Researchers will use H-MRS imaging in patients with fibromyalgia to determine whether reduction of the excitatory neurotransmitter glutamate in the insula (a specific area of the brain) is associated with decreased sensations of pain and related mood dysfunction in this disorder.
Fibromyalgia is a chronic pain disorder thought to result from a disturbance in the way the central nervous system processes pain. These patients spontaneously report pain throughout their bodies even though there is no inflammatory or anatomical damage. In addition to chronic pain, patients also suffer from related mood disturbances such as anxiety and depression. The Michigan investigators and others have recently shown that fibromyalgia patients may have heightened neural activity in a region of the brain called the insula, and that this excess activity may be related to elevated levels of the excitatory neurotransmitter glutamate. The insula is a complex brain structure with diverse functions that include processing pain, regulating emotion, and facilitating the sense of self-awareness.
Recent research suggests that the anterior and posterior portions of the insula carry out different functions, with posterior neurons coordinating sensory aspects of pain while anterior neurons process related mood disturbances and anxiety. The Michigan researchers hypothesize, therefore, that reducing glutamate in these separate portions of the insula will correlate with reduced pain and anxiety, respectively. They will explore this hypothesis using H-MRS imaging (proton magnetic resonance spectroscopy). This imaging method measures concentrations of specific brain metabolites, in this case glutamate, in defined brain areas. They will undertake H-MRS imaging in 20 fibromyalgia patients before and following a one-month course of acupuncture treatment, which has been demonstrated to reduce pain within a relatively short period. Changes in glutamate levels in the anterior and posterior insula will be correlated with measures of patients’ anxiety and pain levels, respectively.