Cellular Basis of Growth Cone Turning
Christopher Cohan Principal Investigator
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The adult nervous system depends on highly specific pathways that interconnect nerve cells with their appropriate targets such as muscles, sensory organs, and other cells within the nervous system. This pattern is established early in development by unknown mechanisms that allow growing nerve fibers to navigate their environment. The goal of this proposal is to identify the basic mechanisms that steer nerve fibers to their targets. This will be accomplished by studying the internal organization and movements of tiny structures that form the growing end of nerve fibers, called growth cones. Living growth cones will be observed microscopically using computer-based imaging while chemical agents are released in front of them to either attract or repel their growth. As growth cones turn, measurements will be made of regional changes in ions that enter the nerve fiber to signal a change in direction. In addition, regional changes in the internal scaffold of filaments that determine growth cone shape and that form the structural basis of changes in movement will be identified.<br/><br/>The turning of growth cones in response to chemical signals is a fundamental event that allows nerve fibers to establish highly specific pathways in the nervous system. The highly specific nature of these pathways is crucial for nervous system function, which depends on point-to-point communication within the nervous system. This project will reveal a fundamental property of nerve cells that allows them to be guided to their appropriate target locations.