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Testing the involvement of the prefrontal cortex in lucid dreaming: A tDCS study

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... She concluded that dreams contain a variety of lucidity levels as opposed to a distinct grouping. The Dream Lucidity Questionnaire (DLQ; Stumbrys et al., 2013) is a 12-item questionnaire that asks participants how much they agree with certain statements related to lucid dreaming (e.g., how much control they had over the dream, or how sure they were about being asleep). Responses are made on a 5-point Likert scale (0 = not at all, 1 = just a little, 2 = moderately, 3 = pretty much, 4 = very much), and the first question is a direct assessment of lucidity on a continuous scale (I was aware that I was dreaming). ...
... The next questionnaire was an extended (19-item) version of the Dream Lucidity Questionnaire (DLQ). The original DLQ (Stumbrys et al., 2013) is a 12-item questionnaire assessing dream awareness and various aspects that often coincide with lucidity (e.g., dream control and access to waking memories). Response options of the DLQ follow a 5-point Likert scale (0 = not at all, 1 = just a little, 2 = moderately, 3 = pretty much, 4 = very much). ...
... With the current study, we propose that an additional line of investigation should be into the non-binary expression of dream awareness within lucid dreams (see also Mota-Rolim et al., 2010;Noreika et al., 2010;. Though several existing questionnaires use a continuous scale in measuring lucidity (e.g., Stumbrys et al., 2013;Voss et al., 2013), they are almost exclusively used to bin dreams into a dichotomous lucid or non-lucid categorization. Emphasizing the full distribution of scores on these or novel scales might provide more sensitive insight into what induces lucidity and how lucidity impacts waking life. ...
Article
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Dream lucidity, or being aware that one is dreaming while dreaming, is not an all-or-none phenomenon. Often, subjects report being some variant of “a little lucid” as opposed to completely or not at all. As recent neuroimaging work begins to elucidate the neural underpinnings of lucid experience, understanding subtle phenomenological variation within lucid dreams is essential. Here, we focus on the variability of lucid experience by asking participants to report their awareness of the dream on a 5-point Likert scale (from not at all to very much). Participants implemented a combination of mnemonic training lucid dream induction methods at home for one week and provided detailed reports about their dream experiences each morning. Consistent with previous research, cognitive induction methods led to about half of participants reporting at least one lucid dream and about half of all dreams including some level of lucidity. However, we also show that induction success rate varies significantly depending on the minimum criteria for lucidity. Participants also reported how much they adhered to specific components of each induction method, and the amount of mnemonic rehearsal during a brief early awake period was predictive of lucidity level. Furthermore, lucidity levels were positively correlated with dream control, dream bizarreness, and next-morning positive affect. Lastly, we asked participants open-ended questions about why they chose particular levels of lucidity. We focus a qualitative discussion on responses to those “semi-lucid” dreams (rated just a little, moderately, or pretty much lucid) to explore why participants rate their dreams as having intermediate levels of awareness. Together, the present study explores the frequency of semi-lucid dreams, what they are, why they might arise, their correlates, and how they impact methodological concerns in lucid dreaming research.
... during REM sleep increases dreamed self-awareness (Stumbrys, Erlacher, & Schredl, 2013;Voss et al., 2014). First (Stumbrys et al., 2013), transcranial direct current (tDC) stimulation over dorsolateral prefrontal cortex elevated self-rated lucid dreaming relative to a sham condition. ...
... during REM sleep increases dreamed self-awareness (Stumbrys, Erlacher, & Schredl, 2013;Voss et al., 2014). First (Stumbrys et al., 2013), transcranial direct current (tDC) stimulation over dorsolateral prefrontal cortex elevated self-rated lucid dreaming relative to a sham condition. Second (Voss et al., 2014), transcranial alternating current (tAC) stimulation at some frequencies-25 Hz and, especially, 40 Hz-over frontal regions increased dreamed self-awareness relative to sham in lucid dreaming-naïve participants. ...
... Key among these flaws were an absence of gold standard identification of lucid dreaming with pre-arranged signalling (LaBerge, Nagel, Dement, & Zarcone, 1981), a very low threshold for accepting participant self-ratings as evidence for self-awareness, and violation of assumptions of case independence for statistical comparisons, i.e., treating multiple dreams from individuals as wholly independent observations (thus increasing risk of Type I errors) (Kenny & Judd, 1986;Zimmerman, Williams, & Zumbo, 1992). These studies also decreased the likelihood of inducing lucid dreams by selecting lucid dreaming-naïve participants (Voss et al., 2014) and using nighttime sleep protocols (Stumbrys et al., 2013;Voss et al., 2014) which miss the circadian peak in REM sleep propensity that is captured by a midmorning nap (Webb, Agnew, & Sternthal, 1966). Nonetheless, the recruitment of lucid dreaming-naïve participants can be viewed as an advantage insofar as the results are generalizable to a larger segment of the general population. ...
... Yet, executive functions are not necessarily impaired during dreaming. It is possible to be aware of dreaming while a dream is happening, with partial or total control of the dream contents by the dreamer, a phenomenon called lucid dreaming (LD; Laberge et al., 1986;Stumbrys et al., 2013;Voss et al., 2014). Recent studies using functional magnetic resonance imaging (Dresler et al., 2012) and electroencephalography indicate that LD is related to increased activity in the prefrontal cortex (Voss et al., , 2014Mota-Rolim et al., 2010;Neider et al., 2011;Dresler et al., 2012;Stumbrys et al., 2013). ...
... It is possible to be aware of dreaming while a dream is happening, with partial or total control of the dream contents by the dreamer, a phenomenon called lucid dreaming (LD; Laberge et al., 1986;Stumbrys et al., 2013;Voss et al., 2014). Recent studies using functional magnetic resonance imaging (Dresler et al., 2012) and electroencephalography indicate that LD is related to increased activity in the prefrontal cortex (Voss et al., , 2014Mota-Rolim et al., 2010;Neider et al., 2011;Dresler et al., 2012;Stumbrys et al., 2013). In agreement with this notion, transcranial electrical stimulation of the prefrontal cortex can induce dream awareness during REM sleep (Stumbrys et al., 2013;Voss et al., 2014). ...
... Recent studies using functional magnetic resonance imaging (Dresler et al., 2012) and electroencephalography indicate that LD is related to increased activity in the prefrontal cortex (Voss et al., , 2014Mota-Rolim et al., 2010;Neider et al., 2011;Dresler et al., 2012;Stumbrys et al., 2013). In agreement with this notion, transcranial electrical stimulation of the prefrontal cortex can induce dream awareness during REM sleep (Stumbrys et al., 2013;Voss et al., 2014). Frontal cortex activity correlates with self-consciousness, working memory, and attention (Postle, 2006). ...
... Two studies have attempted to induce lucid dreams through transcranial electrical stimulation of the frontal cortex during REM sleep. Stumbrys, Erlacher and Schredl (2013b) tested direct current stimulation and Voss et al. (2014) tested alternating current stimulation. We review each of these studies in turn. ...
... In an investigation of the effect of transcranial direct current stimulation (tDCS) on lucid dreaming, Stumbrys et al. (2013b) applied either tDCS or sham stimulation (counterbalanced across nights) over a frontolateral scalp region in 19 participants. ...
... Compared to sham stimulation, tDCS resulted in a small numerical increase in selfratings of the unreality of dream objects as assessed by the Dream Lucidity Questionnaire (DLQ; Stumbrys et al., 2013b). Post-hoc analyses revealed that this effect was seen only in subjects with a high baseline frequency of lucid dreams, but not in participants with little or no lucid dreaming experience. ...
Article
Full-text available
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.
... The absence of awareness, and the lack of voluntary control during dream experience are both intriguing issues for dream scientists. In this regard, the researchers started becoming interested in modulating the level of consciousness during sleep, namely, inducing lucid dream experiences [26,108,109]. Hobson et al. [110] proposed that lucid dreaming may stem from the reactivation of dorsolateral prefrontal cortex that, as mentioned, appear deactivated during REM Sleep [41][42][43]. In this vein, Stumbrys et al. [108] applied tDCS stimulation over the dorsolateral prefrontal cortex during REM sleep and observed a small increase of self-reported lucid dreaming only in frequent lucid dreamers. ...
... Hobson et al. [110] proposed that lucid dreaming may stem from the reactivation of dorsolateral prefrontal cortex that, as mentioned, appear deactivated during REM Sleep [41][42][43]. In this vein, Stumbrys et al. [108] applied tDCS stimulation over the dorsolateral prefrontal cortex during REM sleep and observed a small increase of self-reported lucid dreaming only in frequent lucid dreamers. ...
... Here, we have also mentioned that dream contents and the level of consciousness during sleep may be manipulated. The few studies investigating induction of lucid dreams with electrical brain stimulation (tDCS and tACS) have found fascinating but sparse effects on dreaming [26,[107][108][109], and a method for reliably inducing lucid dreams by electrical stimulation of the brain is still yet to be found. Moreover, further applications of TMS should be expanded to change the level of consciousness [112]. ...
Article
Full-text available
Dream research has advanced significantly over the last twenty years, thanks to the new applications of neuroimaging and electrophysiological techniques. Many findings pointed out that mental activity during sleep and wakefulness shared similar neural bases. On the other side, recent studies have highlighted that dream experience is promoted by significant brain activation, characterized by reduced low frequencies and increased rapid frequencies. Additionally, several studies confirmed that the posterior parietal area and prefrontal cortex are responsible for dream experience. Further, early results revealed that dreaming might be manipulated by sensory stimulations that would provoke the incorporation of specific cues into the dream scenario. Recently, transcranial stimulation techniques have been applied to modulate the level of consciousness during sleep, supporting previous findings and adding new information about neural correlates of dream recall. Overall, although multiple studies suggest that both the continuity and activation hypotheses provide a growing understanding of neural processes underlying dreaming, several issues are still unsolved. The impact of state-/trait-like variables, the influence of circadian and homeostatic factors, and the examination of parasomnia-like events to access dream contents are all opened issues deserving further deepening in future research.
... Overall emotional tone was computed as the difference of self-rated positive emotions and self-rated negative emotions. In addition, they had to fi ll in the two-paged Dream Lucidity Questionnaire (DLQ: Stumbrys, Erlacher, & Schredl, 2013). The categories of the 13 DLQ items ranged from 0 = not at all, 1= somewhat, ...
