opposing views about the ontogenetic origins of REM ..

views about the ontogenetic origins of REM ..

I review the evidence in support of this general hypothesis

The sentinel hypothesis of REM sleep was put forward by Frederick Snyder in 1966. This hypothesis does not explain the muscle paralysis of REM sleep; however, a logical analysis might suggest that the muscle paralysis exists to prevent the animal from fully waking up unnecessarily, and allowing it to return easily to deeper sleep. This does not occur for either cats or humans, although humans are more likely to wake from REM sleep than from NREM sleep. Snyder hypothesized that REM sleep activates an animal periodically, to scan the environment for possible predators. It is based upon the observation that REM sleep in several mammals (the rat, the hedgehog, the rabbit, and the rhesus monkey) is followed by a brief awakening.

One of the most favored theories of REM sleep is titled the Ontogenetic Hypothesis of REM sleep.

known as the Ontogenetic Hypothesis of REM sleep, ..

Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep.People have proposed many hypotheses about the functions of dreaming.

The Sentinel hypothesis of REM sleep …

However, because processes of neuronal plasticity do not cease altogether in the brain, REM sleep may continue to be implicated in neurogenesis in adults as a source of sustained spontaneous stimulation. One important theoretical consequence of the Ontogenetic Hypothesis is that REM sleep may have no essentially vital function in the mature brain, i.e., once the development of CNS has completed.

We hypothesize an ontogenetic function of REM sleep; ..

Rapid eye movement sleep - Wikipedia

Corneal Respiration in Closed EyeThe second component of the hypothesis, that there would be a metabolicproblem when the aqueous humor is stagnant, can be established by semitheoreticalconsiderations.

Rapid eye movement sleep (REM ..

It is more likelythat the corneal exposure provided by the lid separation is sufficientto promote an adequate thermal circulation in the anterior chamber. When I first came across this paper during a literature survey, I believedit argued against the hypothesis, since rabbits were on record as havingepisodes of REM sleep (Weiss and Roldan, 1964).

Rapid eye movement sleep - Wikipedia, the free …

Moreover, when the animal is awake, it is unlikely that the aqueousin the closed eye is stirred because observation of an open eye under theslit lamp shows that its movements, as well as head movements, are normallyrare (Maurice, 1995). Thus the breakdown of the cornea after prolonged lid closure is in accordancewith the stagnant aqueous humor hypothesis and could be considered to supportit, if one accepts the validity of Fatt's calculations that show that theoxygen supply under the closed lid would be adequate if the anterior chamberis stirred.

21/10/2013 · Rapid eye movement sleep ..

AB - The biological function of REM sleep is defined in terms of the functions of neural processes that selectively operate during the REM sleep state. The high amounts of REM sleep expressed by the young during a period of central nervous system plasticity suggest that one function of REM sleep is in development. The phenomenon of activity-dependent development has been clearly shown to be one mechanism by which early sensory experience can affect the course of neural development. Activity-dependent development may be a ubiquitous process in brain maturation by which activity in one brain region can influence the developmental course of other regions. We hypothesize an ontogenetic function of REM sleep; namely, the widespread control of neuronal activity exerted by specific REM sleep processes help to direct brain maturation through activity-dependent developmental mechanisms. Preliminary tests of the hypothesis have been conducted in the developing feline visual system, which has long been known to incorporate information derived from visual experience in establishing neuronal connectivity. We find that suppression of REM sleep processes by an instrumental REM deprivation procedure results in a significant enhancement of the effects of altered visual experience by monocular occlusion. Bilateral brainstem lesions that selectively block the occurrence of ponto-geniculo-occipital (PGO) waves are sufficient to produce similar results. These data indicate that the propagation of phasic influences during REM sleep interacts with other processes subserving neural development. This source of influence appears not to derive from the environment but rather stems from an intrinsic source of genetic origin. Examination of the neural activity associated with PGO waves in the lateral geniculate nucleus reveals a distribution of facilitatory influence markedly different from that induced by visual experience. We conclude that REM sleep directs the course of brain maturation in early life through the control of neural activity.

of this reaction shows striking similarities to REM en

In support of this theory, research finds that in goal-oriented dreams, eye gaze is directed towards the dream action, determined from correlations in the eye and body movements of patients who enact their dreams. Against this hypothesis is that such eye movements occur in those born blind and in fetuses in spite of lack of vision. Also, binocular REMs are non-conjugated (i.e., the two eyes do not point in the same direction at a time) and so lack a fixation point. According to "scanning hypothesis", the directional properties of REM sleep are related to a shift of gaze in dream imagery.