Intrinsic brain connectivity in fibromyalgia is associated with chronic pain intensity

TLDR

Fibromyalgia is a central chronic pain syndrome marked by widespread, fluctuating pain, and studies have documented altered brain activity in these patients. This study aimed to examine the connectivity between multiple brain networks in fibromyalgia patients and how such connectivity relates to spontaneous pain intensity. Resting‑state fMRI data from 18 fibromyalgia patients and 18 matched controls were analyzed with dual‑regression independent component analysis to assess intrinsic connectivity in the default mode, executive attention, and medial visual networks and its covariance with pain levels. Fibromyalgia patients showed increased connectivity within the default mode and right executive attention networks, greater coupling between the default mode network and the insular cortex, and stronger insula‑network connectivity correlated with higher spontaneous pain, indicating that resting‑state network activity is linked to clinical pain intensity.

Abstract

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.