Alike but not the same: Psychological profiles of COVID-19 vaccine skeptics.

One of the challenges of the SARS-CoV-2 pandemic was a widespread skepticism about vaccination. To elucidate the underlying mental and emotional predispositions, we examined a sample of 1428 participants using latent profile analysis (LPA) on selected personality trait variables, mental health status, and measures of irrational beliefs. LPA revealed five distinct profiles: two classes of non-skeptics and three of skeptics. The smaller non-skeptic class reported the highest rates of mental health problems, along with high levels of neuroticism, hostility, interpersonal sensitivity, and external locus of control. The larger non-skeptic class was psychologically well-balanced. Conversely, the skeptic groups shared strong distrust of COVID-19 vaccination but differed in emotional and mental profiles, leading to graded differences in endorsing extreme conspiracy beliefs. This suggests that vaccine skepticism is not solely a result of mental illness or emotional instability; rather extreme skepticism manifests as a nuanced, graded phenomenon contingent on personality traits and conspirational beliefs.

Dreaming during a pandemic: Low incorporation of COVID-19-specific themes and lucidity in dreams of psychiatric patients and healthy controls

The present study examined the impact of the COVID-19 pandemic on the emotional quality of dreams, the incorporation of pandemic-related themes, and the occurrence of lucid dreaming. Dream reports and lucidity ratings of psychiatric outpatients (n = 30) and healthy controls (n = 81) during two lockdowns in Germany were compared to those of healthy controls (n = 33) before the pandemic. Results confirmed previous reports that pandemic-specific themes were incorporated into dreams. Overall, however, incorporation into dreams was rare. Contrary to expectations, psychiatric outpatients did not differ from controls in the frequency of dream incorporation of pandemic-related content. Moreover, incorporation was independent of psychiatric symptoms and loneliness. Loneliness was, however, associated with threat-related content, suggesting that it represents a risk for bad dreams but not for crisis-specific dream incorporation. Regarding lucid dreaming, both groups had similar scores for its underlying core dimensions, i.e., insight, control, and dissociation, during the two lockdowns. Scores for control and dissociation but not insight were lower compared to the pre-pandemic sample. Our working hypothesis is that REM sleep during lockdowns intensified as a means of increased emotional consolidation, rendering the associated mental state less hybrid and thereby less lucid. (AU)

Dreaming during a pandemic: Low incorporation of COVID-19-specific themes and lucidity in dreams of psychiatric patients and healthy controls.

The present study examined the impact of the COVID-19 pandemic on the emotional quality of dreams, the incorporation of pandemic-related themes, and the occurrence of lucid dreaming. Dream reports and lucidity ratings of psychiatric outpatients (n = 30) and healthy controls (n = 81) during two lockdowns in Germany were compared to those of healthy controls (n = 33) before the pandemic. Results confirmed previous reports that pandemic-specific themes were incorporated into dreams. Overall, however, incorporation into dreams was rare. Contrary to expectations, psychiatric outpatients did not differ from controls in the frequency of dream incorporation of pandemic-related content. Moreover, incorporation was independent of psychiatric symptoms and loneliness. Loneliness was, however, associated with threat-related content, suggesting that it represents a risk for bad dreams but not for crisis-specific dream incorporation. Regarding lucid dreaming, both groups had similar scores for its underlying core dimensions, i.e., insight, control, and dissociation, during the two lockdowns. Scores for control and dissociation but not insight were lower compared to the pre-pandemic sample. Our working hypothesis is that REM sleep during lockdowns intensified as a means of increased emotional consolidation, rendering the associated mental state less hybrid and thereby less lucid.

Adapting to a major crisis: Sleep and mental health during two lockdowns.

The present study aimed at investigating the impact of the pandemic on sleep and mental health in healthy individuals (n = 78) as well as in psychiatric outpatients (n = 30) during the first and the second lockdown in Germany, in March and November 2020, respectively. Sleep quality and anxiety were worse in patients compared with controls during both lockdowns. Further, patients but not controls exhibited higher levels of depression and overall psychiatric symptomatology during the second lockdown. No differences were found in the perceived threat evoked by the pandemic. The data suggest that healthy individuals adapt flexibly to the difficult situation over the time course of the pandemic, whereas psychiatric patients seem to get worse, indicating difficulties in adapting to stressful circumstances.

Investigating Nuisance Effects Induced in EEG During tACS Application.

