It is often true in biology that things are more complex than they first seem, and this is especially accurate for sleep: what is sleep, what are its mechanisms and what is it for? The discovery of Rapid Eye Movement (REM) sleep - an excited state characterised by intense brain activity and vivid dreaming - tells us sleep is not just for rest. With so many unanswered questions, sleep research is an exciting field to follow. In this Insight, Naturehighlights a diverse Collection of articles ranging from how sleep affects our understanding of consciousness to the consolidation of our memories. Supported by the National Institutes of Health. As always,Naturecarries sole responsibility for all editorial content.
