View Full Version : Optogenetics and OCD

06-10-13, 05:23 PM
From Ed Yong over at National Geographic: Making and Breaking Compulsive Behaviour (

It starts:
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.

The mice didn’t start off with their compulsions. Over five days, psychiatrist Susanne Ahmari used flashes of light to activate neurons that run between two regions at the front of their brains—the orbitofrontal cortex (OFC) and the striatum. She didn’t do it for long—just five minutes a day—but slowly, the mice groomed themselves more and more.
Meanwhile, a few states away, another group of scientists did the opposite. Eric Burguičre at MIT in Boston worked with mice that were born without a gene called Sapap3—a loss that leads to anxiety, repetitive grooming, and other symptoms that are similar to those of OCD.

There are references to other experiments that have had different levels of success, but the whole idea of optogenetics is fascinating. Here is a method of influencing gene expression - silencing gene activity by targeting a specific gene in a specific location with a specific light frequency at specific intervals - that can correct what, up to now, has been considered a psychiatric disorder.

It's obviously "not ready for prime time," since this is a solitary success and worked only in mice, but the implications are interesting to consider.

06-10-13, 08:23 PM
My cat does this... we think it's stress related- when he can venture outside, he grooms less- when he's cooped up inside too long, he grooms excessively. The vet calls it OCD, but it's been a gradual change in his behavior. I wonder if the same is with the mice.

06-10-13, 08:28 PM
Well, in both cases, the mice were bred to have this gene on or off, so they started off either grooming too much or grooming too little before the experiment started. Grooming is both a simple and an essential part of mouse behavior and development, and we can probably extrapolate that it serves a similar function in other animals that groom. We can't make such broad assumptions with humans, but discoveries like these lead to things we can use with people at some point.

06-11-13, 02:29 AM
wait... so you are trying to breed humans that groom themselves?

06-11-13, 02:51 AM
This is an interesting example of how identifying and targeting genes can be helpful in finding working therapies.

06-11-13, 03:07 AM
Great find

06-11-13, 07:47 AM
Ed has a weekly feature on Saturdays that's nothing but links. Besides all his excellent articles on Biology and Science Journalism, you can find tons of fascinating finds - and debunking articles on things that aren't really finds at all.

This in particular is interesting especially when you compare it with his previous article on optogenetics and depression (which didn't work as well as hoped) and some of his articles and links to transcranial magnetic stimulation and deep brain stimulation. They're a good illustration of how specific we have to get when trying to address things on a genetic or epigenetic level. Reductionist thinking just doesn't work when you're dealing with highly specialized parts!