Pharmacologic attenuation of cross-modal sensory augmentation within the chronic pain insula.
Pain can be elicited through all mammalian sensory pathways yet cross-modal sensory integration, and its relationship to clinical pain, is largely unexplored. Centralized chronic pain conditions such as fibromyalgia are often associated with symptoms of multisensory hypersensitivity. In this study, female patients with fibromyalgia demonstrated cross-modal hypersensitivity to visual and pressure stimuli compared with age- and sex-matched healthy controls. Functional magnetic resonance imaging revealed that insular activity evoked by an aversive level of visual stimulation was associated with the intensity of fibromyalgia pain. Moreover, attenuation of this insular activity by the analgesic pregabalin was accompanied by concomitant reductions in clinical pain. A multivariate classification method using support vector machines (SVM) applied to visual-evoked brain activity distinguished patients with fibromyalgia from healthy controls with 82% accuracy. A separate SVM classification of treatment effects on visual-evoked activity reliably identified when patients were administered pregabalin as compared with placebo. Both SVM analyses identified significant weights within the insular cortex during aversive visual stimulation. These data suggest that abnormal integration of multisensory and pain pathways within the insula may represent a pathophysiological mechanism in some chronic pain conditions and that insular response to aversive visual stimulation may have utility as a marker for analgesic drug development.
Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, MI, USA.|Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI, USA.
Steven E
SE
Harte
Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, MI, USA.|Functional MRI Laboratory, Office of Research, University of Michigan, Ann Arbor, MI, USA.
Eric
E
Ichesco
Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, MI, USA.
Johnson P
JP
Hampson
Functional MRI Laboratory, Office of Research, University of Michigan, Ann Arbor, MI, USA.
Scott J
SJ
Peltier
Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
Tobias
T
Schmidt-Wilcke
Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, MI, USA.|Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI, USA.
Daniel J
DJ
Clauw
Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, MI, USA.|Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI, USA.
Richard E
RE
Harris
D000328:Adult; D000344:Afferent Pathways / Q000000981:diagnostic imaging / Q000502:physiology; D000700:Analgesics / Q000494:pharmacology / Q000627:therapeutic use*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000187:drug effects*; D005260:Female; D005356:Fibromyalgia / Q000188:drug therapy* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D010775:Photic Stimulation; D000069583:Pregabalin / Q000494:pharmacology / Q000627:therapeutic use*; D011312:Pressure; D060388:Support Vector Machine; D064232:Visual Analog Scale
D000700:Analgesics; D000069583:Pregabalin; D010100:Oxygen