New developments in sleep research: molecular genetics, gene expression, and systems neurobiology.

Understanding the mechanisms that underlie the control of sleep and wakefulness is a major research area in neuroscience. This mini-symposium review highlights some recent developments at the gene, molecular, cellular, and systems levels that have advanced this field. The studies discussed below use organisms ranging from flies to humans and focus on the interaction between the sleep homeostatic and circadian systems, the consequences of mutations in genes involved in the circadian clock on sleep timing, the effects of sleep deprivation on brain gene expression, the discovery of "sleep active" neurons in the cerebral cortex, the role of the hypocretin/orexin system in the maintenance of sleep and wakefulness, and the interaction between sleep and learning.