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What does a cat dream about?

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Abstract

When the neural systems which are responsible for postural atonia during paradoxical sleep are destroyed, sleeping cats periodically display stereotyped motor activity, revealing a rich repertoire of non-goal-directed 'oneiric behaviour'.

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... Since REM sleep dominates the sleep episode more during early developmental periods in comparison to later in life (50% vs. 25%), some researchers have argued for a role of REM sleep in general brain maturation (Marks, Shaffery, Oksenberg, Speciale, Roffwarg, 1995;Mirmiran, 1995;Roffwarg, Muzio, Dement, 1966); however, also a life-long preparational function of REM sleep has been proposed. One of the first approaches in this direction was the hypothesis of Jouvet (1979), Jouvet (1998) that REM sleep serves as a genetic programming system for the brain. Based on the brain maturation hypothesis and Dewan's (1970) metaphor of the brain being a computer programmed during REM sleep, Jouvet (1979) suggested that innate behaviors are rehearsed during REM sleep to prepare for their application in waking life. ...
... One of the first approaches in this direction was the hypothesis of Jouvet (1979), Jouvet (1998) that REM sleep serves as a genetic programming system for the brain. Based on the brain maturation hypothesis and Dewan's (1970) metaphor of the brain being a computer programmed during REM sleep, Jouvet (1979) suggested that innate behaviors are rehearsed during REM sleep to prepare for their application in waking life. He later revised his approach, now assuming that REM sleep constitutes an iterative genetic programming helping to maintain the process of psychological individuation (Jouvet, 1998). ...
Article
Over the years, rapid eye movement (REM) sleep has been associated with general memory consolidation, specific consolidation of perceptual, procedural, emotional and fear memories, brain maturation and preparation of waking consciousness. More recently, some of these associations (e.g. general and procedural memory consolidation) have been shown to be unlikely, while others (e.g. brain maturation and consciousness) remain inconclusive. In this review, we argue that both behavioral and neurophysiological evidence supports a role of REM sleep for amygdala-related memory processing: the amygdala-hippocampus-medial prefrontal cortex network involved in emotional processing, fear memory and valence consolidation shows strongest activity during REM sleep, in contrast to the hippocampus-medial prefrontal cortex only network which is more active during non-REM sleep. However, more research is needed to fully understand the mechanisms
... This system prevents animals from performing "in real life" the imaginary movements that they make when dreaming, which would render them extremely vulnerable, and therefore subject to be preyed upon. This idea derives mainly from the pioneering work of Jouvet (1979), who, upon damaging specific brainstem nuclei, noted that animals exhibited typical behavior such as running, cleaning themselves and masticating during REMS, as they no longer possessed muscle inhibition. These behavior patterns have been readily associatedhypothetically -to dreaming (Jouvet and Delorme, 1965;Jouvet, 1979). ...
... This idea derives mainly from the pioneering work of Jouvet (1979), who, upon damaging specific brainstem nuclei, noted that animals exhibited typical behavior such as running, cleaning themselves and masticating during REMS, as they no longer possessed muscle inhibition. These behavior patterns have been readily associatedhypothetically -to dreaming (Jouvet and Delorme, 1965;Jouvet, 1979). Dahlitz and Parkes (1993) speculate that a lack of synchrony between changes in brain activity and muscle atonia is the mechanism responsible for bodily immobilization during SP. ...
... Animals that have undergone a lesion of their locus coeruleus present motor expressions of their dreams, e.g. hunting in sleeping cats (Jouvet 1979). Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al. 1970). ...
... Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al. 1970). Speech produced by humans during sleep corresponds to their dream contents (Jouvet 1979). The quality of dreams depends on the type of sleep; more negative-emotional type dreaming occurs during REM (i.e. ...
