9513420 Thompson Two major types of cells are contained within the nervous system: neurons, which are the cells that generate, conduct and transmit information to other cells; and glia, which are the cells that surround and support the neurons. Glial cells are important in the repair of nerve tissue after injury; one class of glia, the Schwann cells, assist in regeneration of damaged axons (nerve fibers) by extending long processes that then serve as substrates along which the new axons re-grow. If some of the many motor axons that innervate a muscle are damaged, the remaining axons begin to send new "sprouts" to make new connections with the denervated muscle fibers. During sprouting, the surrounding Schwann cells appear to extend processes that induce the growth of nearby axons, and guide those growing axons to denervated fibers. This project uses physiological and immunohistochemical techniques to determine the roles that muscle activity and gene expression of particular molecules play in the guidance of axons, with particular emphasis on cell adhesion molecules. Results from this work will be important in understanding how the other cells of the nervous system influence the specific targeting of sprouting nerve cells during development and regeneration, and will have an impact on developmental biology and cell biology as well as neuroscience.
