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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] [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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2
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Carr P. The value of visioning: Augmenting EMDR with alpha-band alternating bilateral photic stimulation for trauma treatment in schizophrenia. Med Hypotheses 2020; 144:110184. [DOI: 10.1016/j.mehy.2020.110184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/27/2020] [Accepted: 08/13/2020] [Indexed: 11/28/2022]
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3
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Kahn D. Reactions to Dream Content: Continuity and Non-continuity. Front Psychol 2019; 10:2676. [PMID: 31849778 PMCID: PMC6901388 DOI: 10.3389/fpsyg.2019.02676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/13/2019] [Indexed: 11/13/2022] Open
Abstract
Although dream content may at times be quite outlandish or illogical, the dreamer’s emotional reactions to these events are not outlandish or illogical. Our study shows that the dreamer’s emotional reaction to people and events are similar to what they would have been in wake life. There is continuity between the emotional reactions of the dream and wake-self, even though situations may arise that are not likely or possible in wake life. For example, a dream may include people and places that span different times that are weaved together as if they were occurring at the moment. Further, the behavior of the dream-self is often different than that of the wake-self. When this happens, there is a non-continuity between the behavior of the dream and wake-self. Thus, there is both continuity and non-continuity between the dream and wake-self: Continuity in emotional reactions and non-continuity in the kinds of situations and behaviors that occur while dreaming. In the Kahn and Hobson, 2005a study, 58.7% of participants reported that their thinking within the context of the dream was similar to what it would have been had they been awake. About 55.1% of participants also reported that their thinking about the context of the dream was different than it would have been had they been awake. This difference affords the dream-self with novel experiences but that still elicit emotional reactions that are similar to how its wake-self would react. In essentially, every case when a comment was given to the question on thinking in the Kahn and Hobson, 2005a study, participants reported about how they emotionally reacted within the context of the dream and how they emotionally reacted about the content of the dream in comparison to how they would have reacted if awake.
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4
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Lynn SJ, Maxwell R, Merckelbach H, Lilienfeld SO, Kloet DVHVD, Miskovic V. Dissociation and its disorders: Competing models, future directions, and a way forward. Clin Psychol Rev 2019; 73:101755. [DOI: 10.1016/j.cpr.2019.101755] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 06/20/2019] [Accepted: 07/15/2019] [Indexed: 12/18/2022]
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Abstract
Dreaming is a ubiquitous phenomenon in human beings and has been discussed, researched, and hypothesized since a long time. The substrate, physiological mechanism, and function of dreaming have been explained by many scientists from the neurological, psychiatric, psychological, and philosophical perspective. With the development of scientific technology, many theories of dreaming have been established. In the present review, we first summarize the different theories of dreaming; furthermore, we introduce memory consolidation and reconsolidation. Lastly, we propose that memory might be associated with memory reconsolidation and list the explanations.
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Affiliation(s)
- Hongyi Zhao
- Department of Neurology, The Seventh Medical Center of PLA General Hospital, Beijing 100700, China
- Department of Neurology, NO. 984 Hospital of the PLA, Beijing 100094, China
| | - Dandan Li
- Department of Neurology, The Seventh Medical Center of PLA General Hospital, Beijing 100700, China
| | - Xiuzhen Li
- Department of Neurology, NO. 984 Hospital of the PLA, Beijing 100094, China
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6
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Voss U, D'Agostino A, Kolibius L, Klimke A, Scarone S, Hobson JA. Insight and Dissociation in Lucid Dreaming and Psychosis. Front Psychol 2018; 9:2164. [PMID: 30483185 PMCID: PMC6241172 DOI: 10.3389/fpsyg.2018.02164] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 10/22/2018] [Indexed: 11/13/2022] Open
Abstract
Dreams and psychosis share several important features regarding symptoms and underlying neurobiology, which is helpful in constructing a testable model of, for example, schizophrenia and delirium. The purpose of the present communication is to discuss two major concepts in dreaming and psychosis that have received much attention in the recent literature: insight and dissociation. Both phenomena are considered functions of higher order consciousness because they involve metacognition in the form of reflective thought and attempted control of negative emotional impact. Insight in dreams is a core criterion for lucid dreams. Lucid dreams are usually accompanied by attempts to control the dream plot and dissociative elements akin to depersonalization and derealization. These concepts are also relevant in psychotic illness. Whereas insightfulness can be considered innocuous in lucid dreaming and even advantageous in psychosis, the concept of dissociation is still unresolved. The present review compares correlates and functions of insight and dissociation in lucid dreaming and psychosis. This is helpful in understanding the two concepts with regard to psychological function as well as neurophysiology.
