Intrinsic brain connectivity in fibromyalgia is associated with chronic pain intensity

Abstract

Objective. Fibromyalgia (FM) is considered to be the prototypical central chronic pain syndrome and is associated with widespread pain that fluctuates spontaneously. Multiple studies have demonstrated altered brain activity in these patients. The objective of this study was to investigate the degree of connectivity between multiple brain networks in patients with FM, as well as how activity in these networks correlates with the level of spontaneous pain.Methods. Resting-state functional magnetic resonance imaging (FMRI) data from 18 patients with FM and 18 age-matched healthy control subjects were analyzed using dual-regression independent components analysis, which is a data-driven approach for the identification of independent brain networks. Intrinsic, or resting-state, connectivity was evaluated in multiple brain networks: the default mode network (DMN), the executive attention network (EAN), and the medial visual network (MVN), with the MVN serving as a negative control. Spontaneous pain levels were also analyzed for covariance with intrinsic connectivity.Results. Patients with FM had greater connectivity within the DMN and right EAN (corrected P [P corr ] < 0.05 versus controls), and greater connectivity between the DMN and the insular cortex, which is a brain region known to process evoked pain. Furthermore, greater intensity of spontaneous pain at the time of the FMRI scan correlated with greater intrinsic connectivity between the insula and both the DMN and right EAN (P corr < 0.05).Conclusion. These findings indicate that resting brain activity within multiple networks is associated with spontaneous clinical pain in patients with FM. These findings may also have broader implications for how subjective experiences such as pain arise from a complex interplay among multiple brain networks.

Effects of long-term acupuncture treatment on resting-state brain activity in migraine patients: A randomized controlled trial on active acupoints and inactive acupoints

“…These findings were consistent with previous evidence which supports the position that genuine acupuncture leads to stronger DMN deactivation than sham acupuncture on healthy subjects [44]. Previous resting-state fMRI studies have shown that various pain diseases were associated with abnormal connectivity patterns among DMN regions [45,46], and our research group confirmed that migraine patients without aura had a DMN abnormality compared with healthy controls [39]. The DMN has previously been suggested as a potential neural marker of treatment efficacy in chronic pain, and our findings demonstrated that active acupuncture analgesia could be achieved by regulating the migraineurs' resting state and changing the dysfunctional architecture of the DMN.…”

Delayed pain decrease following M1 tDCS in spinal cord injury: A randomized controlled clinical trial

“…For patients with lower pain level, it is possible that the sensorimotor cortex does not show pathophysiological modification or is less alerted when compared to patients with higher pain intensity. Indeed, several neuroimaging studies have demonstrated the correlation between pain intensity and degree of abnormal activity and connectivity within areas of the pain matrix in various chronic pain syndromes [60,64,65]. Future research to identify biomarkers and predictors of tDCS response could help to identify who and why some patients could benefit from this treatment, as well as to develop a patient-tailored stimulation protocol.…”

“…For instance, it has been shown that pain reduction induced by pregabalin intake was related to a decrease in connectivity between the default mode network (DMN) and the insular cortex [59], which is hyperactivated in patients with chronic pain [60,61]. In another neuroimaging study (i.e., functional MRI) evaluating the effects of M1 tDCS in patients with fibromyalgia, the authors demonstrated that tDCS induced a significant reduction in functional connectivity between the thalamus and the supplementary motor area, the medial prefrontal cortex and the cerebellum [62].…”

Optimizing and Interpreting Insular Functional Connectivity Maps Obtained During Acute Experimental Pain: The Effects of Global Signal and Task Paradigm Regression

“…However, the resulting descriptions of the function of the insula in such patients contain inconsistencies. For example, the insula (among other areas) had an increased connectivity to an organized set of areas known as the default mode network (DMN) at baseline in patients with chronic low back pain (Kornelsen et al, 2013; and in fibromyalgia (Napadow et al, 2010), whereas others found that insula to DMN connectivity at baseline was unchanged in complex regional pain syndrome (Bolwerk et al, 2013).…”