The goal of my lab's research is to understand smell and taste, the chemical senses. Most of my lab's recent research has focused on the Drosophila olfactory system. Olfactory receptor neurons (ORNs) in the fly antenna project to the antennal lobe in the brain (analogous to the mammalian olfactory bulb). There, ORN axons segregate into channels termed glomeruli, where they make synapses with second-order neurons (projection neurons, PNs). By comparing the odor responses of ORNs and PNs corresponding to the same glomerulus, we found that these neurons respond differently to the same odor stimuli, and that this transformation improves the ability of a linear decoder to discriminate between different odor stimuli. Part of this transformation results from the unusual properties of ORN-PN synapses. Our recent results show that glomeruli are linked by both excitatory connections and inhibitory connections. These connections are mediated by local interneurons. We are currently investigating the idea that lateral excitation increases the sensitivity of this circuit when odor stimuli are weak, whereas lateral excitation increases the contrast between different glomeruli when odor stimuli are strong. Finally, we have described specialized ORNs that are highly selective for a fly pheromone. We found that PNs postsynaptic to these ORNs are also very selective for this odor, suggesting that pheromones may be processed by specialized channels in the brain.