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Affiliation(s)
- Ursula Voss
- Psychology, Johann Wolfgang Goethe-Universität Frankfurt am Main, Frankfurt, Germany.,VITOS Hochtaunus Klinik, Psychiatrisches Krankenhaus, Friedrichsdorf, Germany
| | - Armando D'Agostino
- Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - Luca Kolibius
- Psychology, Johann Wolfgang Goethe-Universität Frankfurt am Main, Frankfurt, Germany.,VITOS Hochtaunus Klinik, Psychiatrisches Krankenhaus, Friedrichsdorf, Germany
| | - Ansgar Klimke
- Psychology, Johann Wolfgang Goethe-Universität Frankfurt am Main, Frankfurt, Germany.,Department of Psychiatry, Psychiatry Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Silvio Scarone
- Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - J Allan Hobson
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
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van Heugten-van der Kloet D, Llewellyn S. Editorial: Fragmentation in Sleep and Mind: Linking Dissociative Symptoms, Sleep, and Memory. Front Psychol 2018; 8:2248. [PMID: 29312087 PMCID: PMC5744075 DOI: 10.3389/fpsyg.2017.02248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/11/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Dalena van Heugten-van der Kloet
- Faculty of Health and Life Sciences, Department of Psychology, Health & Professional Development, Oxford Brookes University, Oxford, United Kingdom.,Nuffield Department of Clinical Neurosciences, The Sir William Dunn School of Pathology, Sleep and Circadian Neuroscience Institute, University of Oxford, Oxford, United Kingdom
| | - Sue Llewellyn
- Faculty of Humanities, University of Manchester, Manchester, United Kingdom
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Horton CL. Consciousness across Sleep and Wake: Discontinuity and Continuity of Memory Experiences As a Reflection of Consolidation Processes. Front Psychiatry 2017; 8:159. [PMID: 28936183 PMCID: PMC5594063 DOI: 10.3389/fpsyt.2017.00159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 08/11/2017] [Indexed: 01/31/2023] Open
Abstract
The continuity hypothesis (1) posits that there is continuity, of some form, between waking and dreaming mentation. A recent body of work has provided convincing evidence for different aspects of continuity, for instance that some salient experiences from waking life seem to feature in dreams over others, with a particular role for emotional arousal as accompanying these experiences, both during waking and while asleep. However, discontinuities have been somewhat dismissed as being either a product of activation-synthesis, an error within the consciousness binding process during sleep, a methodological anomaly, or simply as yet unexplained. This paper presents an overview of discontinuity within dreaming and waking cognition, arguing that disruptions of consciousness are as common a feature of waking cognition as of dreaming cognition, and that processes of sleep-dependent memory consolidation of autobiographical experiences can in part account for some of the discontinuities of sleeping cognition in a functional way. By drawing upon evidence of the incorporation, fragmentation, and reorganization of memories within dreams, this paper proposes a model of discontinuity whereby the fragmentation of autobiographical and episodic memories during sleep, as part of the consolidation process, render salient aspects of those memories subsequently available for retrieval in isolation from their contextual features. As such discontinuity of consciousness in sleep is functional and normal.
