title: The contribution of sensory system functional connectivity reduction to clinical pain in fibromyalgia.
abstract: Fibromyalgia typically presents with spontaneous body pain with no apparent cause and is considered pathophysiologically to be a functional disorder of somatosensory processing. We have investigated potential associations between the degree of self-reported clinical pain and resting-state brain functional connectivity at different levels of putative somatosensory integration. Resting-state functional magnetic resonance imaging was obtained in 40 women with fibromyalgia and 36 control subjects. A combination of functional connectivity-based measurements were used to assess (1) the basic pain signal modulation system at the level of the periaqueductal gray (PAG); (2) the sensory cortex with an emphasis on the parietal operculum/secondary somatosensory cortex (SII); and (3) the connectivity of these regions with the self-referential "default mode" network. Compared with control subjects, a reduction of functional connectivity was identified across the 3 levels of neural processing, each showing a significant and complementary correlation with the degree of clinical pain. Specifically, self-reported pain in fibromyalgia patients correlated with (1) reduced connectivity between PAG and anterior insula; (2) reduced connectivity between SII and primary somatosensory, visual, and auditory cortices; and (3) increased connectivity between SII and the default mode network. The results confirm previous research demonstrating abnormal functional connectivity in fibromyalgia and show that alterations at different levels of sensory processing may contribute to account for clinical pain. Importantly, reduced functional connectivity extended beyond the somatosensory domain and implicated visual and auditory sensory modalities. Overall, this study suggests that a general weakening of sensory integration underlies clinical pain in fibromyalgia.
authors.affiliation: MRI Research Unit, CRC Mar, Hospital del Mar, Barcelona, Spain Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM G21, Barcelona, Spain Department of Clinical and Health Psychology, Autonomous University of Barcelona, Barcelona, Spain Human Pharmacology and Neurosciences, Institute of Neuropsychiatry and Addiction, Hospital del Mar Research Institute, Barcelona, Spain Department of Psychology and Neuroscience, University of Colorado, Boulder, CO, USA Rheumatology Department, Hospital CIMA Sanitas, Barcelona, Spain Department of Psychiatry, Melbourne Neuropsychiatry Centre, The University of Melbourne, Melbourne, Australia Rheumatology Department, Hospital del Mar, Barcelona, Spain.
authors.forename: Jesus
authors.initials: J
authors.lastname: Pujol
authors.forename: Dídac
authors.initials: D
authors.lastname: Macià
authors.forename: Alba
authors.initials: A
authors.lastname: Garcia-Fontanals
authors.forename: Laura
authors.initials: L
authors.lastname: Blanco-Hinojo
authors.forename: Marina
authors.initials: M
authors.lastname: López-Solà
authors.forename: Susana
authors.initials: S
authors.lastname: Garcia-Blanco
authors.forename: Violant
authors.initials: V
authors.lastname: Poca-Dias
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: Oren
authors.initials: O
authors.lastname: Contreras-Rodríguez
authors.forename: Jordi
authors.initials: J
authors.lastname: Monfort
authors.forename: Ferran
authors.initials: F
authors.lastname: Garcia-Fructuoso
authors.forename: Joan
authors.initials: J
authors.lastname: Deus
mesh_terms: D000328:Adult; D001931:Brain Mapping; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D010147:Pain Measurement; D010487:Periaqueductal Gray / Q000503:physiopathology*; D013003:Somatosensory Cortex / Q000503:physiopathology*
keywords: Fibromyalgia; Functional connectivity; Pain modulation; Sensory system; fMRI