1
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Tononi G, Boly M, Cirelli C. Consciousness and sleep. Neuron 2024; 112:1568-1594. [PMID: 38697113 PMCID: PMC11105109 DOI: 10.1016/j.neuron.2024.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 05/04/2024]
Abstract
Sleep is a universal, essential biological process. It is also an invaluable window on consciousness. It tells us that consciousness can be lost but also that it can be regained, in all its richness, when we are disconnected from the environment and unable to reflect. By considering the neurophysiological differences between dreaming and dreamless sleep, we can learn about the substrate of consciousness and understand why it vanishes. We also learn that the ongoing state of the substrate of consciousness determines the way each experience feels regardless of how it is triggered-endogenously or exogenously. Dreaming consciousness is also a window on sleep and its functions. Dreams tell us that the sleeping brain is remarkably lively, recombining intrinsic activation patterns from a vast repertoire, freed from the requirements of ongoing behavior and cognitive control.
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Affiliation(s)
- Giulio Tononi
- Department of Psychiatry, University of Wisconsin, Madison, WI 53719, USA.
| | - Melanie Boly
- Department of Neurology, University of Wisconsin, Madison, WI 53719, USA
| | - Chiara Cirelli
- Department of Psychiatry, University of Wisconsin, Madison, WI 53719, USA
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2
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Cataldi J, Stephan AM, Haba-Rubio J, Siclari F. Shared EEG correlates between non-REM parasomnia experiences and dreams. Nat Commun 2024; 15:3906. [PMID: 38724511 PMCID: PMC11082195 DOI: 10.1038/s41467-024-48337-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 04/26/2024] [Indexed: 05/12/2024] Open
Abstract
Sleepwalking and related parasomnias result from incomplete awakenings out of non-rapid eye movement sleep. Behavioral episodes can occur without consciousness or recollection, or in relation to dream-like experiences. To understand what accounts for these differences in consciousness and recall, here we recorded parasomnia episodes with high-density electroencephalography (EEG) and interviewed participants immediately afterward about their experiences. Compared to reports of no experience (19%), reports of conscious experience (56%) were preceded by high-amplitude EEG slow waves in anterior cortical regions and activation of posterior cortical regions, similar to previously described EEG correlates of dreaming. Recall of the content of the experience (56%), compared to no recall (25%), was associated with higher EEG activation in the right medial temporal region before movement onset. Our work suggests that the EEG correlates of parasomnia experiences are similar to those reported for dreams and may thus reflect core physiological processes involved in sleep consciousness.
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Affiliation(s)
- Jacinthe Cataldi
- Center for Investigation and Research on Sleep, Lausanne University Hospital, Lausanne, Switzerland
- The Sense Innovation and Research Center, Lausanne and Sion, Lausanne, Switzerland
| | - Aurélie M Stephan
- Center for Investigation and Research on Sleep, Lausanne University Hospital, Lausanne, Switzerland
- The Sense Innovation and Research Center, Lausanne and Sion, Lausanne, Switzerland
- The Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - José Haba-Rubio
- Center for Investigation and Research on Sleep, Lausanne University Hospital, Lausanne, Switzerland
| | - Francesca Siclari
- Center for Investigation and Research on Sleep, Lausanne University Hospital, Lausanne, Switzerland.
- The Sense Innovation and Research Center, Lausanne and Sion, Lausanne, Switzerland.
- The Netherlands Institute for Neuroscience, Amsterdam, The Netherlands.
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3
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Martinec Nováková L, Miletínová E, Kliková M, Bušková J. Nocturnal exposure to a preferred ambient scent does not affect dream emotionality or post-sleep core affect valence in young adults. Sci Rep 2024; 14:10369. [PMID: 38710748 DOI: 10.1038/s41598-024-60226-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 04/19/2024] [Indexed: 05/08/2024] Open
Abstract
Emotions experienced within sleep mentation (dreaming) affect mental functioning in waking life. There have been attempts at enhancing dream emotions using olfactory stimulation. Odors readily acquire affective value, but to profoundly influence emotional processing, they should bear personal significance for the perceiver rather than be generally pleasant. The main objective of the present sleep laboratory study was to examine whether prolonged nocturnal exposure to self-selected, preferred ambient room odor while asleep influences emotional aspects of sleep mentation and valence of post-sleep core affect. We asked twenty healthy participants (12 males, mean age 25 ± 4 years) to pick a commercially available scented room diffuser cartridge that most readily evoked positively valenced mental associations. In weekly intervals, the participants attended three sessions. After the adaptation visit, they were administered the odor exposure and odorless control condition in a balanced order. Participants were awakened five minutes into the first rapid eye movement (REM) stage that took place after 2:30 a.m. and, if they had been dreaming, they were asked to rate their mental sleep experience for pleasantness, emotional charge, and magnitude of positive and negative emotions and also to evaluate their post-sleep core affect valence. With rs < 0.20, no practically or statistically significant differences existed between exposure and control in any outcome measures. We conclude that in young, healthy participants, the practical value of olfactory stimulation with self-selected preferred scents for enhancement of dream emotions and post-sleep core affect valence is very limited.
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Affiliation(s)
- Lenka Martinec Nováková
- Department of Chemical Education and Humanities, University of Chemistry and Technology, Prague, Technická 5, 16628, Prague 6 - Dejvice, Czech Republic.
| | - Eva Miletínová
- National Institute of Mental Health, Topolová 748, 25067, Klecany, Czech Republic
- 3rd Faculty of Medicine, Charles University, Ruská 87, 10000, Prague 10, Czech Republic
| | - Monika Kliková
- National Institute of Mental Health, Topolová 748, 25067, Klecany, Czech Republic
- 3rd Faculty of Medicine, Charles University, Ruská 87, 10000, Prague 10, Czech Republic
| | - Jitka Bušková
- National Institute of Mental Health, Topolová 748, 25067, Klecany, Czech Republic
- 3rd Faculty of Medicine, Charles University, Ruská 87, 10000, Prague 10, Czech Republic
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4
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Zeman A. Aphantasia and hyperphantasia: exploring imagery vividness extremes. Trends Cogn Sci 2024; 28:467-480. [PMID: 38548492 DOI: 10.1016/j.tics.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 05/12/2024]
Abstract
The vividness of imagery varies between individuals. However, the existence of people in whom conscious, wakeful imagery is markedly reduced, or absent entirely, was neglected by psychology until the recent coinage of 'aphantasia' to describe this phenomenon. 'Hyperphantasia' denotes the converse - imagery whose vividness rivals perceptual experience. Around 1% and 3% of the population experience extreme aphantasia and hyperphantasia, respectively. Aphantasia runs in families, often affects imagery across several sense modalities, and is variably associated with reduced autobiographical memory, face recognition difficulty, and autism. Visual dreaming is often preserved. Subtypes of extreme imagery appear to be likely but are not yet well defined. Initial results suggest that alterations in connectivity between the frontoparietal and visual networks may provide the neural substrate for visual imagery extremes.
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Affiliation(s)
- Adam Zeman
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; University of Exeter Medical School, Exeter, UK.
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5
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Salvesen L, Capriglia E, Dresler M, Bernardi G. Influencing dreams through sensory stimulation: A systematic review. Sleep Med Rev 2024; 74:101908. [PMID: 38417380 PMCID: PMC11009489 DOI: 10.1016/j.smrv.2024.101908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/29/2024] [Accepted: 02/12/2024] [Indexed: 03/01/2024]
Abstract
Sleep is typically considered a state of disconnection from the environment, yet instances of external sensory stimuli influencing dreams have been reported for centuries. Explaining this phenomenon could provide valuable insight into dreams' generative and functional mechanisms, the factors that promote sleep continuity, and the processes that underlie conscious awareness. Moreover, harnessing sensory stimuli for dream engineering could benefit individuals suffering from dream-related alterations. This PRISMA-compliant systematic review assessed the current evidence concerning the influence of sensory stimulation on sleep mentation. We included 51 publications, of which 21 focused on auditory stimulation, ten on somatosensory stimulation, eight on olfactory stimulation, four on visual stimulation, two on vestibular stimulation, and one on multimodal stimulation. Furthermore, nine references explored conditioned associative stimulation: six focused on targeted memory reactivation protocols and three on targeted lucid reactivation protocols. The reported frequency of stimulus-dependent dream changes across studies ranged from 0 to ∼80%, likely reflecting a considerable heterogeneity of definitions and methodological approaches. Our findings highlight a lack of comprehensive understanding of the mechanisms, functions, and neurophysiological correlates of stimulus-dependent dream changes. We suggest that a paradigm shift is required for meaningful progress in this field.
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Affiliation(s)
- Leila Salvesen
- Sleep, Plasticity, and Conscious Experience Group, MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Elena Capriglia
- Sleep, Plasticity, and Conscious Experience Group, MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy; Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
| | - Martin Dresler
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Giulio Bernardi
- Sleep, Plasticity, and Conscious Experience Group, MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy.
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Sayk C, Saftien S, Koch N, Ngo HVV, Junghanns K, Wilhelm I. Cortical hyperarousal in individuals with frequent nightmares. J Sleep Res 2024; 33:e14003. [PMID: 37688512 DOI: 10.1111/jsr.14003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/09/2023] [Accepted: 07/01/2023] [Indexed: 09/11/2023]
Abstract
Nightmares are common among the general population and psychiatric patients and have been associated with signs of nocturnal arousal such as increased heart rate or increased high-frequency electroencephalographic (EEG) activity. However, it is still unclear, whether these characteristics are more of a trait occurring in people with frequent nightmares or rather indicators of the nightmare state. We compared participants with frequent nightmares (NM group; n = 30) and healthy controls (controls; n = 27) who spent 4 nights in the sleep laboratory over the course of 8 weeks. The NM group received six sessions of imagery rehearsal therapy (IRT), the 'gold standard' of cognitive-behavioural therapy for nightmares, between the second and the third night. Sleep architecture and spectral power were compared between groups, and between nights of nightmare occurrence and nights without nightmare occurrence in the NM group. Additionally, changes before and after therapy were recorded. The NM group showed increased beta (16.25-31 Hz) and low gamma (31.25-35 Hz) power during the entire night compared to the controls, but not when comparing nights of nightmare occurrence to those without. Moreover, low gamma activity in rapid eye movement sleep was reduced after therapy in the NM group. Our findings indicate, cortical hyperarousal is more of a trait in people with frequent nightmares within a network of other symptoms, but also malleable by therapy. This is not only a new finding for IRT but could also lead to improved treatment options in the future that directly target high-frequency EEG activity.