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Affiliation(s)
- Caroline L Horton
- DrEAMSLab, Psychology, Bishop Grosseteste University, Lincoln, United Kingdom
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Llewellyn S. Crossing the invisible line: De-differentiation of wake, sleep and dreaming may engender both creative insight and psychopathology. Conscious Cogn 2016; 46:127-147. [DOI: 10.1016/j.concog.2016.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 09/13/2016] [Indexed: 12/21/2022]
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Hopkins J. Free Energy and Virtual Reality in Neuroscience and Psychoanalysis: A Complexity Theory of Dreaming and Mental Disorder. Front Psychol 2016; 7:922. [PMID: 27471478 PMCID: PMC4946392 DOI: 10.3389/fpsyg.2016.00922] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 06/03/2016] [Indexed: 11/22/2022] Open
Abstract
The main concepts of the free energy (FE) neuroscience developed by Karl Friston and colleagues parallel those of Freud's Project for a Scientific Psychology. In Hobson et al. (2014) these include an innate virtual reality generator that produces the fictive prior beliefs that Freud described as the primary process. This enables Friston's account to encompass a unified treatment-a complexity theory-of the role of virtual reality in both dreaming and mental disorder. In both accounts the brain operates to minimize FE aroused by sensory impingements-including interoceptive impingements that report compliance with biological imperatives-and constructs a representation/model of the causes of impingement that enables this minimization. In Friston's account (variational) FE equals complexity minus accuracy, and is minimized by increasing accuracy and decreasing complexity. Roughly the brain (or model) increases accuracy together with complexity in waking. This is mediated by consciousness-creating active inference-by which it explains sensory impingements in terms of perceptual experiences of their causes. In sleep it reduces complexity by processes that include both synaptic pruning and consciousness/virtual reality/dreaming in REM. The consciousness-creating active inference that effects complexity-reduction in REM dreaming must operate on FE-arousing data distinct from sensory impingement. The most relevant source is remembered arousals of emotion, both recent and remote, as processed in SWS and REM on "active systems" accounts of memory consolidation/reconsolidation. Freud describes these remembered arousals as condensed in the dreamwork for use in the conscious contents of dreams, and similar condensation can be seen in symptoms. Complexity partly reflects emotional conflict and trauma. This indicates that dreams and symptoms are both produced to reduce complexity in the form of potentially adverse (traumatic or conflicting) arousals of amygdala-related emotions. Mental disorder is thus caused by computational complexity together with mechanisms like synaptic pruning that have evolved for complexity-reduction; and important features of disorder can be understood in these terms. Details of the consilience among Freudian, systems consolidation, and complexity-reduction accounts appear clearly in the analysis of a single fragment of a dream, indicating also how complexity reduction proceeds by a process resembling Bayesian model selection.
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Affiliation(s)
- Jim Hopkins
- Research Department of Clinical Educational and Health Psychology, University College LondonLondon, UK
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Horton CL, Malinowski JE. Autobiographical memory and hyperassociativity in the dreaming brain: implications for memory consolidation in sleep. Front Psychol 2015; 6:874. [PMID: 26191010 PMCID: PMC4488598 DOI: 10.3389/fpsyg.2015.00874] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/13/2015] [Indexed: 12/17/2022] Open
Abstract
In this paper we argue that autobiographical memory (AM) activity across sleep and wake can provide insight into the nature of dreaming, and vice versa. Activated memories within the sleeping brain reflect one’s personal life history (autobiography). They can appear in largely fragmentary forms and differ from conventional manifestations of episodic memory. Autobiographical memories in dreams can be sampled from non-REM as well as REM periods, which contain fewer episodic references and become more bizarre across the night. Salient fragmented memory features are activated in sleep and re-bound with fragments not necessarily emerging from the same memory, thus de-contextualizing those memories and manifesting as experiences that differ from waking conceptions. The constructive nature of autobiographical recall further encourages synthesis of these hyper-associated images into an episode via recalling and reporting dreams. We use a model of AM to account for the activation of memories in dreams as a reflection of sleep-dependent memory consolidation processes. We focus in particular on the hyperassociative nature of AM during sleep.
