title: Specific brain morphometric changes in spinal cord injury with and without neuropathic pain.
abstract: Why only certain patients develop debilitating pain after spinal chord injury and whether structural brain changes are implicated remain unknown. The aim of this study was to determine if patients with chronic, neuropathic below-level pain have specific cerebral changes compared to those who remain pain-free. Voxel-based morphometry of high resolution, T1-weighted images was performed on three subject groups comprising patients with pain (SCI-P, n = 18), patients without pain (SCI-N, n = 12) and age- and sex-matched controls (n = 18). The SCI-P group was first compared directly with the SCI-N group and then subsequently with controls. Overall, grey and white matter changes dependent on the presence of pain were revealed. Significant changes were found within the somatosensory cortex and also in corticospinal tracts and visual-processing areas. When the SCI-P group was directly compared with the SCI-N group, reduced grey matter volume was found in the deafferented leg area of the somatosensory cortex bilaterally. This region negatively correlated with pain intensity. Relative to controls, grey matter in this paracentral primary sensory cortex was decreased in SCI-P but conversely increased in SCI-N. When compared with controls, discrepant corticospinal tract white matter reductions were found in SCI-P and in SCI-N. In the visual cortex, SCI-N showed increased grey matter, whilst the SCI-N showed reduced white matter. In conclusion, structural changes in SCI are related to the presence and degree of below-level pain and involve but are not limited to the sensorimotor cortices. Pain-related structural plasticity may hold clinical implications for the prevention and management of refractory neuropathic pain.
authors.affiliation: Department of Psychiatry, University of Cambridge, Addenbrooke's Hospital, Level E4, Box 189, Hills Road, Cambridge CB2 2QQ, UK.
authors.forename: Tom B
authors.initials: TB
authors.lastname: Mole
authors.affiliation: Unit of Neuroscience, School of Clinical Sciences, Pain Research Institute, Lower Lane, Liverpool L9 7AL, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: MacIver
authors.affiliation: Department of Molecular and Cellular Physiology, Institute of Translational Medicine (PGR), University of Liverpool, Whelan Building, Liverpool L69 3GB, UK.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Sluming
authors.affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
authors.forename: Gerard R
authors.initials: GR
authors.lastname: Ridgway
authors.affiliation: Walton Centre for Neurology and Neurosurgery NHS Trust, Lower Lane, Fazakerley, Liverpool L9 7JL, UK.
authors.forename: Turo J
authors.initials: TJ
authors.lastname: Nurmikko
mesh_terms: D000328:Adult; D000368:Aged; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000209:etiology / Q000473:pathology*; D009929:Organ Size / Q000502:physiology; D011712:Pyramidal Tracts / Q000473:pathology*; D013003:Somatosensory Cortex / Q000473:pathology; D013119:Spinal Cord Injuries / Q000150:complications / Q000473:pathology*
keywords: 10.020: Structural MRI; 40.100: Systems Pain; 40.130: Systems Somatosensory; 50.140: Pain syndromes Other; 50.160: Spinal cord; 50.180: Trauma; ASIA, American Spinal Injury Association; BAI, Beck Anxiety Inventory; BDI, Beck Depression Inventory; GM, grey matter; SCI, spinal cord injury; SCI-N, spinal cord injury without pain; SCI-P, spinal cord injury with pain; VBM, voxel-based morphometry; WM, white matter