Brain Tours: Obsessive Compulsive Disorder

(updated 12/2014)

The current working model is some sort of a defect in a circuit that involves the frontal cortex and the “anterior cingulate” (which can be viewed via the Mood tour) as well as some inner-brain structures called “basal ganglia”.Leon  This Tour tries to help you understand more about the basal ganglia part of this presumed OCD circuit.

You’ll remember that the R complex is the “housekeeping brain” we all have, in addition to our limbic system and our cortex. Now imagine you had a brain that could get “stuck” on one housekeeping task, like cleaning or checking safety or organizing. Some people are like that, as you probably know. They can get stuck for an hour washing their hands; or checking the emergency brake on the car; or organizing the kitchen before they start cooking. Imagine we could get Oscar, who has just this brain problem, in a brain scanner while he was “stuck” like that. Some part of this “housekeeping brain” ought to show up on the scan as abnormally active, right?

Well, a research team from UCLA has done just that. Here’s Oscar worrying about whether he really set the emergency brake.

R_comp2 (1)

Whoa! All right, let’s get organized here. This will be the trickiest brain structure we’ve tried to look at yet. You might prefer to work your way through Tours 1-4 before you try what follows here, because the 3-dimensional nature of the structure involved (the “caudate”) makes interpreting the picture above rather difficult.

You may have recognized this as a PET scan, although it’s less clear because it’s an old version, and it is shown in a view you haven’t seen before. Let’s look at the structure it illustrates first, this “caudate” thing, and then look at the caudate itself from just the same point of view as this PET scan — then, we’ll return to the scan and talk about what it means.

Go to Tour #1 if you haven’t learned about your 3 brains yet. Follow the signs to the “R complex” tour and take that too: you’ll need that basic introduction to the “basal ganglia”. From those tours, you’ll remember the “caudate”. Here it is again, at the arrow:

caudarrow

 

Now, let’s take Oscar, who’s all dressed up for work.

jpphoto

You may have taken the Tour in which we were looking at Cindy’s right brain half after her left half went to lunch. Well, imagine this time Oscar’s fairy godmother waved her magic wand the other way, and Oscar’s front half went off for dinner. We’re looking at what’s left behind to write grant applications (ignore the white-circled structures; you may have seen them on the amygdala Tour; focus on the dark-gold circled structures almost in the center of the brain, one on the left and one on the right circled less boldly so you can see the structure better):

coroncaudate

 

When Oscar was all there, you were looking at his eyes; now you see this? Look at it this way: you were looking in through the windshield of a car, and now the car’s been split into a front half and a back half just behind the front seats. Where you would have seen the top of the steering wheel, and the two front seat passengers; you now see the back seat people and the window behind them. In the medical lingo, this is called a “coronal section”. If that’s not making any sense to you, hang on, another way of looking at it is coming up next.

The gold circles in the picture above are, believe it or not, a portion of that gold arch we called the caudate. Remember that? Here it is again:

caudatecuts

 

Imagine we took off the front half of this brain, the part in front of the gold line, and then looked at it from the front. You’d see that top half of the caudate right near the middle (and since there are two of them, one on each side, you’d see two ovals, one on each side right near the middle of the brain). And the amygdala, which is also cut by the gold line, would also be visible. That’s what the MRI above shows. Here it is again. See if you can make sense to the two different views (side and front):

coroncaudate (1)

 

If you’ve “got it”, you’d understand that viewed from in front like this, the caudate is “coming toward you”: there is more of it, and as it comes toward you from the computer screen, it would even get bigger, because the “head” is fatter than the arch farther back. Imagine a view from the front like this closer to the front of Oscar’s head: the two caudate parts, still near the center of the head, would be even bigger, more like the diameter of the thicker gold line above. In MRI views, you imagine you’re looking at Oscar himself, so the thicker gold caudate above is his right one. We’ll now look at that same spot — Oscar’s right caudate, near the head of that structure — using a different camera.

R_comp2 (2)

To see the R brain at work we need to watch someone really extremely active on some housekeeping task. Unfortunately, there’s a mental illness like that, called “obsessive compulsive disorder”. Part of the function of these basal ganglia is to make sure something got done. It’s like their job is to continually go back and make sure you didn’t leave anything in your hotel room. And that goes for any “housekeeping” activity you do. Did you really wash your hands well enough? Did you really remember to lock the door?

If somebody has “obsessive compulsive disorder” (OCD) they can get stuck in this “really?” questioning. The French call it folie de doubt — a mental illness of doubting. We caught Oscar stuck in such a loop, so we could see what parts of his brain are overactive (well, the UCLA OCD research team did Schwartz et al). That’s how his picture was taken, in the UCLA PET scanner.

R_comp2 (3)

Now, what’s too active here?. Well, to see that we need a “normal” case with which to compare. We’ll use Oscar after he got better with treatment as the “normal case”, to make sure we’re comparing Oscars with Oscars.

 

R_comp3

 

Notice that just to the left of the middle of Oscar’s head there’s a yellow region in the pre-treatment scan that’s almost but not quite gone(turned more orange)  in the after-treatment scan. See that? That region is part of the R brain, a part of the “basal gangia” called the caudate nucleus. You are seeing a treatment change the activity in that part of the brain.

What treatment was it that made the activity in Oscar’s basal ganglia change?  Psychotherapy; a psychotherapy specific for obsessive compulsive disorder called “Exposure and Response Prevention” or ERP.

It’s not easy to find ERP in most places; it takes a behavioral specialist. But if that’s what you’re looking for — and that’s what you should look for if you have OCD that’s not fully responded to a serotonin-based antidepressant, the usual starting point for treatment — you can just ask therapists directly: “do you do Exposure and Response Prevention treatment for OCD?” If the answer’s no, and you can keep shopping, do so until you find one. If you can’t find one, backtrack to those who say they do CBT (Cognitive Behavioral Therapy). That’s a close relative. You and that therapist could get some OCD manuals and work through them together to “make your own” version of ERP locally.  Good luck with the process…