Kaplan CM, Schrepf A, Ichesco E, et al. - Researchers investigated the interaction between peripheral inflammation, the principal nociceptive stimulus in rheumatoid arthritis (RA), and brain connectivity in RA patients with comorbid fibromyalgia (FM). Functional connectivity magnetic resonance imaging was performed on RA patients with (FM+, n = 27) and without (FM-, n = 27) comorbid FM. The analysis revealed higher levels of ESR to be correlated with increased insula - left IPL, left IPL - dorsal anterior cingulate and left IPL - medial prefrontal cortex functional connectivity. This study for the first time yielded neurobiological evidence suggesting a possible link between comorbid FM in RA and peripheral inflammation; pro-nociceptive patterns of brain connectivity seems mediating this link. Comorbid symptoms in patients with such ‘bottom-up' pain centralization may partially respond to anti-inflammatory treatments.