Subjective perception of tonic pain is selectively encoded by gamma oscillations in the medial prefrontal cortex, differing fundamentally from objective stimulus intensity and brief pain stimuli.
Observational
Gamma oscillations in the medial prefrontal cortex selectively encode the subjective perception of tonic pain, providing a potential brain marker for ongoing chronic pain.
Under physiological conditions, momentary pain serves vital protective functions. Ongoing pain in chronic pain states, on the other hand, is a pathological condition that causes widespread suffering and whose treatment remains unsatisfactory. The brain mechanisms of ongoing pain are largely unknown. In this study, we applied tonic painful heat stimuli of varying degree to healthy human subjects, obtained continuous pain ratings, and recorded electroencephalograms to relate ongoing pain to brain activity. Our results reveal that the subjective perception of tonic pain is selectively encoded by gamma oscillations in the medial prefrontal cortex. We further observed that the encoding of subjective pain intensity experienced by the participants differs fundamentally from that of objective stimulus intensity and from that of brief pain stimuli. These observations point to a role for gamma oscillations in the medial prefrontal cortex in ongoing, tonic pain and thereby extend current concepts of the brain mechanisms of pain to the clinically relevant state of ongoing pain. Furthermore, our approach might help to identify a brain marker of ongoing pain, which may prove useful for the diagnosis and therapy of chronic pain.
Schulz et al. (Sun,) conducted a observational in Healthy. Tonic painful heat stimuli was evaluated on Subjective perception of tonic pain and its relation to brain activity. Subjective perception of tonic pain is selectively encoded by gamma oscillations in the medial prefrontal cortex, differing fundamentally from objective stimulus intensity and brief pain stimuli.