... Item 1 of the DLQ was formulated as follows: "I was aware that I was dreaming.". In addition to the 12 original items devised by Stumbrys et al. (2013) an extra question was added: "I was sure that events in my dream would not affect reality". The total score consisted of the means of the 13 items. ...
... One explanation might be that brief and transient thoughts about being in a dream might not be recorded, i.e., might be missing from the dream report -this lack of reporting every detail of the dream has been shown for emotions (Schredl & Doll, 1998) and bizarreness (Schredl & Erlacher, 2003). In order to validate lucid dream questionnaires like the DLQ (Stumbrys et al., 2013) or the LuCid (Voss, Schemelleh-Engel, Windt, Frenzel, & Hobson, 2013), it would be very interesting to carry out in-depth qualitative studies into the specifi c dream experiences associated with dreams that are not fully lucid ("I am fully aware that I am dreaming") but contain some form of lucidity measured on the self-rating scales of the respective questionnaire. ...
Article
Lucidity is a rare phenomenon, thus different induction techniques are used to increase the frequency of lucid dreaming. The aim of the present study was to investigate the effect of lucid dream induction (three different cognitive methods: Dream diary, Wake-up-back-to-Bed, and reality testing/reflection) on external rated lucidity, dream length, overall emotional tone, and bizarreness. Overall, 110 participants completed the three-week study protocol. Results showed only few external-rated lucid dreams compared to the high percentage dreams including some form of self-rated lucidity. The small effect of increasing positive dream emotions during the course of the study fit in with the framework of the Imagery Rehearsal Therapy. No effects on dream length and dream bizarreness were found.
... At the neurophysiological level, activation patterns of the FPCN in REM sleep may differentiate between lucid and non-lucid (regular) dreaming. Deactivated regions of the FPCN in regular dreaming become reactivated in lucid dreaming (Dresler et al., 2012Filevich, Dresler, Brick, & Kühn, 2015;Hobson, 2009;Spoormaker, Czisch, & Dresler, 2010;Stumbrys, Erlacher, & Schredl, 2013). The rlPFC and dlPFC are among regions of the FPCN whose increased activation is observable during lucid dreaming (Dresler et al., 2012;Stumbrys et al., 2013;Filevich et al., 2015). ...
... Deactivated regions of the FPCN in regular dreaming become reactivated in lucid dreaming (Dresler et al., 2012Filevich, Dresler, Brick, & Kühn, 2015;Hobson, 2009;Spoormaker, Czisch, & Dresler, 2010;Stumbrys, Erlacher, & Schredl, 2013). The rlPFC and dlPFC are among regions of the FPCN whose increased activation is observable during lucid dreaming (Dresler et al., 2012;Stumbrys et al., 2013;Filevich et al., 2015). It is also shown that stimulating the dlPFC activity by transcranial direct current stimulation (tDCS) during REM sleep may influence lucidity in the dream (Stumbrys et al., 2013). ...
... The rlPFC and dlPFC are among regions of the FPCN whose increased activation is observable during lucid dreaming (Dresler et al., 2012;Stumbrys et al., 2013;Filevich et al., 2015). It is also shown that stimulating the dlPFC activity by transcranial direct current stimulation (tDCS) during REM sleep may influence lucidity in the dream (Stumbrys et al., 2013). The rlPFC and dlPFC are associated with metacognitive evaluation, cognitive control, and meta-awareness Schmitz, Kawahara-Baccus, & Johnson, 2004;Fleming, Weil, Nagy, Dolan, & Rees, 2010;Fox & Girn, 2018). ...
Article
The dynamic framework of mind wandering (Christoff, Irving, Fox, Spreng, & Andrews-Hanna, 2016) is reviewed and modified through integrating the construct of mindful meta-awareness. The dynamic framework maintains that mind wandering belongs to a family of spontaneous thought phenomena. The key defining feature of mind wandering is ‘spontaneity’ which characterizes the dynamic nature of thoughts in the framework. The argument is made that incorporating the mindful meta-awareness construct modifies the dynamic framework as follows: (1) the framework’s criteria for mind wandering do not hold anymore as meta-awareness changes the relationship between thoughts and constraints, and (2) lucid dreaming can be categorized as unguided thought while at the same time being dependent on deliberate constraints. Finally, the application of this modified framework will be discussed in terms of the treatment of mental disorders related to spontaneous thought alterations, in particular depression and nightmares.
... Effects found for tactile stimulations were not very strong and are hard to generalize because of the different stimuli and conditions. Two studies used transcranial brain stimulation, indicating that transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) may lead to an increase in lucidity (Stumbrys, Erlacher, & Schredl, 2013;Voss et al., 2014). ...
... Lucid dream recall frequency was assessed on an 8-point Likert scale which also showed a high retest reliability (r = .89; Stumbrys, Erlacher, & Schredl, 2013), using the anchors: 0 -never; 1 -less than once a year; 2 -about once a year; 3 -about 2-4 times a year; 4 -about once a month; 5 -about 2-3 times a month; 6 -about once a week, and 7 -several times a week. ...
... Earlier studies tried to devise categorical external rating systems based on perceived self-reflectiveness during dreaming and dream control (Stewart & Koulack, 1989). More recent efforts focused on self-report questionnaires to measure different aspects of lucidity including the Dream Lucidity Questionnaire (DLQ) developed by Stumbrys, Erlacher, and Schredl (2013) and the Lucidity and Consciousness in Dreams (LuCiD) scale introduced by Voss, Schermelleh-Engel, . Such scales can be filled out not only by the participant to get a subjective measure but could be also applied as a rating scale by an external rater. ...
Thesis
Full-text available
In sports practice a well-established method is mental practice which is, for example, applied in elite sports to intensify practice and to offer additional practice sessions when opportunities for physical practice are limited (Erlacher, 2007). It is also used on other areas, such as surgery and music. There is a special way of mentally rehearsing movements without physical activity: in our dreams (Stumbrys, 2014). In so called lucid dreams, the dreamer is consciously aware that he or she is dreaming and can thus decide to carry out actions deliberately (Schredl & Erlacher, 2004). In a survey by Erlacher, Stumbrys, and Schredl (2011–2012) it was shown that within a German sample 9% of all athletes who had lucid dreams used the lucid dream state to practice motor skills, for most of them with a positive impact on physical performance. Furthermore, anecdotal examples and previous qualitative and quantitative research has demonstrated that practicing movements in lucid dreams is possible and could possibly even improve performance in waking life for (overview see e.g. Stumbrys, 2014). However, the effectiveness of lucid dream practice had not yet been studies in a controlled sleep laboratory setting. The aim of this investigation was to further explore the effectiveness of lucid dream practice, and to derive practical implications for athletes. A particular goal was to assess the effectiveness of lucid dream practice using signal verified lucid dreams in a sleep laboratory. Furthermore, an extensive qualitative interview study was intended to explore the potential as well as phenomenal experience and difficulties of lucid dream practice. A similar study was planned for musicians to investigate if lucid dream practice can also be applied in this area. Since a requirement for lucid dream practice is to actually achieve lucidity in the dream state, another goal of this investigation was to test two ways of lucid dream induction by external stimulation. The first chapter of this dissertation gives an introduction into mental practice, including evidence that mental practice can improve physical performance in sport and other areas, such as music education. The second chapter first provides some information on sleep and dreams, followed by characteristics and applications of lucid dreams. Chapter three addresses lucid dream induction. The attached book chapter includes a detailed description and evaluation of induction techniques and discusses research problems. Then a study on lucid dream induction through visual and tactile stimulation is presented (Paper 1). Chapter four contains the most important contributions of this investigation: After introducing lucid dream practice, a sleep laboratory study is outlined which investigated the effectiveness of lucid dream practice using a dart throwing task (Paper 2). Then an extensive qualitative study is presented in which 16 athletes were interviewed about their experiences with lucid dream practice (Paper 3), followed by a smaller pilot study in which the potential of lucid dream practice for musicians was explored (Paper 4). Finally, in the last chapter the findings of all studies are summarized and discussed, deriving implications for both sports practice and future research.
... Yet, executive functions are not necessarily impaired during dreaming. It is possible to be aware of dreaming while a dream is happening, with partial or total control of the dream contents by the dreamer, a phenomenon called lucid dreaming (LD; Laberge et al., 1986;Stumbrys et al., 2013;Voss et al., 2014). Recent studies using functional magnetic resonance imaging (Dresler et al., 2012) and electroencephalography indicate that LD is related to increased activity in the prefrontal cortex (Voss et al., , 2014Mota-Rolim et al., 2010;Neider et al., 2011;Dresler et al., 2012;Stumbrys et al., 2013). ...
... It is possible to be aware of dreaming while a dream is happening, with partial or total control of the dream contents by the dreamer, a phenomenon called lucid dreaming (LD; Laberge et al., 1986;Stumbrys et al., 2013;Voss et al., 2014). Recent studies using functional magnetic resonance imaging (Dresler et al., 2012) and electroencephalography indicate that LD is related to increased activity in the prefrontal cortex (Voss et al., , 2014Mota-Rolim et al., 2010;Neider et al., 2011;Dresler et al., 2012;Stumbrys et al., 2013). In agreement with this notion, transcranial electrical stimulation of the prefrontal cortex can induce dream awareness during REM sleep (Stumbrys et al., 2013;Voss et al., 2014). ...
... Recent studies using functional magnetic resonance imaging (Dresler et al., 2012) and electroencephalography indicate that LD is related to increased activity in the prefrontal cortex (Voss et al., , 2014Mota-Rolim et al., 2010;Neider et al., 2011;Dresler et al., 2012;Stumbrys et al., 2013). In agreement with this notion, transcranial electrical stimulation of the prefrontal cortex can induce dream awareness during REM sleep (Stumbrys et al., 2013;Voss et al., 2014). Frontal cortex activity correlates with self-consciousness, working memory, and attention (Postle, 2006). ...
... Dream Lucidity Questionnaire (DLQ, Stumbrys et al., 2013). The DLQ measures different aspects of lucidity within dreams. ...
... The total DLQ score was derived as mean of all original items except for item 7 and 12. This was because these questions loaded poorly (< 0.4) in the original factor analysis that produced the DLQ; relating predominantly to recall of "waking facts, episodes or intentions" and not lucidity per se (Stumbrys et al, 2013). As such, all DLQ scores were out of a maximum of 40 points. ...
