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Charles Fernyhough - One of the best experts on this subject based on the ideXlab platform.
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when words and pictures come alive relating the modality of intrusive thoughts to modalities of hypnagogic Hypnopompic hallucinations
Personality and Individual Differences, 2011Co-Authors: Simon Mccarthyjones, Laura J. Barnes, Georgina E. Hill, Lindsey Marwood, Peter Moseley, Charles FernyhoughAbstract:Hypnagogic and Hypnopompic (H&H) hallucinations are those experienced on the borders of sleep and waking. Intrusive thoughts have been proposed to relate to the occurrence of such experiences. In a sample of students (N = 299), the present study investigated the relation between auditory and felt-presence H&H experiences, and specific modalities of intrusive thought (auditory and visual) whilst controlling for age, gender, depression, anxiety and thought suppression. The psychometric properties of the Durham Hypnagogic and Hypnopompic Hallucinations Questionnaire (DHQ) were also examined. Exploratory (N = 299) and, in a second sample, confirmatory (N = 502) factor analyses showed good internal and test–retest reliability for the auditory and felt-presence subscales of the DHQ, but not for the visual subscale. Regression analyses indicated that the sole predictor of auditory H&H hallucinations was intrusive auditory imagery, and the sole predictor of felt-presence H&H experiences was intrusive visual imagery. Explanations for these findings are considered and implications for future research are discussed.
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When words and pictures come alive: Relating the modality of intrusive thoughts to modalities of hypnagogic/Hypnopompic hallucinations
Personality and Individual Differences, 2011Co-Authors: Simon Mccarthy-jones, Laura J. Barnes, Georgina E. Hill, Lindsey Marwood, Peter Moseley, Charles FernyhoughAbstract:Hypnagogic and Hypnopompic (H&H) hallucinations are those experienced on the borders of sleep and waking. Intrusive thoughts have been proposed to relate to the occurrence of such experiences. In a sample of students (N = 299), the present study investigated the relation between auditory and felt-presence H&H experiences, and specific modalities of intrusive thought (auditory and visual) whilst controlling for age, gender, depression, anxiety and thought suppression. The psychometric properties of the Durham Hypnagogic and Hypnopompic Hallucinations Questionnaire (DHQ) were also examined. Exploratory (N = 299) and, in a second sample, confirmatory (N = 502) factor analyses showed good internal and test–retest reliability for the auditory and felt-presence subscales of the DHQ, but not for the visual subscale. Regression analyses indicated that the sole predictor of auditory H&H hallucinations was intrusive auditory imagery, and the sole predictor of felt-presence H&H experiences was intrusive visual imagery. Explanations for these findings are considered and implications for future research are discussed.
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A phenomenological survey of auditory verbal hallucinations in the hypnagogic and Hypnopompic states
Phenomenology and the Cognitive Sciences, 2010Co-Authors: Simon R. Jones, Charles Fernyhough, Frank LarøiAbstract:The phenomenology of auditory verbal hallucinations (AVHs) occurring in hypnagogic and Hypnopompic (H&H) states has received little attention. In a sample of healthy participants ( N = 325), 108 participants reported H&H AVHs and answered subsequent questions on their phenomenology. AVHs in the H&H state were found (1) to be more likely to only feature the occasional clear word than to be clear, (2) to be more likely to be one-off voices than to be recurrent voices, (3) to be more likely to be voices of people known to the individual than unknown persons, (4) to be more likely to talk directly to the person rather than not, and (5) to only rarely give commands, ask questions, or to result in an interactive conversation. Their phenomenology was similar to normative AVHs in wakefulness (as established by previous research) in that the voice-hearer was usually the target of the voice, and the voice was more likely to be of a recognized person. However, H&H AVHs differed from AVHs in wakefulness in that commands and questions were rare, and there was typically no dialogical engagement with the voice. We conclude by proposing that two distinct types of H&H AVHs may exist (which we term “dialogic” and “monologic”), based on an analysis of the phenomenology of the experience, and suggest avenues for future research.