Thesis
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The Umwelt concept of Jakob von Uexküll considers animals as subjects that inhabit their own subjective universe which is determined by the animal's sensory perception and cognitive abilities. Dolphins present an interesting species to investigate its Umwelt because cetaceans underwent a drastic change in lifestyle in the course of evolution because these mammals returned from a terrestrial life back into the water. Although bottlenose dolphins are intensively studied there are still many knowledge gaps. Here we studied some aspects of the dolphins' Umwelt by asking: (1) how their nocturnal acoustic Umwelt is arranged; (2) what the production of vocal copies can tell us about the dolphins' perception of their environment; (3) whether they are able to perceive tastes (4) or odours; (5) whether they are sensitive to magnetic stimuli. We found that the dolphins' nocturnal Umwelt was characterized by a temporally patterned vocal activity that also included vocal copies of sounds that the dolphins had heard during the day. This is a striking separation between auditory memory formation and vocal copy production and the copies might be a vocally expressed nocturnal rehearsal of day events. Thus, vocalizations can serve as possible indicators of events or objects that are meaningful to the dolphins. Regarding dolphins' perceptive abilities, we found that they were sensitive to both gustatory and olfactory food-related stimuli. They might use this ability to locate and/or evaluate prey. Further, dolphins responded to a magnetic stimulus, suggesting that they are magnetosensitive, what could be useful for navigation. So far, chemo- and magnetoreception have not been considered seriously as potentially functional in dolphins. The results obtained during this thesis fill some of the gaps that still exist in the knowledge of the dolphin's Umwelt and therefore contribute to a better understanding of this species. Moreover, they illustrate that even already intensively studied species may still hold important facets of their biology to reveal and that research should broaden the view and remain unbiased when studying a topic.
... Actually, memories of salient events can lead to rehearsal in the form of dreams during sleep both in humans and animals (Cipolli et al., 2004). Animals that have undergone a lesion of their locus coeruleus present motor expressions of their dreams, e.g., hunting in sleeping cats (Jouvet, 1979). Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al., 1970). ...
... Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al., 1970). Speech produced by humans during sleep corresponds to their dream contents (Jouvet, 1979). The quality of dreams depends on the type of sleep; more negative-emotional type dreaming occurs during REM (i.e., rapid eye movement) sleep (Stickgold et al., 2001), whereas during non-REM (or day) dreams, the episodic memory (memory of an event as a whole) is more involved (Stickgold et al., 2001;Vandekerckhove and Cluydts, 2010): an "offline model of the world" where events and social interactions are associated in a "vivid and multimodal simulation of real experience" (Revonsuo, 2000). ...
Article
Full-text available
Alban Lemasson and Martine Hausberger have contributed equally to this work. The mechanisms underlying vocal mimicry in animals remain an open question. Delphinidae are able to copy sounds from their environment that are not produced by conspecifics. Usually, these mimicries occur associated with the context in which they were learned. No reports address the question of separation between auditory memory formation and spontaneous vocal copying although the sensory and motor phases of vocal learning are separated in a variety of songbirds. Here we show that captive bottlenose dolphins produce , during their nighttime resting periods, non-dolphin sounds that they heard during performance shows. Generally, in the middle of the night, these animals produced vocal copies of whale sounds that had been broadcast during daily public shows. As their life history was fully known, we know that these captive dolphins had never had the opportunity to hear whale sounds before then. Moreover, recordings made before the whale sounds started being broadcast revealed that they had never emitted such sounds before. This is to our knowledge the first evidence for a separation between formation of auditory memories and the process of learning to produce calls that match these memories in a marine mammal. One hypothesis is that dolphins may rehearse some special events heard during the daytime and that they then express vocally what could be conceived as a more global memory. These results open the way for broader views on how animals might rehearse life events while resting or maybe dreaming.
... Actually, memories of salient events can lead to rehearsal in the form of dreams during sleep both in humans and animals (Cipolli et al., 2004). Animals that have undergone a lesion of their locus coeruleus present motor expressions of their dreams, e.g., hunting in sleeping cats (Jouvet, 1979). Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al., 1970). ...
... Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al., 1970). Speech produced by humans during sleep corresponds to their dream contents (Jouvet, 1979). The quality of dreams depends on the type of sleep; more negative-emotional type dreaming occurs during REM (i.e., rapid eye movement) sleep (Stickgold et al., 2001), whereas during non-REM (or day) dreams, the episodic memory (memory of an event as a whole) is more involved (Stickgold et al., 2001; Vandekerckhove and Cluydts, 2010): an " offline model of the world " where events and social interactions are associated in a " vivid and multimodal simulation of real experience " (Revonsuo, 2000). ...
Conference Paper
Delphinids are able to copy sounds from their environment that are not produced by conspecifics. So far these mimicries occur associated with the context in which they were learned. No separation between auditory memory formation and spontaneous vocal copying was observed as it is for example in songbirds. In our study we report that bottlenose dolphins (Tursiops truncatus) are able to produce, during night time non-dolphin sounds that they heard during the day: they copy whale sounds that had been broadcast during daily public presentations. We know that these captive dolphins had never had the opportunity to hear whale sounds before then. Moreover, recordings made before the whale sounds started being broadcast revealed that they had never emitted such sounds before. This is, to our knowledge, the first evidence of a separation between formation of auditory memories and the production of calls that match these memories in a marine mammal. One hypothesis is that dolphins may rehearse special events heard during the day time and that they then express vocally what could be conceived as a more global memory. These results open the way for broader views on how animals might rehearse life events while resting or may be dreaming.
... Actually, memories of salient events can lead to rehearsal in the form of dreams during sleep both in humans and animals (Cipolli et al., 2004). Animals that have undergone a lesion of their locus coeruleus present motor expressions of their dreams, e.g., hunting in sleeping cats (Jouvet, 1979). Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al., 1970). ...
... Vocalizations during sleep are commonly reported, as for instance in horses (Ruckebusch et al., 1970). Speech produced by humans during sleep corresponds to their dream contents (Jouvet, 1979). The quality of dreams depends on the type of sleep; more negative-emotional type dreaming occurs during REM (i.e., rapid eye movement) sleep (Stickgold et al., 2001), whereas during non-REM (or day) dreams, the episodic memory (memory of an event as a whole) is more involved (Stickgold et al., 2001;Vandekerckhove and Cluydts, 2010): an "offline model of the world" where events and social interactions are associated in a "vivid and multimodal simulation of real experience" (Revonsuo, 2000). ...
Conference Paper
It is known that delphinidae can associate heard sounds with salient events/objects and mimic these sounds, mostly in the corresponding context. Thus, one can wonder whether dolphins, as other animals and humans, have a sort of sensory memory of events. Here we show that a group of five bottlenose dolphins in the Planète Sauvage dolphinarium (France) produced, during their nighttime resting periods, non-dolphin sounds that they heard during performance shows. In total, 3246 vocalizations were recorded during >120 hours (2588 vocalizations during >100 hours at day, 658 vocalizations during >20 hours at night). Generally in the middle of the night, these animals produced vocal copies of whale sounds that had been broadcast during daily shows. Recordings made before the whale sounds started being broadcast revealed that they have never emitted such sounds before. These unusual vocalizations differ from all other sounds in the dolphins’ repertoire. The similarity between the dolphins’ copies and the model whale sounds was substantiated by a discriminant function analysis with measured acoustic parameters and a playback experiment with human audience. This is to our knowledge the first evidence for the production of sounds heard during day salient events in a nocturnal resting context in marine mammals.
... This system prevents animals from performing "in real life" the imaginary movements that they make when dreaming, which would render them extremely vulnerable, and therefore subject to be preyed upon. This idea derives mainly from the pioneering work of Jouvet (1979), who, upon damaging specific brainstem nuclei, noted that animals exhibited typical behavior such as running, cleaning themselves and masticating during REMS, as they no longer possessed muscle inhibition. These behavior patterns have been readily associatedhypothetically -to dreaming (Jouvet and Delorme, 1965;Jouvet, 1979). ...
