Awakening to the behavioral analysis of sleep in Drosophila.

Perhaps the most observable of the many circadian oscillations that have been described in both vertebrate and invertebrate animals is the daily alterations in periods of rest and activity. Recent studies in the fruit fly Drosophila melanogaster suggest that these periods of inactivity are not simply rest but share many of the fundamental components that define mammalian sleep. Thus, quiescent episodes are characterized by reduced awareness of the environment and are homeostatically regulated. Although this field is in its infancy, recent studies have focused on the interaction between circadian and homeostatic processes. These results indicate that components of the circadian clock may play a substantial role in mechanisms underlying sleep homeostasis at the molecular level. In this article, the author reviews recent advances obtained using Drosophila as a model system to elucidate fundamental components of sleep regulation.