The findings could help detect pain in people with limited communication abilities, such as those in a coma, small children and dementia patients. Professor Irene Tracey, University of Oxford, whose team made the discovery, said, "Pain is a complex, multidimensional experience, which causes activity in many brain regions involved with things like attention, feeling emotions such as fear, locating where the pain is, and so on. But the dorsal posterior insula seemed to be specific to the actual 'hurt level' of pain itself."
The researchers tracked brain activity in 17 healthy volunteers who had a cream containing capsaicin (the active ingredient in chillies) applied onto their right leg, causing a burning sensation. The volunteers indicated how much this burning sensation hurt them. Once the pain sensation began to fade, the researchers 'rekindled' the burning sensation by putting a hot water bottle where the cream was applied. A few minutes later, they provided participants pain relief by switching to a cooling water bottle. The study participants' ratings of how much the pain hurt accordingly went up and then down.