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Not only … but also: REM sleep creates and NREM Stage 2 instantiates landmark junctions in cortical memory networks. Neurobiol Learn Mem 2015; 122:69-87. [PMID: 25921620 DOI: 10.1016/j.nlm.2015.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 04/16/2015] [Accepted: 04/16/2015] [Indexed: 12/13/2022]
Abstract
This article argues both rapid eye movement (REM) and non-rapid eye movement (NREM) sleep contribute to overnight episodic memory processes but their roles differ. Episodic memory may have evolved from memory for spatial navigation in animals and humans. Equally, mnemonic navigation in world and mental space may rely on fundamentally equivalent processes. Consequently, the basic spatial network characteristics of pathways which meet at omnidirectional nodes or junctions may be conserved in episodic brain networks. A pathway is formally identified with the unidirectional, sequential phases of an episodic memory. In contrast, the function of omnidirectional junctions is not well understood. In evolutionary terms, both animals and early humans undertook tours to a series of landmark junctions, to take advantage of resources (food, water and shelter), whilst trying to avoid predators. Such tours required memory for emotionally significant landmark resource-place-danger associations and the spatial relationships amongst these landmarks. In consequence, these tours may have driven the evolution of both spatial and episodic memory. The environment is dynamic. Resource-place associations are liable to shift and new resource-rich landmarks may be discovered, these changes may require re-wiring in neural networks. To realise these changes, REM may perform an associative, emotional encoding function between memory networks, engendering an omnidirectional landmark junction which is instantiated in the cortex during NREM Stage 2. In sum, REM may preplay associated elements of past episodes (rather than replay individual episodes), to engender an unconscious representation which can be used by the animal on approach to a landmark junction in wake.
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van Heugten - van der Kloet D, Cosgrave J, Merckelbach H, Haines R, Golodetz S, Lynn SJ. Imagining the impossible before breakfast: the relation between creativity, dissociation, and sleep. Front Psychol 2015; 6:324. [PMID: 25859231 PMCID: PMC4374390 DOI: 10.3389/fpsyg.2015.00324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 03/06/2015] [Indexed: 11/13/2022] Open
Abstract
Dissociative symptoms have been related to higher rapid eye movement sleep density, a sleep phase during which hyperassociativity may occur. This may enhance artistic creativity during the day. To test this hypothesis, we conducted a creative photo contest to explore the relation between dissociation, sleep, and creativity. During the contest, participants (N = 72) took one photo per day for five consecutive days, based on specific daily themes (consisting of single words) and the instruction to take as creative a photo as possible each day. Furthermore, they completed daily measures of state dissociation and a short sleep diary. The photos and their captions were ranked by two professional photographers and two clinical psychologists based on creativity, originality, bizarreness, and quality. We expected that dissociative people would rank higher in the contest compared with low-dissociative participants, and that the most original photos would be taken on days when the participants scored highest on acute dissociation. We found that acute dissociation predicted a higher ranking on creativity. Poorer sleep quality and fewer hours of sleep predicted more bizarreness in the photos and captions. None of the trait measures could predict creativity. In sum, acute dissociation related to enhanced creativity. These findings contribute to our understanding of dissociative symptomatology.
