Sensory effects of passive hind-limb cycling after spinal cord injury
department or school: Medicine, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Crawford, Mark Alexander
issued: 2013-07-01T00:00:00
issued: 2012
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Spinal cord injury (SCI) is a devastating insult to the nervous system with implications for locomotor, autonomic and sensory function. Past studies indicate that passively moving the lower limbs may be beneficial for locomotor recovery after SCI, however the literature lacks in studies addressing autonomic and sensory ramifications of passive exercise. I used a well-established passive exercise model, which consists of cycling the hind-limbs of adult male Wistar rats with complete transection SCI at the third thoracic segment (T3), beginning 5 days after injury and continuing for 4 weeks (5 days / week, 1 hour total cycling/day). I measured Hoffman (H)-reflex latency and motoneuron recruitment after the cycling intervention. Latency of the H-wave was shorter in duration and motoneuron recruitment was enhanced after SCI when compared to uninjured controls. Exercise did not affect these properties. I performed histological analysis of parvalbumin-expressing neurons of lumbar (L) and sacral (S) dorsal root ganaglia (DRGs). Proprioceptive neurons at L1/L2 and L4/L5 levels demonstrated somal size decreases after SCI and further decreases with exercise, while there was no change at the L6/S1 level. This effect may be due to exercise-induced changes in neurotrophic support of proprioceptive neurons by target tissues. The autonomic/cardiovascular effects of passive exercise are largely unknown. I focused on two common cardiovascular conditions associated with SCI, autonomic dysreflexia (AD) and orthostatic hypotension (OH). AD occurs in individuals with an injury above T6, and is marked by massive spikes in blood pressure (BP) due to a normally-innocuous stimulus below the injury level. OH is a large drop in BP upon being seated upright, assessed via tilting the animal to a 90 degree head-up position. Passive exercise led to a 50% reduction in AD severity, as measured by beat-to-beat BP measurements and an established method for inducing AD. In contrast, I found no change …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/43776
extent: video/mp4
note: SENSORY EFFECTS OF PASSIVE HIND-LIMB CYCLING AFTER SPINAL CORD INJURY by Mark Alexander Crawford B.Sc. (Honours), Thompson Rivers University, 2007 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate Studies (Neuroscience) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) December 2012 © Mark Alexander Crawford, 2012 Abstract Spinal cord injury (SCI) is a devastating insult to the nervous system with implications for locomotor, autonomic and sensory function. Past studies indicate that passively moving the lower limbs may be beneficial for locomotor recovery after SCI, however the literature lacks in studies addressing autonomic and sensory ramifications of passive exercise. I used a well-established passive exercise model, which consists of cycling the hind-limbs of adult male Wistar rats with complete transection SCI at the third thoracic segment (T3), beginning 5 days after injury and continuing for 4 weeks (5 days / week, 1 hour total cycling/day). I measured Hoffman (H)-reflex latency and motoneuron recruitment after the cycling intervention. Latency of the H-wave was shorter in duration and motoneuron recruitment was enhanced after SCI when compared to uninjured controls. Exercise did not affect these properties. I performed histological analysis of parvalbumin- expressing neurons of lumbar (L) and sacral (S) dorsal root ganaglia (DRGs). Proprioceptive neurons at L1/L2 and L4/L5 levels demonstrated somal size decreases after SCI and further decreases with exercise, while there was no change at the L6/S1 level. This effect may be due to exercise-induced changes in neurotrophic support of proprioceptive neurons by target tissues. The autonomic/cardiovascular effects of passive exercise are largely unknown. I focused on two common cardiovascular conditions associated with SCI, autonomic dysreflexia (AD) and orthostatic hypotension (OH). AD occurs in individuals with an injury above T6, and is ma…
has type: Thesis/Dissertation
date issued: 2013-05
is shown at: 10.14288/1.0073479
language: eng
degree discipline: Neuroscience
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-ShareAlike 3.0 Unported
rights URI: http://creativecommons.org/licenses/by-sa/3.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/43776