Meaning of brain scans for ’pain’ called into question

Patterns of brain activity thought to show pain responses have been called into question after researchers from UCL and the University of Reading saw such patterns in rare patients born without a sense of pain. The study, published in JAMA Neurology and funded by the Medical Research Council and European Commission, was designed to test the 'pain matrix'. This is a pattern of brain activity that has been so consistently observed in almost every neuroimaging study of pain in humans that it is often considered a marker for pain. The association is so pervasive that the 'pain matrix' has been used in research to suggest that social rejection or mental effort can cause 'pain'. To test whether this pattern actually represents the sense of pain, researchers used functional magnetic resonance imaging (fMRI) to measure brain activity in two rare individuals born without the ability to feel pain and four age-matched healthy volunteers. They were exposed to painful 'pinprick' stimuli while their brain activity was measured. The people with no sense of pain showed the same pattern of brain activity as the healthy volunteers, casting doubt on the theory that this pattern represents pain.