Mechanisms and Physiologic Effects of REM Sleep and Its Disruption

Since the discovery of rapid eye movement（REM）sleep in the 1950s, it is known that mammals and birds have two different sleep states：REM sleep and non-REM sleep. Recent advances in genetics have enabled researchers to identify many neuronal circuits responsible for the regulation of the two states of sleep. Moreover, the physiological functions of each sleep state are now becoming gradually unveiled, especially in the areas of learning and memory. In addition, the relationship between sleep and various diseases such as dementia have attracted increasing attention. Sleep abnormalities including REM sleep behavior disorder often precede dementia. Here, we focus on REM sleep and review recent findings on its mechanism, roles, and involvement in dementia.