Transcranial alternating-current stimulation (tACS) in the frequency range of 1-100 Hz has come to be used routinely in electroencephalogram (EEG) studies of brain function through entrainment of neuronal oscillations. It turned out, however, to be highly non-trivial to remove the strong stimulation signal, including its harmonic and non-harmonic distortions, as well as various induced higher-order artifacts from the EEG data recorded during the stimulation. In this paper, we discuss some of the problems encountered and present methodological approaches aimed at overcoming them. To illustrate the mechanisms of artifact induction and the proposed removal strategies, we use data obtained with the help of a schematic demonstrator setup as well as human-subject data.

Sleep spindles and K-complex activities are decreased in spinocerebellar ataxia type 2: relationship to memory and motor performances.

BACKGROUND: Sleep spindles and K-complexes are electroencephalographic hallmarks of non-rapid eye movement (non-REM) sleep that provide valuable information into brain functioning, plasticity and sleep functions in normal and pathological conditions. However, they have not been systematically investigated in spinocerebellar ataxias (SCA). To close this gap, the current study was carried out to quantify sleep spindles and K-complexes in SCA2 and to assess their relationship with clinical and molecular measures, as well as with memory and attention/executive functioning. METHODS: In this study, 20 SCA2 patients, 20 preclinical carriers and 20 healthy controls underwent whole-night polysomnographic (PSG) recordings as well as sleep interviews, ataxia scoring and neuropsychological assessments. Sleep spindles and K-complexes were automatically detected during non-REM sleep stage 2 (N2). Their densities were evaluated as events/minute. RESULTS: Compared to controls, sleep spindle density was significantly reduced in SCA2 patients and preclinical subjects. By contrast, K-complex density was specifically and significantly decreased only in SCA2 patients. Reduced spindle activity correlated with measures of verbal memory, whereas reduced K-complex activity correlated with age, ataxia severity and N3 sleep percentage in SCA2 patients. CONCLUSIONS: Findings document an impairment of N2 sleep microstructure in SCA2 already in prodromal stages, suggesting an early involvement of thalamo-cortical and/or cortical circuits underlying the generation of sleep spindles and K-complexes. Thus, sleep spindle density may serve as useful biomarker for deficits of neural plasticity mechanisms underlying verbal memory alterations in patients. It may also serve as promising outcome measure in further therapeutical trials targeting memory decline in SCA2. With regard to K-complexes, they have potential usefulness as marker of sleep protection.

Insight and Dissociation in Lucid Dreaming and Psychosis.

Dreams and psychosis share several important features regarding symptoms and underlying neurobiology, which is helpful in constructing a testable model of, for example, schizophrenia and delirium. The purpose of the present communication is to discuss two major concepts in dreaming and psychosis that have received much attention in the recent literature: insight and dissociation. Both phenomena are considered functions of higher order consciousness because they involve metacognition in the form of reflective thought and attempted control of negative emotional impact. Insight in dreams is a core criterion for lucid dreams. Lucid dreams are usually accompanied by attempts to control the dream plot and dissociative elements akin to depersonalization and derealization. These concepts are also relevant in psychotic illness. Whereas insightfulness can be considered innocuous in lucid dreaming and even advantageous in psychosis, the concept of dissociation is still unresolved. The present review compares correlates and functions of insight and dissociation in lucid dreaming and psychosis. This is helpful in understanding the two concepts with regard to psychological function as well as neurophysiology.

A template model of embodiment while dreaming: Proposal of a mini-me.

Dreams are usually centered around a dream self capable of tasks generally impossible in waking, e.g. flying or walking through walls. Moreover, the bodily dream self appears relatively stable and insensitive to changes of the embodied wake self, raising the question of whether and to what extent the dream self is embodied. To further explore its determinants, we tested whether the dream self would be affected by either pre-sleep focused attention to a body part or by its experimental alteration during the day. Choosing a repeated-measures design, we analyzed how often key words reflecting the experimental manipulations appeared in the dream reports. Results suggest that the dream self is not affected by these manipulations, strengthening the hypothesis that, in the majority of dreams, the dream self is only weakly embodied, utilizing a standard template of embodiment akin to a prototype of self operating independently from the physical waking self.

Induction of self awareness in dreams through frontal low current stimulation of gamma activity.

Recent findings link fronto-temporal gamma electroencephalographic (EEG) activity to conscious awareness in dreams, but a causal relationship has not yet been established. We found that current stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Other stimulation frequencies were not effective, suggesting that higher order consciousness is indeed related to synchronous oscillations around 25 and 40 Hz.

