Sensitivity to pain expectations: A Bayesian model of individual differences

Abstract

The thoughts and feelings people have about pain (referred to as 'pain expectations') are known to alter the perception of pain. However little is known about the cognitive processes that underpin pain expectations, or what drives the differing effect that pain expectations have between individuals. This paper details the testing of a model of pain perception which formalises the response to pain in terms of a Bayesian prior-to-posterior updating process. Using data acquired from a short and deception-free predictive cue task, it was found that this Bayesian model predicted ratings of pain better than other, simpler models. At the group level, the results confirmed two core predictions of predictive coding; that expectation alters perception, and that increased uncertainty in the expectation reduces its impact on perception. The addition of parameters relating to trait differences in pain expectation improved the fit of the model, suggesting that such traits play a significant role in perception above and beyond the influence of expectations triggered by predictive cues. When the model parameters were allowed to vary by participant, the model's fit improved further. This final model produced a characterisation of each individual's sensitivity to pain expectations. This model is relevant for the understanding of the cognitive basis of pain expectations and could potentially act as a useful tool for guiding patient stratification and clinical experimentation.

The Importance of Sensory Processing in Mental Health: A Proposed Addition to the Research Domain Criteria (RDoC) and Suggestions for RDoC 2.0

“…An emerging theme in computational psychiatry in relation to sensory sensitivity is a failure of sensory attenuation — usually cast in terms of a failure to modulate the precision of sensory prediction errors within a predictive coding framework. Psychophysically, this translates directly into a failure to modulate sensory sensitivity, and has been proposed as a key etiological factor in many conditions, ranging from autism to schizophrenia and from depression to chronic pain disorders (Pellicano and Burr, 2012; Adams et al, 2013; Van de Cruys et al, 2014; Powers et al, 2017; Clark et al, 2018; Hoskin et al, 2019), some of which we will further explore below.…”

The relationship between fear generalization and pain modulation: an investigation in healthy participants

“…Assimilation-contrast theory (41) suggests that the distance between prior experience and the actual stimulus is crucial. When the distance is small (i.e., when the stimulus is not too discrepant from our existing anchor), pain perception will be biased towards the expected level of pain (i.e., assimilation) (25). However, when the reality is very different to our expectations, "we will experience the real, discrepant stimulus as even more discrepant compared to our expectations" (19, p.182).…”

“…i.e., ambiguous stimuli that were neither clearly painful or non-painful) are experienced as painful more often when paired with a CS+, compared to a CS- (23). Pain modulation is mediated by expectations (19,24,25) and emotional states such as fear (9,22,26). The question remains whether similar expectancies and fear elicited by GSs may play a mediating role in experiencing threshold-USs as painful or not.…”

Pessimistic dairy calves are more vulnerable to pain-induced anhedonia

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