A metal probe attached to the underbelly of my arm heated up and cooled down at set intervals. I was told that although the heat probe would feel uncomfortable, my skin would not be burned. During one exposure, I was instructed to think of the pain as positively as possible, during another to think of it as negatively. After each sequence, I was asked to rate my pain on a 0-to-10 scale, with 10 being the worst pain I could imagine.

Although I discovered that I could make the pain fluctuate depending on whether I was imagining that I was sunbathing or was the victim of an inquisition, I still rated all the pain as low — ranging from a 1 to a 3. If 10 was being slowly burned alive, I felt I should at least be begging for mercy to justify a rating of 5. So I insisted that Mackey turn up the dial so I could get a real response. But even during the moments when I was actively trying to imagine the pain as negatively as possible, it remained in a mental box of "not even burned," which kept it from really hurting: hurting, that is, the way a burn would.

As it turned out, I got a second-degree burn that later darkened into a square mark. Mackey was more than a little dismayed as we watched the reddening skin pucker, but I was thrilled. Naturally the protocol had been carefully designed not to injure anyone, yet in my case that protection had failed because of the very phenomenon it was designed to study: expectation — the effect of the mind on pain or placebo.

I had recently spent several weeks observing Mackey in the university's pain clinic, where he is associate director. I was so convinced that Mackey — then a tall sandy-haired 39-year-old with a deep interest in technology (he got a Ph.D. in electrical engineering before he went to medical school) and an air of radiant integrity — would not burn me that my brain had not perceived the stimulus as a threat and generated pain. I admired him, I trusted him, I was positive that he wouldn't hurt me. And, ipso facto, he hadn't.

Mackey's genius as a practitioner, I thought, lay partly in his ability to similarly inspire patients. "When I started working with pain patients, I realized how much of the treatment involved trying to reverse learned helplessness," he said — to rally them out of the despair ingrained from years of unremitting pain and cajole their minds to chip in its own analgesic to their therapies. "The purpose of this study is to show patients their mind matters," Mackey said.

The mark of the burn is barely visible now, but for a couple of years afterward, at times when my chronic pain was making me miserable, the sight of it would both encourage and reproach me. Here is the ultimate proof that my mind can control pain, I would think, yet I didn't know how to make it wake up and do so. I could take the edge off the pain by conjuring positive images, but the effects didn't last, and I never again had the remarkable placebo response that masked a second-degree burn. In fact, a mild burn from spilling tea on my hand one day brought tears to my eyes.

When the real-time neuroimaging study began, I couldn't wait to try it.





The area of the brain that the scanner focuses on is the rostral anterior cingulate cortex (rACC). The rACC (a quarter-size patch in the middle-front of the brain, the cingular cortex) plays a critical role in the awareness of the nastiness of pain: the feeling of dislike for it, a loathing so intense that you are immediately compelled to try to make it stop. Indeed, the pain of pain, you might say, its defining element, is the way in which the sensation is suffused with a particular unpleasantness researchers refer to as dysphoria. Since pain is a perception, it's not pain if you don't experience it as hurting. You can feel hot or cold or pressure, and note them simply as stimuli, but when they exceed a certain intensity, the rACC kicks in, and suddenly they become painful, riveting your attention and causing you to recoil.