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In a dark time: Development, validation, and correlates of the Durham hypnagogic and Hypnopompic hallucinations questionnaire
Personality and Individual Differences, 2009Co-Authors: Simon R. Jones, Charles Fernyhough, David M. MeadsAbstract:Abstract One factor limiting research involving hypnagogic and Hypnopompic (H&H) hallucinations is the lack of a brief, valid and reliable self-report measure of such experiences. The present paper reports on the development of the Durham Hypnagogic and Hypnopompic Hallucinations Questionnaire (DHQ), which consists of three unidimensional subscales assessing the presence of auditory, visual, and felt-presence experiences in the H&H state. In a sample of 18–29 year olds ( N = 365) this scale was found to have satisfactory psychometric properties. A subsample ( n = 293) completed self-report measures of intrusive thoughts, thought suppression and transliminality. Intrusive thoughts and the conscious desire to undertake thought suppression both correlated with levels of auditory, but not visual or felt-presence H&H hallucinations. Transliminality correlated with all DHQ subscales, but significantly more strongly with felt-presence than visual H&H experiences. Implications of these findings are considered, and recommendations for future research made.
Simon J. Sherwood - One of the best experts on this subject based on the ideXlab platform.
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A Web Survey of the Content, Sensory Modalities, and Interpretation of Hypnagogic and Hypnopompic experiences/Una Encuesta En la Red Sobre Contenido, Modalidades Sensoriales, E Interpretacion De Experiencia Hipnagogicas E hipnopompicas/Un Sondage Enl
Journal of Parapsychology, 2012Co-Authors: Simon J. SherwoodAbstract:Various anomalous experiences have been reported just as people are falling asleep (hypnagogic state) or awakening from sleep (Hypnopompic state). These states might be conducive to the operation of paranormal processes but might also facilitate the misinterpretation of normal experiences (Sherwood, 2000a, 2000b, 2002). Surveys have found that people who report more childhood experiences of hypnagogic/ Hypnopompic imagery or sleep paralysis also report a greater number of anomalous experiences during childhood or adulthood (Sherwood, 1999, 2000a). More specifically, hypnagogic/Hypnopompic imagery has been associated with reports of extrasensory perception (ESP), apparitions and communication with the dead, out-of-body experiences (OBEs), visions of past lives and experiences involving extraterrestrials (e.g., Glicksohn, 1989; Gurney, Myers, & Podmore, 1886; Leaning, 1925; McCreery, 1993; McKellar, 1957; Mavromatis, 1983, 1987; Spanos, Cross, Dickson, & DuBreuil, 1993). It is therefore important to investigate the range of imagery and experiences reported in these states and how they are interpreted. The terms "hypnagogic imagery" and "Hypnopompic imagery" were introduced by Maury (1848) and Myers (1903), respectively, and refer to imagery of varying sensory modalities that is experienced in the borderline states just as one is falling asleep or awakening from sleep, respectively. The images are typically fairly brief in duration (Nielsen, 1992) but can be extremely vivid and realistic. Some writers distinguish between imagery that occurs in the hypnagogic and Hypnopompic states (e.g., Glicksohn, 1989; McKellar, 1989) but others do not (e.g., Mavromatis, 1987). Previous experimental and survey research has tended to focus on hypnagogic (HG) imagery (e.g., see Mavromatis, 1987; Schacter, 1976), although some articles on Hypnopompic (HP) imagery have been published (e.g., Gillespie, 1989, 1997). This bias may be understandable, to some extent, considering that HG seems to be more common than HP imagery. Surveys have estimated that about 33-75% (Glicksohn, 1989; Leaning, 1925; McKellar, 1957; McKellar & Simpson, 1954; Richardson, Mavromatis, Mindel, & Owens, 1981) of people have experienced HG imagery on at least one occasion compared with 21.4% (McKellar, 1957) to 67.6% for HP imagery (Richardson et al., 1981). One recent large-scale survey estimated that 37% (12.5%) of the UK population had experienced some form of HG (or HP) imagery at least twice a week during the preceding year (Ohayon, Priest, Caulet, & Guilleminault, 1996). These different estimates may reflect the different survey techniques and different terminology used in these studies and/or the fact that not everyone may remember their HG/HP experiences. Apart from the focus upon HG imagery, researchers have also focused upon the visual and auditory modalities as