Researchers found brain differences in people who could tolerate high levels of pain and those who were more sensitive.
A research team found individual differences in the grey matter of certain parts of the brain linked to one's pain threshold, a Wake Forest Baptist Medical Center news release reported.
Grey matter had been known to process information while white matter is associated with communication between different regions of the brain. The researchers looked for a connection between grey matter and pain sensitivity in 116 healthy volunteers.
"There has been a huge growth in the study of brain structure and how it relates to chronic pain. In particular, chronic pain has been associated with loss of brain tissue in certain regions of the brain. However, nothing was known about the relationship between pain sensitivity and brain structure in healthy subjects. We had the data and the tools to undertake this analysis in order to address this question," Robert Coghill, Ph.D., professor of neurobiology and anatomy at Wake Forest Baptist and senior author of the study told Headlines and Global News in an e-mail.
The researchers asked the participants to rate their level of pain when a small spot on their skin was heated to 120 degrees Fahrenheit. The study subjects were then given an MRI scan to evaluate their brain structure and grey matter composition.
"Subjects with higher pain intensity ratings had less grey matter in brain regions that contribute to internal thoughts and control of attention," Nichole Emerson, B.S., a graduate student in the Coghill lab and first author of the study, said in the news release.
One's grey matter composition is determined by a number of factors.
"Studies of twins indicate that around [one-third] of pain sensitivity is determined by genetics, while the remaining [two-thirds] might be related to the environment and past history. We could speculate that a similar relationship might be seen with regional differences in gray matter, as changes in brain structure can be related to the activities of the individual," Coghill told HNGN.
Individuals with higher pain levels tended to have less grey matter in their "cingulate cortex, precuneus and areas of the posterior parietal cortex, " the news release reported.
"Default mode activity may compete with brain activity that generates an experience of pain, such that individuals with high default mode activity would have reduced sensitivity to pain," Coghill said in the news release.
Regions of the posterior parietal cortex have been linked to attention in the past. The finding suggests those who are better at focusing may also have an easier time keeping their pain levels under control. The conclusion could have important implications in the future of pain research.
"More than 100 million Americans are affected by pain. Currently, most treatments for pain are simply not good enough, in part because one individual does not respond to treatment like another individual. Being able to better predict an individual's pain sensitivity may allow doctors to individualize treatment, such that insensitive individuals are not overmedicated, while highly sensitive individuals get the aggressive pain management that they need in order to get back to work more quickly," Coghill told HNGN.