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Affiliation(s)
- Clara Sayk
- Department of Psychiatry and Psychotherapy, Translational Psychiatry Unit, University of Lübeck, Lübeck, Germany
| | - Sophia Saftien
- Department of Psychiatry and Psychotherapy, Translational Psychiatry Unit, University of Lübeck, Lübeck, Germany
| | - Nicole Koch
- Department of Psychiatry and Psychotherapy, Translational Psychiatry Unit, University of Lübeck, Lübeck, Germany
| | - Hong-Viet V Ngo
- Department of Psychology, University of Lübeck, Lübeck, Germany
- Center for Brain, Behaviour and Metabolism, University of Lübeck, Lübeck, Germany
- Department of Psychology, University of Essex, Colchester, UK
| | - Klaus Junghanns
- Department of Psychiatry and Psychotherapy, Translational Psychiatry Unit, University of Lübeck, Lübeck, Germany
| | - Ines Wilhelm
- Department of Psychiatry and Psychotherapy, Translational Psychiatry Unit, University of Lübeck, Lübeck, Germany
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Tomacsek V, Blaskovich B, Király A, Reichardt R, Simor P. Altered parasympathetic activity during sleep and emotionally arousing wakefulness in frequent nightmare recallers. Eur Arch Psychiatry Clin Neurosci 2024; 274:265-277. [PMID: 36862312 PMCID: PMC10914885 DOI: 10.1007/s00406-023-01573-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 02/13/2023] [Indexed: 03/03/2023]
Abstract
Nightmare disorder is characterized by dysfunctional emotion regulation and poor subjective sleep quality reflected in pathophysiological features such as abnormal arousal processes and sympathetic influences. Dysfunctional parasympathetic regulation, especially before and during rapid eye movement (REM) phases, is assumed to alter heart rate (HR) and its variability (HRV) of frequent nightmare recallers (NM). We hypothesized that cardiac variability is attenuated in NMs as opposed to healthy controls (CTL) during sleep, pre-sleep wakefulness and under an emotion-evoking picture-rating task. Based on the polysomnographic recordings of 24 NM and 30 CTL participants, we examined HRV during pre-REM, REM, post-REM and slow wave sleep, separately. Additionally, electrocardiographic recordings of resting state before sleep onset and under an emotionally challenging picture-rating task were also analyzed. Applying repeated measures analysis of variance (rmANOVA), a significant difference was found in the HR of NMs and CTLs during nocturnal segments but not during resting wakefulness, suggesting autonomic dysregulation, specifically during sleep in NMs. As opposed to the HR, the HRV values were not significantly different in the rmANOVA in the two groups, implying that the extent of parasympathetic dysregulation on a trait level might depend on the severeness of dysphoric dreaming. Nonetheless, in the group comparisons, the NM group showed increased HR and reduced HRV during the emotion-evoking picture-rating task, which aimed to model the nightmare experience in the daytime, indicating disrupted emotion regulation in NMs under acute distress. In conclusion, trait-like autonomic changes during sleep and state-like autonomic responses to emotion-evoking pictures indicate parasympathetic dysregulation in NMs.
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Affiliation(s)
- Vivien Tomacsek
- Doctoral School of Psychology, ELTE Eötvös Loránd University, Budapest, Hungary.
- Institute of Psychology, ELTE Eötvös Loránd University, 46 Izabella Street, Budapest, 1064, Hungary.
| | - Borbála Blaskovich
- Institute of Medical Psychology, Faculty of Medicine, Ludwig Maximilian University of Munich, Munich, Germany
| | - Anna Király
- National Institute of Locomotor Diseases and Disabilities, Budapest, Hungary
| | - Richárd Reichardt
- Institute of Education and Psychology at Szombathely, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Péter Simor
- Institute of Psychology, ELTE Eötvös Loránd University, 46 Izabella Street, Budapest, 1064, Hungary
- UR2NF, Neuropsychology and Functional Neuroimaging Research Unit at CRCN-Center for Research in Cognition and Neurosciences and UNI-ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
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8
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Deperrois N, Petrovici MA, Senn W, Jordan J. Learning beyond sensations: How dreams organize neuronal representations. Neurosci Biobehav Rev 2024; 157:105508. [PMID: 38097096 DOI: 10.1016/j.neubiorev.2023.105508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/05/2023] [Accepted: 12/09/2023] [Indexed: 12/25/2023]
Abstract
Semantic representations in higher sensory cortices form the basis for robust, yet flexible behavior. These representations are acquired over the course of development in an unsupervised fashion and continuously maintained over an organism's lifespan. Predictive processing theories propose that these representations emerge from predicting or reconstructing sensory inputs. However, brains are known to generate virtual experiences, such as during imagination and dreaming, that go beyond previously experienced inputs. Here, we suggest that virtual experiences may be just as relevant as actual sensory inputs in shaping cortical representations. In particular, we discuss two complementary learning principles that organize representations through the generation of virtual experiences. First, "adversarial dreaming" proposes that creative dreams support a cortical implementation of adversarial learning in which feedback and feedforward pathways engage in a productive game of trying to fool each other. Second, "contrastive dreaming" proposes that the invariance of neuronal representations to irrelevant factors of variation is acquired by trying to map similar virtual experiences together via a contrastive learning process. These principles are compatible with known cortical structure and dynamics and the phenomenology of sleep thus providing promising directions to explain cortical learning beyond the classical predictive processing paradigm.
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Affiliation(s)
| | | | - Walter Senn
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Jakob Jordan
- Department of Physiology, University of Bern, Bern, Switzerland; Electrical Engineering, Yale University, New Haven, CT, United States
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9
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Gott JA, Stücker S, Kanske P, Haaker J, Dresler M. Acetylcholine and metacognition during sleep. Conscious Cogn 2024; 117:103608. [PMID: 38042119 DOI: 10.1016/j.concog.2023.103608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/03/2023] [Accepted: 11/16/2023] [Indexed: 12/04/2023]
Abstract
Acetylcholine is a neurotransmitter and neuromodulator involved in a variety of cognitive functions. Additionally, acetylcholine is involved in the regulation of REM sleep: cholinergic neurons in the brainstem and basal forebrain project to and innervate wide areas of the cerebral cortex, and reciprocally interact with other neuromodulatory systems, to produce the sleep-wake cycle and different sleep stages. Consciousness and cognition vary considerably across and within sleep stages, with metacognitive capacity being strikingly reduced even during aesthetically and emotionally rich dream experiences. A notable exception is the phenomenon of lucid dreaming-a rare state whereby waking levels of metacognitive awareness are restored during sleep-resulting in individuals becoming aware of the fact that they are dreaming. The role of neurotransmitters in these fluctuations of consciousness and cognition during sleep is still poorly understood. While recent studies using acetylcholinesterase inhibitors suggest a potential role of acetylcholine in the occurrence of lucid dreaming, the underlying mechanisms by which this effect is produced remains un-modelled and unknown; with the causal link between cholinergic mechanisms and upstream psychological states being complex and elusive. Several theories and approaches targeting the association between acetylcholine and metacognition during wakefulness and sleep are highlighted in this review, moving through microscopic, mesoscopic and macroscopic levels of analysis to detail this phenomenon at several organisational scales. Several exploratory hypotheses will be developed to guide future research towards fully articulating how metacognition is affected by activity at the acetylcholine receptor.
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Affiliation(s)
- Jarrod A Gott
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Sina Stücker
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Philipp Kanske
- Clinical Psychology and Behavioral Neuroscience, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
| | - Jan Haaker
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Martin Dresler
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
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10
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Horton CL. The neurocognition of dreaming: key questions and foci. Emerg Top Life Sci 2023; 7:477-486. [PMID: 38130166 DOI: 10.1042/etls20230099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 12/23/2023]
Abstract
Until recently, understanding the neurobiology of dreaming has relied upon on correlating a subjective dream report with a measure of brain activity or function sampled from a different occasion. As such, most assumptions about dreaming come from the neuroscience of rapid eye-movement (REM) sleep from which many, but not all, dream reports are recalled. Core features of REM sleep (intense emotional activation, a reduction in activity in most frontal regions, particularly the dorsolateral prefrontal cortex, along with increased dopamine, acetylcholine, cholinergic activation) align with typical dream characteristics (characterised by fear, reduced reality monitoring, increased bizarreness and hyperassociativity, respectively). The default mode network offers a way of understanding the nature of dreaming more independently from a REM sleep context, and electroencephalography methods paired with serial awakenings to elicit dream reports demonstrate how high-frequency activity in posterior regions may be associated with dreaming. Nevertheless, all measures of dreaming rely fundamentally on recall processes, so our understanding of dreaming must embrace and address memory's crucial involvement in dream report production.
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Affiliation(s)
- Caroline L Horton
- DrEAMSLab, Bishop Grosseteste University, Longdales Road, Lincoln LN1 3DY, U.K
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11
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Siegel JM. REM sleep function: Mythology vs. reality. Rev Neurol (Paris) 2023; 179:643-648. [PMID: 37625974 PMCID: PMC10725301 DOI: 10.1016/j.neurol.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/01/2023] [Indexed: 08/27/2023]
Abstract
Since the discovery of REM (Rapid Eye Movement) sleep in 1953, misconceptions have arisen as to the evidence for its adaptive function and its relation to dreams. Eye movements recorded during REM sleep have not been consistently reported to mirror the eye movements predicted by dream reports. But evidence on eye movement and somatic motor expression from patients with REM sleep behavior disorder (RBD) is consistent with dream enacting behavior. The assumption that dreaming occurs only in REM sleep is incorrect, with numerous reports of nonREM dreaming. However, there may be qualitative differences between REM and nonREM dreams. Early studies that suggested a vital role for REM sleep in psychological well-being are refuted by studies of pharmacologically induced partial or complete REM sleep suppression. Studies of sleep across species show that the primitive monotreme mammals, platypus and echidna, have far more REM sleep than any other homeotherm group, whereas birds have far less REM sleep than any other homeotherm group. Human REM sleep amounts are not unusual, are correlated with nonREM sleep durations but are not correlated with intelligence. Across groups of homeotherms, REM sleep time is highly and inversely correlated (r=-0.975, P=0.02) with average core body temperature, suggesting that REM sleep cycles with nonREM sleep to regulate brain temperature during sleep. Cetacean mammals (dolphins and whales) do not have REM sleep despite their very large brain sizes and impressive cognitive abilities. Reports of "REM sleep-like states" in arachnids, cephalopods and in zebrafish larvae are lacking critical evidence that the observed behaviors are occurring during sleep and that the behaviors are homologous to mammalian REM sleep.