these seem to be the most common form of HG imagery (Foulkes & Vogel, 1965; Hori, Hayashi, & Morikawa, 1994; McKellar & Simpson, 1954; Mavromatis, 1987; Schacter, 1976). However, comparatively little is known about imagery that occurs in other sensory modalities, such as olfactory, gustatory (taste), tactile, thermal, kinesthetic, bodily and synesthetic sensations, plus sensations of a presence (Leaning, 1925; Mavromatis, 1987; Schacter, 1976). It is also known that imagery in more than one sensory modality can occur simultaneously (e.g., McKellar, 1957; McKellar & Simpson, 1954; Mavromatis, 1987; Oswald, 1962). These combinations of imagery might enhance the degree of realism of the experiences; it may be that the greater the number of different attributes, the more hallucinatory the experience (Nielsen, 1992). Attempts to classify the content of the imagery have also focused on HG imagery and visual imagery in particular (Leaning, 1925; Mavromatis, 1987). Leaning (1925) identified five categories of visual HG imagery: (a) Formless (e.g., spots or clouds of light); (b) Faces; (c) Designs and objects; (d) Landscapes; (e) Scenes. …
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a web survey of the content sensory modalities and interpretation of hypnagogic and Hypnopompic experiences una encuesta en la red sobre contenido modalidades sensoriales e interpretacion de experiencia hipnagogicas e hipnopompicas un sondage enligne
Journal of Parapsychology, 2012Co-Authors: Simon J. SherwoodAbstract:Various anomalous experiences have been reported just as people are falling asleep (hypnagogic state) or awakening from sleep (Hypnopompic state). These states might be conducive to the operation of paranormal processes but might also facilitate the misinterpretation of normal experiences (Sherwood, 2000a, 2000b, 2002). Surveys have found that people who report more childhood experiences of hypnagogic/ Hypnopompic imagery or sleep paralysis also report a greater number of anomalous experiences during childhood or adulthood (Sherwood, 1999, 2000a). More specifically, hypnagogic/Hypnopompic imagery has been associated with reports of extrasensory perception (ESP), apparitions and communication with the dead, out-of-body experiences (OBEs), visions of past lives and experiences involving extraterrestrials (e.g., Glicksohn, 1989; Gurney, Myers, & Podmore, 1886; Leaning, 1925; McCreery, 1993; McKellar, 1957; Mavromatis, 1983, 1987; Spanos, Cross, Dickson, & DuBreuil, 1993). It is therefore important to investigate the range of imagery and experiences reported in these states and how they are interpreted. The terms "hypnagogic imagery" and "Hypnopompic imagery" were introduced by Maury (1848) and Myers (1903), respectively, and refer to imagery of varying sensory modalities that is experienced in the borderline states just as one is falling asleep or awakening from sleep, respectively. The images are typically fairly brief in duration (Nielsen, 1992) but can be extremely vivid and realistic. Some writers distinguish between imagery that occurs in the hypnagogic and Hypnopompic states (e.g., Glicksohn, 1989; McKellar, 1989) but others do not (e.g., Mavromatis, 1987). Previous experimental and survey research has tended to focus on hypnagogic (HG) imagery (e.g., see Mavromatis, 1987; Schacter, 1976), although some articles on Hypnopompic (HP) imagery have been published (e.g., Gillespie, 1989, 1997). This bias may be understandable, to some extent, considering that HG seems to be more common than HP imagery. Surveys have estimated that about 33-75% (Glicksohn, 1989; Leaning, 1925; McKellar, 1957; McKellar & Simpson, 1954; Richardson, Mavromatis, Mindel, & Owens, 1981) of people have experienced HG imagery on at least one occasion compared with 21.4% (McKellar, 1957) to 67.6% for HP imagery (Richardson et al., 1981). One recent large-scale survey estimated that 37% (12.5%) of the UK population had experienced some form of HG (or HP) imagery at least twice a week during the preceding year (Ohayon, Priest, Caulet, & Guilleminault, 1996). These different estimates may reflect the different survey techniques and different terminology used in these studies and/or the fact that not everyone may remember their HG/HP experiences. Apart from the focus upon HG imagery, researchers have also focused upon the visual and auditory modalities as these seem to be the most common form of HG imagery (Foulkes & Vogel, 1965; Hori, Hayashi, & Morikawa, 1994; McKellar & Simpson, 1954; Mavromatis, 1987; Schacter, 1976). However, comparatively little is known about imagery that occurs in other sensory modalities, such as olfactory, gustatory (taste), tactile, thermal, kinesthetic, bodily and synesthetic sensations, plus sensations of a presence (Leaning, 1925; Mavromatis, 1987; Schacter, 1976). It is also known that imagery in more than one sensory modality can occur simultaneously (e.g., McKellar, 1957; McKellar & Simpson, 1954; Mavromatis, 1987; Oswald, 1962). These combinations of imagery might enhance the degree of realism of the experiences; it may be that the greater the number of different attributes, the more hallucinatory the experience (Nielsen, 1992). Attempts to classify the content of the imagery have also focused on HG imagery and visual imagery in particular (Leaning, 1925; Mavromatis, 1987). Leaning (1925) identified five categories of visual HG imagery: (a) Formless (e.g., spots or clouds of light); (b) Faces; (c) Designs and objects; (d) Landscapes; (e) Scenes. …
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Relationship between the Hypnagogic/Hypnopompic States and Reports of Anomalous Experiences
Journal of Parapsychology, 2002Co-Authors: Simon J. SherwoodAbstract:A whole range of anomalous experiences (1) has been reported during the hypnagogic or Hypnopompic states that surround periods of sleep. It is not uncommon for people to experience brief, vivid, and often strange imagery or to find themselves temporarily unable to move or speak during these periods between wakefulness and sleep. These brief sensations and the temporary paralysis are known as hypnagogic or Hypnopompic imagery and sleep paralysis, (2) respectively (American Sleep Disorders Association [ASDA], 1990). Recent surveys found that people who report more childhood experiences of hypnagogic/Hypnopompic imagery or sleep paralysis also report a greater number of anomalous experiences during childhood or adulthood (Sherwood, 1999, 2000). More specifically, hypnagogic/Hypnopompic imagery has been associated with reports of extrasensory perception (ESP), apparitions and communication with the dead, out-of-the-body experiences (OBEs), visions of past lives, and experiences involving extraterrestrials (e.g., Glicksohn, 1989; Gurney, Myers, & Podmore, 1886; Leaning, 1925; Mavromatis, 1983, 1987; McCreery, 1993; McKellar, 1957; Spanos, Cross, Dickson, & DuBreuil, 1993). In addition to the above anomalous experiences, sleep paralysis has also been associated with reports of psychokinesis (PK) and near-death experiences (NDEs) (Baker, 1992; Green & McCreery, 1994; Rose & Blackmore, 1996; Rose, Hogan, & Blackmore, 1997; Spanos et al., 1993; Spanos, McNulty, DuBreuil, Pires, & Burgess, 1995). The question is: are the hypnagogic/Hypnopompic states conducive to anomalous processes and events or are normal hypnagogic/Hypnopompic features being misinterpreted? Perhaps both statements are true? The aim of this article is to consider evidence for each of these possibilities. First, it is necessary to outline the characteristics of the hypnagogic/Hypnopompic states and the features of some of the experiences that can occur within them. CHARACTERISTICS OF HYPNAGOGIC/Hypnopompic STATES Most research, both experimental and survey-based, seems to have focused on the hypnagogic state (the period between wakefulness and sleep, i.e., just as a person is falling asleep). Comparatively little research has been carried out on the Hypnopompic state (the period between sleep and wakefulness, i.e., just as a person is waking from sleep). Thus, this article focuses mainly on the hypnagogic state. The hypnagogic state, like the sleep state, is fairly complex and contains a number of steps and stages (Mavromatis, 1983; Rechtschaffen, 1994). Hori, Hayashi, and Morikawa (1994) concluded that the sleep onset period is unique and cannot be accurately categorised as either waking or sleeping. It is very difficult to determine the precise point of falling asleep, except by using arbitrary criteria, because the transition is gradual, because the changes are not always synchronised, and because there are large individual differences in when the changes occur (Lavie, 1996; Rechtschaffen, 1994). During alert wakefulness, eye movements are fairly rapid, and the normal EEC trace consists of irregular waves of high frequency (Bray, Cragg, Macknight, Mills, & Taylor, 1992). As a person relaxes or becomes drowsy, there is an increase in alpha activity (8-12 Hz), and eye movements become slower and less frequent (Parker, 1975; Rechtschaffen, 1994). In fact, the presence of slow eye movements is considered to be an extremely accurate indicator of hypnagogic mentation (Schacter, 1976). Stickgold and Hobson (1994) found that as the period of eyelid movement quiescence lengthens, that is, as the eyelids move less, mentation becomes more dreamlike. This contrasts with the positive association between eyelid movements and dreamlike mentation during REM sleep. As a person passes through the hypnagogic period into the early stages of non-REM sleep, there is a decline in alpha activity and a concomitant increase in slower theta activity (4-7 Hz; Baddia, Wright, & Wauquier, 1994; Bray et al. …