Article
Full-text available
Lucid dreaming—the phenomenon of experiencing waking levels of self-reflection within one’s dreams—is associated with more wake-like levels of neural activation in prefrontal brain regions. In addition, alternating periods of wakefulness and sleep might increase the likelihood of experiencing a lucid dream. Here we investigate the association between sleep fragmentation and lucid dreaming, with a multi-centre study encompassing four different investigations into subjective and objective measures of sleep fragmentation, nocturnal awakenings, sleep quality and polyphasic sleep schedules. Results across these four studies provide a more nuanced picture into the purported connection between sleep fragmentation and lucid dreaming: While self-assessed numbers of awakenings, polyphasic sleep and physiologically validated wake-REM sleep transitions were associated with lucid dreaming, neither self-assessed sleep quality, nor physiologically validated numbers of awakenings were. We discuss these results, and their underlying neural mechanisms, within the general question of whether sleep fragmentation and lucid dreaming share a causal link.
... In addition, transcranial current stimulation has been used during rapid eye movement sleep to stimulate areas of the brain linked with dream lucidity. In two studies (Stumbrys et al., 2013;Voss et al., 2014), this technique had a small but statistically significant effect on self-reported dream lucidity. ...
... These techniques may prevent the dreamer from experiencing insufficient clarity, a factor detrimental to lucid dream control . In the same line, it is possible that such techniques accentuate specific aspects of dream lucidity, such as coherence of thoughts and emotions, and memory of waking life (Stumbrys et al., 2013;Voss et al., 2013). While research has typically focused on lucid dream induction techniques Stumbrys et al., 2012), their utility may be limited if the dream is experienced as unstable, or if dream lucidity is too poor. ...
Article
The objective of the present study is to explore lucid dream control strategies (LDCSs) facilitating the production of outcomes that are impossible in the real world. Participants are 107 adults who experienced at least one lucid dream per year. They completed an online survey including an open question on LDCSs. Responses were analyzed using a content analysis method with a consensus approach. The results revealed five categories of LDCSs used within the lucid dreams: verbal strategies, strategies based on the use of the dream’s objects or environment, strategies based on the use of the oneiric body, strategies based on the management of emotions, and other strategies. Within these categories, 35 LDCSs were identified. These were used individually or in combination. Three additional LDCSs were used in waking. In conclusion, several LDCSs that were identified could be tested in the context of the lucid dream therapy for chronic nightmares.
... All groups were required to keep a daily dream diary with instructions to write down the contents of their dream upon awakening and rate the lucidity experienced in their dreams using the dream lucidity questionnare (DLQ; [9]). Participants preceded this report by completing an 'evening' section on the previous night, containing information that could potentially affect their ensuing sleep and dream experiences. ...
... For the DLQ, only the items associated with the main lucidity factor were used for further analysis (see [9]). Likewise for the LuCiD, only items associated with the main dream insight factor were used (see [10]). ...
Research
Full-text available
Metacognitive reflections on one's current state of mind are largely absent during dreaming. Lucid dreaming as the exception to this rule is a rare phenomenon; however, its occurrence can be facilitated through cognitive training. A central idea of respective training strategies is to regularly question one's phenomenal experience: is the currently experienced world real , or just a dream? Here, we tested if such lucid dreaming training can be enhanced with dream-like virtual reality (VR): over the course of four weeks, volunteers underwent lucid dreaming training in VR scenarios comprising dream-like elements, classical lucid dreaming training or no training. We found that VR-assisted training led to significantly stronger increases in lucid dreaming compared to the no-training condition. Eye signal-verified lucid dreams during polysomnography supported behavioural results. We discuss the potential mechanisms underlying these findings, in particular the role of synthetic dream-like experiences, incorporation of VR content in dream imagery serving as memory cues, and extended dissociative effects of VR session on subsequent experiences that might amplify lucid dreaming training during wakefulness. This article is part of the theme issue ‘Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.
... Dream Lucidity Questionnaire (DLQ; Stumbrys et al., 2013) is a 12-item questionnaire 86 that asks participants how much they agree with certain statements related to lucid 87 dreaming (e.g., how much control they had over the dream, or how sure they were about 88 being asleep). Responses are made on a 5-point Likert scale (0 = not at all, 1 = just a 89 ...
... The next questionnaire was an 149 extended (19-item) version of the Dream Lucidity Questionnaire (DLQ). The original DLQ 150 (Stumbrys et al., 2013) is a 12-item questionnaire assessing dream awareness and 151 various aspects that often coincide with lucidity (e.g., dream control and access to waking 152 memories). Response options of the DLQ follow a 5-point Likert scale (0 = not at all, 1 = 153 just a little, 2 = moderately, 3 = pretty much, 4 = very much). ...
Preprint
Dream lucidity, or the real-time awareness of a dream, is not an all-or-none phenomenon. Often, subjects report being some variant of “a little lucid” as opposed to completely or not at all. As recent neuroimaging work begins to elucidate the neural underpinnings of lucid experience, understanding subtle phenomenological variation within lucid dreams is essential. Here, we focus on the variety of lucid experience by asking participants to report their awareness of the dream on a 5-point Likert scale (from not at all to very much). Participants implemented lucid dream induction methods at home for one week and provided detailed reports about their dream experiences each morning. Consistent with previous research, cognitive induction methods led to about half of participants reporting at least one lucid dream and about half of all dreams including some level of lucidity. However, we also show that induction success rate varies significantly depending on the minimum criteria for lucidity. Participants also reported how much they adhered to specific components of each induction method, and the amount of mnemonic rehearsal during a brief early awake period was predictive of lucidity level. Furthermore, lucidity levels were positively correlated with dream bizarreness and next-morning positive affect. Lastly, we asked participants open-ended questions to interrogate why they chose particular levels of lucidity. We focus a qualitative discussion on responses to those “semi-lucid” dreams (rated just a little, moderately, or pretty much lucid) to explore why participants rate their dreams as having middle levels of awareness. Together, the present study explores the frequency of semi-lucid dreams, what they are, why they might arise, their correlates, and how they impact methodological concerns in lucid dreaming research.
... Another recent fMRI study found that several areas that are normally deactivated during REM sleep were reactivated during lucid dreaming, including the bilateral precuneus, cuneus, parietal lobules, and prefrontal and occipito-temporal cortices (Dresler et al., 2012). The involvement of the dorsolateral prefrontal cortex (DLPFC) in lucid dreaming during REM sleep has also been supported by another low current brain stimulation study (Stumbrys, Erlacher, & Schredl, 2013). ...
... Recently, researchers found that OBEs can be triggered by stimulating a particular brain region -temporo-parietal junction -and people with brain lesion in this area tend to have spontaneous OBEs (Blanke & Arzy, 2005). Lucid dreaming, conversely, can be triggered by stimulating frontal brain regions (Stumbrys et al., 2013;Voss et al., 2014). ...
Article
Full-text available
Despite the fact that lucid dream research and transpersonal psychology have common grounds, overlapping interests and a great potential to contribute to each other, the two fields over the recent decades evolved rather separately. The present article aims to renew the mutual dialogue by introducing the recent advancements of lucid dream research to the transpersonal community, discussing the relevance and providing some common directions for the future. It is argued that lucid dreaming is a transpersonal experience in itself, which can be mapped and explored, and also used as a gateway to facilitate further transpersonal and mystical experiences. Lucid dreaming can be used therapeutically as a tool for transpersonal psychotherapy or as a spiritual practice. Finally, it may help to gain some insights into the nature of consciousness. Combining empirical findings from lucid dream research with transpersonal frameworks might be a fruitful approach to advance the understanding of farther reaches of human dream nature.
... Thereby, electrodes are placed on the prefrontal cortex and a low frequency current is applied during REM sleep. A similar study was done by Stumbrys, Erlacher, and Schredl (2013b): electrodes were placed on the dorsolateral prefrontal cortex and transcranial direct current stimulation was used in an attempt to trigger lucidity. ...
... Poor effectiveness was seen in alpha feedback and water stimuli. More recent studies showed effectiveness of galantamine, vitamin B12 (Aspy et al., 2018;LaBerge, LaMarca, & Baird, 2018;Sparrow et al., 2016), and brain stimulation (Stumbrys et al., 2013b) in terms of inducing lucidity. ...
Article
A variety of induction techniques have been proposed to increase lucid dream frequency. An online survey was performed asking about knowledge of lucid dreaming and lucid dream induction techniques. The initial sample size was N=1380 with a subsample of N=716 who were asked questions concerning lucid dream induction techniques. The findings indicate that one quarter of all participants had heard of lucid dreaming once or several times via literature, the Internet or friends. An increase in age was negatively correlated to previous knowledge of lucid dreaming whereas female gender and higher education showed a positive correlation to knowledge about lucid dreaming via literature and friends. The lucid dream induction techniques of reality checks, critical questions, hypnosis and supplements are most commonly known to the subsample of the survey participants. Except for hypnosis these techniques are also the most often applied. The total number of techniques that are known correlated negatively with age, but not with gender or education. No significant differences, however, were found for the total number of techniques that were applied. It would be very interesting to study whether the reported application of these induction techniques - carried out in the home setting by the individual alone - had beneficial effects on lucid dream frequency as the efficacy of most induction techniques were only studied within formal research projects.
... However, while the majority of people report having experienced a lucid dream at least once in their lives, for most people lucid dreams occur very infrequently [6]. Accordingly, the development of reliable methods of inducing lucid dreams is an important focus of research [4,[7][8][9][10][11][12][13]. ...
... Two recent studies have attempted to induce lucid dreams with electrical stimulation of the brain and it might be asked how these techniques compare with the current approach. In one study, Stumbrys et al. [12] applied either tDCS or sham stimulation (counterbalanced across nights) to the frontal cortex during REM sleep. 7 out of 109 dreams were classified as having a clear indication of lucidity by a judge: 3 from sham stimulation and 4 from tDCS stimulation. ...