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Affiliation(s)
- J M Siegel
- Psychiatry and Biobehavioral Sciences, UCLA Center for Sleep Research, Los Angeles, CA 90095, United States; Neurobiology Research 151A3, North Hills, CA 91343, United States.
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12
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Erdeniz B, Tekgün E, Lenggenhager B, Lopez C. Visual perspective, distance, and felt presence of others in dreams. Conscious Cogn 2023; 113:103547. [PMID: 37390767 DOI: 10.1016/j.concog.2023.103547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 07/02/2023]
Abstract
The peripersonal space, that is, the limited space surrounding the body, involves multisensory coding and representation of the self in space. Previous studies have shown that peripersonal space representation and the visual perspective on the environment can be dramatically altered when neurotypical individuals self-identify with a distant avatar (i.e., in virtual reality) or during clinical conditions (i.e., out-of-body experience, heautoscopy, depersonalization). Despite its role in many cognitive/social functions, the perception of peripersonal space in dreams, and its relationship with the perception of other characters (interpersonal distance in dreams), remain largely uncharted. The present study aimed to explore the visuospatial properties of this space, which is likely to underlie self-location as well as self/other distinction in dreams. 530 healthy volunteers answered a web-based questionnaire to measure their dominant visuo-spatial perspective in dreams, the frequency of recall for felt distances between their dream self and other dream characters, and the dreamers' viewing angle of other dream characters. Most participants reported dream experiences from a first-person perspective (1PP) (82%) compared to a third-person perspective (3PP) (18%). Independent of their dream perspective, participants reported that they generally perceived other dream characters in their close space, that is, at distance of either between 0 and 90 cm, or 90-180 cm, than in further spaces (180-270 cm). Regardless of the perspective (1PP or 3PP), both groups also reported more frequently seeing other dream characters from eye level (0° angle of viewing) than from above (30° and 60°) or below eye level (-30° and -60°). Moreover, the intensity of sensory experiences in dreams, as measured by the Bodily Self-Consciousness in Dreams Questionnaire, was higher in individuals who habitually see other dream characters closer to their personal dream self (i.e., within 0-90 cm and 90-180 cm). These preliminary findings offer a new, phenomenological account of space representation in dreams with regards to the felt presence of others. They might provide insights not only to our understanding of how dreams are formed, but also to the type of neurocomputations involved in self/other distinction.
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Affiliation(s)
- Burak Erdeniz
- İzmir University of Economics, Department of Psychology, İzmir, Turkey
| | - Ege Tekgün
- İzmir University of Economics, Department of Psychology, İzmir, Turkey
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13
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CampBell T, Hurwitz A, Bartel R, Rose R, Dean J, Markle T. COVID-19 nightmare response and stress: A new Mexico sample based survey. Sleep Med 2022; 99:23-29. [PMID: 35930935 PMCID: PMC9296252 DOI: 10.1016/j.sleep.2022.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/03/2022] [Accepted: 07/14/2022] [Indexed: 11/20/2022]
Abstract
Studies conducted during the COVID-19 Pandemic have reported increased rates of mental illnesses including depression, anxiety, and post-traumatic stress disorder (PTSD) [1]. A common symptom of mental illness is change in Rapid Eye Movement (REM) sleep, the phase of sleep associated with dreaming and nightmares. The COVID-19 pandemic offers a unique opportunity to evaluate the effects of systemic stress on nightmares. In this study, we investigate whether the COVID-19 pandemic affects nightmare frequency and content using a web-based survey within the state of New Mexico. The survey returned 197 responses showing an increase in the quantity of both bad dreams and nightmares. Furthermore, significant changes in nightmare themes were reported compared to relative rates prior to the pandemic (RR 1,42, p < 0.01; RR 5, p < 0.001). This novel data supports that increased stress from the COVID-19 pandemic has altered dream and nightmare content and frequency.
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Affiliation(s)
- Tim CampBell
- University of New Mexico, 1 University Hospital, Albuquerque, NM, 87110, USA
| | - Ariel Hurwitz
- University of New Mexico, 1 University Hospital, Albuquerque, NM, 87110, USA
| | - Robyn Bartel
- University of New Mexico, 1 University Hospital, Albuquerque, NM, 87110, USA
| | - Rachel Rose
- University of New Mexico, 1 University Hospital, Albuquerque, NM, 87110, USA
| | - Jeremy Dean
- University of New Mexico, 1 University Hospital, Albuquerque, NM, 87110, USA
| | - Tom Markle
- University of New Mexico, 1 University Hospital, Albuquerque, NM, 87110, USA.
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14
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Perogamvros L, Park HD, Schwartz S. Commentary on the paper "The heartbeat evoked potential is a questionable biomarker in nightmare disorder: A replication study. By Bogdany, T., Perakakis, P., Bodizs, R., Simor, P., 2021. Neuroimage Clin 33, 102933". Neuroimage Clin 2022; 36:103196. [PMID: 36137497 PMCID: PMC9493136 DOI: 10.1016/j.nicl.2022.103196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Lampros Perogamvros
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Center for Sleep Medicine, Geneva University Hospitals, Geneva, Switzerland.
| | - Hyeong-Dong Park
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
| | - Sophie Schwartz
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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15
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Abstract
The phenomenon of dreaming about the laboratory when participating in a sleep study is common. The content of such dreams draws upon episodic memory fragments of the participant's lab experience, generally, experimenters, electrodes, the lab setting, and experimental tasks. However, as common as such dreams are, they have rarely been given a thorough quantitative or qualitative treatment. Here we assessed 528 dreams (N = 343 participants) collected in a Montreal sleep lab to 1) evaluate state and trait factors related to such dreams, and 2) investigate the phenomenology of lab incorporations using a new scoring system. Lab incorporations occurred in over a third (35.8%) of all dreams and were especially likely to occur in REM sleep (44.2%) or from morning naps (48.4%). They tended to be related to higher depression scores, but not to sex, nightmare-proneness or anxiety. Common themes associated with lab incorporation were: Meta-dreaming, including lucid dreams and false awakenings (40.7%), Sensory incorporations (27%), Wayfinding to, from or within the lab (24.3%), Sleep as performance (19.6%), Friends/Family in the lab (15.9%) and Being an object of observation (12.2%). Finally, 31.7% of the lab incorporation dreams included relative projections into a near future (e.g., the experiment having been completed), but very few projections into the past (2.6%). Results clarify sleep stage and sleep timing factors associated with dreamed lab incorporations. Phenomenological findings further reveal both the typical and unique ways in which lab memory elements are incorporated de novo into dreaming. Identified themes point to frequent social and skillful dream scenarios that entail monitoring of one's current state (in the lab) and projection of the self into dream environments elaborated around local space and time. The findings have implications for understanding fundamental dream formation mechanisms but also for appreciating both the advantages and methodological pitfalls of conducting laboratory-based dream collection.
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Affiliation(s)
- Claudia Picard-Deland
- Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Montréal, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
| | - Tore Nielsen
- Dream & Nightmare Laboratory, Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Montréal, Canada
- Department of Psychiatry and Addictology, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
| | - Michelle Carr
- Department of Psychiatry, University of Rochester Medical Center, Rochester, New York, United States of America
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16
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Shen Y, Cao X, Zeng NN, Wang Y, Zhang H, Zangen A, Yuan TF. Emergence of Sexual Dreams and Emission Following Deep Transcranial Magnetic Stimulation over the Medial Prefrontal and Cingulate Cortices. CNS Neurol Disord Drug Targets 2021; 20:310-311. [PMID: 33297923 DOI: 10.2174/1871527319666201209111620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 09/01/2020] [Accepted: 09/15/2020] [Indexed: 06/12/2023]
Abstract
In a pilot study involving methamphetamine dependents receiving deep Transcranial Magnetic Stimulation (dTMS) targeting the medial prefrontal and cingulate cortices with H7 coil (Brainsway, Israel), we assessed clinical outcomes from patients receiving 20 sessions of dTMS treatments over 4 weeks (5 days on, 2 days off). Although the primary outcome was the behavioral changes related to addiction, we encountered a phenomenon of robust increases in sexual dreams and emission in a patient recruited for this study, which may inform alterations in cortical excitability following dTMS treatment.
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Affiliation(s)
- Ying Shen
- Rehabilitation Medicine Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xinyu Cao
- Addiction Rehabilitation Department, Da Lian Shan Institute of Addiction Rehabilitation, Nanjing, China
| | - Ning-Ning Zeng
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yingjie Wang
- Social Work Department, Nanjing University of Finance and Economics, Nanjing, China
| | - Hangbin Zhang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Abraham Zangen
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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17
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Abstract
Nightmare disorder and recurrent isolated sleep paralysis are rapid eye movement (REM) parasomnias that cause significant distress to those who suffer from them. Nightmare disorder can cause insomnia due to fear of falling asleep through dread of nightmare occurrence. Hyperarousal and impaired fear extinction are involved in nightmare generation, as well as brain areas involved in emotion regulation. Nightmare disorder is particularly frequent in psychiatric disorders and posttraumatic stress disorder. Nonmedication treatment, in particular imagery rehearsal therapy, is especially effective. Isolated sleep paralysis is experienced at least once by up to 40% of the general population, whereas recurrence is less frequent. Isolated sleep paralysis can be accompanied by very intense and vivid hallucinations. Sleep paralysis represents a dissociated state, with persistence of REM atonia into wakefulness. Variations in circadian rhythm genes might be involved in their pathogenesis. Predisposing factors include sleep deprivation, irregular sleep-wake schedules, and jetlag. The most effective therapy consists of avoiding those factors.
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Affiliation(s)
- Ambra Stefani
- Department of Neurology, Medical University of Innsbruck (MUI), Anichstrasse 35, 6020, Innsbruck, Austria
| | - Birgit Högl
- Department of Neurology, Medical University of Innsbruck (MUI), Anichstrasse 35, 6020, Innsbruck, Austria.
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18
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Abstract
The presence of dreams in human sleep, especially in REM sleep, and the detection of physiologically similar states in mammals has led many to ponder whether animals experience similar sleep mentation. Recent advances in our understanding of the anatomical and physiological correlates of sleep stages, and thus dreaming, allow a better understanding of the possibility of dream mentation in nonhuman mammals. Here, we explore the potential for dream mentation, in both non-REM and REM sleep across mammals. If we take a hard-stance, that dream mentation only occurs during REM sleep, we conclude that it is unlikely that monotremes, cetaceans, and otariid seals while at sea, have the potential to experience dream mentation. Atypical REM sleep in other species, such as African elephants and Arabian oryx, may alter their potential to experience REM dream mentation. Alternatively, evidence that dream mentation occurs during both non-REM and REM sleep, indicates that all mammals have the potential to experience dream mentation. This non-REM dream mentation may be different in the species where non-REM is atypical, such as during unihemispheric sleep in aquatic mammals (cetaceans, sirens, and Otariid seals). In both scenarios, the cetaceans are the least likely mammalian group to experience vivid dream mentation due to the morphophysiological independence of their cerebral hemispheres. The application of techniques revealing dream mentation in humans to other mammals, specifically those that exhibit unusual sleep states, may lead to advances in our understanding of the neural underpinnings of dreams and conscious experiences.
