Purpose of Review: This article outlines the fundamental brain mechanisms that control sleep-wake patterns and reviews how pathologic changes in these control mechanisms contribute to common sleep disorders.
Recent Findings: Discrete but interconnected clusters of cells located within the brainstem and hypothalamus comprise the circuits that generate wakefulness, non–rapid eye movement (non-REM) sleep, and REM sleep. These clusters of cells use specific neurotransmitters, or collections of neurotransmitters, to inhibit or excite their respective sleep- and wake-promoting target sites. These excitatory and inhibitory connections modulate not only the presence of wakefulness or sleep, but also the levels of arousal within those states, including the depth of sleep, degree of vigilance, and motor activity. Dysfunction or degeneration of wake- and sleep-promoting circuits is associated with narcolepsy, REM sleep behavior disorder, and age-related sleep disturbances.
Summary: Research has made significant headway in identifying the brain circuits that control wakefulness, non-REM, and REM sleep and has led to a deeper understanding of common sleep disorders and disturbances.
Address correspondence to Dr John H. Peever, Department of Cell and Systems Biology, University of Toronto, 25 Harbord St, Toronto, ON M5S 3G5, Canada, email@example.com.
Relationship Disclosure: Dr Horner has received personal compensation for serving as a consultant for Dairy Farmers of Canada and Viord Inc and receives royalties from BookBaby for his book, The Universal Pastime: Sleep and Rest Explained. Dr Horner has received grants from Canada Research Chair (950-229813), the Canadian Institutes of Health Research (MT-15563), and the National Sanitarium Association Innovative Research Program (00144051). Dr Peever has received grant support from the Canadian Institutes of Health Research.
Unlabeled Use of Products/Investigational Use Disclosure: Drs Horner and Peever report no disclosures.