Neuroscience 1, Philosophy 0

"I think, therefore I have a brain."

Okay, so it's not as catchy as Rene Descartes's original maxim, "I think, therefore I am." But if the philosopher were alive today, he'd agree that his famous phrase--which assumed that mind and brain are completely separate things--needs some updating.

Studies of stroke victims, as well as brain imaging research, support the idea that the mind essentially is the brain. Or, at least, it's what the brain does. But if you want further evidence, consider a recent study demonstrating that psychotherapy can alter brain function.

Researchers at UCLA treated patients with obsessive-compulsive disorder (OCD) to about 10 weeks of cognitive and behavioral therapy. The scientist also took "before" and "after" pictures of patients' brains using PET scans, which visualize brain activity

The PET scans revealed that In OCD patients, several parts of the brain--notably the caudate nucleus, orbital cortex, and thalamus--were running in overdrive. "What therapy does is break up this reverberating loops, this worry circuit," reports Louis Baxter, M.D., a psychiatrist and pharmacologist at both UCLA and the University of Alabama.

Indeed, in patients who responded to treatment, these brain regions no longer lit up in unison on PET scans. Meaning, of course, that purely psychological therapy had some very biological effects on the brain.

All of which might give pause to anybody who still divides mental disorders into diseases of the brain and diseases of the mind. "I think that to separate the brain from the mind at a deep level doesn't make much sense," says Baxter. "Descartes was a good mathematician but a bad philosopher."

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