We live in a world of sights, sounds, flavors, and smells, and how this sensory world is represented in our mind is a fascinating and challenging question. Our overall goal is to understand how olfactory information is processed by the brain of an animal to give rise to stereotyped behaviors. We are using a versatile genetic organism, the vinegar fly Drosophila melanogaster, to perform genetic experiments that link neural functions to stereotyped olfactory behaviors. The fly is an excellent system for such investigations. Drosophila require their sense of smell for food seeking, finding mates, or for avoiding harmful substances. The neuronal organization of the fly olfactory system is remarkably similar to the mammalian system, and understanding how the fly makes sense of its olfactory world could shed light on how we make sense of ours.

We recently developed a new repressible binary expression system, the Q-system, which allows us to genetically control the activity of small populations of neurons. We can activate or silence these neurons, and assay how such perturbations affect the fly’s behavior. We have focused our initial olfactory attentions on determining the function of a population of neurons, the projection neurons (PNs), that carry olfactory information from the antennal lobe to the lateral horn- a poorly understood olfactory center. We aim to determine what olfactory information is relayed by the projection neuron population to the lateral horn, and how such information is further processed and relayed to additional regions of the brain. Our long term goal is to identify and characterize all the neurons in the fly brain that are required for the sense of smell. With only 100,000 neurons, the fly is a good tractable model to understand the neural basis of perception.