A patient reports chronic pain despite lacking any apparent tissue damage. Which mechanism explains this phenomenon, considering descending modulation pathways are intact?

💡 Explanation

Increased substance P receptor sensitivity in the dorsal horn neurons can amplify pain signals even without increased nociceptor input, because this heightened sensitivity causes neurons to fire more readily. Therefore, the perception of chronic pain arises despite intact modulation and the absence of tissue damage, rather than altered glial activation, endorphin release, or nociceptor sensitization.

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