Article
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Lucid dreaming is a remarkable state of consciousness in which one is aware of the fact that one is dreaming while continuing to dream. Based on the strong relationship between physiological activation during rapid eye-movement sleep and lucid dreaming, our pilot research investigated whether enhancing cortical activation via acetylcholinesterease inhibition (AChEI) would increase the frequency of lucid dreams and found AChEI to be a promising method for lucid dream induction. In the current study we sought to quantify the size and reliability of the effect of AChEI on lucid dreaming, dream recall and dream content as well as to test the effectiveness of an integrated lucid dream induction protocol which combined cholinergic stimulation with other methods for lucid dream induction. Participants (N = 121) with high dream recall and an interest in lucid dreaming were randomly assigned counterbalanced orders of 3 doses of galantamine (0, 4 and 8 mg). On 3 consecutive nights, they awoke approximately 4.5 hours after lights out, recalled a dream, ingested the capsules and stayed out of bed for at least 30 minutes. Participants then returned to bed and practiced the Mnemonic Induction of Lucid Dreams technique while returning to sleep. The percentage of participants who reported a lucid dream was significantly increased for both 4 mg (27%, odds ratio = 2.29) and 8 mg doses (42%, odds ratio = 4.46) compared to the active placebo procedure (14%). Galantamine also significantly increased dream recall, sensory vividness and complexity (p
... These findings are controversial, given that the degree of self-awareness apparently induced by the stimulation was lower than the threshold originally established as a cutoff for the instrument used in the study (neurocritic.blogspot, 2018); however, additional light support can be found in Stumbrys, Erlacher and Schredl (2013). Regardless, Voss does not support or advocate for the use of this method in commercial devices until more research is completed (Hurd, 2015). ...
Article
An experimental home study examined the impact of a pre-sleep protocol for enhancing self-awareness, lucidity, and responsiveness in dreams. It included ingesting the cholinesterase inhibitor galantamine--which is widely reported to increase the frequency of lucid dreaming--prior to engaging in middle-of-the-night meditation and the imaginary reliving of a distressing dream while exercising new responses. Thirty-five participants completed an eight-night study, which included pre- and post-baseline nights and six conditions: waking for 40 min before returning to bed, called Wake-Back-to-Bed (WBTB); Wake-Back-to-Bed plus placebo (WBTB + P); Wake-Back-to-Bed plus galantamine (WBTB + G); meditation and dream reliving (MDR); meditation and dream reliving plus placebo (MDR + P); and meditation and dream reliving plus galantamine (MDR + G). The outcome measures included lucidity, reflectiveness, interactive behavior, role change, constructive action, and fear and threat, as measured by the participants' self-ratings. The results support the use of this protocol in further studies of lucid dream induction and nightmare/trauma resolution.
... dreaming was stimulated by blockbuster films like "Inception" (director: Christopher Nolan, released in 2010; Bulkeley & Welt, 2014) and the media interest in studies indicating that lucid dreaming can be induced by transcranial direct or alternate current stimulation (Stumbrys, Erlacher, & Schredl, 2013b;Voss et al., 2014), for example, start-up websites advertising such an apparatus for home use, and the beneficial effects of lucid dream training on motor skills activities (Schädlich et al., 2017). This heightened interest resulted in a number of books explaining the art of lucid dreaming (Johnson, 2017;Tuccillo, 2013;Waggoner & McCready, 2015). ...
Article
In recent years, the interest in lucid dreaming (dreaming with the conscious knowledge that one is dreaming) was stimulated by blockbuster films like "Inception" and the media interest in studies indicating that lucid dreaming can be beneficial. However, systematic studies regarding the attitude toward lucid dreams are lacking. An online survey was completed by 1,380 persons (777 women and 603 men), whose mean age was 51.63 ± 14.13 years. The six-item scale measuring attitude toward lucid dreams showed high internal consistency. The attitude toward lucid dreams was highly correlated with the general attitude toward lucid dreams and decreased with age; women reported a more positive attitude. However, the attitude toward lucid dreams was markedly lower than the attitude toward dreams in general. It would be interesting to study what the bases of the attitude toward lucid dreams are, for example, information in the media, personal experience, and reports of friends.
... In support of a causal role for this activity, one study found that external entrainment of low-gamma oscillations during REM sleep enhanced self-awareness and lucidity (Voss et al., 2014). Another study showed that transcranial direct current stimulation of the dorsolateral prefrontal cortex is associated with enhanced lucidity during REM sleep (analogous to the above-cited studies of minimal conscious access (Stumbrys et al., 2013). Given that lucid dreaming is considered a hybrid of REM sleep and waking (Voss et al., 2009), studies demonstrating a causal role for the prefrontal cortex in lucid dreaming thus also support a role for the prefrontal cortex in waking consciousness. ...
Article
We review the central tenets and neuroanatomical basis of the global neuronal workspace (GNW) hypothesis, which attempts to account for the main scientific observations regarding the elementary mechanisms of conscious processing in the human brain. The GNW hypothesis proposes that, in the conscious state, a non-linear network ignition associated with recurrent processing amplifies and sustains a neural representation, allowing the corresponding information to be globally accessed by local processors. We examine this hypothesis in light of recent data that contrast brain activity evoked by either conscious or non-conscious contents, as well as during conscious or non-conscious states, particularly general anesthesia. We also discuss the relationship between the intertwined concepts of conscious processing, attention, and working memory.
... In line with the above ideas, several studies have attempted to induce lucid dreams through electrical stimulation of the frontal cortex during REM sleep. One study tested whether transcranial direct current stimulation (tDCS) applied to the frontal cortex would increase lucid dreaming 70 . While tDCS resulted in a small numerical increase in self-ratings of the unreality of dream objects, it did not significantly increase the number of lucid dreams as rated by judges or confirmed through the eye-signaling method. ...
Article
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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.
... Pharmacologically, increasing the levels of dopamine could also potentially alleviate lucid nightmares , McLaughlin, Blum, Oscar-Berman, Febo, Demetrovics, et al., 2015, McLaughlin et al., 2016. The assumption whether lucid nightmares have lower levels of lucidity or metacognition than ordinary lucid dreams (LaBerge & Rheingold, 1990) can be tested empirically-by using questionnaires such as the Lucidity and Consciousness in Dreams Scale (Voss et al., 2013), the Dream Lucidity Questionnaire (Stumbrys, Erlacher, & Schredl, 2013b), or Metacognitive, Affective, Cognitive Experience Questionnaire (Kahan & Sullivan, 2012). ...
Article
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This article reports the first systematic study on lucid nightmares—terrifying lucid dreams with a lack of dream control. An online survey was completed by 634 participants, of whom 574 had had previous lucid dream experience. According to the reports of lucid dreamers, less than half of them had experienced a lucid nightmare, and only 1% of them could be considered as suffering from lucid nightmares—experiencing them once a week or more frequently. Lucid nightmares appear to be as distressing as ordinary nightmares. Lack of dream control and intense fear are among their most common features, followed by violent autonomous dream characters and the inability to wake up. Lucid nightmares are more likely to occur for women and nightmare sufferers, yet also for more frequent lucid dreamers and for those who experience lucid dreams spontaneously rather than them being induced deliberately. Key methodological points, for example, whether the awakening criterion in the definition of lucid nightmares should be included, are addressed, and suggestions for future research are provided.
... The PAEM technique to flag LD during REM sleep has been widely used in physiological (LaBerge et al., 1981;Brylowski et al., 1989;Mota-Rolim et al., 2010;Dresler et al., 2012), pathological (Tang et al., 2006;Dodet et al., 2014;Oudiette et al., 2018), and artificial (Stumbrys et al., 2013;Mota-Rolim et al., 2019) conditions. Additionally, LD flagged by PAEM has also been described during non-REM sleep stages N1 (sleep onset) and N2 (superficial sleep) (LaBerge, 1980;Stumbrys and Erlacher, 2012;Mota-Rolim et al., 2015), but not during N3 (deep sleep). ...
... Unihemispheric tDCS has been shown to facilitate motor imagery during REM sleep 35 and to modulate visual imagery during Stage 2 NREM sleep 36 , but not during slow wave sleep 37 or REM sleep 38 . Furthermore, frontal tDCS increases lucidity in experienced lucid dreamers 39 ; and frontal transcranial alternating current stimulation (tACS) increases dissociation, insight and control in novice lucid dreamers 40 . tDCS has also been reported to modulate mind wandering in wakefulness 41 . ...
Article
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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.
... The main lucidity measure was a 19-item questionnaire relating to lucid experiences during the reported dream. This 19-item questionnaire was a composite of items from the Dream Lucidity Questionnaire (DLQ; (Stumbrys, Erlacher, & Schredl, 2013) and the Lucid Skills Questionnaire (LUSK; (Schredl, Rieger, & Göritz, 2018); between the two questionnaires there are 4 items that overlap, 9 questions unique to the DLQ and 6 questions unique to the LUSK. For all items, participants were asked to rate the extent to which they agreed with the statements, from 0 (not at all) to 4 (very much). ...
Article
Introduction Lucid dreaming (being aware that one is dreaming) is typically a positive experience that may enhance positive mood even after waking. There is concern, however, that lucid dreaming may interfere with sleep quality. In the current experiment, participants practiced common lucid dream induction techniques over the course of a week, and kept a daily sleep and dream diary. The study objective was to assess relationships between dream lucidity and subjective sleep quality, dream emotional content, and subsequent waking mood. Methods There were 32 participants aged 19–33 in this open label, single arm study (mean=22.63±3.48; 6 males, 24 females). All participants completed a sleep and dream diary for 7 days that included scaled items (1–7 scale) concerning subjective sleep quality, negative and positive emotional intensity of a dream (if recalled). Participants also completed a 19-item lucidity questionnaire, and the Positive and Negative Affect Schedule. Average scores for the week were computed for all measures and Pearson’s correlations conducted between lucidity and all other measures. Participants with no dream recall (n=5) were excluded. Within-subjects analyses were undertaken by selecting each participant’s highest and lowest lucidity night (n=22; 5 participants with only minimum lucidity excluded). Results Positive correlations were found between lucidity and dream positive emotion (r=.490, n=27, p=.009) and positive waking mood (r=.638, n=27, p<.001); there were no other significant correlations (all p>.1). Higher lucidity was associated with more positive dream content (t(21)= -3.214, p=.004) and positive waking mood (t(25)=-4.568, p<.001); no other significant differences were observed. Conclusion These data indicate that lucidity is associated with positive dreams and waking mood, with no detriment to self-reported sleep quality. The findings provide preliminary support of lucid dreaming as an intervention to improve wellbeing and mood in the short term. Support N/A
... Taitz (2011) found that daily RT for 2 weeks was ineffective. Poor success rates were reported in laboratory studies of external stimulation (flashing lights and vibration; Franc et al., 2014) and transcranial direct current stimulation (tDCS) to the dorsolateral prefrontal cortex (DLPFC) during REM sleep (Stumbrys et al., 2013). Dyck et al. (2017) found that keeping a dream diary, RT, and a combined WBTB and affirmation technique were ineffective. ...
