Monday, February 3, 2014

When in pain, are you a baby or linebacker? Brain study offers clues

When it comes to pain, do you cry like a baby at the slightest bump or are you a football player, pushing through the anguish without a pause? New research shows how you react to pain may be linked to how much grey matter you have in certain areas of the brain.
A study published in January in the journal Pain found less pain sensitivity in people who had denser grey matter in the areas that control how we focus attention and areas involved in daydreaming. The findings may help doctors to recognize which patients will need less pain medication after surgery and also give clues to the development of chronic pain syndromes.
For the new study, researchers tested the pain sensitivity of 116 healthy volunteers by touching them with a probe that was heated to 120 degrees Fahrenheit and then asking them to rate the level of the pain on a scale of 0 to 10. Several days later the volunteers were given an MRI, which found that those who were least sensitive to pain were the ones with the most grey matter in the posterior cingulate cortex, the precuneus, the intraparietal sulcus, and the inferior parietal lobule. The researchers suspect that people with more grey matter in these areas are better able to distract themselves from pain messages.
There’s a constant competition for what your brain will pay attention to, “and pain is very good at winning,” said study co-author Robert Coghill, a professor of neurobiology and anatomy at the Wake Forest Baptist Medical Center in Winston-Salem, N.C. “It’s very good at cutting through all that stuff floating around in your head. The more focused you are on something that is not related to the pain, the better able you are to disregard it.”
Our brains are constructed so we can be distracted from the sensation of pain in certain circumstances, such as when athletes are competing. For example, in a recent op-ed in The New York Times, former Denver Broncos tight end Nate Jackson said something in football “grants men temporary invincibility, makes them immune to pain and anguish.”
The Wake Forest findings support prior research showing "you need lots of brain matter to help reduce the amount of pain information that enters the brain," although it doesn’t address whether people who have less grey matter were born that way or became that way as a result of life experiences, said Dr. Jordan Karp, associate professor of psychiatry and anesthesiology at the University of Pittsburgh School of Medicine and medical director of geriatric psychiatry at UPMC Pain Medicine.
Prior research has shown that chronic pain can lead to a thinning of grey matter. And, in light of the new research, those changes may set up a vicious cycle of pain killing off the very nerves that might help dull its cuts. “We do know that long-term exposure to pain really seems to have a toxic effect on both brain functioning and brain physiology and anatomy,” Karp said.
It may make sense that iron-will football players can be impervious to pain, but regular folks can be just as good at ignoring pain messages if they’re focused on something they deem to be important.
When 70-year-old Colleen Bickman is deeply involved in an activity, she barely notices when she bumps or bangs into something. “I’m fairly oblivious when I stub a toe,” said the Monte Sereno, Calif. retiree. “Sometimes I find a bruise and I don’t know where I got it. I don’t always feel it the instant it happens.”
Many people don’t realize that pain sensitivity varies.
“People are like, ‘OK, why are you whining? That wouldn’t hurt me,’” said Dr. Kirsten Tillisch, an associate professor of digestive diseases at the UCLA David Geffen School of Medicine. “Just why some people are more sensitive is a key question.”
So, is it hopeless for those who were born super sensitive to pain? 
You can train your brain to focus on other things, Coghill said. A prior Wake Forest study on pain and meditation found meditation not only affected people’s ratings of pain, but also their brains’ responses to it.
Ultimately, Coghill said, “when we have a rich and varied life, that’s going to be a real buffer against pain.”
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