FIBROMYALGIA: CENTRAL FACTORS IN ITS ETIOPATHOGENESIS - SECOND CYCLE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. There is substantial evidence of abnormal pain sensitivity and functional brain activity in patients with fibromyalgia (FM). We will test 10 hypotheses derived from our model of abnormal pain perception in FM regarding the effects of stress on pain sensitivity and functional activity in brain structures that process pain. We will assess the effects of noxious thermal stimulation and personnally relevant, stressful imagery on pain thresholds and tolerance, magnitude estimates of sensory intensity and unpleasantness, and functional activity of brain structures that process the sensory and affective dimensions of pain. We will perform these evaluation procedures with 120, non-depressed, right-handed women with FM and 60, non-depressed, healty control women. The patients will be classified in one of two groups according to symptom onset (traumatic vs. insidious). We hypothesize that during noxious thermal stimulation patients, compared to controls, will a) produce higher ratings of pain intensity and unpleasantness; and b) show an abnormal pattern of brain activation characterized by bilateral increases in regional cerebral blood flow (rCBF) in the somatosensory cortices and inceases in the ipsilateral anterior cingulate (AC) cortex. We also hypothesize that during exposure to personally relevant, stressful imagery, patients, compared to controls will show a) smaller increases in salivary cortisol; and b) greater increases in blood pressure, pulse rate, thermal pain intensity and unpleasantness ratings, and thermal pain-induced change in the contralateral and ipsilateral somatosensory cortices as well as in the ipsilateral AC cortex. This study will allow us to assess the effects of stress on pain perception and functional brain activity in patients with FM independently of the influence of affective disorders.