Exploring the Limits of the Olfactory Sensory System in Discriminating Odors

In addition to our other senses, ones sense of smell remains integral to ones perception of the world. The ability to discriminate between odors has been essential for the survival of many animals, including humans, from its uses in identifying food and more. Understanding how odor discrimination works between different odors and at different concentrations is crucial. The purpose of this study is to understand the minimum neuronal activity needed to be able to distinguish between odors. It is known that olfactory combinatorial coding, or the use of different combinations of olfactory receptors on olfactory sensory neurons (OSNs), is the mechanism used to differentiate between odors. Therefore, this study aimed to discover the minimum of active OSNs needed to discriminate between odors. This is accomplished by using Drosophila larvae as a model organism and modifying the genetic makeup to inhibit OSNs. To determine whether larvae could discriminate, an established assay for classical conditioning was used to associate one of two odors with a sugar reward. After several rounds of learning, a test was performed to assess whether learning, and therefore discrimination, was accomplished. Initial results seem to indicate that a small number of OSNs is sufficient to discriminate between odors. Fundamental studies such as this provide the foundation to understand the olfactory system and for future research that could lead to real-life applications.

Project Mentor: David Tadres

Faculty Advisor: Matthieu Louis