Pain in context: The role of context in generalization, extinction and return of fear of contextual pain-related fear.

Growing evidence supports the idea that pain-related fear is even more disabling than pain itself, and contributes to the transition from acute to chronic pain. Some people fear movements that they associate with increased pain and bodily harm. Such proprioceptive fear is common in chronic back/neck pain, and a subgroup develops pain at multiple body locations. Patients with such widespread pain often fail to identify signals for increased pain, and report more intense pain, lower functionality, and lower quality of life. To date, the mechanisms involved in the spreading of pain are largely unknown and no medical solution is available for this challenging group of widespread pain patients. This project presents an experimental model for widespread pain based on pain unpredictability leading to contextual rather than cued pain-related fear. We examine the generalization, extinction and return of contextual pain-related fear. In particular, we expect that pain unpredictability not only fosters fear generalization but also the spreading of pain inducing increased pain sensitivity. We also expect that context exposure and restored pain predictability reduces contextual pain-related fear, and that exposure to unsignaled pain/stressors reinstates contextual pain-related fear. Given its unique relevance for musculoskeletal pain, a proprioceptive fear conditioning model in which arm movements are (un)paired with a painful electrocutaneous stimulus will be used to test our hypothesis.