How Thinking Can Change the Brain

The Dalai Lama, who had watched a brain operation during a visit to an American medical school over a decade earlier, asked the surgeons a startling question: Can the mind shape brain matter?
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At the University of Toronto, Dr. Mayberg, Zindel Segal and their colleagues first used brain imaging to measure activity in the brains of depressed adults. Some of these volunteers then received paroxetine (the generic name of the antidepressant Paxil), while others underwent 15 to 20 sessions of cognitive-behavior therapy, learning not to catastrophize. That is, they were taught to break their habit of interpreting every little setback as a calamity, as when they conclude from a lousy date that no one will ever love them.

All the patients' depression lifted, regardless of whether their brains were infused with a powerful drug or with a different way of thinking. Yet the only "drugs" that the cognitive-therapy group received were their own thoughts.

The scientists scanned their patients' brains again, expecting that the changes would be the same no matter which treatment they received, as Dr. Mayberg had found in her placebo study. But no. "We were totally dead wrong," she says. Cognitive-behavior therapy muted overactivity in the frontal cortex, the seat of reasoning, logic, analysis and higher thought. The antidepressant raised activity there. Cognitive-behavior therapy raised activity in the limbic system, the brain's emotion center. The drug lowered activity there.

With cognitive therapy, says Dr. Mayberg, the brain is rewired "to adopt different thinking circuits."
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Through attention, UCSF's Michael Merzenich and a colleague wrote, "We choose and sculpt how our ever-changing minds will work, we choose who we will be the next moment in a very real sense, and these choices are left embossed in physical form on our material selves."

The discovery that neuroplasticity cannot occur without attention has important implications. If a skill becomes so routine you can do it on autopilot, practicing it will no longer change the brain. And if you take up mental exercises to keep your brain young, they will not be as effective if you become able to do them without paying much attention.
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Prof. Davidson then used fMRI imaging to detect which regions of the monks' and novices' brains became active during compassion meditation. The brains of all the subjects showed activity in regions that monitor one's emotions, plan movements, and generate positive feelings such as happiness. Regions that keep track of what is self and what is other became quieter, as if during compassion meditation the subjects opened their minds and hearts to others.

More interesting were the differences between the monks and the novices. The monks had much greater activation in brain regions called the right insula and caudate, a network that underlies empathy and maternal love. They also had stronger connections from the frontal regions to the emotion regions, which is the pathway by which higher thought can control emotions.

In each case, monks with the most hours of meditation showed the most dramatic brain changes. That was a strong hint that mental training makes it easier for the brain to turn on circuits that underlie compassion and empathy.

"This positive state is a skill that can be trained," Prof. Davidson says. "Our findings clearly indicate that meditation can change the function of the brain in an enduring way.