Special issue: Sleep

“[W]e still don’t really know why we sleep,” writes Science Senior editor Peter Stern in an introduction to a special issue of the journal. “It is time to acknowledge and enjoy the honey-heavy due of slumber,” Stern says. The special issue that follows – four Reviews and a Policy Forum – summarizes recent insights concerning the basic mechanisms underlying sleep and the many functions our brains perform during this time. It also focuses on the restorative and health-promoting aspect for individuals and for wider society.

Although it is obvious what benefits derive from other common and strong physiological drives, such as hunger, sex, and thirst, it is less obvious what drives us to sleep and what benefits accrue, say Nicholas P. Franks and William Wisden in a Review. “Understanding the biochemical or circuit basis for the sleep drive could enable the benefits of sleep to be artificially stimulated with a new generation of sedative drugs,” Franks and Wisden write. A separate Review by Gabrielle Girardeau and Vítor Lopes-dos-Santos discusses sleep’s significance for healthy cognition, including memory. The authors review how electrical signatures have been guiding our understanding of the circuits and processes that sustain memory consolidation during sleep and highlight how these brain patterns evoke future directions for research. A Review by Laura D. Lewis discusses advances in understanding how sleep maintains the physiological health of the brain through interconnected systems of neuronal activity and fluid flow. Recognizing these linked causes and consequences of sleep has shed new light on why sleep is important for such disparate aspects of brain function, she writes. A fourth Review by Michael A. Grandner and Fabian-Xosé Fernandez discusses the way in which sleep has been conceptualized as a set of interrelated physiological processes, sometimes devoid of greater biological and social-environmental context. “Contextualizing sleep health with respect to its determinants—from individual- to societal-level factors—would enable neuroscientists to more effectively translate sleep health into clinical practice,” they write. Finally, a Policy Forum by Gautam Rao and colleagues tackles the question, “Why do people not sleep more, given…predicted benefits?” The authors discuss recent progress in informing sleep policy through field experiments, which have been rare in sleep science until recently.