Disrupted functional connectivity of the pain network in fibromyalgia.
OBJECTIVE
To investigate the impact of chronic pain on brain dynamics at rest.


METHODS
Functional connectivity was examined in patients with fibromyalgia (FM) (n = 9) and healthy controls (n = 11) by calculating partial correlations between low-frequency blood oxygen level-dependent fluctuations extracted from 15 brain regions.


RESULTS
Patients with FM had more positive and negative correlations within the pain network than healthy controls. Patients with FM displayed enhanced functional connectivity of the anterior cingulate cortex (ACC) with the insula (INS) and basal ganglia (p values between .01 and .05), the secondary somatosensory area with the caudate (CAU) (p = .012), the primary motor cortex with the supplementary motor area (p = .007), the globus pallidus with the amygdala and superior temporal sulcus (both p values < .05), and the medial prefrontal cortex with the posterior cingulate cortex (PCC) and CAU (both p values < .05). Functional connectivity of the ACC with the amygdala and periaqueductal gray (PAG) matter (p values between .001 and .05), the thalamus with the INS and PAG (both p values < .01), the INS with the putamen (p = .038), the PAG with the CAU (p = .038), the secondary somatosensory area with the motor cortex and PCC (both p values < .05), and the PCC with the superior temporal sulcus (p = .002) was also reduced in FM. In addition, significant negative correlations were observed between depression and PAG connectivity strength with the thalamus (r = -0.64, p = .003) and ACC (r = -0.60, p = .004).


CONCLUSIONS
These findings demonstrate that patients with FM display a substantial imbalance of the connectivity within the pain network during rest, suggesting that chronic pain may also lead to changes in brain activity during internally generated thought processes such as occur at rest.
Research Institute on Health Sciences, University of the Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca, Spain.
Ignacio
I
Cifre
Carolina
C
Sitges
Daniel
D
Fraiman
Miguel Ángel
MÁ
Muñoz
Pablo
P
Balenzuela
Ana
A
González-Roldán
Mercedes
M
Martínez-Jauand
Niels
N
Birbaumer
Dante R
DR
Chialvo
Pedro
P
Montoya
D000222:Adaptation, Physiological; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D059350:Chronic Pain / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology* / Q000523:psychology; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D009434:Neural Pathways; D058748:Pain Perception / Q000502:physiology; D012039:Regional Blood Flow; D012146:Rest / Q000502:physiology*; D013850:Thinking / Q000502:physiology; D013997:Time Factors