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Séminaire impromptu - Emmanuel PerisseNeural circuits for value-based decision in Drosophila.

Abstract :

In both mammals andflies, dopamine neurons assign opposing valence to stimuli during appetitive or aversive learning. Dopamine is also involved during the decision-making process when one is confronted to choices of different values. By using Drosophila in the context of an aversive-based paradigm, we investigate the neural circuits required for value-based decisions. In this paradigm, flies are exposed to three events: a non-reinforced odor, an odor paired with a 60V electric shock and an odor paired with a 30V electric shock. Surprisingly, we found that during the conditioning phase, a subset of rewarding dopaminergic neurons is required to evaluate the lesser of two voltages (Perisse et al., 2013). We are now working on determining which part and how the reinforcing dopamine circuit is involved in this evaluation process.

Flies are later forced to make a “relative choice” between the two odors paired with an electric shock or an “absolute choice” between one odor paired with an electric shock and the non-reinforced odor. We found that a “relative choice” requires specific neural circuits in the mushroom body involved in approach and avoidance behavior (the ab core and ab surface neurons) while “absolute choice” requires only the avoidance circuit (the ab surface neurons) (Perisse et al., 2013). We conclude that the ab core neurons are part of the relative valuation and approach behavior. We are currently working on determining how dopamine is also involved in the evaluation circuit during relative choice and how it could be associated to the role of the mushroom body ab core neurons. 

Selected publications

Perisse E, Yin Y, Lin A, Lin S, Huetteroth W, Waddell S. Different Kenyon cell populations drive learned approach and avoidance in Drosophila. (2013) Neuron, 79, 945–956.