title: Abnormal resting state functional connectivity of the periaqueductal grey in patients with fibromyalgia.
abstract: OBJECTIVE
  Emerging evidence associates chronic pain syndrome, such as fibromyalgia, with endogenous pain modulatory system dysfunction, leading to an impaired descending pain inhibition. In this study, using resting-state functional magnetic resonance imaging (fMRI), we aimed at seeking possible functional connectivity changes of the periaqueductal gray (PAG), a brainstem area that belongs to the endogenous pain modulatory system, in patients with fibromyalgia.
  
  
  METHODS
  In 20 patients with fibromyalgia and 15 healthy subjects, we investigated PAG functional connectivity using resting-state fMRI. We also analysed the correlation between clinical variables, such as pain severity, disease duration, and depressive personality traits with PAG functional connectivity.
  
  
  RESULTS
  Compared with control subjects, we identified that patients with fibromyalgia had an increased PAG connectivity with insula, anterior cingulate cortex, and anterior prefrontal cortex. The functional connectivity between PAG and the rostral ventral medulla, however, was not concordantly increased. PAG functional connectivity correlated with pain severity, disease duration, and the depressive personality trait rating.
  
  
  CONCLUSIONS
  Our fMRI study showing abnormal resting state functional connectivity of the PAG suggests that patients with fibromyalgia have an endogenous pain modulatory system dysfunction, possibly causing an impaired descending pain inhibition. This abnormal PAG functioning might underlay the chronic pain these patients suffer from.
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Truini
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Tinelli
authors.affiliation: Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Italy. mariachiara.gerardi@gmail.com.
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Gerardi
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Calistri
authors.affiliation: Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Iannuccelli
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: La Cesa
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Tarsitani
authors.affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston; and Harvard Medical School, Boston, MA, USA.
authors.forename: Caterina
authors.initials: C
authors.lastname: Mainero
authors.affiliation: Rheumatology Unit, Luigi Sacco University Hospital, Milan, Italy.
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Sarzi-Puttini
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cruccu
authors.affiliation: Department of Neurology and Psychiatry, Sapienza University of Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Caramia
authors.affiliation: Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Di Franco
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D059350:Chronic Pain / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005356:Fibromyalgia / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010487:Periaqueductal Gray / Q000503:physiopathology*