A differentiating empirical linguistic analysis of dreamer activity in reports of EEG-controlled REM-dreams and hypnagogic hallucinations.

We present Activity Analysis as a new method for the quantification of subjective reports of altered states of consciousness with regard to the indicated level of simulated motor activity. Empirical linguistic activity analysis was conducted with dream reports conceived immediately after EEG-controlled periods of hypnagogic hallucinations and REM-sleep in the sleep laboratory. Reports of REM-dreams exhibited a significantly higher level of simulated physical dreamer activity, while hypnagogic hallucinations appear to be experienced mostly from the point of passive observer. This study lays the groundwork for clinical research on the level of simulated activity in pathologically altered states of subjective experience, for example in the REM-dreams of clinically depressed patients, or in intrusions and dreams of patients diagnosed with PTSD.

Measuring consciousness in dreams: the lucidity and consciousness in dreams scale.

In this article, we present results from an interdisciplinary research project aimed at assessing consciousness in dreams. For this purpose, we compared lucid dreams with normal non-lucid dreams from REM sleep. Both lucid and non-lucid dreams are an important contrast condition for theories of waking consciousness, giving valuable insights into the structure of conscious experience and its neural correlates during sleep. However, the precise differences between lucid and non-lucid dreams remain poorly understood. The construction of the Lucidity and Consciousness in Dreams scale (LuCiD) was based on theoretical considerations and empirical observations. Exploratory factor analysis of the data from the first survey identified eight factors that were validated in a second survey using confirmatory factor analysis: INSIGHT, CONTROL, THOUGHT, REALISM, MEMORY, DISSOCIATION, NEGATIVE EMOTION, and POSITIVE EMOTION. While all factors are involved in dream consciousness, realism and negative emotion do not differentiate between lucid and non-lucid dreams, suggesting that lucid insight is separable from both bizarreness in dreams and a change in the subjectively experienced realism of the dream.

Lucid dreaming: an age-dependent brain dissociation.

The current study focused on the distribution of lucid dreams in school children and young adults. The survey was conducted on a large sample of students aged 6-19 years. Questions distinguished between past and current experience with lucid dreams. Results suggest that lucid dreaming is quite pronounced in young children, its incidence rate drops at about age 16 years. Increased lucidity was found in those attending higher level compared with lower level schools. Taking methodological issues into account, we feel confident to propose a link between the natural occurrence of lucid dreaming and brain maturation.

Sleep disorders in spinocerebellar ataxia type 2 patients.

BACKGROUND: Sleep disturbances are common features in spinocerebellar ataxias (SCAs). Nevertheless, sleep data on SCA2 come from scarce studies including few patients, limiting the evaluation of the prevalence and determinants of sleep disorders. OBJECTIVE: To assess the frequency and possible determinants of sleep disorders in the large and homogeneous SCA2 Cuban population. METHODS: Thirty-two SCA2 patients and their age- and sex-matched controls were studied by video-polysomnography and sleep interviews. RESULTS: The most striking video-polysomnography features were rapid eye movement (REM) sleep pathology and periodic leg movements (PLMs). REM sleep abnormalities included a consistent reduction of the REM sleep percentage and REM density as well as an increase in REM sleep without atonia (RWA). REM sleep and REM density decreases were closely related to the increase in ataxia scores, whereas the RWA percentage was influenced by the cytosine-adenine-guanine (CAG) repeats. PLMs were observed in 37.5% of cases. The PLM index showed a significant association with the ataxia score and disease duration but not with CAG repeats. CONCLUSIONS: REM sleep pathology and PLMs are closely related to SCA2 severity, suggesting their usefulness as disease progression markers. The RWA percentage is influenced by the CAG repeats and might thus be a sensitive parameter for reflecting polyglutamine toxicity. Finally, as PLMs are sensible to drug treatment, they represents a new therapeutic target for the symptomatic treatment of SCA2.

