What Causes Obsessive Compulsive Disorder? Obsessive compulsive disorder is a severe, chronic mental illness that affects millions of individuals. However, the mechanisms underlying this disease are still largely unknown (see the Perspective by Rauch and Carlezon Jr. ). Ahmari et al. (p. 1234 ) stimulated glutamatergic pathways between the orbitofrontal cortex and the ventromedial striatum and used grooming to assess obsessive compulsive behavior in mice. Repetitive stimulation over days triggered changes in the neuronal responses of the ventromedial striatum. Over time, the behavior of the animals became independent of stimulation and could be prevented by the antidepressant fluoxetine. Burguière et al. (p. 1243 ) investigated the neural basis of obsessive compulsive symptoms in a mutant mouse that showed excessive expression of a conditioned form of grooming.

Repeated Cortico-Striatal Stimulation Generates Persistent OCD-Like Behavior