Glomerular Signals Underlying Olfactory Navigation
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Date
2020
Authors
Nouboussi Nkenfack, Nelly Merveille
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
The olfactory system is the least-studied sense, although it plays key roles in different aspects of our existence. Our lab and others have examined the behavioral structure of olfactory navigation and have found that mice use a combination of serial and stereo cues to locate the source of an odor. Our next goal is to compare sampling movements directly against sensory input in freely moving mice in order to establish a correlation between sensory input and mouse behavior. Most imaging studies have been conducted on restrained mice, which allows for better control. However, animals behave differently when restrained, and specific behavioral dynamics can only be studied when the animal can move naturally in the environment. The first step in this goal, which is the topic of this project, is to successfully express fluorescence indicators in the olfactory bulb and to detect this expression using our imaging apparatus. For this purpose, we have been troubleshooting the surgical and imaging techniques necessary to begin our experiments. To achieve the expression of our fluorescence sensor GCaMP, we either injected a virus encoding the fluorescence protein into mice brains or engineered mice to encode the sensor gene in their genome. Histology revealed that we successfully expressed GCaMP in some mice, while we could only observe background fluorescence in others. This could result from the frying of the bulb due to continuous expression of the protein or degradation of the virus. Despite the difficulty of the surgeries, we could visualize activity in the glomeruli of live mice with the two-photon microscope, although our success rate remains low. We are continuously adjusting our protocol to improve our techniques, so we can move on to the next stage of our project.
Description
38 pages
Keywords
Biology, Olfaction, Imaging, Mitral Layer, GCaMP, Fluorescence, Glomerular Signals