Sensorimotor behaviour in rats after lesions of dorsal spinal pathways

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Date
2008Author
Kanagal, Srikanth Gopinath
Type
ThesisDegree Level
DoctoralMetadata
Show full item recordAbstract
To investigate the roles of different dorsal spinal pathways in controlling movements in rats, I performed lesions of specific spinal pathways and measured the behaviour abilities of rats using different sensorimotor behavioural tests. The first experiment was designed to understand the contribution of sensory pathways traveling in the dorsal funiculus during locomotion and skilled movements using sensitive behavioural tests. I demonstrated that ascending sensory fibers play an important role during overground locomotion and contribute to skilled forelimb movements. The second experiment compared the differences in sensorimotor abilities caused by dorsal funicular lesions performed at two different levels of rat spinal cord. My results showed that the pathways present in the cervical and thoracic dorsal funiculus exert different functional effects over control of limb movement during locomotion. The third experiment investigated the compensatory potential of dorsal funicular pathways after dorsolateral funicular injuries in rats. My results showed that dorsal funicular pathways do not compensate for loss of dorsolateral pathways during the execution of locomotor tasks, though there is indirect evidence that rats with dorsolateral funicular lesions might rely more on ascending sensory pathways in the dorsolateral funiculus during skilled forelimb movements. Finally, the fourth experiment was designed to investigate the compensation from dorsolateral funicular pathways after injuries to pyramidal tract in rats. I demonstrated that pathways running in the spinal dorsolateral funiculus do provide compensatory input to spinal circuitry to maintain skilled reaching abilities after lesions of the pyramidal tract but these same pathways do not appear to compensate during either overground locomotion or skilled locomotion. Thus, this compensatory response is task-specific. These results highlight the fact that behavioural context determines the nature of compensation from spared pathways after spinal cord injuries.
Degree
Doctor of Philosophy (Ph.D.)Department
Veterinary Biomedical SciencesProgram
Veterinary Biomedical SciencesSupervisor
Muir, Gillian D.Committee
Magnuson, David S.K.; Janz, David M.; Hiebert, Linda M.; Doucette, J. Ronald; Singh, BaljitCopyright Date
2008Subject
Skilled forepaw usage
rat models for partial spinal cord injury
Task specific compensation
Compensation
Dorsolateral funiculus
Rubrospinal tract
Deficits
Dorsal funiculus
Single pellet reaching
Ascending sensory pathways
Corticospinal tract
Pyramidal tract
Rats
Spinal cord injury
Behaviour
Dorsal spinal pathways
Ground reaction forces
Overground locomotion
Horizontal ladder
Skilled locomotion