title: Brain circuitry underlying pain in response to imagined movement in people with spinal cord injury.
abstract: Pain following injury to the nervous system is characterized by changes in sensory processing including pain. Although there are many studies describing pain evoked by peripheral stimulation, we have recently reported that pain can be evoked in subjects with complete spinal cord injury (SCI) during a motor imagery task. In this study, we have used functional magnetic resonance imaging to explore brain sites underlying the expression of this phenomenon. In 9 out of 11 subjects with complete thoracic SCI and below-level neuropathic pain, imagined foot movements either evoked pain in a previously non-painful region or evoked a significant increase in pain within the region of on-going pain (3.2+/-0.7-5.2+/-0.8). In both controls (n=19) and SCI subjects, movement imagery evoked signal increases in the supplementary motor area and cerebellar cortex. In SCI subjects, movement imagery also evoked increases in the left primary motor cortex (MI) and the right superior cerebellar cortex. In addition, in the SCI subjects, the magnitude of activation in the perigenual anterior cingulate cortex and right dorsolateral prefrontal cortex was significantly correlated with absolute increases in pain intensity. These regions expanded to include right and left anterior insula, supplementary motor area and right premotor cortex when percentage change in pain intensity was examined. This study demonstrates that in SCI subjects with neuropathic pain, a cognitive task is able to activate brain circuits involved in pain processing independently of peripheral inputs.
authors.affiliation: Pain Management Research Institute, University of Sydney, Royal North Shore Hospital, St. Leonards 2065, Australia Department of Anatomy and Histology, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Gustin
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Wrigley
authors.forename: Luke A
authors.initials: LA
authors.lastname: Henderson
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Siddall
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D019018:Imagery, Psychotherapy / Q000379:methods; D007092:Imagination / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply / Q000503:physiopathology*; D009068:Movement / Q000502:physiology*; D009434:Neural Pathways / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D010146:Pain / Q000209:etiology* / Q000523:psychology; D059408:Pain Management; D013119:Spinal Cord Injuries / Q000150:complications*
chemical_list: D010100:Oxygen