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Affiliation(s)
- Paul R. Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Jerome M. Siegel
- Department of Psychiatry, School of Medicine, and Brain Research Institute, University of California, Los Angeles, California
- Brain Research Institute, Neurobiology Research, Sepulveda VA Medical Center, Los Angeles, California
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19
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Carr M, Haar A, Amores J, Lopes P, Bernal G, Vega T, Rosello O, Jain A, Maes P. Dream engineering: Simulating worlds through sensory stimulation. Conscious Cogn 2020; 83:102955. [PMID: 32652511 PMCID: PMC7415562 DOI: 10.1016/j.concog.2020.102955] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/19/2020] [Accepted: 05/18/2020] [Indexed: 01/14/2023]
Abstract
We explore the application of a wide range of sensory stimulation technologies to the area of sleep and dream engineering. We begin by emphasizing the causal role of the body in dream generation, and describe a circuitry between the sleeping body and the dreaming mind. We suggest that nearly any sensory stimuli has potential for modulating experience in sleep. Considering other areas that might afford tools for engineering sensory content in simulated worlds, we turn to Virtual Reality (VR). We outline a collection of relevant VR technologies, including devices engineered to stimulate haptic, temperature, vestibular, olfactory, and auditory sensations. We believe these technologies, which have been developed for high mobility and low cost, can be translated to the field of dream engineering. We close by discussing possible future directions in this field and the ethics of a world in which targeted dream direction and sleep manipulation are feasible.
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Affiliation(s)
- Michelle Carr
- Sleep & Neurophysiology Research Laboratory, Department of Psychiatry, University of Rochester Medical Center, Rochester, NY, USA.
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20
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Spanò G, Pizzamiglio G, McCormick C, Clark IA, De Felice S, Miller TD, Edgin JO, Rosenthal CR, Maguire EA. Dreaming with hippocampal damage. eLife 2020; 9:e56211. [PMID: 32508305 PMCID: PMC7279885 DOI: 10.7554/elife.56211] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/05/2020] [Indexed: 01/20/2023] Open
Abstract
The hippocampus is linked with both sleep and memory, but there is debate about whether a salient aspect of sleep - dreaming - requires its input. To address this question, we investigated if human patients with focal bilateral hippocampal damage and amnesia engaged in dreaming. We employed a provoked awakening protocol where participants were woken up at various points throughout the night, including during non-rapid eye movement and rapid eye movement sleep, to report their thoughts in that moment. Despite being roused a similar number of times, dream frequency was reduced in the patients compared to control participants, and the few dreams they reported were less episodic-like in nature and lacked content. These results suggest that hippocampal integrity may be necessary for typical dreaming to occur, and aligns dreaming with other hippocampal-dependent processes such as episodic memory that are central to supporting our mental life.
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Affiliation(s)
- Goffredina Spanò
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College LondonLondonUnited Kingdom
| | - Gloria Pizzamiglio
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College LondonLondonUnited Kingdom
| | - Cornelia McCormick
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University Hospital BonnBonnGermany
| | - Ian A Clark
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College LondonLondonUnited Kingdom
| | - Sara De Felice
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College LondonLondonUnited Kingdom
| | - Thomas D Miller
- Department of Neurology, Royal Free HospitalLondonUnited Kingdom
| | - Jamie O Edgin
- Department of Psychology, University of ArizonaTucsonUnited States
| | - Clive R Rosenthal
- Nuffield Department of Clinical Neurosciences, University of OxfordOxfordUnited Kingdom
| | - Eleanor A Maguire
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College LondonLondonUnited Kingdom
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21
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Noreika V, Windt JM, Kern M, Valli K, Salonen T, Parkkola R, Revonsuo A, Karim AA, Ball T, Lenggenhager B. Modulating dream experience: Noninvasive brain stimulation over the sensorimotor cortex reduces dream movement. Sci Rep 2020; 10:6735. [PMID: 32317714 PMCID: PMC7174293 DOI: 10.1038/s41598-020-63479-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 03/14/2020] [Indexed: 01/01/2023] Open
Abstract
Recently, cortical correlates of specific dream contents have been reported, such as the activation of the sensorimotor cortex during dreamed hand clenching. Yet, despite a close resemblance of such activation patterns to those seen during the corresponding wakeful behaviour, the causal mechanisms underlying specific dream contents remain largely elusive. Here, we aimed to investigate the causal role of the sensorimotor cortex in generating movement and bodily sensations during REM sleep dreaming. Following bihemispheric transcranial direct current stimulation (tDCS) or sham stimulation, guided by functional mapping of the primary motor cortex, naive participants were awakened from REM sleep and responded to a questionnaire on bodily sensations in dreams. Electromyographic (EMG) and electroencephalographic (EEG) recordings were used to quantify physiological changes during the preceding REM period. We found that tDCS, compared to sham stimulation, significantly decreased reports of dream movement, especially of repetitive actions. Other types of bodily experiences, such as tactile or vestibular sensations, were not affected by tDCS, confirming the specificity of stimulation effects to movement sensations. In addition, tDCS reduced EEG interhemispheric coherence in parietal areas and affected the phasic EMG correlation between both arms. These findings show that a complex temporal reorganization of the motor network co-occurred with the reduction of dream movement, revealing a link between central and peripheral motor processes and movement sensations of the dream self. tDCS over the sensorimotor cortex interferes with dream movement during REM sleep, which is consistent with a causal contribution to dream experience and has broader implications for understanding the neural basis of self-experience in dreams.
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Affiliation(s)
- Valdas Noreika
- Department of Psychology, University of Cambridge, CB2 3EB, Cambridge, United Kingdom.
- Department of Psychology and Speech-Language Pathology, University of Turku, 20014, Turku, Finland.
| | - Jennifer M Windt
- Department of Philosophy, Monash University, VIC 3800, Clayton, Australia
| | - Markus Kern
- Translational Neurotechnology Lab, University of Freiburg, 79106, Freiburg, Germany
| | - Katja Valli
- Department of Psychology and Speech-Language Pathology, University of Turku, 20014, Turku, Finland
- Department of Cognitive Neuroscience and Philosophy, University of Skövde, 54128, Skövde, Sweden
| | - Tiina Salonen
- Department of Psychology and Speech-Language Pathology, University of Turku, 20014, Turku, Finland
| | - Riitta Parkkola
- Department of Radiology, University and University Hospital of Turku, 20521, Turku, Finland
| | - Antti Revonsuo
- Department of Psychology and Speech-Language Pathology, University of Turku, 20014, Turku, Finland
- Department of Cognitive Neuroscience and Philosophy, University of Skövde, 54128, Skövde, Sweden
| | - Ahmed A Karim
- Department of Psychiatry and Psychotherapy, University of Tübingen, 72076, Tübingen, Germany
- Department of Psychology and Neuroscience, Jacobs University, 28759, Bremen, Germany
- Department of Health Psychology and Neurorehabilitation, SRH Mobile University, Riedlingen, Germany
| | - Tonio Ball
- Translational Neurotechnology Lab, University of Freiburg, 79106, Freiburg, Germany
| | - Bigna Lenggenhager
- Department of Psychology, University of Zurich, 8050, Zurich, Switzerland
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22
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Mamelak M. Nightmares and the Cannabinoids. Curr Neuropharmacol 2020; 18:754-768. [PMID: 31934840 PMCID: PMC7536831 DOI: 10.2174/1570159x18666200114142321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 12/21/2019] [Accepted: 01/11/2020] [Indexed: 11/22/2022] Open
Abstract
The cannabinoids, Δ9 tetrahydrocannabinol and its analogue, nabilone, have been found to reliably attenuate the intensity and frequency of post-traumatic nightmares. This essay examines how a traumatic event is captured in the mind, after just a single exposure, and repeatedly replicated during the nights that follow. The adaptive neurophysiological, endocrine and inflammatory changes that are triggered by the trauma and that alter personality and behavior are surveyed. These adaptive changes, once established, can be difficult to reverse. But cannabinoids, uniquely, have been shown to interfere with all of these post-traumatic somatic adaptations. While cannabinoids can suppress nightmares and other symptoms of post-traumatic stress disorder, they are not a cure. There may be no cure. The cannabinoids may best be employed, alone, but more likely in conjunction with other agents, in the immediate aftermath of a trauma to mitigate or even abort the metabolic changes which are set in motion by the trauma and which may permanently alter the reactivity of the nervous system. Steps in this direction have already been taken.
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Affiliation(s)
- Mortimer Mamelak
- Department of Psychiatry, University of Toronto, Baycrest Hospital, Permanent Address: 19 Tumbleweed Road, Toronto, OntarioM2J 2N2, Canada
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23
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Scarpelli S, Bartolacci C, D'Atri A, Gorgoni M, De Gennaro L. Mental Sleep Activity and Disturbing Dreams in the Lifespan. Int J Environ Res Public Health 2019; 16:E3658. [PMID: 31569467 PMCID: PMC6801786 DOI: 10.3390/ijerph16193658] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/11/2019] [Accepted: 09/27/2019] [Indexed: 02/05/2023]
Abstract
Sleep significantly changes across the lifespan, and several studies underline its crucial role in cognitive functioning. Similarly, mental activity during sleep tends to covary with age. This review aims to analyze the characteristics of dreaming and disturbing dreams at different age brackets. On the one hand, dreams may be considered an expression of brain maturation and cognitive development, showing relations with memory and visuo-spatial abilities. Some investigations reveal that specific electrophysiological patterns, such as frontal theta oscillations, underlie dreams during sleep, as well as episodic memories in the waking state, both in young and older adults. On the other hand, considering the role of dreaming in emotional processing and regulation, the available literature suggests that mental sleep activity could have a beneficial role when stressful events occur at different age ranges. We highlight that nightmares and bad dreams might represent an attempt to cope the adverse events, and the degrees of cognitive-brain maturation could impact on these mechanisms across the lifespan. Future investigations are necessary to clarify these relations. Clinical protocols could be designed to improve cognitive functioning and emotional regulation by modifying the dream contents or the ability to recall/non-recall them.
