2016 Volume 56 Issue 5 Pages 419-426
Central sensitization and descending facilitation may play important roles in the pathogenesis and maintenance of pain in fibromyalgia (FM). Brain imaging MRI scans of FM patients are characterized by 1) augmented brain responses to experimental pain stimuli, 2) changes in brain morphology (atrophy) in brain regions of pain processing, and 3) changed resting-state functional connectivity. Characteristic functional connectivity of brain networks in FM patients is summarized from the literature as follows ; FM patients had more positive and negative correlations within the pain network than healthy controls. FM patients displayed enhanced functional connectivity of the anterior cingulate cortex (ACC) with the insular cortex (IC) and basal ganglia. On the other hand, functional connectivity of the ACC/IC/thalamus with areas involved in the descending inhibitory system, such as the periaqueductal gray matter (PAG) and the rostral ventromedial medulla (RVM) was reduced in FM patients. Increased insular connectivity to the default mode network (DMN), a network whose activity is increased during non-task resting states, was also observed in FM patients. The reduction of DMN-IC connectivity following acupuncture therapy was correlated with diminished pain. Moreover, FM patients treated with Cognitive Behavioral Therapy showed improvement of brain connectivity and reported less pain. These findings strongly suggest that the brain network connectivity measures could potentially be used in studies elucidating mechanisms of pain in FM patients or clinical settings to evaluate the effective therapeutic strategy for FM. Exercise is commonly recommended in the management of people with FM. In FM patients, positive relationships between physical activity and brain responses to pain were observed in regions implicated in pain regulation, suggesting that physically active FM patients appear to maintain their ability to modulate pain.
