Taste responses in defined cell types in gustatory cortex

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 DESCRIPTION (provided by applicant): Ingestive decisions play a key role in a number of human conditions including obesity, diabetes, anorexia, hypertension, and coronary artery disease. One of the most important factors regulating these decisions is the sense of taste. The gustatory cortex in mammals has been shown to be involved in taste learning and behavior, and electrophysiological studies have shown that taste-activated neurons in this area tend to be broadly tuned (with regard to taste quality), multi-modal, and modulated by behavioral state. However, it is not clear how taste quality itself is encoded in the GC, and whether stimulus tuning in individual neurons varies as a function of cell type or functional connection. Two-photon (2P) imaging is a technique that allows for the simultaneous recording of taste-evoked responses in a large numbers of neurons in vivo. However, only a couple of 2P studies in the taste system have been published to date. We will combine 2P imaging with specific identification of cell types, accomplished by either Cre-dependent expression or retrograde labeling. Collectively, these experiments will test the hypothesis that taste sensitivities and tuning profile vary in GC neurons as a function of cortical depth, cell type (pyramidal cell vs. interneuron) or projection pattern. Aim 1 will investigate compare taste responses in Thy1-expressing pyramidal cells and Calretinin-expressing interneurons to the greater population of all labeled cells in GC. Aim 2 will investigate taste responses in GC neurons retrogradely labeled from either gustatory thalamus or basolateral amygdala.