... This idea derives mainly from the pioneering work of Jouvet (1979), who, upon damaging specific brainstem nuclei, noted that animals exhibited typical behavior such as running, cleaning themselves and masticating during REMS, as they no longer possessed muscle inhibition. These behavior patterns have been readily associatedhypothetically -to dreaming (Jouvet and Delorme, 1965;Jouvet, 1979). Dahlitz and Parkes (1993) speculate that a lack of synchrony between changes in brain activity and muscle atonia is the mechanism responsible for bodily immobilization during SP. ...
... This system prevents animals from performing "in real life" the imaginary movements that they make when dreaming, which would render them extremely vulnerable, and therefore subject to be preyed upon. This idea derives mainly from the pioneering work of Jouvet (1979), who, upon damaging specific brainstem nuclei, noted that animals exhibited typical behavior such as running, cleaning themselves and masticating during REMS, as they no longer possessed muscle inhibition. These behavior patterns have been readily associatedhypothetically -to dreaming (Jouvet and Delorme, 1965;Jouvet, 1979). ...
... This idea derives mainly from the pioneering work of Jouvet (1979), who, upon damaging specific brainstem nuclei, noted that animals exhibited typical behavior such as running, cleaning themselves and masticating during REMS, as they no longer possessed muscle inhibition. These behavior patterns have been readily associatedhypothetically -to dreaming (Jouvet and Delorme, 1965;Jouvet, 1979). Dahlitz and Parkes (1993) speculate that a lack of synchrony between changes in brain activity and muscle atonia is the mechanism responsible for bodily immobilization during SP. ...
Article
Full-text available
Sleep paralysis (SP) is a dissociative state that occurs mainly during awakening. SP is characterized by altered motor, perceptual, emotional and cognitive functions, such as inability to perform voluntary movements, visual hallucinations, feelings of chest pressure, delusions about a frightening presence and, in some cases, fear of impending death. Most people experience SP rarely, but typically when sleeping in supine position; however, SP is considered a disease (parasomnia) when recurrent and/or associated to emotional burden. Interestingly, throughout human history, different peoples interpreted SP under a supernatural view. For example, Canadian Eskimos attribute SP to spells of shamans, who hinder the ability to move, and provoke hallucinations of a shapeless presence. In the Japanese tradition, SP is due to a vengeful spirit who suffocates his enemies while sleeping. In Nigerian culture, a female demon attacks during dreaming and provokes paralysis. A modern manifestation of SP is the report of “alien abductions”, experienced as inability to move during awakening associated with visual hallucinations of aliens. In all, SP is a significant example of how a specific biological phenomenon can be interpreted and shaped by different cultural contexts. In order to further explore the ethnopsychology of SP, in this review we present the “Pisadeira”, a character of Brazilian folklore originated in the country’s Southeast, but also found in other regions with variant names. Pisadeira is described as a crone with long fingernails who lurks on roofs at night and tramples on the chest of those who sleep on a full stomach with the belly up. This legend is mentioned in many anthropological accounts; however, we found no comprehensive reference on the Pisadeira from the perspective of sleep science. Here, we aim to fill this gap. We first review the neuropsychological aspects of SP, and then present the folk tale of the Pisadeira. Finally, we summarize the many historical and artistic manifestations of SP in different cultures, emphasizing the similarities and differences with the Pisadeira.
... A pioneering series of experiments on cats by Michel Jouvet suggests that they do; indeed, this work illustrated apparent dream-enacting behaviours in cats many years before the same was observed in humans in REM Sleep Behaviour Disorder (Jouvet & Michel, 1959;Jouvet, 1962). Jouvet (1979) reported that following pontine lesions, no alterations were observed during wakefulness or Slow-Wave Sleep, but during REM sleep typical atonia was absent, and cats were observed performing complex behaviors during sleep such as stalking (as if pursuing prey), attacking behaviors, flight behaviors, and grooming. Subsequent research has confirmed these findings (Henley & Morrison, 1974, Hendricks, Morrison, & Mann, 1982. ...