Article
Full-text available
The International Lucid Dream Induction Study (ILDIS) investigated and compared the effectiveness of five different combinations of lucid dream induction techniques including reality testing (RT), Wake Back to Bed (WBTB), the Mnemonic Induction of Lucid Dreams (MILD) technique, the Senses Initiated Lucid Dream (SSILD) technique, and a hybrid technique combining elements of both MILD and SSILD. Participants with an interest in lucid dreaming (N = 355) completed a pre-test questionnaire and then a baseline sleep and dream recall logbook for 1 week before practicing the lucid dream induction techniques for another week. Results indicated that the MILD technique and the SSILD technique were similarly effective for inducing lucid dreams. The hybrid technique showed no advantage over MILD or SSILD. Predictors of successful lucid dream induction included superior general dream recall and the ability to fall asleep within 10 min of completing the lucid dream induction techniques. Successful lucid dream induction had no adverse effect on sleep quality. Findings indicated that the techniques were effective regardless of baseline lucid dreaming frequency or prior experience with lucid dreaming techniques. Recommendations for further research on lucid dream induction techniques are provided.
... They know that their subjective experiences are detached from reality. Lucid dreaming has been associated with heightened activity in the prefrontal cortex (Dresler et al. 2012;Stumbrys, Erlacher, and Schredl 2013). Perhaps this is why we recognize the illusory nature of dream percepts during lucid dreams. ...
Book
This book puts forward a mechanistic account of subjective experience based on a review of the current cognitive neuroscience literature on conscious perception, attention, and metacognition. It is argued that current empirical studies are often misinterpreted. An undue focus has been placed on perceptual capacity rather than subjective experience per se. Null findings are often overemphasized despite the limited sensitivity of the methods used. A synthesis is proposed to combine the advantages and intuitions of both global and local theories of consciousness. This will be discussed in the context of our understanding of the sense of agency, emotion, rationality, culture, philosophical theories, and clinical applications. Taking insights from both physiology and current research in artificial intelligence, the resulting view directly addresses the qualitative nature of subjective experience.
... The main lucidity measure was a 19-item questionnaire relating to lucid experiences during the reported dream. This 19-item questionnaire was a composite of items from the Dream Lucidity Questionnaire (DLQ; (Stumbrys, Erlacher, & Schredl, 2013) and the Lucid Skills Questionnaire (LUSK; (Schredl, Rieger, & Göritz, 2018); between the two questionnaires there are 4 items that overlap, 9 questions unique to the DLQ and 6 questions unique to the LUSK. For all items, participants were asked to rate the extent to which they agreed with the statements, from 0 (not at all) to 4 (very much). ...
Article
Lucid dreaming is a unique phenomenon with potential applications for therapeutic interventions. Few studies have investigated the effects of lucidity on an individual’s waking mood, which could have valuable implications for improving psychological wellbeing. The current experiment aims to investigate whether the experience of lucidity enhances positive waking mood, and whether lucidity is associated with dream emotional content and subjective sleep quality. 20 participants were asked to complete lucid dream induction techniques along with an online dream diary for one week, which featured a 19-item lucidity questionnaire, and subjective ratings of sleep quality, dream emotional content, and waking mood. Results indicated that higher lucidity was associated with more positive dream content and elevated positive waking mood the next day, although there was no relationship with sleep quality. The results of the research and suggestions for future investigations, such as the need for longitudinal studies of lucidity and mood, are discussed.
... All recorded dream reports were transcribed, randomly permutated and scored by a blinded judge for lucidity on a 3-point scale (0 no evidence of a lucid dream, 1possible indications of a lucid dream, 2clear indication of a lucid dream), which was shown to have a good interrater agreement (r = 0.86; Stumbrys, Erlacher, & Schredl, 2013b). Furthermore, the judge also rated the dream reports about sensory sensation like smell, taste and touch. ...
Article
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The reliable induction of lucid dreams is a challenge in lucid dream research. In a previous study by our research group we were able to induce in about 50% of the participants a lucid dream in a single sleep laboratory night by combining a wake-up-back-to-bed sleep protocol and a mnemonic technique. In the present study, we extended our previous procedure by additional presentation of an odor during sleep to reactivate memory traces about reality testing. In total 16 male participants spent a single night in the sleep lab whereas the procedure induced in two participants a lucid dream (12.5%). The induction rate stays below the success rate of our previous study and therefore odor-cueing seems not a promising technique for inducing lucid dreams. Beside the odor presentation, several other methodological changes have been made, which will be discussed and hopefully help further dream engineering to improve induction techniques.
... All recorded dream reports were transcribed, randomly permutated and scored by a blinded judge for lucidity on a 3point scale (0 -no evidence of a lucid dream, 1 -possible indications of a lucid dream, 2 -clear indication of a lucid dream), which was shown to have a good interrater agreement (Stumbrys et al., 2013b). ...
Article
Full-text available
Lucid dreaming offers many opportunities to study consciousness processes. However, laboratory research in this area is limited because frequent lucid dreamers are rare. Several studies demonstrated that different methods of induction could increase the number of lucid dreams. In four field studies, a combination of a wake-up-back-to-bed (WBTB) sleep protocol and a mnemonic technique (MILD) showed promising results. To further investigate the effectiveness of this combined approach, we conducted a sleep laboratory experiment with four different conditions. The general experimental procedure was the following: Participants were awakened after 6 h of sleep from a subsequent REM period and kept awake for 30 or 60 min, during which they were asked to practice MILD or a control task (e.g., reading). Then they returned to bed for a morning sleep period. In the first condition eleven sport students, who attended a seminar on sleep and dreams, spent one night in a sleep laboratory. To avoid biases due to the seminar attendance (e.g., higher motivation), in the second condition 15 participants who did not attend the seminar were recruited. In the third condition, 14 sport students were tested with a shorter awakening period (30 min). Finally, the fourth condition served as a control condition, whereas eleven sport students slept two non-consecutive nights in a laboratory. Instead of MILD, in one night the participants read a book (fiction, unrelated to dreams), while in the other night they played a Nintendo Wii video game. In the first three conditions, six (54%), eight (53%), and five participants (36%) reported lucid dreams during the morning sleep period, whereas three, (27%), four (27%), and two participants (14%) produced PSG-verified eye signals. In contrast, in the reading condition, only one (9%) participant reported lucid dreams and no eye movements. No lucid dreams were observed in the Wii condition. The findings of the present study show that by using a combination of WBTB and MILD, lucid dreams can be effectively induced in people who are not selected for their lucid dream abilities.
... The Dream Lucidity Questionnaire (DLQ; Stumbrys et al., 2013). The DLQ measures different aspects of lucidity within dreams. ...
Article
Full-text available
Nightmares are intensely negative dreams that awaken the dreamer. Frequent nightmares are thought to reflect an executive deficit in regulating arousal. Within a diathesis-stress framework, this arousal is specific to negative contexts, though a differential susceptibility framework predicts elevated arousal in response to both negative and positive contexts. The current study tested these predictions by assessing subjective arousal and changes in frontal oxyhemoglobin (oxyHB) concentrations during negative and positive picture-viewing in nightmare sufferers (NM) and control subjects (CTL). 27 NM and 27 CTL subjects aged 18–35 rated subjective arousal on a 1–9 scale following sequences of negative, neutral and positive images; changes in oxyHB were measured by Near-Infrared Spectroscopy (NIRS) using a 2 × 4 template on the frontal pole. Participants also completed the Highly Sensitive Person Scale, a trait marker for differential susceptibility; and completed a dream diary reporting negative and positive dream emotionality. The NM group had higher trait sensitivity, yet higher ratings of negative but not positive emotion in diary dreams. NM compared to CTL subjects reported higher subjective arousal in response to picture-viewing regardless of valence. Dysphoric dream distress, measured prospectively, was negatively associated with frontal activation when viewing negative pictures. Results suggest NM sufferers are highly sensitive to images regardless of valence according to subjective measures, and that there is a neural basis to level of trait and prospective nightmare distress. Future longitudinal or intervention studies should further explore positive emotion sensitivity and imagery in NM sufferers.
... Some important insights into the neural correlates of the periods of dream lucidity have been provided by transcranial stimulation techniques. In particular, transcranial direct current stimulation (tDCS), which can modulate cortical excitability over PFC areas, has shown that (a) cathodal-frontal and anodal-parietal stimulation increases reports of visual dream imagery during stage 2 NREM [116]; (b) interhemispheric paired pulse transcranial magnetic stimulation (TMS) has shown a lower interhemispheric connectivity during REM sleep, which may account for such dream features as the lack of insight, time distortion, and amnesia [117]; and (c) the stimulation of PFC can induce dream lucidity during REM sleep in some subjects [118]. ...
Chapter
Dreaming is a subjective experience created during sleep and accessible for recollection after awakening. Experimental studies, developed after the discovery of rapid eye movement (REM) sleep, indicate that, contrary to popular opinion, dreaming occurs, albeit with some quantitative and qualitative differences, during all stages and cycles of sleep. By monitoring sleep stages using electropolygraphic techniques, a successful dream recall is obtained after about 80% of awakenings from REM sleep and about 50% after NREM sleep in healthy subjects. Investigation on patients with acute cortical lesions has shown that the cessation of dreaming is caused by damage to either posterior brain areas, mostly unilateral, located in or near the temporo-parieto-occipital (TPO) junction, or anterior brain areas, mostly bilateral, in the ventromedial prefrontal cortex (vmPFC). Neuroimaging studies have both confirmed these findings and disclosed the role played in dream generation by some subcortical structures, such as the hippocampus and the amygdala. Recent advances in electrophysiological [e.g., surface high-density electroencephalographic (hd-EEG) and intracranial recordings], transcranial stimulation and neuroimaging techniques are providing relevant insights into the neural correlates of dreaming in healthy individuals and patients with brain damage, neurodegenerative diseases, sleep disorders, or parasomnias. These approaches are shedding light on the neural bases of (a) inter- and intraindividual differences in dream recall, (b) temporal localization of specific dream properties (e.g., lucidity), (c) how episodic and semantic memories are processed and incorporated into dream content, and (d) some dreamlike experiences (such as daydreaming and mind wandering) that occur while awake. These findings, which complement those from neuropsychological studies on brain-damaged patients, point to an overlap between functional and structural cerebral substrates of waking and REM sleep mental imagery.
