"CU Boulder professor links brain's expectations and pain sensation" (Boulder Daily Camera)
"Pain can be a self-fulfilling prophecy - new brain imaging research shows that when we expect something to hurt it does, even if the stimulus isn't so painful." (Science Daily)
With the overuse of pain medication and the growing aging population in our communities, interest in the mechanisms and practical aspects of pain and pain management is high. Tor Wager led the publication of research that takes pain research that shows clear connections between psychology and neuroscience.
From the research abstract (https://www.nature.com/articles/s41562-018-0455-8): Beliefs and expectations often persist despite evidence to the contrary. Here we examine two potential mechanisms underlying such ‘self-reinforcing’ expectancy effects in the pain domain: modulation of perception and biased learning. In two experiments, cues previously associated with symbolic representations of high or low temperatures preceded painful heat. We examined trial-to-trial dynamics in participants’ expected pain, reported pain and brain activity. Subjective and neural pain responses assimilated towards cue-based expectations, and pain responses in turn predicted subsequent expectations, creating a positive dynamic feedback loop. Furthermore, we found evidence for a confirmation bias in learning: higher- and lower-than-expected pain triggered greater expectation updating for high- and low-pain cues, respectively. Individual differences in this bias were reflected in the updating of pain-anticipatory brain activity. Computational modelling provided converging evidence that expectations influence both perception and learning. Together, perceptual assimilation and biased learning promote self-reinforcing expectations, helping to explain why beliefs can be resistant to change.