Every individual’s experience of pain is unique – but that makes it harder to treat. 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.
But my recent work, in collaboration with my colleague Enrico Schulz and his team, showed new insights into a type of brainwave called gamma oscillations that scientists think may be linked to pain perception.
The long search for a pain gauge
Over the past few decades, technological advancements gave researchers the opportunity to finally start developing an objective measurement of pain. In the early 1990s, neuroimaging techniques such as PET scans and fMRIs became a popular way to study pain. This led to a focus on physiological measures of brain activity.
Scientists became excited by the idea of identifying some sort of “pain centre” or “pain network” within the brain. However, studies of the brain activation during pain experiments showed that even innocuous stimuli (for example, warmth, touch or vibration when participants weren’t expecting it) can activate the brain similarly to painful stimuli.
Brain oscillations
Decades of research have shown the type of brainwave called gamma oscillations are a good measure of human response to stimulus in general, not just pain. In the 2000s, experimental work showed that gamma oscillations increased in amplitude following both brief and prolonged thermal painful stimuli in healthy volunteers.
What our results mean
The more we understand about people’s unique response to pain, the closer we can get to giving them the right pain relief. 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.