Imaging Glomerular Signaling of Unrestrained Olfactory Search in mice

Abstract

Olfaction is vital for many crucial animal behaviors such as social interaction, avoiding predators, and locating food. Our goal is to understand how an animal navigates toward the source of an odor. However, little is known about how odors are coded to inform olfactory search behavior. Air turbulence can cause odor distributions to be highly variable and unpredictable. Although we have previously characterized specific behavioral patterns in turbulent odor plumes, little is known about how odors are translated into movements. Our goal is to capture and understand the sensory input that informs these previously observed behaviors. We do this by injecting iGluSnFR, a fluorescent glutamate reporter, into the mitral cell layer of the olfactory bulb. This reporter tells us how glutamate released from olfactory sensory neuron terminals influences activity of mitral cells. iGluSnFR's fast kinetics allows us to observe and measure glutamate levels as the mouse performs olfactory navigation. By revealing activity in olfactory sensory neurons during olfactory navigation, this technique can tell us how odor informs the mouse's brain during active sampling. Following the development of this technique, we will image from iGluSnFR mice performing our olfactory search task to determine the neural computation that connects movement and sensation. Understanding how mice translate odor into behavior will inform our understanding of active sensory sampling behaviors in humans.