Date on Master's Thesis/Doctoral Dissertation
Anatomical Sciences and Neurobiology
Anatomical Sciences and Neurobiology, PhD
Committee Co-Chair (if applicable)
propriospional; spinal cord injury; assessment; neurophysiology; electrophysiology
Spinal Cord Injury (SCI) in humans is a heterogeneous diagnosis, resulting in variable paralysis and paresthesia based on the mechanism, rostro-caudal location, and severity of injury. Both neurophysiological and anatomical studies have suggested that subclinical residual supraspinal-spinal connectivity exists in a subset of individuals deemed to have motor and sensory complete injuries. Recent reports of volitional movement in chronic, motor complete individuals during epidural spinal stimulation have provided compelling evidence that these residual projections may be capable of mediating volitional movement when the functional state of spinal circuitry is electrically modulated. It was the goal of this project to identify subclinical and pathway-specific subliminal influences on spinal excitability after human SCI, and further to determine their relationship to volitional muscle activation after injury. Results demonstrated that volitional muscle activation can be identified and quantified in an objective manner via neurophysiological assessment, with greater resolution than current clinical measures. Electrophysiological studies probing the nervous system in subjects with chronic SCI, evidence was obtained of residual descending influence even in subjects classified as having motor and sensory complete injuries. Comparisons between volitional muscle activation and detection of descending modulation of multisegmental muscle responses in incomplete SCI participants revealed that interlimb modulation of a given motor pool was a strong predictor of predicted volitional movement, but was also observed in muscles without volitional activation, suggesting the pathways mediating the observed modulation may be necessary but not sufficient for volitional muscle activation after SCI.
Atkinson, Darryn A., "Identification of residual descending pathways after human spinal cord injury." (2016). Electronic Theses and Dissertations. Paper 2591.