Retrospenial cortical deactivation during painful stimulation of fibromyalgic patients.

To study fibromyalgic pain this article contrasts positron emission tomographic measures of regional cerebral blood flow (rCBF) during externally induced acute pain and rest in eight fibromyalgia syndrome patients. An expected pattern of frontal and parietal cortical activation during acute pain as compared to rest was observed. However, reduced rCBF was additionally found in the retrosplenial cortex during acute pain as compared to rest. This may reflect that externally induced pain inhibits fibromyalgic pain and syndrome-related evaluative processes located in the retrosplenial cortex, and that fibromyalgic pain results from exaggerated attention to sub-noxious pain signaling, that is, secondary hyperalgesia.