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Affiliation(s)
- Serena Scarpelli
- Department of Psychology, "Sapienza" University of Rome, Via dei Marsi, 78, 00185 Rome, Italy.
| | - Chiara Bartolacci
- Department of Psychology, "Sapienza" University of Rome, Via dei Marsi, 78, 00185 Rome, Italy.
| | - Aurora D'Atri
- Department of Psychology, "Sapienza" University of Rome, Via dei Marsi, 78, 00185 Rome, Italy.
| | - Maurizio Gorgoni
- Department of Psychology, "Sapienza" University of Rome, Via dei Marsi, 78, 00185 Rome, Italy.
| | - Luigi De Gennaro
- Department of Psychology, "Sapienza" University of Rome, Via dei Marsi, 78, 00185 Rome, Italy.
- IRCCS Santa Lucia Foundation, 00142 Rome, Italy.
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24
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Sikka P, Revonsuo A, Noreika V, Valli K. EEG Frontal Alpha Asymmetry and Dream Affect: Alpha Oscillations over the Right Frontal Cortex during REM Sleep and Presleep Wakefulness Predict Anger in REM Sleep Dreams. J Neurosci 2019; 39:4775-4784. [PMID: 30988168 PMCID: PMC6561691 DOI: 10.1523/jneurosci.2884-18.2019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/12/2019] [Accepted: 03/16/2019] [Indexed: 02/02/2023] Open
Abstract
Affective experiences are central not only to our waking life but also to rapid eye movement (REM) sleep dreams. Despite our increasing understanding of the neural correlates of dreaming, we know little about the neural correlates of dream affect. Frontal alpha asymmetry (FAA) is considered a marker of affective states and traits as well as affect regulation in the waking state. Here, we explored whether FAA during REM sleep and during evening resting wakefulness is related to affective experiences in REM sleep dreams. EEG recordings were obtained from 17 human participants (7 men) who spent 2 nights in the sleep laboratory. Participants were awakened 5 min after the onset of every REM stage after which they provided a dream report and rated their dream affect. Two-minute preawakening EEG segments were analyzed. Additionally, 8 min of evening presleep and morning postsleep EEG were recorded during resting wakefulness. Mean spectral power in the alpha band (8-13 Hz) and corresponding FAA were calculated over the frontal (F4-F3) sites. Results showed that FAA during REM sleep, and during evening resting wakefulness, predicted ratings of dream anger. This suggests that individuals with greater alpha power in the right frontal hemisphere may be less able to regulate (i.e., inhibit) strong affective states, such as anger, in dreams. Additionally, FAA was positively correlated across wakefulness and REM sleep. Together, these findings imply that FAA may serve as a neural correlate of affect regulation not only in the waking but also in the dreaming state.SIGNIFICANCE STATEMENT We experience emotions not only during wakefulness but also during dreaming. Despite our increasing understanding of the neural correlates of dreaming, we know little about the neural correlates of dream emotions. Here we used electroencephalography to explore how frontal alpha asymmetry (FAA)-the relative difference in alpha power between the right and left frontal cortical areas that is associated with emotional processing and emotion regulation in wakefulness-is related to dream emotions. We show that individuals with greater FAA (i.e., greater right-sided alpha power) during rapid eye movement sleep, and during evening wakefulness, experience more anger in dreams. FAA may thus reflect the ability to regulate emotions not only in the waking but also in the dreaming state.
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Affiliation(s)
- Pilleriin Sikka
- Department of Psychology and Turku Brain and Mind Center, University of Turku, 20014 Turku, Finland,
- Department of Cognitive Neuroscience and Philosophy, University of Skövde, 54 128 Skövde, Sweden, and
| | - Antti Revonsuo
- Department of Psychology and Turku Brain and Mind Center, University of Turku, 20014 Turku, Finland
- Department of Cognitive Neuroscience and Philosophy, University of Skövde, 54 128 Skövde, Sweden, and
| | - Valdas Noreika
- Department of Psychology, University of Cambridge, Cambridge CB2 3EB, United Kingdom
| | - Katja Valli
- Department of Psychology and Turku Brain and Mind Center, University of Turku, 20014 Turku, Finland
- Department of Cognitive Neuroscience and Philosophy, University of Skövde, 54 128 Skövde, Sweden, and
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25
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Abstract
Lucid dreaming refers to the phenomenon of becoming aware of the fact that one is dreaming during ongoing sleep. Despite having been physiologically validated for decades, the neurobiology of lucid dreaming is still incompletely characterized. Here we review the neuroscientific literature on lucid dreaming, including electroencephalographic, neuroimaging, brain lesion, pharmacological and brain stimulation studies. Electroencephalographic studies of lucid dreaming are mostly underpowered and show mixed results. Neuroimaging data is scant but preliminary results suggest that prefrontal and parietal regions are involved in lucid dreaming. A focus of research is also to develop methods to induce lucid dreams. Combining training in mental set with cholinergic stimulation has shown promising results, while it remains unclear whether electrical brain stimulation could be used to induce lucid dreams. Finally, we discuss strategies to measure lucid dreaming, including best-practice procedures for the sleep laboratory. Lucid dreaming has clinical and scientific applications, and shows emerging potential as a methodology in the cognitive neuroscience of consciousness. Further research with larger sample sizes and refined methodology is needed.
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Affiliation(s)
- Benjamin Baird
- Wisconsin Institute for Sleep and Consciousness, University of Wisconsin-Madison, Madison, WI, USA.
| | - Sergio A Mota-Rolim
- Brain Institute, Physiology Department and Onofre Lopes University Hospital - Federal University of Rio Grande do Norte, Natal, Brazil
| | - Martin Dresler
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, the Netherlands
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26
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Baird B, Castelnovo A, Gosseries O, Tononi G. Frequent lucid dreaming associated with increased functional connectivity between frontopolar cortex and temporoparietal association areas. Sci Rep 2018; 8:17798. [PMID: 30542052 PMCID: PMC6290891 DOI: 10.1038/s41598-018-36190-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/15/2018] [Indexed: 01/09/2023] Open
Abstract
Humans typically lack awareness that they are dreaming while dreaming. However, at times a remarkable exception occurs and reflective consciousness can be regained while dreaming, referred to as lucid dreaming. While most individuals experience lucid dreams rarely there is substantial variance in lucid dream frequency. The neurobiological basis of lucid dreaming is unknown, but evidence points to involvement of anterior prefrontal cortex (aPFC) and parietal cortex. This study evaluated the neuroanatomical/neurofunctional correlates of frequent lucid dreams and specifically whether functional connectivity of aPFC is associated with frequent lucid dreams. We analyzed structural and functional magnetic resonance imaging from an exceptional sample of fourteen individuals who reported ≥3 lucid dreams/week and a control group matched on age, gender and dream recall that reported ≤1 lucid dream/year. Compared to controls, the frequent lucid dream group showed significantly increased resting-state functional connectivity between left aPFC and bilateral angular gyrus, bilateral middle temporal gyrus and right inferior frontal gyrus, and higher node degree and strength in left aPFC. In contrast, no significant differences in brain structure were observed. Our results suggest that frequent lucid dreaming is associated with increased functional connectivity between aPFC and temporoparietal association areas, regions normally deactivated during sleep.
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Affiliation(s)
- Benjamin Baird
- Wisconsin Institute for Sleep and Consciousness Department of Psychiatry, University of Wisconsin, Madison, USA.
| | - Anna Castelnovo
- Wisconsin Institute for Sleep and Consciousness Department of Psychiatry, University of Wisconsin, Madison, USA
- Sleep and Epilepsy Center Neurocenter of Southern Switzerland, Civic Hospital (EOC) of Lugano, Lugano, Switzerland
| | - Olivia Gosseries
- Wisconsin Institute for Sleep and Consciousness Department of Psychiatry, University of Wisconsin, Madison, USA
- Coma Science Group GIGA-Consciousness, University of Liege, Liege, Belgium
| | - Giulio Tononi
- Wisconsin Institute for Sleep and Consciousness Department of Psychiatry, University of Wisconsin, Madison, USA.
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27
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Zandonai T, Lugoboni F, Zamboni L. A risk for athletes: when the desire to sleep becomes a nightmare. A brief case report on benzodiazepine addiction. Psychopharmacology (Berl) 2018; 235:3359-3360. [PMID: 30251160 DOI: 10.1007/s00213-018-5047-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 09/19/2018] [Indexed: 11/26/2022]
Affiliation(s)
- Thomas Zandonai
- Mind, Brain and Behavior Research Center (CIMCYC), Department of Experimental Psychology, University of Granada, Campus de Cartuja s/n, 18071, Granada, Spain.
| | - Fabio Lugoboni
- Department of Internal Medicine, Unit of Addiction Medicine, Hospital Trust of Verona, Policlinico "G.B. Rossi", P.le Scuro 10, 37134, Verona, Italy
| | - Lorenzo Zamboni
- Department of Internal Medicine, Unit of Addiction Medicine, Hospital Trust of Verona, Policlinico "G.B. Rossi", P.le Scuro 10, 37134, Verona, Italy
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Siclari F, Bernardi G, Cataldi J, Tononi G. Dreaming in NREM Sleep: A High-Density EEG Study of Slow Waves and Spindles. J Neurosci 2018; 38:9175-9185. [PMID: 30201768 PMCID: PMC6199409 DOI: 10.1523/jneurosci.0855-18.2018] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 01/08/2023] Open
Abstract
Dreaming can occur in both rapid eye movement (REM) and non-REM (NREM) sleep. We recently showed that in both REM and NREM sleep, dreaming is associated with local decreases in slow wave activity (SWA) in posterior brain regions. To expand these findings, here we asked how specific features of slow waves and spindles, the hallmarks of NREM sleep, relate to dream experiences. Fourteen healthy human subjects (10 females) underwent nocturnal high-density EEG recordings combined with a serial awakening paradigm. Reports of dreaming, compared with reports of no experience, were preceded by fewer, smaller, and shallower slow waves, and faster spindles, especially in central and posterior cortical areas. We also identified a minority of very steep and large slow waves in frontal regions, which occurred on a background of reduced SWA and were associated with high-frequency power increases (local "microarousals") heralding the successful recall of dream content. These results suggest that the capacity of the brain to generate experiences during sleep is reduced in the presence of neuronal off-states in posterior and central brain regions, and that dream recall may be facilitated by the intermittent activation of arousal systems during NREM sleep.SIGNIFICANCE STATEMENT By combining high-density EEG recordings with a serial awakening paradigm in healthy subjects, we show that dreaming in non-rapid eye movement sleep occurs when slow waves in central and posterior regions are sparse, small, and shallow. We also identified a small subset of very large and steep frontal slow waves that are associated with high-frequency activity increases (local "microarousals") heralding successful recall of dream content. These results provide noninvasive measures that could represent a useful tool to infer the state of consciousness during sleep.
