New insights into REM sleep crack an enduring mystery

REM sleep -- the phase of night-time mammalian sleep physiology where dreams occur -- has long fascinated scientists, clinicians, philosophers, and artists alike, but the identity of the neurons that control REM sleep, and its function in sleep have been controversial due to a lack of precise genetic methods to study the sleeping brain. Now, in a remarkable demonstration of a recent brain technology, neuroscientists provide the first answers to both questions, identifying a neural circuit in the