RecruitingPain Processing in Inflammatory and Non-Inflammatory Chronic Pain SyndromesFibromyalgia (FM) is a chronic musculoskeletal pain disorder that afflicts up to 4% of the general population. The evaluation of pain mechanisms in FM has shown predominant central abnormalities and therefore has been designated as nociplastic pain syndrome. Rheumatoid arthritis (RA) is characterized by polyarthritis and pain from inflamed tissues, consistent with nociceptive pain. FM and RA patients may utilize overlapping pain mechanisms resulting in nociceptive and nociplastic pain.