Researchers use fMRI to examine patterns of brain activation in patients with chronic pain

Cognition is known to influence pain perception. As a result, several mind-body and psychological therapies are commonly used to treat chronic pain. A new study from the October issue of Anesthesiology analyzed whether two of the most commonly applied strategies involve different brain systems.

Researchers from Stanford University examined patterns of brain activation in patients with chronic pain using functional magnetic resonance imaging (fMRI) during two common cognitive strategies, external focus of attention and reappraisal.

Findings showed each cognitive strategy involved a different brain system with only a small amount of overlap. During external focus of attention, subjects are asked to draw their focus away from the pain. Brain activity was observed mainly in the cortical areas. While during reappraisal, subjects are instructed to change the interpretation of the pain from threatening to non-threatening. Activity was found in deep brain structures, as well as in some cortical regions. Only one area was observed to be active during both strategies.

"In the past, it has been unclear whether pain therapies work in the same way to manipulate brain systems related to pain. However, we found that the two cognitive strategies we looked at use different brain systems," said senior study author Sean C. Mackey, M.D., Ph.D. "Our study helped support that each cognitive strategy may have a unique brain pattern distinct from other strategies."

The data also showed that not every mind-body or psychological treatment for chronic pain works in the same manner, but instead may involve distinctly different brain pathways. This may explain why one strategy may be effective in one patient but not effective in others. Researchers hope to amplify responses in the future using real-time fMRI neurofeedback to directly control brain systems.