With a Presidential Young Investigator award from the National Science Foundation, Dr. Sally Hoskins will continue her innovative work on the molecular mechanisms regulating neuronal differentiation. She will focus her research on two aspects of the development of the nervous system: the initial differentiation of neurons during embryogenesis, and the formation of connections between neurons at later developmental stages. Dr. Hoskins will capitalize on her striking finding that thyroid hormones can induce the development of a new and specific axonal projection of the retinotectal system. Using powerful molecular techniques. She will isolate hormone-activated genes related to axonal pathfinding and 2) the thyroid hormone receptor. These data will help elucidate the mechanism(s) which ensure that neurons connect properly with appropriate targets, a profoundly important yet little-understood aspect of neuronal development.