... All recorded dream reports were transcribed, randomly permutated and scored by a blinded judge for lucidity on a 3point scale (0 -no evidence of a lucid dream, 1 -possible indications of a lucid dream, 2 -clear indication of a lucid dream), which was shown to have a good interrater agreement (Stumbrys et al., 2013b). ...
... Based on the present data, it seems difficult to explain these differences. As mentioned earlier, future studies should include self-rating scales to measure lucidity (Kahan, 1994;Stumbrys, Erlacher, & Schredl, 2013b) in dreams elicited by dream diaries. ...
Article
Most studies looking into the relationship between lucid dream frequency and personality were based on questionnaire measures of lucid dream frequency. Thus, the aim was to investigate the effect of keeping a dream diary on lucid dream frequency and the correlates of the frequency of lucid dreams in the diary with the Big Five personality factors. The study included 1,612 dreams reported by 425 persons. The present findings showed that lucid dreams are quite rare (1.36%) in an unselected student sample. The frequency of lucid dream in the 2-week diary period was lower than the retrospectively estimated lucid dream frequency. Whereas the negative association between lucid dream frequency and agreeableness was reported previously, the negative correlation between lucid dream frequency and neuroticism is a new finding. Furthermore, the exploratory analysis showed that a considerable number of lucid dreams did not include some form of dream control. Furthermore, it would be very interesting to study the relationship between personality, especially neuroticism and agreeableness, and lucid dreaming in a more detailed way.
... Firstly, lucid dreaming was associated with fewer memory disturbances (Table 6). Memory plays an important role in becoming lucid in a dream: In non-lucid dreaming working memory is impaired due to a relative deactivation of the dorsolateral prefrontal cortex (DLPFC) and therefore the dreamer is not able to recognize that one is dreaming, while in lucid dreams the DLPFC gets reactivated allowing the insight into the current state of consciousness (Stumbrys et al., 2013b). Some techniques of lucid dreaming, such as Mnemonic Induction of Lucid Dreams (MILD) are based specifically on prospective memory training (LaBerge, 1980). ...
Article
Lucid dreams—dreams in which the dreamer is aware that they are dreaming—are generally positive and empowering experiences, for which a variety of benefits have been demonstrated, for example, alleviating nightmares and insomnia, improving motor skills, contributing to creativity and personal growth. Recently, however, certain concerns were raised about the possible risks of lucid dreaming on sleep and health. This study aimed to explore three potential domains of adverse effects—sleep quality, dissociation, and mental well-being—as well as to capture any self-observed negative consequences of lucid dreams within an online sample (N = 489) in which the majority of respondents (94%) were lucid dreamers. According to the results, lucid dream frequency was not associated with poorer sleep quality or with greater dissociation but was linked to greater mental well-being. Moreover, most of the lucid dreams were reported to be emotionally positive experiences and the majority of lucid dreamers did not ascribe any negative consequences to lucid dreaming. Thus, at least from the present findings, the experience of lucid dreaming does not seem to exert evident detrimental effects, although a small proportion of lucid dreams (about 10%) were negatively toned. However, to establish causal relationships future longitudinal studies are needed.
... De plus, une étude tentant de répliquer les résultats de (VOSS et al., 2014) avec exactement le même paradigme a échoué à montrer un effet significatif de la stimulation sur la lucidité (BLANCHETTE-CARRIÈRE et al., 2020). De surcroît, un autre type de stimulation transcorticale directe n'a lui produit qu'un effet limité sur la lucidité, et uniquement chez les rêveurs lucides fréquents (STUMBRYS et al., 2013). Enfin, DODET et al., 2015 ont mesuré l'activité de hautes fréquences dans les aires frontales chez 12 narcoleptiques, qui ont été capables de produire 30 épisodes de SP lucide (vérifiés par le code oculaire LRLR), soit un échantillon de données dix fois plus grand. ...
Thesis
Les expériences de notre nuit sont souvent décrites comme des îlots d'activité mentale, internement générées dans un océan d'inconscience. En sous-texte de cette vision se cachent deux pré-supposés que le sommeil lent est un modèle d'inconscience et que le traitement sensoriel du monde extérieur en sommeil paradoxal ne peut être qu'inconscient. Dans cette thèse, nous avons voulu tester ces pré-supposés avec une approche empruntant à trois littératures complémentaires : celle de la conscience, celle du sommeil sain et pathologique et celle de la philosophie de l'esprit. Dans une première étude nous avons mis en évidence l'existence de "blackout' de nuit : une absence total de rappel de contenu du couche au lever dans l'hypersomnie Idiopathique. Nous pensons que notre démonstration de l'existence du phénomène de blackout est intéressante car elle permet, par contraste, de mettre en évidence l'existence d'une expérience minimale de la nuit, comme les philosophes l'avaient suggéré. Dans deux autres études nous avons montré la capacité de patients narcoleptiques (lucides ou non) à traiter l'extérieur pendant des siestes en utilisant comme réponses les muscles de leurs visages. Cela suggère qu'un traitement conscient dans le sommeil peut avoir lieu en sommeil paradoxal chez ces patients. L'ensemble de ce travail de thèse invite à penser que l'idée selon laquelle on perd conscience pendant que l'on dort serait à réévaluer. En effet, une réelle perte de conscience dans le sommeil, si elle existe, pourrait être plutôt transitoire et négligeable face à la fabuleuse pluralité des processus qui se déroulent en son sein.
... Sleep laboratory studies indicated that specific brain areas are more activated in REM sleep with lucid dreaming compared to REM sleep without lucid dreams, e.g., the prefrontal cortex (Dresler et al., 2012;Voss et al., 2009). Experimental studies (Stumbrys et al., 2013b;Voss et al., 2014) support this notion as stimulation of the prefrontal areas by tDCS or tACS can increase lucidity. One study (Loo & Cheng, 2021) indicated that high performance in an attentional network task-the attentional network is partly located in the frontal areas (Ptak, 2011)-was positively related to lucid dreaming frequency. ...
Article
Previous research identified personality and neurophysiological traits that are associated with inter-individual differences in lucid dreaming frequency. The present study investigated the question as to whether sensory processing sensitivity is related to lucid dreaming. Overall, 1,807 persons (1,008 woman, 799 men) with a mean age of 47.75 ± 14.41 years completed the German High Sensitive Person Scale, a Big Five personality inventory, and the lucid dream frequency scale. As expected, Aesthetic Sensitivity and Low Sensory Threshold (two of the three sensory processing factors) were positively related to lucid dream frequency. Moreover, extraversion and low agreeableness were also related to lucid dreaming frequency. Although the effect sizes of these relationships are relatively small, this research can shed light on the mechanism underlying the inter-individual differences in lucid dream frequency.
... Despite this definition, dream lucidity is not a purely dichotomous state (i.e., either present or absent; Stumbrys et al., 2012). Dream lucidity involves multiple components, such as the degree of control over one's own actions and over the dream, awareness of the hallucinatory nature of the dream components (e.g., the dream characters, the dreamer's oneiric body), and access to episodic memories from waking life (for dream lucidity scales, see Stumbrys et al., 2013;Voss et al., 2013). ...
Article
This article presents the feeling priming theory (FPT) of dreaming. According to the FPT, dreaming favors the motivation to avoid aversive anticipated events and to approach gratifying anticipated events. It is suggested that one component of anticipated emotions—anticipated feelings—is reproduced in dreams. Upon awakening and during the day, these anticipated feelings would remain activated (primed) in memory. Consequently, anticipated emotions would exert a greater influence on avoidance and approach behaviors, mainly through an increase in the intensity of anticipatory feelings (i.e., feelings of fear or hope/desire). This article comprises five main sections. First, the need for a new theory of the function of dreaming is addressed. Second, key constructs of the theory are described, including the constructs of “emotion” and “feeling.” Third, a brief overview of the theory is presented. Fourth, seven hypotheses that constitute the core of the theory are discussed along with supporting evidence. Fifth, an explanation of nightmares based on the proposed theory is offered. The FPT represents an alternative to theories that attribute an emotion regulation function to dreaming. It offers a new perspective on the relationship between dreaming and waking emotions. In particular, the FPT does not label nightmares as dysfunctional. Instead, nightmares and other dysphoric dreams are hypothesized to result from the same processes as normal dreaming.
... Sleep laboratory research shows that lucid dreams predominantly occur during the rapid eye movement (REM) stage of sleep and can be verified on the sleep recording by volitional eye movements (LaBerge et al., 1986), though they could also arise during non-REM stage 1 and non-REM stage 2 of sleep (Mota-Rolim et al., 2015;Stumbrys & Erlacher, 2012). Lucidity in dreams is associated with the reactivation of the prefrontal brain areas (Stumbrys et al., 2013b), which are relatively dormant during non-lucid REM dreaming, and this reactivation empowers insight and metacognition in the dream state. Although frequent lucid dreaming is a rare ability, a fairly recent meta-analysis indicates that about 55% of individuals have experienced it at least once in their lifetime and about 23% have lucid dreams on a regular basis-once a month or more frequently (Saunders et al., 2016). ...
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Lucid dreams, in which the dreamers are aware that they are dreaming, can be a source of spiritual and mystical experiences. This empirical study aimed to explore the relationship between lucid dreaming and spirituality, taking into account the role of mystical lucid dream experience, in an online sample of 471 respondents, 95% of whom had lucid dream experience and 65% were frequent lucid dreamers. The findings support the relationship between lucid dreaming and spirituality: spiritual transcendence was positively associated with both lucid dream frequency and mystical lucid dream experiences. Thus having recurrent lucid dreams and mystical experiences in them may foster spiritual growth, rendering lucid dreaming possibly a viable spiritual practice, especially within the secular context. However, the correlative nature of the present research does not imply causality and further longitudinal research confirming this is needed.
... Hypnosis assists with pain relief via two brain areas that also play a role in lucid dreaming: the prefrontal cortex and the precuneus (Dillworth, Mendoza, & Jensen, 2011;Dresler et al., 2012;Goffaux et al., 2014;Stumbrys, Erlacher & Schredl, 2013). These neurological overlaps give credence to the idea that lucid dreaming might be able to assist with pain relief through similar mechanisms. ...