Article
The understanding of biological functions of sleep has improved recently, including an understanding of the deep evolutionary roots of sleep among animals. However, dreaming as an element of sleep may be particularly difficult to address in non-human animals because in humans dreaming involves a non-wakeful form of awareness typically identified through verbal report. Here, we argue that parallels that exist between the phenomenology, physiology, and sleep behaviors during human dreaming provide an avenue to investigate dreaming in non-human animals. We review three alternative measurements of human dreaming – neural correlates of dreaming, ‘replay’ of newly-acquired memories, and dream-enacting behaviors – and consider how these may be applied to non-human animal models. We suggest that while animals close in brain structure to humans (such as mammals and birds) may be optimal models for the first two of these measurements, cephalopods, especially octopuses, may be particularly good candidates for the third.
... Both carbachol-induced states presented a common characteristic, the absence of muscle tone typical of REM sleep, confirming that the PLCα is a fundamental region involved in the triggering of partial signs of REM sleep such as muscle atonia. This observation concurs with results from experiments with bilateral PLCα lesions in cats, in which REM sleep without muscle atonia was observed (Jouvet, 1979;Sastre and Jouvet, 1979). Similarly, SLD nucleus lesions in the rat produced REM sleep with muscle tone (Lu et al., 2006). ...
Article
Full-text available
There is little information on either the transition state occurring between slow-wave sleep (SWS) and rapid eye movement (REM) sleep, as well as about its neurobiological bases. This transition state, which is known as the intermediate state (IS), is well-defined in rats but poorly characterized in cats. Previous studies in our laboratory demonstrated that cholinergic stimulation of the perilocus coeruleus α nucleus (PLCα) in the pontine tegmentum of cats induced two states: wakefulness with muscle atonia and a state of dissociated sleep we have called the SPGO state. The SPGO state has characteristics in common with the IS, such including the presence of ponto-geniculo-occipital waves (PGO) and EEG synchronization with δ wave reduction. Therefore, the aims of the present study were (1) to characterize the IS in the cat and, (2), to study the analogy between the SPGO and the different sleep stages showing PGO activity, including the IS. Polygraphic recordings of 10 cats were used. In seven cats carbachol microinjections (20–30 nL, 0.01–0.1 M) were delivered in the PLCα. In the different states, PGO waves were analyzed and power spectra obtained for the δ, θ, α, and β bands of the EEG from the frontal and occipital cortices, and for the θ hippocampal band. Statistical comparisons were made between the values obtained from the different states. The results indicate that the IS constitutes a state with characteristics that are distinct from both the preceding SWS and the following REM sleep, and that SPGO presents a high analogy with the IS. Therefore, the SPGO state induced by administering carbachol in the PLCα nucleus seems to be an expression of the physiological IS of the cat. Consequently, we propose that the PLCα region, besides being involved in the mechanisms of muscle atonia, may also be responsible for organizing the transition from SWS to REM sleep.
... Early on, cats became the predominant model in sleep research (Pampiglione, 1971) and were widely used to study various topics connected to sleep physiology from the beginning of the 20th century. Jouvet (1979) demonstrated behaviour suggestive of dreaming in the cat, when he relieved the muscle tone inhibition characterizing the REM sleep phase, leading to the animals acting out various behaviours without waking up. Meanwhile, large-scale synchronization in the feline cortex was confirmed to underlie the slow rhythmic activity predominating during NREM sleep (Amzica & Steriade, 1995). ...