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Affiliation(s)
| | - Jan Cosgrave
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of OxfordOxford, UK
| | - Harald Merckelbach
- Forensic Psychology Section, Department of Clinical and Psychological Science, Maastricht UniversityMaastricht, Netherlands
| | - Ross Haines
- Department of Statistics, University of OxfordOxford, UK
| | - Stuart Golodetz
- Oxford Smart Specs Group, Nuffield Department of Clinical Neurosciences, University of OxfordOxford, UK
| | - Steven Jay Lynn
- Laboratory of Consciousness and Cognition, Department of Psychology, Binghamton University, State University of New YorkBinghamton, NY, USA
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Such stuff as dreams are made on? Elaborative encoding, the ancient art of memory, and the hippocampus. Behav Brain Sci 2013; 36:589-607. [PMID: 24304746 DOI: 10.1017/s0140525x12003135] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThis article argues that rapid eye movement (REM) dreaming is elaborative encoding for episodic memories. Elaborative encoding in REM can, at least partially, be understood through ancient art of memory (AAOM) principles: visualization, bizarre association, organization, narration, embodiment, and location. These principles render recent memories more distinctive through novel and meaningful association with emotionally salient, remote memories. The AAOM optimizes memory performance, suggesting that its principles may predict aspects of how episodic memory is configured in the brain. Integration and segregation are fundamental organizing principles in the cerebral cortex. Episodic memory networks interconnect profusely within the cortex, creating omnidirectional “landmark” junctions. Memories may be integrated at junctions but segregated along connecting network paths that meet at junctions. Episodic junctions may be instantiated during non–rapid eye movement (NREM) sleep after hippocampal associational function during REM dreams. Hippocampal association involves relating, binding, and integrating episodic memories into a mnemonic compositional whole. This often bizarre, composite image has not been present to the senses; it is not “real” because it hyperassociates several memories. During REM sleep, on the phenomenological level, this composite image is experienced as a dream scene. A dream scene may be instantiated as omnidirectional neocortical junction and retained by the hippocampus as an index. On episodic memory retrieval, an external stimulus (or an internal representation) is matched by the hippocampus against its indices. One or more indices then reference the relevant neocortical junctions from which episodic memories can be retrieved. Episodic junctions reach a processing (rather than conscious) level during normal wake to enable retrieval. If this hypothesis is correct, the stuff of dreams is the stuff of memory.
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Abstract
AbstractI argued that rapid eye movement (REM) dreaming is elaborative emotional encoding for episodic memories, sharing many features with the ancient art of memory (AAOM). In this framework, during non–rapid eye movement (NREM), dream scenes enable junctions between episodic networks in the cortex and are retained by the hippocampus as indices for retrieval. The commentaries, which varied in tone from patent enthusiasm to edgy scepticism, fall into seven natural groups: debate over the contribution of the illustrative dream and disputes over the nature of dreaming (discussed in sect. R1); how the framework extends to creativity, psychopathology, and sleep disturbances (sect. R2); the compatibility of the REM dream encoding function with emotional de-potentiation (sect. R3); scepticism over similarities between REM dreaming and the AAOM (sect. R4); the function of NREM dreams in the sleep cycle (sect. R5); the fit of the junction hypothesis with current knowledge of cortical networks (sect. R6); and whether the hypothesis is falsifiable (including methodological challenges and evidence against the hypothesis) (sect. R7). Although the groups in sections R1–R6 appear quite disparate, I argue they all follow from the associative nature of dreaming.
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Hobson J, Friston K. Waking and dreaming consciousness: neurobiological and functional considerations. Prog Neurobiol 2012; 98:82-98. [PMID: 22609044 PMCID: PMC3389346 DOI: 10.1016/j.pneurobio.2012.05.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 04/12/2012] [Accepted: 05/08/2012] [Indexed: 12/28/2022]
Abstract
This paper presents a theoretical review of rapid eye movement sleep with a special focus on pontine-geniculate-occipital waves and what they might tell us about the functional anatomy of sleep and consciousness. In particular, we review established ideas about the nature and purpose of sleep in terms of protoconsciousness and free energy minimization. By combining these theoretical perspectives, we discover answers to some fundamental questions about sleep: for example, why is homeothermy suspended during sleep? Why is sleep necessary? Why are we not surprised by our dreams? What is the role of synaptic regression in sleep? The imperatives for sleep that emerge also allow us to speculate about the functional role of PGO waves and make some empirical predictions that can, in principle, be tested using recent advances in the modeling of electrophysiological data.
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Affiliation(s)
- J.A. Hobson
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - K.J. Friston
- The Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, United Kingdom
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