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relationship between the hypnagogic Hypnopompic states and reports of anomalous experiences
Journal of Parapsychology, 2002Co-Authors: Simon J. SherwoodAbstract:A whole range of anomalous experiences (1) has been reported during the hypnagogic or Hypnopompic states that surround periods of sleep. It is not uncommon for people to experience brief, vivid, and often strange imagery or to find themselves temporarily unable to move or speak during these periods between wakefulness and sleep. These brief sensations and the temporary paralysis are known as hypnagogic or Hypnopompic imagery and sleep paralysis, (2) respectively (American Sleep Disorders Association [ASDA], 1990). Recent surveys found that people who report more childhood experiences of hypnagogic/Hypnopompic imagery or sleep paralysis also report a greater number of anomalous experiences during childhood or adulthood (Sherwood, 1999, 2000). More specifically, hypnagogic/Hypnopompic imagery has been associated with reports of extrasensory perception (ESP), apparitions and communication with the dead, out-of-the-body experiences (OBEs), visions of past lives, and experiences involving extraterrestrials (e.g., Glicksohn, 1989; Gurney, Myers, & Podmore, 1886; Leaning, 1925; Mavromatis, 1983, 1987; McCreery, 1993; McKellar, 1957; Spanos, Cross, Dickson, & DuBreuil, 1993). In addition to the above anomalous experiences, sleep paralysis has also been associated with reports of psychokinesis (PK) and near-death experiences (NDEs) (Baker, 1992; Green & McCreery, 1994; Rose & Blackmore, 1996; Rose, Hogan, & Blackmore, 1997; Spanos et al., 1993; Spanos, McNulty, DuBreuil, Pires, & Burgess, 1995). The question is: are the hypnagogic/Hypnopompic states conducive to anomalous processes and events or are normal hypnagogic/Hypnopompic features being misinterpreted? Perhaps both statements are true? The aim of this article is to consider evidence for each of these possibilities. First, it is necessary to outline the characteristics of the hypnagogic/Hypnopompic states and the features of some of the experiences that can occur within them. CHARACTERISTICS OF HYPNAGOGIC/Hypnopompic STATES Most research, both experimental and survey-based, seems to have focused on the hypnagogic state (the period between wakefulness and sleep, i.e., just as a person is falling asleep). Comparatively little research has been carried out on the Hypnopompic state (the period between sleep and wakefulness, i.e., just as a person is waking from sleep). Thus, this article focuses mainly on the hypnagogic state. The hypnagogic state, like the sleep state, is fairly complex and contains a number of steps and stages (Mavromatis, 1983; Rechtschaffen, 1994). Hori, Hayashi, and Morikawa (1994) concluded that the sleep onset period is unique and cannot be accurately categorised as either waking or sleeping. It is very difficult to determine the precise point of falling asleep, except by using arbitrary criteria, because the transition is gradual, because the changes are not always synchronised, and because there are large individual differences in when the changes occur (Lavie, 1996; Rechtschaffen, 1994). During alert wakefulness, eye movements are fairly rapid, and the normal EEC trace consists of irregular waves of high frequency (Bray, Cragg, Macknight, Mills, & Taylor, 1992). As a person relaxes or becomes drowsy, there is an increase in alpha activity (8-12 Hz), and eye movements become slower and less frequent (Parker, 1975; Rechtschaffen, 1994). In fact, the presence of slow eye movements is considered to be an extremely accurate indicator of hypnagogic mentation (Schacter, 1976). Stickgold and Hobson (1994) found that as the period of eyelid movement quiescence lengthens, that is, as the eyelids move less, mentation becomes more dreamlike. This contrasts with the positive association between eyelid movements and dreamlike mentation during REM sleep. As a person passes through the hypnagogic period into the early stages of non-REM sleep, there is a decline in alpha activity and a concomitant increase in slower theta activity (4-7 Hz; Baddia, Wright, & Wauquier, 1994; Bray et al. …
Simon R. Jones - One of the best experts on this subject based on the ideXlab platform.
