Objective: There is vast evidence for brain aberrations in patients with fibromyalgia (FM) and it is possible that central plasticity is critical for the transition from acute to chronic pain. However, the relationship between brain structure and function is poorly investigated. Methods: The present study, including 26 FM patients and 13 age- and gender-matched healthy controls, investigated the differences between patients and controls regarding functional connectivity during intermittent pressure pain and measures of brain structure. Magnetic resonance imaging (MRI) was used to obtain high-resolution anatomical images and functional MRI scans for measures of pain-evoked brain activity. Results: FM patients displayed a distinct overlap between decreased cortical thickness, brain volumes and measures of functional regional coherence in the rostral anterior cingulate cortex. The morphometric changes were more pronounced with longer exposure to FM pain. In addition, we found associations between structural and functional changes in the mesolimbic areas of the brain and comorbid depressive symptoms in FM patients. Conclusion: The combined integration of structural and functional measures allowed for a unique characterization of the impact of FM pain on the brain. Our data may lead to the identification of early structural and functional brain alterations in response to pain, which could be used to develop markers to predict the development of FM and other pain disorders. (c) 2013 American College of Rheumatology.