title: Increased Brain Sensorimotor Network Activation after Incomplete Spinal Cord Injury.
abstract: After complete spinal cord injury (SCI), activation during attempted movement of paralyzed limbs is sharply reduced, but after incomplete SCI-the more common form of human injury-it is unknown how attempts to move voluntarily are accompanied by activation of brain motor and sensory networks. Here, we assessed brain activation during ankle movement in subjects with incomplete SCI, among whom voluntary motor function is partially preserved. Adults with incomplete SCI (n = 20) and healthy controls (n = 15) underwent functional magnetic resonance imaging that alternated rest with 0.3-Hz right ankle dorsiflexion. In both subject groups, ankle movement was associated with bilateral activation of primary and secondary sensory and motor areas, with significantly (p < 0.001) greater activation in subjects with SCI within right hemisphere areas, including primary sensorimotor cortex and pre-motor cortex. This result was further evaluated using linear regression analysis with respect to core clinical variables. Poorer locomotor function correlated with larger activation within several right hemisphere areas, including pre- and post-central gyri, possibly reflecting increased movement complexity and effort, whereas longer time post-SCI was associated with larger activation in left post-central gyrus and bilateral supplementary motor area, which may reflect behaviorally useful adaptations. The results indicate that brain adaptations after incomplete SCI differ sharply from complete SCI, are related to functional behavioral status, and evolve with increasing time post-SCI. The results suggest measures that might be useful for understanding and treating incomplete SCI in human subjects.
authors.affiliation: 1 Reeve-Irvine Research Center, University of California , Irvine, Irvine, California.|2 Department of Dance, University of California , Irvine, Irvine, California.
authors.forename: Kelli G
authors.initials: KG
authors.lastname: Sharp
authors.affiliation: 3 Departments of Neurology, Anatomy & Neurobiology, and Physical Medicine & Rehabilitation, University of California , Irvine, Irvine, California.
authors.forename: Robert
authors.initials: R
authors.lastname: Gramer
authors.affiliation: 4 Division of Occupational Therapy, The Ohio State University Medical Center , Columbus, Ohio.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Page
authors.affiliation: 1 Reeve-Irvine Research Center, University of California , Irvine, Irvine, California.|3 Departments of Neurology, Anatomy & Neurobiology, and Physical Medicine & Rehabilitation, University of California , Irvine, Irvine, California.|5 The Sue and Bill Gross Stem Cell Research Center, University of California , Irvine, Irvine, California.
authors.forename: Steven C
authors.initials: SC
authors.lastname: Cramer
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000639:trends; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000000981:diagnostic imaging / Q000502:physiology; D009415:Nerve Net / Q000000981:diagnostic imaging* / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology; D066191:Sensorimotor Cortex / Q000000981:diagnostic imaging* / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging* / Q000503:physiopathology
keywords: functional MRI; gait; motor cortex; sensory cortex; spinal cord injury