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Affiliation(s)
- Francesca Siclari
- Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland,
| | - Giulio Bernardi
- Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland
- MoMiLab Unit, IMT School for Advanced Studies Lucca, 55100 Lucca, Italy
| | - Jacinthe Cataldi
- Lausanne University Hospital and University of Lausanne, 1011 Lausanne, Switzerland
| | - Giulio Tononi
- Department of Psychiatry, University of Wisconsin-Madison, Madison, Wisconsin 53719, and
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Zou Q, Zhou S, Xu J, Su Z, Li Y, Ma Y, Sun H, Wu CW, Gao JH. Dissociated resting-state functional networks between the dream recall frequency and REM sleep percentage. Neuroimage 2018; 174:248-256. [PMID: 29544817 DOI: 10.1016/j.neuroimage.2018.03.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 11/17/2022] Open
Abstract
Rapid eye movement (REM) sleep has been frequently associated with dreaming. However, mounting evidence obtained from behavioral, pharmacological, and brain imaging studies suggests that REM sleep is not indicative of the dream report and may originate from diverse neural substrates in brain functionality. The aim of the current study was to investigate the functional systems associated with inter-individual differences in dream recall and REM sleep through assessments of the resting-state functional connectivity. We collected resting-state functional magnetic resonance imaging (fMRI) data for functional connectivity evaluations from 43 healthy adult volunteers (23 men) before and after sleep. For assessment of the dream recall frequency, a 2-week sleep diary was maintained by all volunteers. In addition, whole-night polysomnography was performed for measuring the REM sleep percentage. Voxel-wise correlation analyses of 12 functional connectivity networks of interest with the dream recall frequency and REM sleep percentage were conducted using general linear model analysis. Both the dream recall frequency and REM sleep percentage showed negative associations with multiple brain functional networks. However, the dream recall frequency was mainly related to functional connectivity within the lateral visual network and thalamus, whereas the REM sleep percentage was mainly associated with connectivity within the frontoparietal networks and cerebellum. In addition, the dream recall frequency showed stronger coupling with the lateral visual network connectivity at night, whereas the coupling between the REM sleep percentage and cerebellum was higher in the morning. This indicated a significant time of day effect. Our results provide neuroimaging evidence that the functional system associated with the dream recall frequency is different from that associated with the REM sleep percentage.
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Affiliation(s)
- Qihong Zou
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
| | - Shuqin Zhou
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Jing Xu
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Beijing City Key Lab for Medical Physics and Engineering, Institution of Heavy Ion Physics, School of Physics, Peking University, Beijing, 100871, China
| | - Zihui Su
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Department of Anatomy & Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada
| | - Yuezhen Li
- Peking University Sixth Hospital (Institute of Mental Health), Beijing, 100191, China; National Clinical Research Center for Mental Disorders, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Yundong Ma
- Peking University Sixth Hospital (Institute of Mental Health), Beijing, 100191, China; National Clinical Research Center for Mental Disorders, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Hongqiang Sun
- Peking University Sixth Hospital (Institute of Mental Health), Beijing, 100191, China; National Clinical Research Center for Mental Disorders, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing, 100191, China
| | - Changwei W Wu
- Taipei Medical University Research Center of Brain and Consciousness, Taipei Medical University, Taipei, 110, Taiwan; Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, 110, Taiwan
| | - Jia-Hong Gao
- Center for MRI Research, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Beijing City Key Lab for Medical Physics and Engineering, Institution of Heavy Ion Physics, School of Physics, Peking University, Beijing, 100871, China; McGovern Institute for Brain Research, Peking University, Beijing, 100871, China; Shenzhen Institute of Neuroscience, Shenzhen, 518057, China.
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Curot J, Valton L, Denuelle M, Vignal JP, Maillard L, Pariente J, Trébuchon A, Bartolomei F, Barbeau EJ. Déjà-rêvé: Prior dreams induced by direct electrical brain stimulation. Brain Stimul 2018; 11:875-885. [PMID: 29530448 PMCID: PMC6028740 DOI: 10.1016/j.brs.2018.02.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 02/09/2018] [Accepted: 02/22/2018] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Epileptic patients sometimes report experiential phenomena related to a previous dream they had during seizures or electrical brain stimulation (EBS). This has been alluded to in the literature as "déjà-rêvé" ("already dreamed"). However, there is no neuroscientific evidence to support its existence and this concept is commonly mixed up with déjà-vu. We hypothesized that déjà-rêvé would be a specific entity, i.e., different from other experiential phenomena reported in epileptic patients, induced by EBS of specific brain areas. METHODS We collected all experiential phenomena related to dreams induced by electrical brain stimulations (EBS) in our epileptic patients (2003-2015) and in a review of the literature. The content of these déjà-rêvé and the location of EBS were analyzed. RESULTS We collected 7 déjà-rêvé in our database and 35 from the literature, which corresponds to an estimated prevalence of 0.3‰ of all EBS-inducing déjà-rêvé. Déjà-rêvé is a generic term for three distinct entities: it can be the recollection of a specific dream ("episodic-like"), reminiscence of a vague dream ("familiarity-like") or experiences in which the subject feels like they are dreaming (literally "a dreamy state"). EBS-inducing "episodic-like" and "familiarity-like" déjà-rêvé were mostly located in the medial temporal lobes. "Dreamy states" were induced by less specific EBS areas although still related to the temporal lobes. CONCLUSIONS This study demonstrates that déjà-rêvé is a heterogeneous entity that is different from déjà-vu, the historical "dreamy state" definition and other experiential phenomena. This may be relevant for clinical practice as it points to temporal lobe dysfunction and could be valuable for studying the neural substrates of dreams.
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Affiliation(s)
- Jonathan Curot
- Toulouse University Hospital, Department of Neurology, Toulouse, FR 31059, France; Centre de Recherche Cerveau et Cognition, CNRS, UMR5549, FR 31052, France.
| | - Luc Valton
- Toulouse University Hospital, Department of Neurology, Toulouse, FR 31059, France; Centre de Recherche Cerveau et Cognition, CNRS, UMR5549, FR 31052, France
| | - Marie Denuelle
- Toulouse University Hospital, Department of Neurology, Toulouse, FR 31059, France
| | | | - Louis Maillard
- Nancy University & CNRS, CRAN, UMR 7039, FR 54516, France; University Hospital of Nancy, Neurology Department Nancy, FR 54035, France
| | - Jérémie Pariente
- Toulouse University Hospital, Department of Neurology, Toulouse, FR 31059, France; INSERM, U1214, TONIC, Toulouse Mind and Brain Institute, FR 31024, France
| | - Agnès Trébuchon
- Aix Marseille Université, Institut de Neurosciences des Systèmes, Marseille, FR 13005, France; AP-HM, Hôpital de la Timone, Service de Neurophysiologie Clinique, Marseille, FR 13005, France
| | - Fabrice Bartolomei
- Aix Marseille Université, Institut de Neurosciences des Systèmes, Marseille, FR 13005, France; AP-HM, Hôpital de la Timone, Service de Neurophysiologie Clinique, Marseille, FR 13005, France
| | - Emmanuel J Barbeau
- Centre de Recherche Cerveau et Cognition, CNRS, UMR5549, FR 31052, France
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Abstract
In the course of the past few years, a series of related studies (Aserinsky and Kleitman, 1955; Goodenough et al., 1959; Wolpert and Trosman, 1958) has demonstrated beyond doubt the association of normal dreaming with the appearance of rapid, binocularly synchronous eye-movements. It has also been claimed that the rapid eye-movements (REMs) represent scanning movements made by the dreamer as he “watches” the visual events of the dream (Dement and Kleitman, 1957a; Dement and Wolpert, 1958). The REMs are absent during dreaming among those with life-long blindness, but are retained for some years by those whose blindness arises later than childhood (Berger et al., 1962a). In a study of undisturbed nocturnal sleep by Dement and Kleitman (1957b) periods of eye-movements were observed to occur fairly regularly at about 90-minute intervals throughout the night in association with the lightest phases of cyclic variation in depth of sleep, as indicated by the electroencephalogram (EEG). These REM periods had a mean duration of about 20 minutes, and 4–6 occurred per night.
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Beutel ME, Dietrich S, Stark R, Brendel G, Silbersweig D. Pursuit of the emerging dialogue between psychoanalysis and neuroscience: Clinical and research perspectives. The International Journal of Psychoanalysis 2017; 85:1493-6. [PMID: 15801523 DOI: 10.1516/tu76-hkhh-c1t4-u7pl] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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van Rijn E, Reid AM, Edwards CL, Malinowski JE, Ruby PM, Eichenlaub JB, Blagrove MT. Daydreams incorporate recent waking life concerns but do not show delayed ('dream-lag') incorporations. Conscious Cogn 2017; 58:51-59. [PMID: 29128282 DOI: 10.1016/j.concog.2017.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 09/21/2017] [Accepted: 10/16/2017] [Indexed: 11/30/2022]
Abstract
This study investigates the time course of incorporation of waking life experiences into daydreams. Thirty-one participants kept a diary for 10 days, reporting major daily activities (MDAs), personally significant events (PSEs) and major concerns (MCs). They were then cued for daydream, Rapid Eye Movement (REM) and N2 dream reports in the sleep laboratory. There was a higher incorporation into daydreams of MCs from the previous two days (day-residue effect), but no day-residue effect for MDAs or PSEs, supporting a function for daydreams of processing current concerns. A day-residue effect for PSEs and the delayed incorporation of PSEs from 5 to 7 days before the dream (the dream-lag effect) have previously been found for REM dreams. Delayed incorporation was not found in this study for daydreams. Daydreams might thus differ in function from REM sleep dreams. However, the REM dream-lag effect was not replicated here, possibly due to design differences from previous studies.
