[Functional imaging of the brain in the investigation of chronic unexplained pain]

Chronic unexplained pain poses a major problem in both clinical practice and society. The traditional psychological explanations have recently been supplemented by neurobiological data from functional neuroimaging studies, particularly functional MRI. Sensitization, hypersensitivity of the nervous system for sensory stimuli, is an important element in several theories about the pathophysiology of chronic pain. Functional MRI has yielded evidence for central sensitization in several chronic pain syndromes; such sensitization seems to occur mainly in regions of secondary pain processing, i.e. outside the primary pathways for sensory stimuli. More accurate insight into the underlying cerebral processes opens up possibilities for the diagnosis and treatment of chronic unexplained pain.