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A phenomenological survey of auditory verbal hallucinations in the hypnagogic and Hypnopompic states
Phenomenology and the Cognitive Sciences, 2010Co-Authors: Simon R. Jones, Charles Fernyhough, Frank LarøiAbstract:The phenomenology of auditory verbal hallucinations (AVHs) occurring in hypnagogic and Hypnopompic (H&H) states has received little attention. In a sample of healthy participants ( N = 325), 108 participants reported H&H AVHs and answered subsequent questions on their phenomenology. AVHs in the H&H state were found (1) to be more likely to only feature the occasional clear word than to be clear, (2) to be more likely to be one-off voices than to be recurrent voices, (3) to be more likely to be voices of people known to the individual than unknown persons, (4) to be more likely to talk directly to the person rather than not, and (5) to only rarely give commands, ask questions, or to result in an interactive conversation. Their phenomenology was similar to normative AVHs in wakefulness (as established by previous research) in that the voice-hearer was usually the target of the voice, and the voice was more likely to be of a recognized person. However, H&H AVHs differed from AVHs in wakefulness in that commands and questions were rare, and there was typically no dialogical engagement with the voice. We conclude by proposing that two distinct types of H&H AVHs may exist (which we term “dialogic” and “monologic”), based on an analysis of the phenomenology of the experience, and suggest avenues for future research.
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In a dark time: Development, validation, and correlates of the Durham hypnagogic and Hypnopompic hallucinations questionnaire
Personality and Individual Differences, 2009Co-Authors: Simon R. Jones, Charles Fernyhough, David M. MeadsAbstract:Abstract One factor limiting research involving hypnagogic and Hypnopompic (H&H) hallucinations is the lack of a brief, valid and reliable self-report measure of such experiences. The present paper reports on the development of the Durham Hypnagogic and Hypnopompic Hallucinations Questionnaire (DHQ), which consists of three unidimensional subscales assessing the presence of auditory, visual, and felt-presence experiences in the H&H state. In a sample of 18–29 year olds ( N = 365) this scale was found to have satisfactory psychometric properties. A subsample ( n = 293) completed self-report measures of intrusive thoughts, thought suppression and transliminality. Intrusive thoughts and the conscious desire to undertake thought suppression both correlated with levels of auditory, but not visual or felt-presence H&H hallucinations. Transliminality correlated with all DHQ subscales, but significantly more strongly with felt-presence than visual H&H experiences. Implications of these findings are considered, and recommendations for future research made.
Allan J. Cheyne - One of the best experts on this subject based on the ideXlab platform.
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what is the link between hallucinations dreams and hypnagogic Hypnopompic experiences
Schizophrenia Bulletin, 2016Co-Authors: Flavie Waters, Jan Dirk Blom, Allan J. Cheyne, Peter Woodruff, Thien Thanh Dangvu, Ben Aldersonday, Daniel CollertonAbstract:By definition, hallucinations occur only in the full waking state. Yet similarities to sleep-related experiences such as hypnagogic and Hypnopompic hallucinations, dreams and parasomnias, have been noted since antiquity. These observations have prompted researchers to suggest a common aetiology for these phenomena based on the neurobiology of rapid eye movement (REM) sleep. With our recent understanding of hallucinations in different population groups and at the neurobiological, cognitive and interpersonal levels, it is now possible to draw comparisons between the 2 sets of experiences as never before. In the current article, we make detailed comparisons between sleep-related experiences and hallucinations in Parkinson's disease, schizophrenia and eye disease, at the levels of phenomenology (content, sensory modalities involved, perceptual attributes) and of brain function (brain activations, resting-state networks, neurotransmitter action). Findings show that sleep-related experiences share considerable overlap with hallucinations at the level of subjective descriptions and underlying brain mechanisms. Key differences remain however: (1) Sleep-related perceptions are immersive and largely cut off from reality, whereas hallucinations are discrete and overlaid on veridical perceptions; and (2) Sleep-related perceptions involve only a subset of neural networks implicated in hallucinations, reflecting perceptual signals processed in a functionally and cognitively closed-loop circuit. In summary, both phenomena are non-veridical perceptions that share some phenomenological and neural similarities, but insufficient evidence exists to fully support the notion that the majority of hallucinations depend on REM processes or REM intrusions into waking consciousness.
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What Is the Link Between Hallucinations, Dreams, and Hypnagogic–Hypnopompic Experiences?
