How different pain levels affect the brain
The University of Oxford team used a new imaging technique to observe how different levels of pain affected the brains of 17 volunteers.
Activity in only one area of the brain – the dorsal posterior insula – matched the participants' self-reported pain ratings.
Read: Transparent brains
This method could be used to help assess pain levels in people who have difficulty providing doctors with that information, such as those in a coma, small children or dementia patients, said the authors of the study published in the journal Nature Neuroscience.
"We have identified the brain area likely to be responsible for the core, 'it hurts', experience of pain," researcher Irene Tracey said in a university news release.
Dorsal posterior insula
"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 seems to be specific to the actual 'hurt level' of pain itself," she explained.
"We were able to find this area by developing a new method of tracking brain activity," Tracey said. "This allowed us to look at more complex brain states that stretch over much longer periods. By tracking pain felt over many hours, we were able to filter out more momentary experiences, such as variations in attention or fear."
Read: Pain control
In the study, 17 healthy volunteers had a cream containing capsaicin (the active ingredient in chili peppers) applied to their right leg, causing a burning sensation. When that pain began to subside, a hot water bottle was applied to the same area, to rekindle the pain. After a few minutes, a cool water bottle was placed on the area to relieve the pain.
While all this was being done, the participants' brains were being scanned and they were telling the researchers about their levels of pain.
Changing activity may ease pain
The results suggest that by changing activity in the dorsal posterior insula, it may be possible to ease pain that doesn't respond to other treatments, the researchers said.
Image: Illustration of the human brain from Shutterstock