Abstract
Learning from experience takes place as a way for an organism to adapt to the environment\r around it. Operant learning is the association of a behavior with either an aversive or rewarding stimulus that naturally triggers an innate response in the organism. Learning is modulated by other behaviors such as sleep, where it has been shown that sleep loss can result in deficiencies in cognitive functions. In Drosophila, study of operant learning has been limited because existing paradigms either focus on aversive instead of appetitive operant learning, or have sensory stimuli that may interfere with operant learning. Here in a novel appetitive operant learning paradigm, we use a Y-Maze to teach flies to turn a certain direction by reinforcing their behavior with sugar as a reward. We found that sleep is necessary for learning in the Y-Maze, where only flies that sleep early on in training end up with a preference to turn towards the reward. As seen in previous paradigms, learning mutants with deficiencies in intracellular second messenger pathways also fail to learn in the Y-Maze. Although sleep is necessary for flies to learn in the Y-Maze, sleep induction through tryptone or optogenetic stimulation by itself is not sufficient in improving learning. Together we show in one of the first self-paced, reward-based operant learning paradigm in Drosophila, sleep is necessary but not sufficient for learning in the Y-Maze, where learning occurs through a cAMP-dependent pathway.