Schizophrenia Bulletin, 2016Co-Authors: Flavie Waters, Jan Dirk Blom, Thien Thanh Dang-vu, Allan J. Cheyne, Ben Alderson-day, Peter Woodruff, Daniel CollertonAbstract:By definition, hallucinations occur only in the full waking state. Yet similarities to sleep-related experiences such as hypnagogic and Hypnopompic hallucinations, dreams and parasomnias, have been noted since antiquity. These observations have prompted researchers to suggest a common aetiology for these phenomena based on the neurobiology of rapid eye movement (REM) sleep. With our recent understanding of hallucinations in different population groups and at the neurobiological, cognitive and interpersonal levels, it is now possible to draw comparisons between the 2 sets of experiences as never before. In the current article, we make detailed comparisons between sleep-related experiences and hallucinations in Parkinson's disease, schizophrenia and eye disease, at the levels of phenomenology (content, sensory modalities involved, perceptual attributes) and of brain function (brain activations, resting-state networks, neurotransmitter action). Findings show that sleep-related experiences share considerable overlap with hallucinations at the level of subjective descriptions and underlying brain mechanisms. Key differences remain however: (1) Sleep-related perceptions are immersive and largely cut off from reality, whereas hallucinations are discrete and overlaid on veridical perceptions; and (2) Sleep-related perceptions involve only a subset of neural networks implicated in hallucinations, reflecting perceptual signals processed in a functionally and cognitively closed-loop circuit. In summary, both phenomena are non-veridical perceptions that share some phenomenological and neural similarities, but insufficient evidence exists to fully support the notion that the majority of hallucinations depend on REM processes or REM intrusions into waking consciousness.
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hypnagogic and Hypnopompic hallucinations during sleep paralysis neurological and cultural construction of the night mare
Consciousness and Cognition, 1999Co-Authors: Allan J. Cheyne, Steve D. Rueffer, Ian R NewbyclarkAbstract:Hypnagogic and Hypnopompic experiences (HHEs) accompanying sleep paralysis (SP) are often cited as sources of accounts of supernatural nocturnal assaults and paranormal experiences. Descriptions of such experiences are remarkably consistent across time and cultures and consistent also with known mechanisms of REM states. A three-factor structural model of HHEs based on their relations both to cultural narratives and REM neurophysiology is developed and tested with several large samples. One factor, labeled Intruder, consisting of sensed presence, fear, and auditory and visual hallucinations, is conjectured to originate in a hypervigilant state initiated in the midbrain. Another factor, Incubus, comprising pressure on the chest, breathing difficulties, and pain, is attributed to effects of hyperpolarization of motoneurons on perceptions of respiration. These two factors have in common an implied alien "other" consistent with occult narratives identified in numerous contemporary and historical cultures. A third factor, labeled Unusual Bodily Experiences, consisting of floating/flying sensations, out-of-body experiences, and feelings of bliss, is related to physically impossible experiences generated by conflicts of endogenous and exogenous activation related to body position, orientation, and movement. Implications of this last factor for understanding of orientational primacy in self-consciousness are considered. Central features of the model developed here are consistent with recent work on hallucinations associated with hypnosis and schizophrenia.
Ian R Newbyclark - One of the best experts on this subject based on the ideXlab platform.
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hypnagogic and Hypnopompic hallucinations during sleep paralysis neurological and cultural construction of the night mare
Consciousness and Cognition, 1999Co-Authors: Allan J. Cheyne, Steve D. Rueffer, Ian R NewbyclarkAbstract:Hypnagogic and Hypnopompic experiences (HHEs) accompanying sleep paralysis (SP) are often cited as sources of accounts of supernatural nocturnal assaults and paranormal experiences. Descriptions of such experiences are remarkably consistent across time and cultures and consistent also with known mechanisms of REM states. A three-factor structural model of HHEs based on their relations both to cultural narratives and REM neurophysiology is developed and tested with several large samples. One factor, labeled Intruder, consisting of sensed presence, fear, and auditory and visual hallucinations, is conjectured to originate in a hypervigilant state initiated in the midbrain. Another factor, Incubus, comprising pressure on the chest, breathing difficulties, and pain, is attributed to effects of hyperpolarization of motoneurons on perceptions of respiration. These two factors have in common an implied alien "other" consistent with occult narratives identified in numerous contemporary and historical cultures. A third factor, labeled Unusual Bodily Experiences, consisting of floating/flying sensations, out-of-body experiences, and feelings of bliss, is related to physically impossible experiences generated by conflicts of endogenous and exogenous activation related to body position, orientation, and movement. Implications of this last factor for understanding of orientational primacy in self-consciousness are considered. Central features of the model developed here are consistent with recent work on hallucinations associated with hypnosis and schizophrenia.