Our understanding of aging and development in humans has advanced significantly through the use of non-invasive imaging methods that have characterized structural and functional changes in the brain during these processes. Neural circuit dynamics, and oscillations in particular, also play a crucial role in aging and development, but studies of these phenomena have been limited primarily to animal models. Each year, millions of elderly adults, as well as millions of children, receive general anesthesia for surgery and other medical procedures. Anesthetic drugs act at specific receptors, such as GABA-A, to induce large stereotyped brain oscillations that act to functionally impair cortical, thalamocortical, and brainstem circuits. Recent studies have shown that anesthesia-induced oscillations undergo striking changes during aging and development. When combined with our understanding of anesthetic mechanisms, these studies provide new insights on how brain circuits change in humans during aging and development. In this talk, I will present data on this natural experiment of anesthesia, aging, and development, and will discuss potential scientific and clinical implications.