psy: Sleep in animals

Evidence: 100 • authority: 72

Sleep is broadly considered a biological necessity in virtually all animals. The large majority of such taxa with documented sleep physiology are bilaterians, though there is increasing evidence of sleep or sleep-like states in non-bilaterians such as Cassiopea jellyfish and hydra (both cnidarians), and sponges. The various criteria which biologists use to define sleep states have been observed in all other animal phyla, often with profound variation in function. In all of these taxa except sponges, regulation of sleep is documented to involve genes whose transcription oscillates with time, known as circadian or clock genes. These genes and the gene networks they regulate give rise to the i…

Evidence: 42 • authority: 72

The neuroscience of sleep is the study of the neuroscientific and physiological basis of the nature of sleep and its functions. Traditionally, sleep has been studied as part of psychology and medicine. The study of sleep from a neuroscience perspective grew to prominence with advances in technology and the proliferation of neuroscience research from the second half of the twentieth century. The importance of sleep is demonstrated by the fact that every day animals spend hours of their time in sleep, and that sleep deprivation can have disastrous effects ultimately leading to death in animals. For a phenomenon so important, the purposes and mechanisms of sleep are only partially understood,…

Evidence: 36 • authority: 80

Fluidity of Brain States: Unihemispheric Sleep and Its Ties to Consciousness

Evidence: 36 • authority: 80

Compartmentalised Brain Homeostasis in Sleep

Evidence: 36 • authority: 80

Unihemispheric Slow Wave Sleep In The Brain Of Dolphins And Seals

Evidence: 36 • authority: 92

The Sentinel Sleep Theory: Unweaving the biological function of REM sleep.. The biological function of Rapid Eye Movement (REM) sleep remains one of neuroscience's great mysteries. In this theoretical research paper, I present the evolutionary theory that explains why REM sleep exists. I demonstrate that REM sleep functions to heighten brain alertness to significantly mitigate the high vulnerability inherent in non‑REM sleep-especially in deep sleep. Every organism with a nervous system must undergo non-REM sleep, a necessity that accompanies a negative and potentially lethal consequence: a higher risk of dying. Because non‑REM sleep substantially reduces alertness and increases the death r…