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Dissertation
The effects of therapeutic interventions on cortical neurons in adult rats with neonatal mid-thoracic transections
Doctor of Philosophy (Ph.D.), Drexel University
Sep 2007
DOI:
https://doi.org/10.17918/00010074
Abstract
Many therapeutic interventions for spinal cord injury (SCI) are presumed to exert their effects at, or below, the level of the injured spinal cord. These interventions include exercise, and the administration of pharmacological agents. While there are clearly beneficial effects of these interventions at or below the injury site, their effects at supraspinal levels are not well understood and rarely addressed. In rats, a T8/T9 transection eliminates the primary source of activation to the hindlimb representation of the primary somatosensory cortex. We therefore studied whether different therapeutic interventions, such as treadmill exercise or the systemic administration of the 5-HT 2C receptor agonist, m-chlorophenylpiperazine (mCPP), modifies the somatotopic organization of the hindlimb representation in the primary somatosensory cortex of adult rats with neonatal T8/T9 transections (spinalized rats). Our outcome measures included the percentage of cells that respond to sensory stimulations of the forelimb skin and by the response magnitude of these cells to sensory and sensorimotor stimulations of the forelimb periphery. Our data suggest that neonatal T8/T9 transection alone does not modify the hindlimb representation of adult rats, but treadmill exercise after neonatal T8/T9 transection does modify the somatotopic organization of the hindlimb representation. This was assessed by comparing the percentage of cells in the hindlimb cortex that responded to sensory stimulations of the forelimb skin. In exercised spinalized rats, the magnitude of the response of cells in hindlimb representation to process sensory and sensorimotor information from the forelimb was greater than that of normal rats. In addition, a subset of spinalized rats that were given daily treadmill exercise respond to the systemic administration of a single dose of mCPP with greater numbers of steps that support their hindquarters during treadmill induced locomotion. The systemic administration of a single dose of mCPP to these rats improved the ability of cells in their hindlimb representations to process sensory input, but had little effect on the response of these cells to sensorimotor inputs. Our results suggest that the effects of therapeutic interventions on cortical cells should be considered in developing rehabilitative strategies for spinal cord injury.
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Details
- Title
- The effects of therapeutic interventions on cortical neurons in adult rats with neonatal mid-thoracic transections
- Creators
- Tina Kao
- Contributors
- Karen Anne Moxon (Advisor) - Drexel University, Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xiii, 160 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Medicine; Pharmacology and Physiology; Drexel University
- Other Identifier
- 991021888746804721