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Researchers have explored various applications of lucid dreaming, but the application of healing has received little attention (Stumbrys & Erlacher, 2016). Chronic pain is a widespread health issue (Wilkerson, Kim, Windsor, & Mareiniss, 2016) and one case study purports substantial chronic pain relief from a single lucid dream (Zappaterra, Jim, & Pangarkar, 2014). The purpose of this study was to investigate the self-reported influence of lucid dreaming on chronic pain, as well as learn more about the individuals who claim to have had such an experience by examining the relationship of certain personality characteristics. A mixed-method approach was utilized in a retrospective manner. Recruitment consisted of individuals who have experienced the phenomenon of relieving or attempting to relieve chronic pain through lucid dreaming. Participants (N = 10) filled out the Tellegen Absorption Scale (TAS) and Plymouth Sensory Imagery Questionnaire (Psi-Q) using an online survey. Additionally, each participant completed a semi-structured interview to gather qualitative data about their subjective experience, as well as measure pain, expectation, and dream vividness using a Numeric Rating Scale-11 (NRS-11). A Wilcoxon signed rank test found a significant reduction in pain when comparing scores before the lucid dream experience (Mdn = 6.63) to after the lucid dream experience (Mdn = 1.25) (T = 45, z = -2.67, p = .004). Spearman's rho was used to test the relationship of the pain differential (i.e., pain before - pain after) and several variables: trait absorption, expectation, dream vividness, and mental imagery ability. None of these variables had a statistically significant relationship with the pain differential. Interviews were transcribed verbatim and coded using thematic analysis (Braun & Clarke, 2006). Five themes emerged: beliefs, expectations, demographics prior to experience, characteristics of the lucid dream, and positive outcomes. This study demonstrated evidence in support of using lucid dreams for chronic pain relief. Lucid dreaming abilities, such as remembering intentions and dream control, were found to be an integral component of many participants’ experiences. Future research should also look at the variable of expectation, as well as intention, positive affect, and insight.
... They know that their subjective experiences are detached from reality. Lucid dreaming has been associated with heightened activity in the prefrontal cortex (Dresler et al. 2012;Stumbrys, Erlacher, and Schredl 2013). Perhaps this is why we recognize the illusory nature of dream percepts during lucid dreams. ...
Chapter
In the chapter we address the remaining issues of consciousness in animals and robots. A good way to address this may be to first figure out what in principle accounts for consciousness in the human cases. From there, we can see if similar mechanisms exist or not in the animals or robots. To make this inductive generalization, we need a theory of consciousness. We introduce the perceptual reality monitoring theory, according to which some animals may not be conscious. And yet, perhaps even a robot or computer program could be. This is to say, it is a functionalist account, based on an empirical interpretation of a variant of higher-order theory of consciousness. To evaluate the theory, we should compare it against other existing theories in terms of plausibility.
... Altered neural activation during sleep correlates with reports of altered experience. For example, the lack of volition and rational control and bizarreness detection is correlated with a reduction in the activation of the dorsolateral prefrontal cortex (Dresler et al. 2014;Kubota et al. 2011;Stumbrys, Erlacher, and Schredl 2013). ...
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Chapter
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Chapter
The body-mind interaction has fascinated scientists for a long time, that is, are the subjective experiences (here: dreaming) related to physiology like brain activity or autonomic activity? If we experience severe fear within a nightmare, is the heart rate increasing? Although, the number of studies in this field is still small, empirical evidence is in favor of an interaction between the body and the mind during sleep.
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Recently, cortical correlates of specific dream contents have been reported, such as the activation of the sensorimotor cortex during dreamed hand clenching. Yet, the causal mechanisms underlying specific dream content remain largely elusive. Here, we investigated how alterations in the excitability of sensorimotor areas through transcranial direct current stimulation (tDCS) might alter dream content. Following bihemispheric tDCS or sham stimulation, participants who were awakened from REM sleep filled out a questionnaire on bodily sensations in dreams. tDCS, compared to sham stimulation, significantly decreased reports of dream movement, especially repetitive actions. Contrary to this, other types of bodily experiences, such as tactile or vestibular sensations, were not affected by tDCS, confirming the specificity of stimulation effects. In addition, tDCS reduced interhemispheric coherence in parietal areas and altered the phasic electromyography correlation between the two arms. These findings reveal that a complex reorganization of the motor network co-occurred with the reduction of dream movement, confirming spatial specificity of the stimulation site. We conclude that tDCS over the sensorimotor cortex causally interferes with dream movement during REM sleep.
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Lucid dreaming occurs when one recognizes that one is dreaming during ongoing sleep. This unique state is an emerging area of scientific research and a promising method for the study of dreaming. Lucid dreams can be objectively verified on a polysomnogram through volitional eye movements. Lucid dreams occur during REM sleep and are associated with increased brain activation. It is unknown whether the state is associated with activation of specific brain regions or rhythms. Lucid dreaming offers a method to research dreamed behaviors and content. Preliminary data suggest it may also be useful in clinical applications, particularly for nightmares.
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The commonsense view is that a lucid dream starts when the dreamer realizes that they are currently dreaming. The notion of realization, however, has been accepted at face value, with little consideration of whether the dreamer realizes that they are dreaming in the sense of actual reasoning, or if it is a mere epiphenomenon of lucid dream initiation. This article offers a solution to this problem by, first, arguing that the transition to lucidity can occur as a result of successful reasoning, and second, building a model of this reasoning in terms of probabilistic reasoning. The established Bayesian model explains realization in lucid dreams taking under consideration two factors: the beliefs that the dreamer holds on what is generally probable and improbable, and the dreamer’s admissibility of being in a dream. Defended against important objections, the model offers an explanation of lucid dream initiation, relevant for future research on dreaming.
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In questa rassegna critica si discute del sogno lucido, cioè dei periodi di sogno in cui si è consapevoli di sognare. Durante un sogno lucido le esperienze vengono correttamente riconosciute dal sognatore come di tipo onirico. Ciò avviene grazie all’attivazione di autocoscienza, accompagnata da un ricordo più accurato di alcuni eventi o informazioni della propria vita in condizioni di veglia, e dalla capacità di guidare le proprie azioni nel sogno in modo intenzionale. Dopo alcuni cenni storici sul sogno lucido, sono discussi i principali risultati ottenuti dalla recente ricerca psicologica e neurobiologica su questo fenomeno, i metodi d’induzione di lucidità, le applicazioni e i modelli scientifici, esaminando infine le principali questioni ancora aperte del sogno lucido e rilevanti per l’elaborazione di un suo modello unitario.
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During dreaming, we experience a wake-like hallucinatory reality, however with restricted reflective abilities: in the face of a bizarre dream environment, we do not realize that we are actually dreaming. In contrast, during the rare phenomenon of lucid dreaming, the dreamer gains insight into the current state of mind while staying asleep. This metacognitive insight often enables the dreamer to control own dream actions and the course of the dream narrative. Lucid dreaming allows for radically new methodological and theoretical approaches and has led to new insights in diverse scientific disciplines beyond classical sleep and dream research, including neuroscience, psychotherapy, philosophy, art, and sports sciences. Here, we review past research and the current knowledge on lucid dreaming. We present insights into the scientific work in a sleep laboratory and describe how lucid dreams can be induced through methodologies from diverse academic backgrounds including psychology, electrical engineering and pharmacology.
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The neural mechanisms underlying lucid dreaming have recently been investigated using brain imaging techniques such as electroencephalography and functional magnetic resonance imaging, which produce insightful but merely correlative results. We propose that research on the neurophysiology of lucid dreaming, for instance concerning the exact relationship between the dorsolateral prefrontal cortex and metacognitive insight into the fact that one is dreaming, should be complemented by methods allowing direct causal interference with neural functioning during sleep. To achieve this aim, several stimulation methods are proposed, i.e. transcranial magnetic stimulation, transcranial direct current stimulation, and galvanic vestibular stimulation. Given the broad range of cognitive and metacognitive processing in dreams, which support a continuous view of lucid and nonlucid dreaming, we further propose that certain aspects of dream lucidity and its neural mechanisms can be investigated in so-called ordinary, nonlucid dreams. This would allow for phenomenologically more comprehensive and practically more efficient experiments in this field of dream research. Such experiments would also provide a solid ground for understanding self-consciousness in lucid and non-lucid dreams, as well as for integrating dream research into more general neurophilosophical theories of consciousness and the self.
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purpose. Transcranial direct current stimulation (tDCS) has been shown to modify the perception threshold of phosphenes elicited by transcranial magnetic stimulation (TMS). The current study was undertaken to examine whether tDCS, when applied over the occipital cortex, is also able to affect visual-evoked potentials (VEPs), which characterize occipital activation in response to visual stimulation, in a polarity-specific way. method. For this purpose, VEPs evoked by sinusoidal luminance grating in an on/off mode were recorded before, immediately after, and 10, 20, and 30 minutes after the end of 5, 10, or 15 minutes of anodal or cathodal tDCS of the primary visual cortex. results. Significant effects were observed only when low-contrast visual stimuli were applied. Cathodal stimulation decreased, whereas anodal stimulation increased the amplitude of the N70 component. The effect of cathodal stimulation was significant immediately after and 10 minutes after the end of stimulation, if the stimulation duration was sufficiently long (i.e., 10–15 minutes). An increase of N70 amplitude by anodal stimulation was significant only 10 minutes after the end of the 15 minutes tDCS. Cathodal stimulation tended also to affect the amplitude of the P100 component; however, the effect of stimulation was inverse. The amplitude increased immediately after the end of cathodal stimulation. In contrast, anodal stimulation did not affect the P100. The latencies of the N70 and the P100 were not affected by tDCS. conclusions. tDCS appears to be a suitable method of inducing reversible excitability changes in a polarity-specific way, not only in the motor but also in the primary visual cortex. The duration of the induced aftereffects depends not only on stimulation duration but also on stimulation polarity. Cathodal stimulation seems to be more effective, in line with previous reports on the motor cortex.
