Mice Show Pain on Their Faces Just Like Humans Do

Mice in pain have facial expressions that are very similar to human facial expressions, according to scientists who have developed the “mouse grimace scale.” The pain expressions of mice could help researchers gauge the effectiveness of new drugs.

People have been using similar facial-expression coding systems in babies and other humans who are unable to verbally express their pain. “No one has every looked for facial expression of pain in anything other than humans,” said Jeffery Mogil of McGill University, co-author of the study published on May 9 in Nature Methods.

Most pain drugs fail in human trials, because pain-drug effectiveness in rodent trials is based on sensitivity to touch, which is not a good indicator of spontaneous pain, Mogil says. The mouse grimace scale adds another way to catalog pain and pain mitigation in laboratory animals.

“This is a true measure of spontaneous pain, a measure that was derived from the analogous human scale,” said Mogil. “If pain researchers would adopt this, we could get more accurate translations [of drug effectiveness] to humans.”

Mogil first noticed that mice can sense the pain of other mice in 2006. He saw that mice were communicating their pain visually, which had to be either by interpreting each other’s facial expressions or body movements. Mogil wondered if we could see whatever the mice were seeing.

Read More www.wired.com/wiredscience/2010/05/mouse-pain-expression/#ixzz0naY0PvmL