Article
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Sleep spindles are phasic events observed in mammalian non-rapid eye movement sleep. They are relevant today in the study of memory consolidation, sleep quality, mental health and ageing. We argue that our advanced understanding of their mechanisms has not exhausted the utility and need for animal model work. This is both because some topics, like cognitive ageing, have not yet been addressed sufficiently in comparative efforts and because the evolutionary history of this oscillation is still poorly understood. Comparisons across species often are either limited to referencing the classical cat and rodent models, or are over-inclusive, uncritically including reports of sleep spindles in rarely studied animals. In this review, we discuss the emergence of new (dog and sheep) models for sleep spindles and compare the strengths and shortcomings of new and old models based on the three validation criteria for animal models-face, predictive, and construct validity. We conclude that an emphasis on cognitive ageing might dictate the future of comparative sleep spindle studies, a development that is already becoming visible in studies on dogs. Moreover, reconstructing the evolutionary history of sleep spindles will require more stringent criteria for their identification, across more species. In particular, a stronger emphasis on construct and predictive validity can help verify if spindle-like events in other species are actual sleep spindles. Work in accordance with such stricter validation suggests that sleep spindles display more universally shared features, like defining frequency, than previously thought.
... Il est pourtant assez difficile de déterminer via l'étude des souvenirs d'expériences oniriques si la réapparition de certains fragments est simplement due à leur récence, favorisant ainsi leur accès, si elle a pour fonction leur consolidation, ou si les souvenirs sont intégrés dans un processus de reconstruction de scènes mentales visant à favoriser l'apprentissage et le développement de comportements. La répétition d'apprentissages moteurs semble, par exemple, être fréquente lors du sommeil paradoxal chez les animaux, comme cela peut s'observer à la suite de la suppression de l'atonie musculaire propre à cette phase [50]. L'hypothèse de la simulation de la menace [51] propose dans ce sens que les rêves auraient pour fonction de préparer les individus à l'affrontement de situations dangereuses en permettant la répétition « offline » des conduites adéquates. ...
Article
Full-text available
Le rêve fait l’objet d’une grande fascination pour la psychologie et les neurosciences depuis le XIXème siècle. Pourtant, en dépit d’avancées récentes, il reste encore profondément énigmatique. Décrit comme un état modifié de conscience survenant au cours du sommeil, caractérisé par des expériences sensorielles, cognitives et émotionnelles vives, il est largement admis que les rapports de rêves sont une traduction des souvenirs de l’expérience rêvée. Toutefois, de nombreux obstacles méthodologiques et théoriques freinent encore les neuroscientifiques dans leurs recherches sur les mécanismes de production et de mémorisation de ces expériences. Ces dernières années, de nombreuses études ont décrit les effets bénéfiques du sommeil sur la mémoire, réactivant l’idée selon laquelle les processus de consolidation des souvenirs pourraient alimenter l’activité onirique. Pourtant, de façon surprenante, les recherches montrent aussi que les rapports de rêves ne peuvent que rarement être reliés à des souvenirs épisodiques précis, et que leur contenu ou leur fréquence ne semblent pas clairement associés aux performances mnésiques.Nous proposons une revue des recherches sur les liens entre rêves et mémoire en abordant deux questions : (1) Peut-on déterminer quels types de souvenirs réapparaissent au sein des rêves ? (2) Les rêves jouent-ils un rôle dans la consolidation et la réorganisation de la mémoire lors du sommeil ? Nous détaillons ensuite un modèle décrivant l’assimilation, lors du sommeil, des souvenirs récents au sein de structures mnésiques globales en cohérence avec les données issues de l’étude neuroscientifique du rêve et les connaissances fournies par l’analyse des récits. Nous soulignons enfin l’importance des rapports fournis par les rêveurs pour l’étude des processus de consolidation mnésique et leur apport à la neuropsychologie dans l’étude du vieillissement et des pathologies neurodégénératives.
Chapter
As early as 1867 Wilhelm Griesinger reported on eye movements not related to vision but related to fantasies. These eye movements occurred both during the transition from wakefulness to sleep and during dreaming. From these observations he concluded that sleep was not a passive but rather an active state. It was another 86 years before Aserinsky and Kleitman (1953) discovered that sleep is not a homogeneous process but is organized in rhythmically occurring cycles of different stages, each of which is characterized by specific behavioral, electrophysiologic, autonomic, and endocrine changes. Since then, sleep was grossly divided into nonREM sleep, also called slow wave sleep (SWS), and REM sleep, also called desynchronized sleep (DS), D sleep, and paradoxical sleep (PS).
