Patients with Fibromyalgia Display Less Functional Connectivity in the Brain's Pain Inhibitory Network

Abstract

BackgroundThere is evidence for augmented processing of pain and impaired endogenous pain inhibition in Fibromyalgia syndrome (FM). In order to fully understand the mechanisms involved in FM pathology, there is a need for closer investigation of endogenous pain modulation. In the present study, we compared the functional connectivity of the descending pain inhibitory network in age-matched FM patients and healthy controls (HC).We performed functional magnetic resonance imaging (fMRI) in 42 subjects; 14 healthy and 28 age-matched FM patients (2 patients per HC), during randomly presented, subjectively calibrated pressure pain stimuli. A seed-based functional connectivity analysis of brain activity was performed. The seed coordinates were based on the findings from our previous study, comparing the fMRI signal during calibrated pressure pain in FM and HC: the rostral anterior cingulate cortex (rACC) and thalamus.ResultsFM patients required significantly less pressure (kPa) to reach calibrated pain at 50 mm on a 0–100 visual analogue scale (p < .001, two-tailed). During fMRI scanning, the rACC displayed significantly higher connectivity to the amygdala, hippocampus, and brainstem in healthy controls, compared to FM patients. There were no regions where FM patients showed higher rACC connectivity. Thalamus showed significantly higher connectivity to the orbitofrontal cortex in healthy controls but no regions showed higher thalamic connectivity in FM patients.ConclusionPatients with FM displayed less connectivity within the brain’s pain inhibitory network during calibrated pressure pain, compared to healthy controls. The present study provides brain-imaging evidence on how brain regions involved in homeostatic control of pain are less connected in FM patients. It is possible that the dysfunction of the descending pain modulatory network plays an important role in maintenance of FM pain and our results may translate into clinical implications by using the functional connectivity of the pain modulatory network as an objective measure of pain dysregulation.

Conditioned Pain Modulation in Patients With Acute and Chronic Low Back Pain

“…Studies that correlate CPM with brain processes have revealed modifications in the activation of different brain areas 14 and in the functional connectivity of the descending inhibitory system. 15 The origin of these changes, however, remains unclear.…”

Fibromyalgia Syndrome in Need of Effective Treatments

“…One study found that FMS patients exhibited higher sensitivity to pain provocation than controls and that they required less pressure to evoke equal pain, but they failed to respond to pain provocation in the primary link in the descending pain-regulating system (the rostral anterior cingulate cortex) (Flodin et al, 2014). Another study comparing the functional connectivity of the descending pain inhibitory network in age-matched FMS patients and healthy controls found that patients displayed less connectivity within the brain's pain inhibitory network during calibrated pressure pain compared with healthy controls (Jensen et al, 2012).…”

“…A number of studies have provided further evidence of dysfunctional connectivity of the pain network in FMS (Jensen et al, 2012;Flodin et al, 2014). One study found that FMS patients exhibited higher sensitivity to pain provocation than controls and that they required less pressure to evoke equal pain, but they failed to respond to pain provocation in the primary link in the descending pain-regulating system (the rostral anterior cingulate cortex) (Flodin et al, 2014).…”

Neuroimagen de la fibromialgia: una enfermedad del cerebro

“…Contrariamente, se constata una reducción del VSG en la circunvolución temporal superior (71,73), INS (71,77,78), COF lateral (72) y medial (71,74,76,79,80), CCA rostral (61,72,76,77,79), CCP (71,76,80), precuneus izquierdo (71,75,76), TAL (48,73), amígdala (48,61), circunvolución parahipocámpica (61,76,79), putamen (48) y SGP (48,75). Es de especial relevancia el decremento del VSG y grosor de la corteza en la CCA en su porción rostral, así como una reducción significativa del VSB en la CCA rostral izquierda y en la COF lateral izquierda (72), puesto que ello conlleva a una desregulación de los mecanismos inhibitorios endógenos en la FM (33,69,72,75,78).…”