We study molecular signaling pathways in the developing nervous system. We investigate how inductive signals are generated, received, and implemented to coordinate cellular growth and differentiation during brain and spinal cord development. Hedgehog proteins are one of several secreted signaling proteins that are essential for normal embryonic development. Understanding the molecular events through which Hedgehog signaling influences progenitor cell proliferation and neuronal specification is of fundamental importance. To gain a better understanding of these cellular responses, we have recently embarked on a systematic effort to identify and characterize sonic hedgehog gene targets. In addition to learning more about how cells respond to Hedgehog signaling in the developing brain, we are using this information to explore later roles for Hedgehog signaling in neurogenesis within the adult brain. Molecular insights into normal pathways of neurogenesis can contribute to the understanding of nervous system diseases and to better strategies for treating these disorders.