Expecting Pain

One of the most striking breakthroughs in pain research has been the discovery of expectancy modulations, according to which subjective experiences do not only reflect nociceptive input but also individuals’ previous knowledge and beliefs. Expectancy modulations are noteworthy for their clinical implications, as convincing individuals of the effectiveness of an analgesic might induce a strong pain relief (placebo effect). Furthermore, expectancy effects have sparkled a major theoretical debate, with influential models suggesting that pain symptoms might be better explained through a Bayesian framework, where the brain estimates the (posterior) probability of body damage, based on the integration of sensory inputs and prior representations. However, pain is a multi-component experience, that has both sensory components and a strong unpleasantness, common with many other painless experiences (e.g., disgust). This raises the question about the nature of the predictive information at play during expectancy, and whether it relates to pain-specifically (“this will hurt”), or rather to an undistinctive negative event (“this will be bad”).