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The discovery of rapid eye movement (REM) sleep revolutionized the field of sleep research. REM sleep is that state in which most of our dreams occur. During REM sleep, the brain is active, while the body is asleep. These characteristics make REM sleep a unique and a paradoxical state. While we are struggling to understand the function of REM sleep, major advances have been made in understanding the cellular mechanisms responsible for REM-sleep control. In this chapter, we have described two neurochemical substrates involved in REM-sleep regulation. One of them is adenosine and the other is glycine. Adenosine is implicated to be the homeostatic regulator of sleep. It has been suggested that adenosine acts via A1 receptors to inhibit wake-promoting neurons and promote the transition from wakefulness to sleep. Adenosine acts on multiple wake-promoting systems including the basal forebrain cholinergic and the non-cholinergic systems, namely the orexinergic, and the histaminergic systems. There are reports suggesting that adenosine may act via A2A receptors and activate sleep-promoting neurons of the preoptic region. In addition, studies suggest a direct role of adenosine in the modulation of REM sleep. During REM sleep, there is a tonic muscle atonia coupled with phasic muscle twitches. This phenomenon is regulated by the dorsolateral pons and ventromedial medulla along with local neurons within the spinal cord. Glycinergic mechanisms are responsible for the control of muscle tone during REM sleep. However, the exact role is under debate.
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Rapid eye movement sleep behavior disorder (RBD) is often defined as dream-enacting behaviors. However, the dreaming features in RBD are less studied than its motor aspects or than RBD as prodromal neurodegeneration. Dream content during RBD is often (40–59%), but not always, recalled afterward. The question whether RBD is not only a motor disorder (loss of muscle atonia) but also a dreaming disorder remains open. On the one hand, RBD-associated dreams differ from “normal” dreaming (in idiopathic RBD as well as in Parkinson’s disease-associated RBD) by a more active/violent content. On the other hand, spontaneous RBD reports may be biased toward remembering scenarios that awakened or injured the sleeping couple. Plus, quiet, ordinary dreaming can also be observed with RBD. When dream content is systematically collected after provoked awakenings in a sleep lab during RBD movements and during quiet REM sleep in RBD patients, its content is not different from that of controls without RBD. RBD behaviors are quite concordant with dream recall, as reported in numerous case reports by history and by direct observation in the sleep laboratory. This concordance has been tested in a single controlled study and debated in the context of the analysis of REM sleep-associated twitches in developing rats. Eventually, RBD can be viewed (via the observation of movements, speech and facial expressions, and their isomorphism with the dream recall) as a (small) window to overtly approach the physiology of dreaming and cognitive processes during REM sleep. It includes how RBD can be used to demonstrate if non-dreamers do actually dream and if eye movements are tightly coordinated with dream images during REM sleep, to test the replay hypothesis for sleep-related verbal and motor memory consolidation and to study the phonetics and semantics of language during sleep.
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Chapter
Even though most parasomnias like sleep terrors, sleepwalking, and REM sleep behavior disorder are quite rare in adults, waking-life impairments and problems associated with parasomnias can be quite severe. It is thus highly recommended that questions regarding parasomnias are included when taking a sleep history so that patients are correctly diagnosed and treated. For the most common parasomnia in adults, the nightmare disorder, an effective treatment (Imagery Rehearsal Therapy) has been developed and tested.
