9316729 Strausfeld Some insect species have in their brain a complex anatomical structure called the mushroom body, which has been linked to learning and behavior. This SGER work explores the hypothesis that the mushroom bodies provide a network of connections, a multiplex neuropile, that mediates visual place memory. The novel approach is to work out "gene expression neuroanatomy" along with behavior in the fruitfly, Drosophila, with its well-known genetics. Gene expression will be used to define genetic subsets of neurons in the mushroom bodies, genetic crosses of Drosophila with behavioral deficits will be made, and the existence of visual place memory will be tested. There is some risk whether genetic tools will be successful in clarifying the neuroanatomy, and will be able to provide a link to the visual memory mechanisms. The results will be important beyond the issues of invertebrate central neuroanatomy, in providing a framework for future genetic and systematic studies of complex memory circuits at the cellular level. This work will have an impact on sensory neurobiology, insect research in general, learning and memory, and evolutionary studies. ***