PI: Erskine, Mary S. Proposal Number: IBN-9722804 Advances in molecular biology have led to the understanding that certain genes, called "immediate early genes" become expressed when cells become active. Techniques have been developed to mark the cells expressing these genes, including the cells of the central nervous system. This symposium presents the work of scientists in several areas of behavior and neuroscience as examples of the use of this technique to mark systems in the brain that are responsive to different types of sensory signals or are involved in controlling a variety of behaviors. By holding the symposium in conjunction with a national scientific meeting, the organizers make information about this technique and its use in behavioral research available to researchers and their students in a wide range fields.