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George Trumbull Ladd39 suggested in 1892 that the visual elements of dreams were derivations of the "psychical synthesis" of night-time retinal sense data. This hypothesis led him to speculate that the eyeballs move during dreaming. "As we look down the street of a strange city, for example, in a dream we probably focus our eyes somewhat as we should do in making the same observation when awake. . . ." Ladd's ingenious surmise went unverified until 1955 when Aserinsky and Kleitman2 reported actual observations of ocular movements during sleep. They described 2 types which appear at separate times during the night in a predictable pattern: (a) slow eye movements (SEM's)—,slow, often asynchronous, gliding excursions of the eyeballs at sleep onset and after every body movement occurring during the night's sleep; (b) rapid eye movements (REM's)—bursts of quick, binocularly synchronous, single and grouped ocular deviations often in clusters
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The bilateral lesion of the medial portion of the nucleus Locus Coeruleus α or of its descending pathway selectively suppresses the muscular atonia during Paradoxical Sleep (PS) in the cat. After such a lesion various stereotyped behaviors (oneiric behavior) occur during PS. The repertoire of the oneiric behavior is described. It corresponds to the natural behavior which may occur during waking (predatory attack, rage, flight, grooming, exploration). Attack is the most frequent behavior occurring during PS while sexual behavior was never noticed. The significance of oneiric behavior is discussed and compared with natural, electrically induced behavior and play.
Article
In the ‘encéphale isolé’ reserpinised cat preparation, either isolated or repetitive phasic events can be recorded in the central visual and oculomotor systems. In this paper the following relationships have been demonstrated. A phasic activity with one component (PGOR with one component), occurring at the levels of the NGL and the occipital cortex, is associated in all the oculomotor nuclei with a phasic activity of one component. An inhibitory potential is recorded in one VIth nucleus with an inhibition of the ipsilateral rectus muscle, and an activating potential with an activation of the contralateral muscle is recorded in the other VIth nucleus. The oblique and superior rectus muscles are usually activated simultaneously with the contralateral rectus muscle. One saccadic movement is recorded on the EOG (horizontal, T.C. 3 sec). In this case, only one generator is active.
1. Phasic activities related to eye movements in the dark in abducens nucleus (N.VI), lateral geniculate body (LGB), visual cortex, and lateral rectus muscle were analyzed in 18 cats with chronically implanted electrodes during waking and sleeping. 2. N.VI waves, both during waking and sleeping, were multiphasic, and two distinct wave forms were noticed on either side of the pons. The N.VI waves preceded each ocular movement by 10--20 msec. 3. Both during waking and paradoxical sleep (PS), N.VI waves always preceded those occurring in the LGB. During waking, eye movement potentials (EMPs) in LGB followed the onset of the N.VI wave with a long (greater than 60 msec) and variable latency, but followed the end of the same wave with a rather constant delay (about 20 msec). During PS, two distinct populations of latency were observed between onset of the pontine waves and that of LGB waves. The latency of one population was less than 35 msec, and of the other more than 66 msec. 4. Since the LGB waves following N.VI waves with a long latency were similar in a number of respects to EMPs during wakefulness (EMPw), they were judged to be EMPs (EMPps), and were distinguished from LGB PGO waves, which followed N.VI waves with a short latency. Cortical EMPps were observed as well, but occurred about 8--10 times less frequently than the PGO wave. 5. In the light of the present results, the mechanisms responsible for EMP and PGO wave activities are discussed.
Article
Bilateral lesions placed in the pontiene tegmentum resulted in episodes of paradoxical sleep in which the characteristic atonia of that sleep stage was absent in six cats. Following each period of synchronized sleep, in which the degree of muscle tone of the dorsal cervical muscles gradually diminished, cats with such lesions would slowly raise their heads, move their limbs at all joints, make several attempts to rise and eventually leap violently. During such episodes they were unresponsive to strong lights, touching and mild pinching. Only sound would arouse them. This behavior appeared as early as the 2nd postoperative day, the 1st day of recording. Such episodes supplanted normal paradoxical sleep with atonia and lasted unchanged for as long as 6 months in one cat until it was killed while still in good health. Complete recovery of atonia was observed in one cat after 3 weeks. Either no recovery or else eventual recovery to excessively active periods of paradoxical sleep while remaining recumbent characterized the sleep of the other four. The conclusion drawn from these experiments and from a review of the literature is that the hypotheses stating that the locus coeruleus or other isolated nuclei of the pons are specifically concerned with the initiation of paradoxical sleep are not clearly supported by available evidence.