Khalid, Zainab2023-09-192023-09-192023-04https://hdl.handle.net/11299/256960University of Minnesota M.S. thesis. April 2023. Major: Stem Cell Biology. Advisor: Ann Parr. 1 computer file (PDF); vii, 65 pages.With spinal cord injury (SCI), despite constantly evolving therapeutic ideas, there is still no effective technique to recover motor function. The corticospinal tract (CST) regulates voluntary movements, and a few studies have demonstrated that CST regeneration can be improved by electrical stimulation of the motor cortex after SCI. Therefore, this has opened up an entirely new avenue of neuromodulation potential for treating human SCI. Primary motor cortex (M1) is the main source of CST, and selectively stimulating excitatory neurons in the M1 could encourage CST axonal regeneration after SCI. This pilot project primarily determines how M1 activation affects axonal regeneration after SCI. Here we have utilized optogenetics, a novel technique to stimulate motor neurons of the CST selectively. We have already successfully performed a significant amount of the optimization work required to develop a functional model. This includes the optogenetics-related parameters, i.e., virus injection coordinates in the M1 area, fiber implantation, and stimulation parameters in intact spinal cord rats. Our results showed stimulation evoked leg movement, strong expression of virally expressed opsin, and neuronal activation markers. Further, we applied optogenetics to stimulate the M1 area in SCI rats for four weeks. We will be looking at neurofilament growths, growth-related proteins, synapse formation, myelination, and stem cell effects, examining whether stimulation of M1 can encourage axonal regeneration and other microenvironmental changes that can lead to improved function. Although this preliminary work is in a subacute injury model, this novel treatment may be applicable after chronic SCI, as the primary mechanism we are focusing on is not neuroprotection but rather axonal regeneration and pro-regenerative effects on the microenvironment. In future experiments, this technique will be paired with regionally focused human spinal neural stem cells to see if direct stimulation of M1 can successfully integrate transplanted cells into the native spinal cord. Positive outcomes would substantially influence our comprehension of the neuronal cell processes underlying potential functional recovery induced by motor cortex stimulation alone or when approaches are combined.enelectromyographylocal field potentialoptogeneticsprimary motor cortexspinal cord injuryspinal neural stem cellsThesis or Dissertation