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Affiliation(s)
| | - Alexander M Reid
- Department of Psychology, Swansea University, Swansea, UK; Department of Psychology, University of York, York, UK
| | | | | | - Perrine M Ruby
- Lyon Neuroscience Research Center, INSERM, CNRS, University of Lyon, Lyon, France
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Vallat R, Chatard B, Blagrove M, Ruby P. Characteristics of the memory sources of dreams: A new version of the content-matching paradigm to take mundane and remote memories into account. PLoS One 2017; 12:e0185262. [PMID: 29020066 PMCID: PMC5636081 DOI: 10.1371/journal.pone.0185262] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 09/08/2017] [Indexed: 11/19/2022] Open
Abstract
Several studies have demonstrated that dream content is related to the waking life of the dreamer. However, the characteristics of the memory sources incorporated into dreams are still unclear. We designed a new protocol to investigate remote memories and memories of trivial experiences, both relatively unexplored in dream content until now. Upon awakening, for 7 days, participants identified the waking life elements (WLEs) related to their dream content and characterized them and their dream content on several scales to assess notably emotional valence. Thanks to this procedure, they could report WLEs from the whole lifespan, and mundane ones before they had been forgotten. Participants (N = 40, 14 males, age = 25.2 ± 7.6) reported 6.2 ± 2.0 dreams on average. For each participant, 83.4% ± 17.8 of the dream reports were related to one or more WLEs. Among all the WLEs incorporated into dreams dated by the participants (79.3 ± 19%), 40.2 ± 30% happened the day before the dream, 26.1 ± 26% the month before (the day before excluded), 15.8 ± 21% the year before the dream (the month before excluded), and 17.9 ± 24% happened more than one year before the dream. As could be expected from previous studies, the majority of the WLEs incorporated into dreams were scored as important by the dreamers. However, this was not true for incorporated WLEs dating from the day before the dream. In agreement with Freud's observations, the majority of the day residues were scored as mundane. Finally, for both positive and negative WLEs incorporated into dreams, the dreamt version of the WLE was rated as emotionally less intense than the original WLE. This result, showing that dreams tend to attenuate the emotional tone of waking-life memories towards a more neutral one, argues in favor of the emotional regulation hypothesis of dreaming.
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Affiliation(s)
- Raphael Vallat
- Lyon Neuroscience Research Center (CRNL), Brain Dynamics and Cognition Team (DYCOG), INSERM UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Benoit Chatard
- Lyon Neuroscience Research Center (CRNL), Brain Dynamics and Cognition Team (DYCOG), INSERM UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Mark Blagrove
- Swansea University, Sleep laboratory, Swansea, Wales, United Kingdom
| | - Perrine Ruby
- Lyon Neuroscience Research Center (CRNL), Brain Dynamics and Cognition Team (DYCOG), INSERM UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
- * E-mail:
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Abstract
This paper attempts to elaborate a fundamental brain mechanism involved in the creation and maintenance of symbolic fields of thought. It will integrate theories of psychic spaces as explored by Donald Winnicott and Wilfred Bion with the neuroscientific examinations of those with bilateral hippocampal injury to show how evidence from both disciplines sheds important light on this aspect of mind. Possibly originating as a way of maintaining an oriented, first person psychic map, this capacity allows individuals a dynamic narrative access to a realm of layered elements and their connections. If the proposed hypothesis is correct, the hippocampus facilitates the integration of this symbolic field of mind, where narrative forms of thinking, creativity, memory, and dreaming are intertwined. Without the hippocampus, there is an inability to engage many typical forms of thought itself. Also, noting the ways these individuals are not impaired supports theories about other faculties of mind, providing insight into their possible roles within human thought. The evidence of different systems working in conjunction with the symbolic field provides tantalizing clues about these fundamental mechanisms of brain and mind that are normally seamlessly integrated, and hints at future areas of clinical and laboratory research, both within neuroscience and psychoanalysis.
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Rousseau A, Belleville G. The mechanisms of action underlying the efficacy of psychological nightmare treatments: A systematic review and thematic analysis of discussed hypotheses. Sleep Med Rev 2017; 39:122-133. [PMID: 29056416 DOI: 10.1016/j.smrv.2017.08.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/06/2017] [Accepted: 08/23/2017] [Indexed: 11/18/2022]
Abstract
Studies of psychotherapeutic treatments for nightmares have yielded support for their effectiveness. However, no consensus exists to explain how they work. This study combines a systematic review with a qualitative thematic analysis to identify and categorize the existing proposed mechanisms of action (MAs) of nightmare treatments. The systematic review allowed for a great number of scholarly publications on supported psychological treatments for nightmares to be identified. Characteristics of the study and citations regarding potential MAs were extracted using a standardized coding grid. Then, thematic analysis allowed citations to be grouped under six different categories of possible MAs according to their similarities and differences. Results reveal that an increased sense of mastery was the most often cited hypothesis to explain the efficacy of nightmare psychotherapies. Other mechanisms included emotional processing leading to modification of the fear structure, modification of beliefs, restoration of sleep functions, decreased arousal, and prevention of avoidance. An illustration of the different variables involved in the treatment of nightmares is proposed. Different avenues for operationalization of these MAs are put forth to enable future research on nightmare treatments to measure and link them to efficacy measures, and test the implications of the illustration.
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Abstract
Study Objectives To replicate and expand upon past research by evaluating sleep and wake electroencephalographic spectral activity in samples of frequent nightmare (NM) recallers and healthy controls. Methods Computation of spectral activity for sleep (non-REM and REM) and wake electroencephalogram recordings from 18 frequent NM recallers and 15 control participants. Results There was higher "slow-theta" (2-5 Hz) for NM recallers than for controls during wake, non-REM sleep and REM sleep. Differences were clearest for frontal and central derivations and for REM sleep cycles 2-4. There was also higher beta activity during NREM sleep for NM recallers. Findings partially replicate past research by demonstrating higher relative "slow-theta" (3-4Hz) for NM recallers than for controls. Conclusions Findings are consistent with a neurocognitive model of nightmares that stipulates cross-state anomalies in emotion processing in NM-prone individuals.
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Affiliation(s)
- Louis-Philippe Marquis
- Department of Psychology, Université de Montréal, Québec, Canada
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Québec, Canada
| | - Tyna Paquette
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Québec, Canada
| | - Cloé Blanchette-Carrière
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Québec, Canada
- Department of Biomedical Sciences, Université de Montréal, Montréal, Québec, Canada
| | - Gaëlle Dumel
- Department of Psychology, Université de Montréal, Québec, Canada
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Québec, Canada
| | - Tore Nielsen
- Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM – Hôpital du Sacré-Coeur de Montréal, Québec, Canada
- Department of Psychiatry, Université de Montréal, Montréal, Québec, Canada
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Scarpelli S, D'Atri A, Mangiaruga A, Marzano C, Gorgoni M, Schiappa C, Ferrara M, De Gennaro L. Predicting Dream Recall: EEG Activation During NREM Sleep or Shared Mechanisms with Wakefulness? Brain Topogr 2017; 30:629-638. [PMID: 28434101 DOI: 10.1007/s10548-017-0563-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/18/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Serena Scarpelli
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy
| | - Aurora D'Atri
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy
| | - Anastasia Mangiaruga
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy
| | - Cristina Marzano
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy
| | - Maurizio Gorgoni
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy
| | - Cinzia Schiappa
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy
| | - Michele Ferrara
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Coppito, L'Aquila, Italy
| | - Luigi De Gennaro
- Department of Psychology, Sapienza University of Rome, Via dei Marsi, 78, 00185, Rome, Italy.
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De Gennaro L, Lanteri O, Piras F, Scarpelli S, Assogna F, Ferrara M, Caltagirone C, Spalletta G. Dopaminergic system and dream recall: An MRI study in Parkinson's disease patients. Hum Brain Mapp 2016; 37:1136-47. [PMID: 26704150 PMCID: PMC6867535 DOI: 10.1002/hbm.23095] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 12/04/2015] [Accepted: 12/05/2015] [Indexed: 02/05/2023] Open
Abstract
We investigated the role of the dopamine system [i.e., subcortical-medial prefrontal cortex (mPFC) network] in dreaming, by studying patients with Parkinson's Disease (PD) as a model of altered dopaminergic transmission. Subcortical volumes and cortical thickness were extracted by 3T-MR images of 27 PD patients and 27 age-matched controls, who were asked to fill out a dream diary upon morning awakening for one week. PD patients do not substantially differ from healthy controls with respect to the sleep, dream, and neuroanatomical measures. Multivariate correlational analyses in PD patients show that dopamine agonist dosage is associated to qualitatively impoverished dreams, as expressed by lower bizarreness and lower emotional load values. Visual vividness (VV) of their dream reports positively correlates with volumes of both the amygdalae and with thickness of the left mPFC. Emotional load also positively correlates with hippocampal volume. Beside the replication of our previous finding on the role of subcortical nuclei in dreaming experience of healthy subjects, this represents the first evidence of a specific role of the amygdala-mPFC dopaminergic network system in dream recall. The association in PD patients between higher dopamine agonist dosages and impoverished dream reports, however, and the significant correlations between VV and mesolimbic regions, however, provide an empirical support to the hypothesis that a dopamine network plays a key role in dream generation. The causal relation is however precluded by the intrinsic limitation of assuming the dopamine agonist dosage as a measure of the hypodopaminergic state in PD. Periodicals, Inc.
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Affiliation(s)
- Luigi De Gennaro
- Department of Psychology, University of Rome "Sapienza,", Rome, Italy
| | - Olimpia Lanteri
- Department of Psychology, University of Rome "Sapienza,", Rome, Italy
| | - Fabrizio Piras
- Department of Clinical and Behavioral Neurology, Santa Lucia Foundation, Rome, Italy
- Centro Studi e Ricerche Enrico Fermi, Compendio del Viminale, Rome, Italy
| | - Serena Scarpelli
- Department of Psychology, University of Rome "Sapienza,", Rome, Italy
| | - Francesca Assogna
- Department of Clinical and Behavioral Neurology, Santa Lucia Foundation, Rome, Italy
| | - Michele Ferrara
- Department of Life, Health and Environmental Sciences, University of L'aquila, Italy
| | - Carlo Caltagirone
- Department of Clinical and Behavioral Neurology, Santa Lucia Foundation, Rome, Italy
- Department of Neuroscience, University of Tor Vergata, Rome, Italy
| | - Gianfranco Spalletta
- Department of Clinical and Behavioral Neurology, Santa Lucia Foundation, Rome, Italy
- Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas
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Abstract
OBJECTIVE To evaluate the frequency, determinants and sleep characteristics of lucid dreaming in narcolepsy. SETTINGS University hospital sleep disorder unit. DESIGN Case-control study. PARTICIPANTS Consecutive patients with narcolepsy and healthy controls. METHODS Participants were interviewed regarding the frequency and determinants of lucid dreaming. Twelve narcolepsy patients and 5 controls who self-identified as frequent lucid dreamers underwent nighttime and daytime sleep monitoring after being given instructions regarding how to give an eye signal when lucid. RESULTS Compared to 53 healthy controls, the 53 narcolepsy patients reported more frequent dream recall, nightmares and recurrent dreams. Lucid dreaming was achieved by 77.4% of narcoleptic patients and 49.1% of controls (P < 0.05), with an average of 7.6±11 vs. 0.3±0.8 lucid dreams/ month (P < 0.0001). The frequency of cataplexy, hallucinations, sleep paralysis, dyssomnia, HLA positivity, and the severity of sleepiness were similar in narcolepsy with and without lucid dreaming. Seven of 12 narcoleptic (and 0 non-narcoleptic) lucid dreamers achieved lucid REM sleep across a total of 33 naps, including 14 episodes with eye signal. The delta power in the electrode average, in delta, theta, and alpha powers in C4, and coherences between frontal electrodes were lower in lucid than non-lucid REM sleep in spectral EEG analysis. The duration of REM sleep was longer, the REM sleep onset latency tended to be shorter, and the percentage of atonia tended to be higher in lucid vs. non-lucid REM sleep; the arousal index and REM density and amplitude were unchanged. CONCLUSION Narcolepsy is a novel, easy model for studying lucid dreaming.
