Mammalian NREM and REM sleep: Why, when and how

• Published in: Neuroscience and biobehavioral reviews 2023-03, Vol.146, p.105041-105041, Article 105041
• Main Authors: Rial, Rubén V., Akaârir, Mourad, Canellas, Francesca, Barceló, Pere, Rubiño, José A., Martín-Reina, Aida, Gamundí, Antoni, Nicolau, M. Cristina
• Format: Article
• Language: English
• Subjects: Animals; Brain Stem; Electroencephalography; Evolution of sleep; Mammals; Nocturnal bottleneck; Origin of NREM sleep; Origin of REM sleep; Sleep - physiology; Sleep, REM - physiology; Wakefulness - physiology
• ISSN: 0149-7634; 1873-7528
• DOI: 10.1016/j.neubiorev.2023.105041

This report proposes that fish use the spinal-rhombencephalic regions of their brain to support their activities while awake. Instead, the brainstem-diencephalic regions support the wakefulness in amphibians and reptiles. Lastly, mammals developed the telencephalic cortex to attain the highest degree of wakefulness, the cortical wakefulness. However, a paralyzed form of spinal-rhombencephalic wakefulness remains in mammals in the form of REMS, whose phasic signs are highly efficient in promoting maternal care to mammalian litter. Therefore, the phasic REMS is highly adaptive. However, their importance is low for singletons, in which it is a neutral trait, devoid of adaptive value for adults, and is mal-adaptive for marine mammals. Therefore, they lost it. The spinal-rhombencephalic and cortical wakeful states disregard the homeostasis: animals only attend their most immediate needs: foraging defense and reproduction. However, these activities generate allostatic loads that must be recovered during NREMS, that is a paralyzed form of the amphibian-reptilian subcortical wakefulness. Regarding the regulation of tonic REMS, it depends on a hypothalamic switch. Instead, the phasic REMS depends on an independent proportional pontine control. •The mammalian REMS is a paralyzed form of rhombencephalic wakefulness.•The NREMS of adult mammals is a paralyzed form of diencephalic wakefulness.•The cortical waking is a consequence of the mammalian cortical development.•The homeostasis of REMS depends on 1) an on-off and 2) a proportional control.•REMS is a neutral trait in adult terrestrial mammals.