ACHEMS 2019
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SPLTRAK Abstract Submission
Posterior Piriform Cortical Modulation of Odor Fear Memory
Brett S. East1,2 & Donald A. Wilson1,2,3,4
1Emotional Brain Institute, Nathan S. Kline Institute, Orangeburg, NY, United States
2Department of Child & Adolescent Psychiatry, New York University School of Medicine, New York, NY, United States
3The Neuroscience Institute, New York University School of Medicine, New York, NY, United States
4Department of Neuroscience and Physiology, New York, NY, United States

Odor perception and hedonics are highly intermeshed at both the behavioral and neural circuit level in humans and non-human animals. This association may in part reflect the fact that the piriform cortex (PCX) is particularly tightly linked with the amygdala. The amygdala targets the posterior PCX (and to a lesser extent the anterior PCX), with the PCX sending reciprocal connections back to the amygdala. The basolateral amygdala (BLA) is required for odor fear learning, and work from our lab has shown that PCX odor responses are shaped by both fear learning and by BLA input. For example, discriminative odor fear conditioning involving both a CS+ and CS- results in odor-specific learned fear responses, as well as narrowing of PCX single-unit odor receptive fields (i.e., enhanced PCX odor acuity). This modification of PCX odor coding may be due to input from the BLA since optogenetic activation of BLA fibers within the PCX can modify single-unit and single-unit ensemble odor responses in anesthetized rodents. However, how the BLA and PCX work in tandem to shape PCX odor coding and hedonics is unknown.  In this work, rats received ibotenic acid lesions of the pPCX (or control) prior to being trained on a differential odor fear task followed by testing for learned freezing 24 hours later. In support of previous work, bilateral pPCX lesions significantly reduced learned, odor-evoked freezing compared to controls suggesting that the pPCX may not only encode odor information but also learned odor associations. Ongoing work is selectively manipulating BLA input to the pPCX during conditioning in order to explore the precise role of communication between PCX and BLA in odor perception and memory.