Effects of a contusive spinal cord injury on cortically-evoked spinal spiking activity in rats
Year: 2020
Type: article
Abstract: Objective The purpose of this study was to determine the effects of spinal cord injury (SCI) on spike activity evoked in the hindlimb spinal cord of the rat from cortical electrical stimulation. Approach Adult, male, Sprague Dawley rats were randomly assigned to a Healthy or SCI group. SCI rats were given a 175 kDyn dorsal midline contusion injury at the level of the T8 vertebrae. At four weeks post-SCI, intracortical microstimulation (ICMS) was delivered at several sites in the hindlimb motor cortex of anesthetized rats, and evoked neural activity was recorded from corresponding sites throughout the dorsoventral depths of the spinal cord and EMG activity from hindlimb muscles. Main results In healthy rats, post-ICMS spike histograms showed reliable, evoked spike activity during a short-latency epoch 10-12 ms after the initiation of the ICMS pulse train (short). Longer latency spikes occurred between ~20-60 ms, generally following a Gaussian distribution, rising above baseline at time L ON , followed by a peak response (L p ), and then falling below baseline at time L OFF . EMG responses occurred between L ON and L p (25-27 ms). In SCI rats, short-latency responses were still present, long-latency responses were disrupted or eliminated, and EMG responses were never evoked. The retention of the short-latency responses indicates that spared descending spinal fibers, most likely via the cortico-reticulospinal pathway, can still depolarize spinal cord motor neurons after a dorsal midline contusion injury. Significance This study provides novel insights into the role of alternate pathways for voluntary control of hindlimb movements after SCI that disrupts the corticospinal tract in the rat.
Source: Journal of Neural Engineering
Institutions: University of Kansas, University of Kansas Medical Center
Language: English
Topic: Spinal Cord Injury Research
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
Funders: Paralyzed Veterans of America Research Foundation, Paralyzed Veterans of America, National Institutes of Health, National Institute on Deafness and Other Communication Disorders, National Institute of Neurological Disorders and Stroke, Eunice Kennedy Shriver National Institute of Child Health and Human Development
Awards: Kansas University Training Program in Neurological and Rehabilitation Sciences, G2436619974, G2656370370, Kansas Intellectual and Developmental Disabilities Research Center, Reorganization of Motor Cortex After Brain Injury, Inducing Neural Plasticity after Spinal Cord Injury to Recover Impaired Voluntary Movement, Core Center for BioBehavioral Sciences of Communication Disorders
OpenAlex ID: W3092979434