There are several known cases of sensory systems where some particular stimulus feature, such as visual space or sound frequency, is represented in some kind of organized "map" in the brain. The sensory system that has been most difficult to map in this way has been taste, in both vertebrates and invertebrates. There now is a lot of information on taste physiology in some invertebrates, and this project utilizes the fly as a model system, where both physiology and anatomy are used to trace particular taste pathways into well-described parts of the fly brain. Standard electrophysiological recordings of single nerve cells in the taste pathway will allow characterization of a cell's sensitivity to different taste compounds, and dye injections of those cells will allow tracing how the central terminals of each tested cell projects into central brain regions. Finding out whether the four different classes of peripheral taste cells have central connectivity that shows functional groupings would be major step in understanding the circuitry underlying taste. Results from study of this model system will have an impact on chemosensory work in other animals, on our understanding of feeding behavior, of central sensory connectivity in general, on insect-plant interactions and potentially on mechanisms for pest control.
