All mice groom themselves to keep their fur clean, but some in a lab in Columbia University, New York, have started grooming to an unusual and excessive degree. This isn’t vanity. Instead, it’s the rodent equivalent of the repetitive rituals that many people with obsessive-compulsive disorder (OCD) go through, like an irresistible urge to wash their hands or clean themselves.

But as Ed Yong relates, researchers have cured this OCD — in mice — using a wee blue light to stimulate a wee tiny part of the brain; and another bunch of researchers have found they can use the light to buzz yet another wee brain area part and make it happen.

Again — in mice. Which we ain’t. But go read this thing: Yong, as usual, delivers all the caveats, as well as the full measure of wonder.

Ed Yong on Making and Breaking Compulsive Behaviour – Phenomena: Not Exactly Rocket Science.