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MIT Better World

By Richard Anthony

Sure, most of us have had successes along the way. But there are usually one or two habits – a persistent weakness for chocolate, an inability to leave your car keys where they’re supposed to go – that seem basically unshakable.

Ann Graybiel, an MIT professor of brain and cognitive sciences, wants to find out why we persist in certain behaviors. She hopes her efforts will someday help yield remedies for unwanted habits.

Graybiel is quick to note that many habits are good. If we had to plan out every step each time we wanted to, say, start the car, daily existence would be a monumental struggle. “We live mostly by habit,” she observes.

But she also says that all habits seem to stem from generally similar types of brain activity. “If we can understand that mechanism,” says Graybiel, “I personally believe that we will find new ways to change behaviors that are destructive.”


In talking about the potential reach of her work, Graybiel notes that habitual behaviors take root in the same brain area linked to some extremely serious ailments. One is Parkinson’s disease, the movement-inhibiting condition whose victims include actor Michael J. Fox. Another is obsessive-compulsive disorder, whose sufferers do things over and over – wash their hands, obsess about a word or memory – even though they know the behavior is senseless.

“One real-life example,” she says, “is a father who would drop his child off at kindergarten. Two blocks later, he’d say to himself, ‘Did I really do it?’ and drive back to find out. Then he’d leave the school again, and the pattern would start all over.”

Her work relates to drug addiction as well. “To me, addictions are habits that have become overwhelmingly compelling, so they dominate us instead of freeing us to do other things.”

Graybiel didn’ t set out hoping to point the way to new strategies for dealing with bad habits or nervous-system disorders. A Harvard grad, she studied for a Ph.D. at MIT with the aim of probing basic issues like how the brain controls our visual apparatus.

After she joined the faculty, that work led her to the question of how the brain fosters behaviors — and soon she was hooked. “If you’re concerned with some of the most devastating disorders we know,” she explains, “that keeps your interest up.”


When many think of the brain and behavior, they think of the famed twin lobes of the frontal cortex – the image that specifically seems to say, “This is a human brain.” In fact, that area is often called the brain’s “executive” because it’s where many will do / won’t do issues get decided.

But it’s not the only region involved in behavior. Graybiel’s focus is another brain region underneath the frontal lobes that harbors a large group of structures known collectively as the basal ganglia.

The basal ganglia have been linked to disorders like Parkinson’s disease, Huntington’s disease, and obsessive-compulsive disorder; to addictions, and to habit formation. Graybiel herself has made key findings about these structures: in research with lab rodents, for example, she and her co-workers discovered that teaching the animals a skill like navigating a simple maze to get a reward — “We use chocolate,” she notes — yielded dramatic changes in selected basal ganglia cells.

Such changes are evidence of learning’s impact on the brain, she says. And it’s learning of the type you’d associate with forming habits: acquired slowly, but once in place, tough to change.

“The process doesn’ t seem to go in reverse,” she notes, “or at least we don’t yet have the means to reverse it.” Still, Graybiel and others are making headway on the question of how behaviors originate in the brain. One discovery is that habits often represent “chunks” of behavior — you get up, start the coffee, get the paper, put out the cat — that are inextricably linked in terms of what’s going on in the brain.


Researchers are also learning more about brain manifestations of behavioral ailments. In obsessive-compulsive disorder and another devastating ailment called Tourette’s syndrome, notes the scientist, brain scans find that “little pieces of cortex and the basal ganglia are lit up all the time.”

And, Graybiel and others are pinpointing specific basal ganglia areas linked to different types of problems. If a lab rodent becomes cocaine-addicted, she notes, and you make a small surgical change in one small area of its basal ganglia, it will “lose its addiction just like that — bang!”

But Graybiel cautions against letting such results fuel undue optimism about easy remedies for human addictions or diseases. Even brain scientists, she says, consider the systems she probes yet-to-be-solved mysteries.

“How can the same brain structures that produce Parkinson’s also produce St. Vitus’ dance — whose symptoms are the opposite of Parkinson’s — along with addictive behavior, and also help us form habits?” she asks. “Right now, it’s impossible to say.”

But in a way, she says, that’ s the point: we need to further explore the machinery at work. And she has a hunch that when we do, we may be surprised at some of the techniques that emerge for confronting — well, how about bad habits?

“If we really understand what’ s going on in the brain,” she says, “we may find we’re able to deal with some of these issues without drugs or drastic measures.”