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Li Yan McCurdy

An animal's fitness is contingent on its ability to make behavioral choices in light of sensory inputs; such decisions are more difficult when the animal must choose between conflicting stimuli. Even though sensory decision-making is a necessary and fundamental cognitive function, its biological basis remains poorly understood. I will be developing a behavioral paradigm that assays decision-making in the face of conflicting gustatory stimuli in Drosophila, to identify the specific neurons involved in sensory decision-making, how they integrate the inputs from two circuits relaying information about conflicting stimuli, and how the neurons' firing patterns encode a decision.

A potential set of neurons involved in the integration of conflicting sensory stimuli is the dopaminergic protocerebral posterior lateral (PPL1) cluster, which has been shown to be involved in appetitive and aversive learning and memory (i.e., PPL1 signaling is involved in the formation of memories from classical conditioning paradigms that link either a sweet taste or an electric shock with a neutral odor). I propose that when a fly is presented with a stimulus that is both appetitive and aversive, the dopaminergic PPL1 neurons are involved in deciding whether to approach or avoid the stimulus. Specifically, I hypothesize that the integration of appetitive and aversive signals occurs either within or downstream of the dopaminergic PPL1 neurons. I also hypothesize that the identified "integrator" neurons integrate the signal by summating the relative saliency of the appetitive and aversive stimuli, and encode the final decision in the form of action potential frequency