ACHEMS 2019
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SPLTRAK Abstract Submission
Flavor experience induces plastic changes in piriform cortical coding of odor valence
Joost Maier & Ellen Walker
Wake Forest School of Medicine, Winston Salem, NC, United States

Most of our experience of the chemosensory world is heavily shaped by individual experience. This is reflected in the anatomical organization of piriform olfactory cortex, which is characterized by diffuse afferent inputs from the olfactory bulb and a high degree of intra- and inter-cortical associative connectivity. However, odor coding by piriform cortical neurons is often studied in the absence of experience or context. Here, we probed rats with natural flavor stimuli in the context of a preference learning task to study how experience and connectivity with extra-olfactory systems drives plastic changes in cortical coding of odor valence. We tested preference for two odorant solutions before and after rats were trained to associate one of the odorants with sweet taste (saccharin). In parallel, we recorded extracellular responses of OC neurons to intra-oral presentation of the same odors. We found that training increased preference for sweet-paired odors, and that this increase in preference was correlated on an animal-by animal basis with an increased ability to decode odors from ensembles of OC neurons. At the cellular level, altered representations were implemented by a complex combination of increases and decreases in the firing rate of individual OC neurons. Odor- and valence-related responses varied dynamically over the course of several seconds following stimulus delivery. These results demonstrate that multisensory input drives experience-dependent plasticity in odor valence representations by altering spatio-temporal dynamics of piriform cortical activity. Ongoing work focuses on contrasting plastic changes that support preference and aversion learning, as well as probing a causal role for taste cortex in mediating plasticity in odor coding.