Where do OCD compulsions live?

Here's a fascinating article about a surprising study on mice that overgroom (called barbering in rats anyway, sometimes they barber their cagemates, scissoring all the fur off and leaving their chums baldish), which is a symptom of OCD in mice.

Mice were cured not via neurological means but via a bone marrow transplant. Which brings up all sorts of interesting thoughts like has anyone been cured or given OCD while getting a bone marrow transplant for a serious illness?

http://www.nature.com/news/2010/100527/full/news.2010.268.html