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In lucid dreams the dreamer is aware that he or she is dreaming. Although such dreams are not that uncommon, many aspects of lucid dream phenomenology are still unclear. An online survey was conducted to gather data about lucid dream origination, duration, active or passive participation in the dream, planned actions for lucid dreams, and other phenomenological aspects. Among the 684 respondents who filled out the questionnaire, there were 571 lucid dreamers (83.5%). According to their reports, lucid dreams most often originate spontaneously in adolescence. The average lucid dream duration is about 14 minutes. Lucid dreamers are likely to be active in their lucid dreams and plan to accomplish different actions (e.g., flying, talking with dream characters, or having sex), yet they are not always able to remember or successfully execute their intentions (most often because of awakening or hindrances in the dream environment). The frequency of lucid dream experience was the strongest predictor of lucid dream phenomenology, but some differences were also observed in relation to age, gender, or whether the person is a natural or self-trained lucid dreamer. The findings are discussed in light of lucid dream research, and suggestions for future studies are provided.
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Lucid dreams – dreams in which the dreamer is aware that is dreaming – most frequently occur during REM sleep, yet there is some evidence suggesting that lucid dreaming can occur during NREM sleep as well. By conduct- ing a sleep laboratory study on lucid dreams, we found two possible instances of lucidity during NREM sleep which are reported here. While lucid dreaming during NREM sleep seems to be much rarer and more difficult to achieve, it appears to be possible and is most likely to occur during N1 sleep, somewhat less likely during N2 sleep and yet to be observed during N3 sleep. Future studies should explore induction methods, underlying neural mechanisms and perceptual/dream content differences between REM and NREM lucid dreams. Furthermore, a consensus agreement is needed to define what is meant by lucid dreaming and create a vocabulary that is helpful in clarifying variable psychophysiological states that can support self-reflective awareness.
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The occurrence of lucid dreaming (dreaming while being conscious that one is dreaming) has been verified for 5 selected subjects who signaled that they knew they were dreaming while continuing to dream during unequivocal REM sleep. The signals consisted of particular dream actions having observable concomitants and were performed in accordance with pre-sleep agreement. The ability of proficient lucid dreamers to signal in this manner makes possible a new approach to dream research--such subjects, while lucid, could carry out diverse dream experiments marking the exact time of particular dream events, allowing derivation of of precise psychophysiological correlations and methodical testing of hypotheses.
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Reports of lucid dreaming (i.e., dreaming while being conscious that one is dreaming) were verified for 13 Ss (aged 21–51 yrs) who signaled by means of voluntary eye-movements that they knew they were dreaming while continuing to dream during REM sleep. Physiological analysis of the resulting 76 signal-verified lucid dreams (SVLDs) revealed that elevated levels of automatic nervous system activity reliably occurred both during and 30 sec preceding the onset of SVLDs, implicating physiological activation as a necessary condition for reflective consciousness during REM dreaming. It is concluded that the ability of proficient lucid dreamers to deliberately perform dream actions in accordance with presleep agreement makes possible determination of psychophysiological correspondence during REM dreaming. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Examined the lucid dreams of 50 Ss as to whether they are also fully lucid for the following corollaries: people in the dreams are dream characters, dream objects are not real, (i.e., actions will not carry over concretely upon awakening), the dreamer does not need to obey waking-life physics to achieve a goal, and memory of the waking world is intact rather than amnestic or fictitious. Many lucid dreams were too brief to evaluate on all corollaries. Only about half of the lengthier accounts were lucid for any particular corollary and less than a quarter were lucid on all 4. A related and reciprocal category of dreams that are lucid in terms of some of these 4 corollaries but miss the realization that "I'm dreaming" were also examined. The correlations among the corollaries, between correlations and length of lucid dreams, and between awareness and degree of experience with lucidity imply that they are on a cohesive continuum. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Studied the association between lucidity and flying dreams in 1,910 dreams from 191 Ss. Flying dreams were likelier to be reported by Ss reporting lucid dreams or any of 3 related categories: prelucid dreams, dreams of sleep, or false awakenings. When flying and lucidity occurred in the same dream, lucidity preceded flight rather than being triggered by it. Possible bases for this relationship of lucid and flying dreams are discussed in terms of their psychological and physiological commonalities. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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To investigate the neural correlates of lucid dreaming. Parallel EEG/fMRI recordings of night sleep. Sleep laboratory and fMRI facilities. Four experienced lucid dreamers. N/A. Out of 4 participants, one subject had 2 episodes of verified lucid REM sleep of sufficient length to be analyzed by fMRI. During lucid dreaming the bilateral precuneus, cuneus, parietal lobules, and prefrontal and occipito-temporal cortices activated strongly as compared with non-lucid REM sleep. In line with recent EEG data, lucid dreaming was associated with a reactivation of areas which are normally deactivated during REM sleep. This pattern of activity can explain the recovery of reflective cognitive capabilities that are the hallmark of lucid dreaming.
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The neural mechanisms underlying lucid dreaming have recently been investigated using brain imaging techniques such as electroencephalography and functional magnetic resonance imaging, which produce insightful but merely correlative results. We propose that research on the neurophysiology of lucid dreaming, for instance concerning the exact relationship between the dorsolateral prefrontal cortex and metacognitive insight into the fact that one is dreaming, should be complemented by methods allowing direct causal interference with neural functioning during sleep. To achieve this aim, several stimulation methods are proposed, i.e. transcranial magnetic stimulation, transcranial direct current stimulation, and galvanic vestibular stimulation. Given the broad range of cognitive and metacognitive processing in dreams, which support a continuous view of lucid and nonlucid dreaming, we further propose that certain aspects of dream lucidity and its neural mechanisms can be investigated in so-called ordinary, nonlucid dreams. This would allow for phenomenologically more comprehensive and practically more efficient experiments in this field of dream research. Such experiments would also provide a solid ground for understanding self-consciousness in lucid and non-lucid dreams, as well as for integrating dream research into more general neurophilosophical theories of consciousness and the self.
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Effects of weak electrical currents on brain and neuronal function were first described decades ago. Recently, DC polarization of the brain was reintroduced as a noninvasive technique to alter cortical activity in humans. Beyond this, transcranial direct current stimulation (tDCS) of different cortical areas has been shown, in various studies, to result in modifications of perceptual, cognitive, and behavioral functions. Moreover, preliminary data suggest that it can induce beneficial effects in brain disorders. Brain stimulation with weak direct currents is a promising tool in human neuroscience and neurobehavioral research. To facilitate and standardize future tDCS studies, we offer this overview of the state of the art for tDCS.
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The goal of the study was to seek physiological correlates of lucid dreaming. Lucid dreaming is a dissociated state with aspects of waking and dreaming combined in a way so as to suggest a specific alteration in brain physiology for which we now present preliminary but intriguing evidence. We show that the unusual combination of hallucinatory dream activity and wake-like reflective awareness and agentive control experienced in lucid dreams is paralleled by significant changes in electrophysiology. 19-channel EEG was recorded on up to 5 nights for each participant. Lucid episodes occurred as a result of pre-sleep autosuggestion. Sleep laboratory of the Neurological Clinic, Frankfurt University. Six student volunteers who had been trained to become lucid and to signal lucidity through a pattern of horizontal eye movements. Results show lucid dreaming to have REM-like power in frequency bands delta and theta, and higher-than-REM activity in the gamma band, the between-states-difference peaking around 40 Hz. Power in the 40 Hz band is strongest in the frontal and frontolateral region. Overall coherence levels are similar in waking and lucid dreaming and significantly higher than in REM sleep, throughout the entire frequency spectrum analyzed. Regarding specific frequency bands, waking is characterized by high coherence in alpha, and lucid dreaming by increased delta and theta band coherence. In lucid dreaming, coherence is largest in frontolateral and frontal areas. Our data show that lucid dreaming constitutes a hybrid state of consciousness with definable and measurable differences from waking and from REM sleep, particularly in frontal areas.
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Recent neuroimaging studies have indicated a predominant role of the anterior prefrontal cortex (aPFC) in deception and moral cognition, yet the functional contribution of the aPFC to deceptive behavior remains unknown. We hypothesized that modulating the excitability of the aPFC by transcranial direct current stimulation (tDCS) could reveal its functional contribution in generating deceitful responses. Forty-four healthy volunteers participated in a thief role-play in which they were supposed to steal money and then to attend an interrogation with the Guilty Knowledge Test. During the interrogation, participants received cathodal, anodal, or sham tDCS. Remarkably, inhibition of the aPFC by cathodal tDCS did not lead to an impairment of deceptive behavior but rather to a significant improvement. This effect manifested in faster reaction times in telling lies, but not in telling the truth, a decrease in sympathetic skin-conductance response and feelings of guilt while deceiving the interrogator and a significantly higher lying quotient reflecting skillful lying. Increasing the excitability of the aPFC by anodal tDCS did not affect deceptive behavior, confirming the specificity of the stimulation polarity. These findings give causal support to recent correlative data obtained by functional magnetic resonance imaging studies indicating a pivotal role of the aPFC in deception.
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In this paper we demonstrate in the intact human the possibility of a non-invasive modulation of motor cortex excitability by the application of weak direct current through the scalp. Excitability changes of up to 40 %, revealed by transcranial magnetic stimulation, were accomplished and lasted for several minutes after the end of current stimulation. Excitation could be achieved selectively by anodal stimulation, and inhibition by cathodal stimulation. By varying the current intensity and duration, the strength and duration of the after-effects could be controlled. The effects were probably induced by modification of membrane polarisation. Functional alterations related to post-tetanic potentiation, short-term potentiation and processes similar to postexcitatory central inhibition are the likely candidates for the excitability changes after the end of stimulation. Transcranial electrical stimulation using weak current may thus be a promising tool to modulate cerebral excitability in a non-invasive, painless, reversible, selective and focal way.
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Content analysis is an important and a frequently applied tool in dream research. Hall and Van de Castle (1) stressed the importance of interrater reliability in the application of content analytic scales, i.e., how good is the agreement between two judges scoring the same dream material independently? The present study investigated the effect of rater training on the interrater reliability of scales developed by Schredl (2). Three samples of 100 dream reports each have been analyzed by two inexperienced judges who received two training sessions after coding 100 and 200 dreams. The results indicate that tie training of raters has a positive effect on interrater reliability and the mean differences of some scales (nominal and interval scales) but not for ordinal scales (e.g., dream emotions). It remains unclear how much training is necessary for different scales and whether it might be necessary to improve the scales themselves if extensive training does not result in a desired improvement in interrater reliability. Thus, more studies investigating rater training for different systems of dream content analysis are needed. (PsycINFO Database Record (c) 2012 APA, all rights reserved)