The contribution of neuroimaging techniques to the understanding of supraspinal pain circuits: Implications for orofacial pain

Chronic pain conditions were associated with increased activity in the somatosensory cortices, anterior cingulate cortex, and the prefrontal cortex, and with decreased activity in the thalamus. Few neuroimaging studies used experimental stimuli to the trigeminal system or included orofacial pain patients. However, the available studies appeared to be in agreement with those using stimuli to other body parts and those concerning other chronic pain conditions. Overall, the available data suggest that chronic (orofacial) pain states may be related to a dysfunctional brain network and may involve a compromised descending inhibitory control system. The somatosensory cortices, anterior cingulate cortex, thalamus, and prefrontal cortex may play a vital role in the pathophysiology of chronic pain and should be the main focus of future neuroimaging studies in chronic pain patients.