Characterizing the Role of Drosophila Larval Local Neurons in Decision Making Behavior

Abstract

Insects primarily rely on their sense of olfaction to detect and sense the world around them. Drosophila larvae specifically use 21 odor receptor neurons to navigate. The olfactory circuit consists of these 21 odor receptor neurons (ORNs) connecting to 21 projection neurons (PNs), but in the synapse between these neurons, local neurons (LNs) play an important role in mediating neuronal activity. Local neurons have been thought to act as a form of communication between different sets of ORNs and PNs using excitation and inhibition. In this thesis, optogenetic stimulation was used to activate inhibitory LNs in the olfactory circuit to further investigate the question of how LNs silence certain ORN signals to affect a choice in larval behavior towards different odorants. Activation resulted in unprecedented results as the larvae completely seized in motion displaying the potency and power that inhibitory neurons play in neuronal activity. This important finding could contribute to the understanding of the integration of local neurons within the olfactory circuit and their role in regulating larval navigation and chemotaxis through inhibitory means.