Basolateral amygdala support of odor valence learning

PROJECT SUMMARY Odors are capable of potently influencing emotional and behavioral responses. The ability to detect odors and assign them hedonic value, or valence, is essential to navigating a world filled with rewards and dangers. Olfactory sensory loss is correlated with changes in emotional responses, reductions in memory, lack of appetite, and overall apathy. Despite strong evidence that odors acquire appetitive and aversive valence, the neural circuitry underlying odor valence learning is unknown. The basolateral amygdala (BLA) acts as a hub for the integration of multisensory information, including olfactory input, with aversive and appetitive outcomes. While there is ample compelling evidence that the BLA encodes for positive (reward) odor valence encoding, whether the same holds true for negative (aversive) odor valence learning is not clear. This is especially true given that studies to date used mildly aversive quinine, which could obscure the firing dynamics associated with more highly aversive outcomes. Dopamine is a potent neurotransmitter that influences cellular plasticity and learning in the BLA, but its influence on odor-valence behavioral learning is unclear. In the proposed F31 NRSA, I will test the hypothesis that through learning, BLA neurons represent the full spectrum of odor valence, both positive and negative, and that the display of learned odor valence behaviors is regulated by dopamine. I will use a combination of electrophysiological and computational methods, optogenetic stimulation, and site-specific pharmacology as mice engage in a go/no-go behavioral task wherein odors are either rewarded or punished. The results from Aim 1 will demonstrate that BLA neurons encode the full spectrum of learned odor valence while the results from Aim 2 will determine the influence of dopamine within the BLA on odor valence learning behavior. Overall, these findings will enhance our understanding of how the brain processes and assigns emotional significance to odors. Furthermore, the results from this project will expand our understanding and appreciation for the role of dopamine in olfactory processing, and has implications for human disorders characterized by disturbed affective regulation.