Structural and Functional Organization of the Peripheral Taste System - PROJECT SUMMARY The sense of taste informs the nutritional value and safety of potential food sources. Because this assessment is critical for the survival of the animal, taste signals immediately evoke stereotypical behaviors (e.g., licking, salivating, retching) leading to acceptance or rejection of the food item. Thus, the taste sensory system presents an exquisite neurobiological circuit to investigate how the brain accurately processes the external environment and sets into motion hardwired behaviors. The overall objective in this application is to understand how taste quality (sweet, bitter, umami, salty, sour), intensity (concentration), and valence (attractive, aversive) information is encoded by the peripheral gustatory system – from the taste buds to gustatory ganglia – before it gets processed in the brain. The central hypothesis posits that while TRCs and gustatory neurons may broaden their tuning, certain taste qualities (particularly those encoding different valences – appetition vs aversion) should remain reliably distinct. This hypothesis will be tested in mice by addressing the following three specific aims: 1) Assess tastant-evoked activity in TRCs in vivo; 2) Visualize tastant-evoked responses in intragemmal gustatory nerve fibers; and 3) Interrogate synaptic-level connectivity in the taste bud. The proposed research is significant because it will provide new insights on how taste information is coded at the periphery.
