title: Global disruption of degree rank order: a hallmark of chronic pain.
abstract: Chronic pain remains poorly understood; yet it is associated with the reorganization of the nervous system. Here, we demonstrate that a unitary global measure of functional connectivity, defined as the extent of degree rank order disruption, kD, identifies the chronic pain state. In contrast, local degree disruption differentiates between chronic pain conditions. We used resting-state functional MRI data to analyze the brain connectome at varying scales and densities. In three chronic pain conditions, we observe disrupted kD, in proportion to individuals' pain intensity, and associated with community membership disruption. Additionally, we observe regional degree changes, some of which were unique to each type of chronic pain. Subjects with recent onset of back pain exhibited emergence of kDonly when the pain became chronic. Similarly, in neuropathic rats kDemerged weeks after injury, in proportion to pain-like behavior. Thus, we found comprehensive cross-species evidence for chronic pain being a state of global randomization of functional connectivity.
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Mansour
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: Alex T
authors.initials: AT
authors.lastname: Baria
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Tetreault
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: Etienne
authors.initials: E
authors.lastname: Vachon-Presseau
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: Pei-Ching
authors.initials: PC
authors.lastname: Chang
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: Lejian
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60610, USA.
authors.forename: A Vania
authors.initials: AV
authors.lastname: Apkarian
authors.affiliation: Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois 60611, USA.|Rehabilitation Institute of Chicago, Chicago, Illinois 60611, USA.
authors.forename: Marwan N
authors.initials: MN
authors.lastname: Baliki
mesh_terms: D000328:Adult; D000818:Animals; D001416:Back Pain / Q000175:diagnosis / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D001930:Brain Injuries / Q000175:diagnosis / Q000503:physiopathology*; D002478:Cells, Cultured; D059350:Chronic Pain / Q000175:diagnosis / Q000503:physiopathology*; D063132:Connectome; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology*; D009473:Neuronal Plasticity; D009619:Nociceptors / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D055815:Young Adult