An analysis to identify different brain responses in patients with chronic pain revealed no aberrant neuroimaging activity related to noxious stimuli, according to an article published in JAMA Network Open.
The analysis included 37 experiments comparing brain responses to noxious stimuli in functional magnetic resonance imaging (fMRI). The primary analysis sought to identify areas associated with aberrant activity in response to noxious stimuli in patients with chronic pain by assessing differences between patients and controls. Follow-up analyses examined the directionality of any differences.
The results revealed no significant differences between 511 patients with chronic pain and 433 healthy controls in brain responses to noxious stimuli that induce pain at the preregistered statistical threshold. However, exploratory analyses suggested that subtle, spatially diffuse differences may exist within the pain network.
The authors note that most of the included experiments matched noxious stimulation in patients and controls using subjective ratings of pain, which may contribute to the observed null results.
They suggest that future work on chronic pain biomarkers may benefit from focus on this core set of pain-responsive areas.