Authors: Dua Azhar, Alexander MacKenzie, Sophie Caron
Mentors: Sophie Caron
Insitution: University of Utah
The mushroom body of the Drosophila melanogaster is a structure in the brain that is necessary for learning, but much of how it functions remains unknown. In this model organism, D. melanogaster’s mushroom body neurons, known as Kenyon cells, and input projection neurons have connections that are random and biased—in which some projection neurons connect with Kenyon cells more than others—allowing the fly to potentially prioritize the learning of particular odors. I investigated the functional consequences and characterizations of these biases in order to understand the biological role they play for the fly using a theoretical and experimental approach. With a computational model of the D. melanogaster olfactory system, how biased connectivity to the mushroom body influences its ability to form associations with various odors and distinguish between similar odors was explored. Experimentally, the morphological features of olfactory circuits were characterized by low to high connectivity rates to the mushroom body, allowing us to see the unique features in these circuits that are beyond the different connectivity rates. Through a combination of immunohistochemistry and confocal microscopy, high-quality images were generated of these different neuronal olfactory circuits and their morphological qualities, such as the number and volume of boutons they project to the mushroom body. Altogether, these findings demonstrate how neural connectivities behind learning shape the representation space in D. melanogaster and impact its learning outcomes.