Covert REM sleep effects on REM mentation: Further methodological considerations and supporting evidence

Nielsen, Toré

doi:10.1017/s0140525x00974028

Cited by 40 publications

(22 citation statements)

References 286 publications

(412 reference statements)

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“…It is interesting to note that REM-like 1.5–3.0 Hz hippocampal/parahippocampal activity increased during the transition from wakefulness to sleep, reaching an average of 82% of tonic REM just shortly after the first electrophysiological signs of sleep (Bódizs et al, 2005). The REM-like 1.5–3.0 Hz hippocampal/parahippocampal activity observed during the wake–sleep transition in this study supports the covert-REM sleep hypothesis of dreaming, which suggests that “hidden” REM sleep features are present during sleep onset, explaining the vivid hypnagogic imagery (Nielsen, 2000). Intriguingly, the two sleep states accompanied by the most vivid imagery (sleep onset and REM sleep) are indeed characterized by a similar hippocampal/parahippocampal slow activity pattern.…”

Section: Hippocampal–neocortical Dialog and Memory Consolidationsupporting

confidence: 81%

Hippocampal Sleep Features: Relations to Human Memory Function

Ferrara¹,

Moroni²,

Gennaro³

et al. 2012

Front. Neur.

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The recent spread of intracranial electroencephalographic (EEG) recording techniques for presurgical evaluation of drug-resistant epileptic patients is providing new information on the activity of different brain structures during both wakefulness and sleep. The interest has been mainly focused on the medial temporal lobe, and in particular the hippocampal formation, whose peculiar local sleep features have been recently described, providing support to the idea that sleep is not a spatially global phenomenon. The study of the hippocampal sleep electrophysiology is particularly interesting because of its central role in the declarative memory formation. Recent data indicate that sleep contributes to memory formation. Therefore, it is relevant to understand whether specific patterns of activity taking place during sleep are related to memory consolidation processes. Fascinating similarities between different states of consciousness (wakefulness, REM sleep, non-REM sleep) in some electrophysiological mechanisms underlying cognitive processes have been reported. For instance, large-scale synchrony in gamma activity is important for waking memory and perception processes, and its changes during sleep may be the neurophysiological substrate of sleep-related deficits of declarative memory. Hippocampal activity seems to specifically support memory consolidation during sleep, through specific coordinated neurophysiological events (slow waves, spindles, ripples) that would facilitate the integration of new information into the pre-existing cortical networks. A few studies indeed provided direct evidence that rhinal ripples as well as slow hippocampal oscillations are correlated with memory consolidation in humans. More detailed electrophysiological investigations assessing the specific relations between different types of memory consolidation and hippocampal EEG features are in order. These studies will add an important piece of knowledge to the elucidation of the ultimate sleep function.

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Section: Hippocampal–neocortical Dialog and Memory Consolidationsupporting

confidence: 81%

Hippocampal Sleep Features: Relations to Human Memory Function

Ferrara¹,

Moroni²,

Gennaro³

et al. 2012

Front. Neur.

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“…First, DRF varies according to the sleep stage preceding awakening (e.g., Dement and Kleitman, 1957b; Nielsen, 2000, for a review). More dream reports are obtained after an awakening during rapid eye movement (REM) sleep than after an awakening during non-REM (NREM) sleep.…”

Section: Experimental Research On Dreamingmentioning

confidence: 99%

Experimental Research on Dreaming: State of the Art and Neuropsychoanalytic Perspectives

Ruby¹

2011

Front. Psychology

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Dreaming is still a mystery of human cognition, although it has been studied experimentally for more than a century. Experimental psychology first investigated dream content and frequency. The neuroscientific approach to dreaming arose at the end of the 1950s and soon proposed a physiological substrate of dreaming: rapid eye movement sleep. Fifty years later, this hypothesis was challenged because it could not explain all of the characteristics of dream reports. Therefore, the neurophysiological correlates of dreaming are still unclear, and many questions remain unresolved. Do the representations that constitute the dream emerge randomly from the brain, or do they surface according to certain parameters? Is the organization of the dream’s representations chaotic or is it determined by rules? Does dreaming have a meaning? What is/are the function(s) of dreaming? Psychoanalysis provides hypotheses to address these questions. Until now, these hypotheses have received minimal attention in cognitive neuroscience, but the recent development of neuropsychoanalysis brings new hopes of interaction between the two fields. Considering the psychoanalytical perspective in cognitive neuroscience would provide new directions and leads for dream research and would help to achieve a comprehensive understanding of dreaming. Notably, several subjective issues at the core of the psychoanalytic approach, such as the concept of personal meaning, the concept of unconscious episodic memory and the subject’s history, are not addressed or considered in cognitive neuroscience. This paper argues that the focus on singularity and personal meaning in psychoanalysis is needed to successfully address these issues in cognitive neuroscience and to progress in the understanding of dreaming and the psyche.

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“…First, by definition, NREM dreaming is clearly not moving the brain to awakening to the same extent REM does. Also, non-REM dreaming apparently only occurs to a limited extent in light sleep stages (Foulkes, 1962; Nielsen, 2000). Wake-up hypothesis posits that it is not dreaming per se that wakes people up, but the intrinsic triggering of the ARAS.…”

Section: Wake-up Hypothesis Predictive and Explanatory Powermentioning

confidence: 99%

Why Does Rem Sleep Occur? A Wake-Up Hypothesis1

Klemm¹

2011

Front. Syst. Neurosci.

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Brain activity differs in the various sleep stages and in conscious wakefulness. Awakening from sleep requires restoration of the complex nerve impulse patterns in neuronal network assemblies necessary to re-create and sustain conscious wakefulness. Herein I propose that the brain uses rapid eye movement (REM) to help wake itself up after it has had a sufficient amount of sleep. Evidence suggesting this hypothesis includes the facts that, (1) when first going to sleep, the brain plunges into Stage N3 (formerly called Stage IV), a deep abyss of sleep, and, as the night progresses, the sleep is punctuated by episodes of REM that become longer and more frequent toward morning, (2) conscious-like dreams are a reliable component of the REM state in which the dreamer is an active mental observer or agent in the dream, (3) the last awakening during a night's sleep usually occurs in a REM episode during or at the end of a dream, (4) both REM and awake consciousness seem to arise out of a similar brainstem ascending arousal system (5) N3 is a functionally perturbed state that eventually must be corrected so that embodied brain can direct adaptive behavior, and (6) cortico-fugal projections to brainstem arousal areas provide a way to trigger increased cortical activity in REM to progressively raise the sleeping brain to the threshold required for wakefulness. This paper shows how the hypothesis conforms to common experience and has substantial predictive and explanatory power regarding the phenomenology of sleep in terms of ontogeny, aging, phylogeny, abnormal/disease states, cognition, and behavioral physiology. That broad range of consistency is not matched by competing theories, which are summarized herein. Specific ways to test this wake-up hypothesis are suggested. Such research could lead to a better understanding of awake consciousness.

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Covert REM sleep effects on REM mentation: Further methodological considerations and supporting evidence

Cited by 40 publications

References 286 publications

Hippocampal Sleep Features: Relations to Human Memory Function

Hippocampal Sleep Features: Relations to Human Memory Function

Experimental Research on Dreaming: State of the Art and Neuropsychoanalytic Perspectives

Why Does Rem Sleep Occur? A Wake-Up Hypothesis1

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