Sleep disorders in spinocerebellar ataxia type 2 patients

Background: Sleep disturbances are common features in spinocerebellar ataxias (SCAs). Nevertheless, sleep data on SCA2 come from scarce studies including few patients, limiting the evaluation of the prevalence and determinants of sleep disorders. Objective: To assess the frequency and possible determinants of sleep disorders in the large and homogeneous SCA2 Cuban population. Methods: Thirty-two SCA2 patients and their age- and sex-matched controls were studied by video-polysomnography and sleep interviews. Results: The most striking video-polysomnography features were rapid eye movement (REM) sleep pathology and periodic leg movements (PLMs). REM sleep abnormalities included a consistent reduction of the REM sleep percentage and REM density as well as an increase in REM sleep without atonia (RWA). REM sleep and REM density decreases were closely related to the increase in ataxia scores, whereas the RWA percentage was influenced by the cytosine-adenine-guanine (CAG) repeats. PLMs were observed in 37.5% of cases. The PLM index showed a significant association with the ataxia score and disease duration but not with CAG repeats. Conclusions: REM sleep pathology and PLMs are closely related to SCA2 severity, suggesting their usefulness as disease progression markers. The RWA percentage is influenced by the CAG repeats and might thus be a sensitive parameter for reflecting polyglutamine toxicity. Finally, as PLMs are sensible to drug treatment, they represents a new therapeutic target for the symptomatic treatment of SCA2(AU)

A mind to go out of: reflections on primary and secondary consciousness.

Dreaming and waking are two brain-mind states, which are characterized by shared and differentiated properties at the levels of brain and consciousness. As part of our effort to capitalize on a comparison of these two states we have applied Edelman's distinction between primary and secondary consciousness, which we link to dreaming and waking respectively. In this paper we examine the implications of this contrastive analysis for theories of mental illness. We conclude that while dreaming is an almost perfect model of organic psychosis, it is less so for schizophrenia and major affective disorder where it must serve a primarily heuristic role helping us to model hallucinations and delusions but not the diseases themselves.

Waking and dreaming: related but structurally independent. Dream reports of congenitally paraplegic and deaf-mute persons.

Models of dream analysis either assume a continuum of waking and dreaming or the existence of two dissociated realities. Both approaches rely on different methodology. Whereas continuity models are based on content analysis, discontinuity models use a structural approach. In our study, we applied both methods to test specific hypotheses about continuity or discontinuity. We contrasted dream reports of congenitally deaf-mute and congenitally paraplegic individuals with those of non-handicapped controls. Continuity theory would predict that either the deficit itself or compensatory experiences would surface in the dream narrative. We found that dream form and content of sensorially limited persons was indifferent from those of non-handicapped controls. Surprisingly, perceptual representations, even of modalities not experienced during waking, were quite common in the dream reports of our handicapped subjects. Results are discussed with respect to feedforward mechanisms and protoconsciousness theory of dreaming.

Changes in EEG pre and post awakening.

This chapter is concerned with behavioral and electrophysiologic evidence of awakenings. Awakenings are understood here as a state change from sleeping to waking. We will discuss the methodological issues and the problem of properly defining an awakening. With regard to phenomena preceding an awakening, we will look at arousals and compare background to event-related activity in the electroencephalography (EEG). As arousability varies between and within species, the relevant EEG correlates of this variability are described. Concerning EEG changes following an awakening, the discussion focuses on sleep inertia effects.

Arousal thresholds during human tonic and phasic REM sleep.

The goal of the present study was to investigate arousal thresholds (ATs) in tonic and phasic episodes of rapid eye movement (REM) sleep, and to compare the frequency spectrum of these sub-states of REM to non-REM (NREM) stages of sleep. We found the two REM stages to differ with regard to behavioural responses to external acoustic stimuli. The AT in tonic REM was indifferent from that in sleep stage 2, and ATs in phasic REM were similar to those in slow-wave sleep (stage 4). NREM and REM stages of similar behavioural thresholds were distinctly different with regard to their frequency pattern. These data provide further evidence that REM sleep should not be regarded a uniform state. Regarding electroencephalogram frequency spectra, we found that the two REM stages were more similar to each other than to NREM stages with similar responsivity. Ocular activity such as ponto-geniculo-occipital-like waves and microsaccades are discussed as likely modulators of behavioural responsiveness and cortical processing of auditory information in the two REM sub-states.

Lucid dreaming: a state of consciousness with features of both waking and non-lucid dreaming.

STUDY OBJECTIVES: 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. DESIGN: 19-channel EEG was recorded on up to 5 nights for each participant. Lucid episodes occurred as a result of pre-sleep autosuggestion. SETTING: Sleep laboratory of the Neurological Clinic, Frankfurt University. PARTICIPANTS: Six student volunteers who had been trained to become lucid and to signal lucidity through a pattern of horizontal eye movements. MEASUREMENTS AND RESULTS: 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. CONCLUSIONS: 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.