Project Summary/Abstract: A unique feature of the peripheral taste system is that the receptor cells die and are replaced. This requires a constant rewiring of the peripheral system. In order for a new taste receptor cell to form a synapse with an existing neuron it must first come into contact with the correct type of neuron. Here, our goal is to understand the cellular dynamics involved in this process. We hypothesize that since many receptor cells are replaced within 10 days, this cellular influx should be accompanied by cellular migration of taste bud cells and/or remodeling by the arbor. To test this hypothesis, we will combine genetic labeling with intra vital two-photon microscopy to examine plasticity in the taste bud over a 10 day period. Aim 1 will examine the migration of precursors into the taste bud as they mature. Aim 2 will measure the growth and retraction of individual nerve branches. These studies will be first to examine taste bud plasticity with direct observation of changes over time in a live animal. Future studies will use this approach to help identify roles of molecular factors underlying the formation of new connections in the taste bud.