Project Summary/Abstract Taste receptor cells (within taste buds) are constantly replaced through adulthood. This raises the question of whether this continuous cell turnover causes remodeling in the taste nerve terminal arbors, which innervate taste receptor cells. More specifically, how does taste receptor cell entry and cell exit within the taste bud influence arbor structure? To answer these questions, I propose to develop an in vivo two-photon imaging method to repeatedly sample the same terminal arbors over time. Aim 1 will examine terminal arbor structure over the average lifespan of a taste receptor cell (10 days). I hypothesize that terminal arbor structure in the epithelium will remodel in this period, while structure beneath the epithelium will remain stable. Aim 2 will examine arbor structure when taste cell turnover is manipulated to elucidate the effects of cell entry and cell exit. I hypothesize that taste cell exit from the bud will promote branch retraction and taste cell entry into the bud will promote branch formation/growth. These experiments are the first to investigate changes in taste neuron anatomy over time using a intra vital imaging approach and will provide direct evidence of extent of nerve fiber remodeling in the taste bud. Future studies will use this approach to investigate the specific molecular mechanisms, in both neurons and taste cells, used to orchestrate plasticity in the taste bud.