Current ideas about the roles of rapid eye movement and non–rapid eye movement sleep in brain development

Abstract

Sleep plays an essential role in health and cognitive performance. Known functions of sleep include recuperating from oxidative stress or toxins accumulated during wakefulness, 1 replenishing energy stores 2 and synthesis of macromolecules, such as growth hormones. 3 They also include executive functioning, 4 memory consolidation, 5 immuno-protection 6 and repair of neural damage. 7 New functions of sleep are still being discovered, such as its role in driving brain development. 8 The amount of sleep peaks during foetal and neonatal life, and this is also a time of rapid brain development. 9 Research has also shown that sleep quantity and brain development both gradually decrease across a person's lifespan. 9 Several studies have shown that sleep deprivation during early development has a detrimental impact on brain maturation, 10,11 and this suggests that sleep is important for brain development. However, there is still a considerable lack of clarity about the nature of the relationship between sleep and brain development and how this relates to the different states of sleep. This review looks at the current understanding of the role of sleep in brain development across the different development stages and focuses on the distinct functions of rapid eye movement (REM) sleep and non-REM (NREM) sleep. There is a scarcity of experimental studies on the relationships between sleep deprivation and brain development in human newborns or young children for ethical reasons. Consequently, most studies have focused on animals or older children and adults and it is important to take care when translating these results to the developing human brain. This narrative review provides a concise overview of the human brain and sleep development, respectively. It also explores the role of sleep in brain development.

Intrinsic maturation of sleep output neurons regulates sleep ontogeny in Drosophila

“…In developing mammals, REM and non-REM sleep are thought to play different roles. 43 The proportion of REM sleep is significantly increased in neonates 4 and plays a critical role in plasticity of the developing visual cortex 11,44,45 as well as selective strengthening of synaptic S1. (legend continued on next page) Article contacts.…”

Early Life Circadian Rhythm Disruption Alters Brain and Behavior in Adulthood

“…If not stress, then this leaves open the possibility that it is the circadian disruption that directly affects development. Given the role that sleep quantity and quality play in brain development 13 , the circadian disruption may have compromised the sleep of the neonatal mice during this critical phase of brain development. Sleep problems have been linked to subsequent changes in brain structures in humans [14][15][16] .…”

“…The animals were exposed to three different tasks to assess different behaviors. Tasks were presented in the following order over different days: Elevated Plus Maze (EPM, day 1), Morris Water Maze (MWM, days 4-8), Delayed Match-to-Sample (DMS, days [12][13][14][15][16][17][18][19]. This order was selected so that the tasks progressed from least to most complex and allowed for anxiety to be assessed by the EPM before the mice had habituated to extensive handling.…”

“…Infancy and childhood are developmental periods that witness tremendous brain maturation, synaptic rearrangements and neural network formation that are critical to support complex cognitive skills 13 . Poor sleep during infancy and childhood are associated with impaired brain development [14][15][16] , delayed socialemotional development [17][18][19] , diminished executive functioning [20][21][22] , delayed language development 23 , lower cognitive performance on neurodevelopmental test 24 and increased rates of anxiety and depression 25 .…”

Intrinsic maturation of sleep output neurons regulates sleep ontogeny in Drosophila

“…How does the unique sleep quality in juvenile flies contribute to neurodevelopment? In mammals, REM and non-REM sleep differentially contribute to development (Knoop et al, 2021). The proportion of REM sleep is significantly increased in neonates (Roffwarg et al, 1966), and plays a critical role in neurodevelopment.…”