| The sense of smell is a central sensory modality vital for the detection of food, predators, and mates. Understanding of the logic of olfaction requires an understanding of the molecular receptors involved in sensing the odors, the functions and connectivity of the neurons that encode olfactory information and how they contribute to odor mediated behavior. Here I use the fruitfly, Drosophila melanogaster, as a model system to understand the principles of olfaction. Using molecular genetics I show that the anatomical connectivity of the olfactory system is precise and allows for a spatial representation of odors in the antennal lobe and the protocerebrum. I then demonstrate that the anatomical map is functional using a calcium sensitive GFP molecule, G-CaMP. Different odors elicit distinct spatial pattern of activity in the antennal lobe that are conserved in different flies. These patterns, reflective of ligand-receptor kinetics, is then communicated to the mushroom body and protocerebral neurons in the brain, where the presence of discrete glomeruli is replaced by an overlapping and interdigitating pattern of projection neuron axons, affording an opportunity to integrate olfactory input. |
