Operant conditioning most faithfully reflects learning in the natural environment. This type of learning is demonstrated by conditioning in the several variations of the Skinner box. For example, a pigeon can be trained to peck a lit key to receive a food reward. Importantly, operant learning has been identified in quite diverse species, indicating this fundamental function of the brain is general and evolutionarily conserved. Despite advances in operant conditioning models and an early understanding of the molecular and neural systems important for this type of learning, the gap between theory and mechanism remains large. Taking advantage of the many tools available for neuroscience investigations in the fruit fly, Drosophila melanogaster, first attempts at closing that gap are proposed. A so-called heat-box will be used to determine gene function within neural circuitry important for temperature perception and operant conditioning in the fly. In this paradigm, individual flies are conditioned to avoid one half of a small chamber by associating that half with a temperature outside the preferred range. Preliminary results identified parts of the neural circuitry critical for sensing warm temperatures (i.e. neurons of the antennae and downstream neural pathways). Genes expressed in those neurons will be investigated for their function in temperature perception. Furthermore, as prior investigation has identified key molecular processes within parts of the neural structure termed the median bundle that are critical for memory formation, novel learning gene function will be examined in this and similar structures. This project will contribute to a growing understanding of the molecular and circuit logic of brain function in the relatively simple fly and will provide unique training opportunities for undergraduate and graduate students in the lab.