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Brain Behav. Sep 2012; 2(5): 541–552.
Published online Jul 10, 2012. doi:  10.1002/brb3.71
PMCID: PMC3489807
Characterization of recovered walking patterns and motor control after contusive spinal cord injury in rats
Christopher N Hansen,1,3* William Linklater,2,3* Raquel Santiago,2,3 Lesley C Fisher,2,3 Stephanie Moran,2,3 John A Buford,1,2,3 and D Michele Basso1,2,3
1Neuroscience Graduate Studies Program, The Ohio State University, Columbus, Ohio
2School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio
3Center for Brain and Spinal Cord Repair (CBSCR), The Ohio State University, Columbus, Ohio
D. Michele Basso, School of Health and Rehabilitation Sciences, The Ohio State University, 106 Atwell Hall, 453 W. 10th Avenue, Columbus, OH 43210. Tel: 614-292-0754; Fax: 614-292-0210; E-mail: Michele.Basso/at/osumc.edu
Funding Information Support for this work was contributed by NINDS#NS07-4882-01A1 (DMB), P30-NS04758, HHSN271200800-0363C (CBSCR).
*Shared first authorship.
Received March 1, 2012; Revised May 10, 2012; Accepted May 14, 2012.
Abstract
Currently, complete recovery is unattainable for most individuals with spinal cord injury (SCI). Instead, recovery is typically accompanied by persistent sensory and motor deficits. Restoration of preinjury function will likely depend on improving plasticity and integration of these impaired systems. Eccentric muscle actions require precise integration of sensorimotor signals and are predominant during the yield (E2) phase of locomotion. Motor neuron activation and control during eccentric contractions is impaired across a number of central nervous system (CNS) disorders, but remains unexamined after SCI. Therefore, we characterized locomotor recovery after contusive SCI using hindlimb (HL) kinematics and electromyographic (EMG) recordings with specific consideration of eccentric phases of treadmill (TM) walking. Deficits in E2 and a caudal shift of locomotor subphases persisted throughout the 3-week recovery period. EMG records showed notable deficits in the semitendinosus (ST) during yield. Unlike other HL muscles, recruitment of ST changed with recovery. At 7 days, the typical dual-burst pattern of ST was lost and the second burst (ST2) was indistinct. By 21 days, the dual-burst pattern returned, but latencies remained impaired. We show that ST2 burst duration is highly predictive of open field Basso, Beattie, Bresnahan (BBB) scores. Moreover, we found that simple changes in locomotor specificity which enhance eccentric actions result in new motor patterns after SCI. Our findings identify a caudal shift in stepping kinematics, irregularities in E2, and aberrant ST2 bursting as markers of incomplete recovery. These residual impairments may provide opportunities for targeted rehabilitation.
Keywords: Kinematics, locomotion, rehabilitation, spinal cord injury
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