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Affiliation(s)
- Pauline Dodet
- Sorbonne Universites, UPMC Univ Paris 06, Paris, France
- Brain Research Institute (CRICM - UPMC-Paris6; Inserm UMR_S 975; CNRS UMR 7225) Paris, France
| | - Mario Chavez
- Sorbonne Universites, UPMC Univ Paris 06, Paris, France
- Brain Research Institute (CRICM - UPMC-Paris6; Inserm UMR_S 975; CNRS UMR 7225) Paris, France
| | - Smaranda Leu-Semenescu
- Brain Research Institute (CRICM - UPMC-Paris6; Inserm UMR_S 975; CNRS UMR 7225) Paris, France
- Sleep Disorders Unit, Pitié-Salpêtrière University Hospital, APHP
- National Reference Center on Narcolepsy, France
| | - Jean-Louis Golmard
- Department of Biostatistics, Salpêtrière Hospital, ER4, Sorbonne Universites, UPMC Univ Paris 06, Paris, France
| | - Isabelle Arnulf
- Sorbonne Universites, UPMC Univ Paris 06, Paris, France
- Brain Research Institute (CRICM - UPMC-Paris6; Inserm UMR_S 975; CNRS UMR 7225) Paris, France
- Sleep Disorders Unit, Pitié-Salpêtrière University Hospital, APHP
- National Reference Center on Narcolepsy, France
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Filevich E, Dresler M, Brick TR, Kühn S. Metacognitive mechanisms underlying lucid dreaming. J Neurosci 2015; 35:1082-8. [PMID: 25609624 PMCID: PMC6605529 DOI: 10.1523/jneurosci.3342-14.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/28/2014] [Accepted: 11/26/2014] [Indexed: 01/30/2023] Open
Abstract
Lucid dreaming is a state of awareness that one is dreaming, without leaving the sleep state. Dream reports show that self-reflection and volitional control are more pronounced in lucid compared with nonlucid dreams. Mostly on these grounds, lucid dreaming has been associated with metacognition. However, the link to lucid dreaming at the neural level has not yet been explored. We sought for relationships between the neural correlates of lucid dreaming and thought monitoring. Human participants completed a questionnaire assessing lucid dreaming ability, and underwent structural and functional MRI. We split participants based on their reported dream lucidity. Participants in the high-lucidity group showed greater gray matter volume in the frontopolar cortex (BA9/10) compared with those in the low-lucidity group. Further, differences in brain structure were mirrored by differences in brain function. The BA9/10 regions identified through structural analyses showed increases in blood oxygen level-dependent signal during thought monitoring in both groups, and more strongly in the high-lucidity group. Our results reveal shared neural systems between lucid dreaming and metacognitive function, in particular in the domain of thought monitoring. This finding contributes to our understanding of the mechanisms enabling higher-order consciousness in dreams.
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Affiliation(s)
- Elisa Filevich
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany,
| | - Martin Dresler
- Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, 6525 EZ Nijmegen, The Netherlands and
| | - Timothy R Brick
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany, Department of Human Development and Family Studies, Pennsylvania State University, University Park, Pennsylvania
| | - Simone Kühn
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany
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Abstract
In this chapter, we review studies investigating the role of sleep in emotional functions. In particular, evidence has recently accumulated to show that brain regions involved in the processing of emotional and reward-related information are activated during sleep. We suggest that such activation of emotional and reward systems during sleep underlies the reprocessing and consolidation of memories with a high affective and motivational relevance for the organism. We also propose that these mechanisms occurring during sleep promote adapted cognitive and emotional responses in the waking state, including overnight performance improvement, creativity, and sexual functions. Activation across emotional-limbic circuits during sleep also appears to promote emotional maturation and the emergence of consciousness in the developing brain.
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Naiman R, Gustafson C. Rubin Naiman, PhD: Sleep and the spectrum of consciousness--learning to love sleep and dreams. Adv Mind Body Med 2015; 29:34-40. [PMID: 25607121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Medrano-Martínez P, Ramos-Platón MJ. [Generation and functions of dreams]. Rev Neurol 2014; 59:359-370. [PMID: 25297479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
INTRODUCTION Over the last decade an ever-increasing number of articles have been published on dreams, which reflects the interest that several fields of neuroscience have in the topic. In this work we review the main scientific theories that have contributed to the body of knowledge on how they are produced and what function they serve. DEVELOPMENT The article discusses the evolution of their scientific study, following a neurophysiological and neurocognitive approach. The first of these two methods seeks to determine the neurobiological mechanisms that generate them and the brain structures involved, while the second considers dreams to be a kind of cognition interacting with that of wake-fulness. Several different hypotheses about the function of dreams are examined, and more particularly those in which they are attributed with a role in the consolidation of memory and the regulation of emotional states. CONCLUSIONS Although the exact mechanism underlying the generation of dreams has not been determined, neurobiological data highlight the importance of the pontine nuclei of the brainstem, several memory systems, the limbic system and the brain reward system and a number of neocortical areas. Neurocognitive data underline the relation between the cognitive and emotional processing that occurs during wakefulness and during sleep, as well as the influence of the surroundings on the content of dreams. With regard to their function, one point to be stressed is their adaptive value, since they contribute to the reprocessing of the information acquired in wakefulness and the control of the emotions. This suggests that dreams participate in the development of the cognitive capabilities.
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Affiliation(s)
| | - M José Ramos-Platón
- Universidad Complutense. Facultad de Psicologia, 28223 Pozuelo de Alarcon, Espana
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Abstract
Converging evidence suggests that dreaming is influenced by the consolidation of memory during sleep. Following encoding, recently formed memory traces are gradually stabilized and reorganized into a more permanent form of long-term storage. Sleep provides an optimal neurophysiological state to facilitate this process, allowing memory networks to be repeatedly reactivated in the absence of new sensory input. The process of memory reactivation and consolidation in the sleeping brain appears to influence conscious experience during sleep, contributing to dream content recalled on awakening. This article outlines several lines of evidence in support of this hypothesis, and responds to some common objections.
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Affiliation(s)
- Erin J Wamsley
- Department of Psychiatry, Harvard Medical School, Boston, MA, 02115, USA,
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Horikawa T, Kamitani Y. [Exploring dream contents by neuroimaging]. Brain Nerve 2014; 66:461-469. [PMID: 24748094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Dreaming is a subjective experience during sleep that is often accompanied by vivid perceptual and emotional contents. Because of its fundamentally subjective nature, the objective study of dream contents has been challenging. However, since the discovery of rapid eye movements during sleep, scientific knowledge on the relationship between dreaming and physiological measures including brain activity has accumulated. Recent advances in neuroimaging analysis methods have made it possible to uncover direct links between specific dream contents and brain activity patterns. In this review, we first give a historical overview on dream researches with a focus on the neurophysiological and behavioral signatures of dreaming. We then discuss our recent study in which visual dream contents were predicted, or decoded, from brain activity during sleep onset periods using machine learning-based pattern recognition of functional MRI data. We suggest that advanced analytical tools combined with neural and behavioral databases will reveal the relevance of spontaneous brain activity during sleep to waking experiences.
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[Music and relaxation promotion brain development of the fetus. Better dreams in the uterus]. MMW Fortschr Med 2014; 156:20. [PMID: 24938050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Compston A. From the archives. ACTA ACUST UNITED AC 2013; 136:2928-32. [PMID: 24195127 DOI: 10.1093/brain/awt260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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49
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Abstract
The recognition of rapid-eye-movement sleep (REM) and its association with dreaming in 1953 by Aserinsky and Kleitman opened a new world to explore in the brain. Discussions at two major symposia in the early 1960s reveal that a state with characteristics resembling both wakefulness and sleep was overturning accepted views of the regulation of the two states. Participants grappled with the idea that cortical activation could occur during sleep. They struggled with picking a name that would capture the essence of REM without focusing on just one aspect of the state. Questioning whether REM in cats could be homologous with that of humans suggested an anthropocentric focus on human dreaming as the essence of the state. The need for biochemical studies was evident given that deprivation of REM caused a rebound in the amount of subsequent REM, which indicated that simple synaptic activity could not support this phenomenon.
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Affiliation(s)
- Adrian R Morrison
- a Department of Animal Biology, School of Veterinary Medicine , University of Pennsylvania , Philadelphia , PA
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Chow HM, Horovitz SG, Carr WS, Picchioni D, Coddington N, Fukunaga M, Xu Y, Balkin TJ, Duyn JH, Braun AR. Rhythmic alternating patterns of brain activity distinguish rapid eye movement sleep from other states of consciousness. Proc Natl Acad Sci U S A 2013; 110:10300-5. [PMID: 23733938 PMCID: PMC3690889 DOI: 10.1073/pnas.1217691110] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Rapid eye movement (REM) sleep constitutes a distinct "third state" of consciousness, during which levels of brain activity are commensurate with wakefulness, but conscious awareness is radically transformed. To characterize the temporal and spatial features of this paradoxical state, we examined functional interactions between brain regions using fMRI resting-state connectivity methods. Supporting the view that the functional integrity of the default mode network (DMN) reflects "level of consciousness," we observed functional uncoupling of the DMN during deep sleep and recoupling during REM sleep (similar to wakefulness). However, unlike either deep sleep or wakefulness, REM was characterized by a more widespread, temporally dynamic interaction between two major brain systems: unimodal sensorimotor areas and the higher-order association cortices (including the DMN), which normally regulate their activity. During REM, these two systems become anticorrelated and fluctuate rhythmically, in reciprocally alternating multisecond epochs with a frequency ranging from 0.1 to 0.01 Hz. This unique spatiotemporal pattern suggests a model for REM sleep that may be consistent with its role in dream formation and memory consolidation.
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Affiliation(s)
- Ho Ming Chow
- Language Section, Voice, Speech, and Language Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
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