International Association for the Study of Pain

• The experience of pain remains impenetrable to scientists because it is so variable.
• So researchers and clinicians still rely on subjective ratings, such as asking patients to rate their pain on a scale of zero to ten.
• Pain is often different in quality (dull, sharp, shocking, throbbing) and it may be hard to remember properly.

The long search for a pain gauge

• In the early 1990s, neuroimaging techniques such as PET scans and fMRIs became a popular way to study pain.
• Both your brain response and your conscious perception of pain are influenced by how much attention you pay to it.
• There is growing evidence that brain response to pain doesn’t always have a meaningful relationship to the level of pain a person is experiencing – heightened brain activity doesn’t always mean heightened pain.

Brain oscillations

• In the 2000s, experimental work showed that gamma oscillations increased in amplitude following both brief and prolonged thermal painful stimuli in healthy volunteers.
• Gamma oscillations may control the connectivity between different brain regions.
• Patient research and recording of electrical activity within the brain seemed to support the idea that gamma oscillations could reflect pain perception better than any other brain response to pain.

What our results mean

• Our findings suggest we must rethink our interpretation of the relationship between pain and gamma oscillations, but that it’s still too early for general rules.
• Some people will feel pain and have no gamma response, while others will show a large response.
• For example, people with chronic pain conditions may have changes in their brain structure and response to pain.