There are multiple theories as to why we sleep. I will present our lab’s work on what circuitries sense the inexorable drive to sleep when we are sleep-deprived (sleep homeostasis). We are interested in if sedative drugs promote these restorative sleep pathways. I will also talk about powerful new sleep-promoting circuitry we have discovered in the basal ganglia and midbrain, which overlaps with circuitry that responds to stress.