' to measure how much pain mice feel

As human stand-ins, rodents key to research on pain and how to relieve it

PARIS - Scientists have for the first time created a sliding scale of pain for mice based on facial expressions, according to a study published Sunday.

The so-called "mouse grimace scale" will speed up the development of new painkillers for humans, and could help reduce unnecessary suffering of mice and other animals in biomedical research, the researchers said.