June 10, 2013
Mouse Brains Help Understand Origins Of OCD
Watch the video "Mice Give New Clues To Origins Of OCD"
Lee Rannals for redOrbit.com - Your Universe Online
Researchers at Columbia University Medical Center are looking at mice in order to understand more about people who suffer from obsessive compulsive disorders (OCD). The team now says they have identified what they believe could be a mechanism underlying the development of OCD. This finding suggests possible approaches to uncovering new treatments for people suffering from the disorder, which affects two to three percent of people around the world.
The researchers reported in the journal Science that they found that the repeated stimulation of specific circuits linking the brain's cortex and striatum induced progressive repetitive behavior. By targeting this region, they believe it could be possible to stop abnormal circuit changes before they become pathological behaviors in people at risk for OCD.
During the study, the team used a new technology known as optogenetics to help stimulate the increased activity that takes place in the brains of OCD patients. When using optogenetics on mice, light-activated ion channels are expressed in subsets of neurons in the animals, and neural circuits are then selectively activated using light delivered through fiberoptic probes.
“What we found was really surprising,” said Susanne Ahmari, assistant professor of clinical psychiatry at Columbia Psychiatry and the New York State Psychiatric Institute. “That activation of cortico-striatal circuits did not lead directly to repetitive behaviors in the mice. But if we repeatedly stimulated for multiple days in a row for only five minutes a day, we saw a progressive development of repetitive behaviors — in this case, repetitive grooming behavior — that persisted up to two weeks after the stimulation was stopped.”
She said that when they treated the mice with fluoxetine — more commonly known by its brand name Prozac and one of the most common medications used for treating OCD — their behavior went back to normal. The team's research may ultimately provide clues for new treatment targets in terms of both novel drug development and direct stimulation techniques.
A study released last week found that structural brain abnormalities in dogs with OCD are similar to those seen in humans with the disorder. Results from this particular study could also bring a new understanding of OCD behaviors in humans.
“While the study sample was small and further research is needed, the results further validate that dogs with CCD can provide insight and understanding into anxiety disorders that affect people,” said Nicholas Dodman, from the Cummings School of Veterinary Medicine at Tufts University and a co-author of the study that appeared in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry.