A novel method for objectively classifying sequential emotion within dreams: a proof-of-concept pilot study.

Traditionally, emotions in dreams have been assessed using subjective ratings by human raters (e.g., external raters or dreamers themselves). These methods have extensive support and utility in dream science, yet they have certain innate limitations due to the subjective nature of the rating methodologies. Attempting to circumvent several of these limitations, we aimed to develop a novel method for objectively classifying and quantifying sequential (word-for-word) emotion within a dream report. We investigated whether sentiment analysis, a branch of natural language processing, could be used to generate continuous positive and negative valence ratings across a dream. In this pilot, proof-of-concept study, we used 14 dream reports collected upon awakening following overnight polysomnography. We also collected pre- and post-sleep affective data and personality metrics. Our objectives included demonstrating that (1) valence ratings derived from sentiment analysis (Valence Aware Dictionary for sEntiment Reasoning [VADER]) could be used to visualize (plot) positive and negative emotion fluctuations within a dream, (2) how the visual properties of emotion fluctuations within a dream (peaks and troughs, area under the curve) can be used to generate novel "emotion indicators" as proxies for emotion regulation throughout a dream, and (3) these emotion indicators correlate with sleep, affective, and personality variables known to be associated with dreaming and emotion regulation. We describe 6 novel, objective dream emotion indicators: Total number of Peaks, total number of Troughs, Positive, Negative, and Overall Emotion Intensity (composites from an "area under the curve" method using the trapezoid rule applied to the peaks and troughs), and the Emotion Gradient (a polynomial trendline fitted to the emotion fluctuations in the dream chart). The latter signifies the overall direction of sequential emotion changes within a dream. Results also showed that ⅚ emotion indicators correlated significantly with at least one existing sleep, affective, or personality variable known to be associated with dreaming and emotion regulation. We propose that the novel emotion indicators potentially serve as proxies for emotion regulation processes unfolding within a dream. These preliminary findings provide a methodological foundation for future studies to test and refine the method in larger and more diverse samples.

Demystifying Jung's "Archetypes" with Embodied Cognition.

Since he first proposed it, Carl Jung's "archetype" theory has faced resistance from a pervasive but seldom examined set of underlying Cartesian assumptions embedded in mainstream psychology. This paradigm assumed a physical universe (and hence body) free of psyche that coincided with an essentially disembodied mind largely concerned with abstract symbol manipulation. This situation led archetype theory to remain largely within insulated psychoanalytic circles for decades. Since the 1980s, however, cognitive psychology has increasingly become embodied from a variety of standpoints. This article shows how the results of embodied cognition and spontaneous thought "demystify" many of the attributes Jung described in his archetype theory, making archetype theory not only more comprehensible but clinically applicable. Combining approaches suggests new avenues of inquiry for experimental research and enriches the psychoanalytic perspective.

Transcription factor E2F4 facilitates SUMOylation to promote HCC progression through interaction with LIN9.

SUMOylation plays a crucial role in numerous cellular biological and pathophysiological processes associated with human disease; however, the mechanisms regulating the genes involved in SUMOylation remain unclear. In the present study, E2F transcription factor 4 (E2F4) was identified as an E2F member related to hepatocellular carcinoma (HCC) progression by public database analysis. It was found that E2F4 promoted the proliferation and invasiveness of HCC cells via SUMOylation using Soft agar and Transwell migration assays. Mechanistically, it was demonstrated that E2F4 upregulated the transcript and protein expression levels of baculoviral IAP repeat containing 5, cell division cycle associated 8 and DNA topoisomerase II α using western blotting. Furthermore, the interaction between E2F4 with lin­9 DREAM multi­vulva class B core complex component (LIN9) was explored by co­immunoprecipitation, immunofluorescence co­localization and bimolecular fluorescence complementation assays. Moreover, it was demonstrated that E2F4 promoted the progression of HCC cells via LIN9. Rescue experiments revealed that LIN9 facilitated the SUMOylation and proliferation of HCC cells, which was prevented by knocking down E2F4 expression. In conclusion, the findings of the present study indicated that E2F4 plays a major role in the proliferation of HCC cells and may be a potential therapeutic target in the future.

Dreaming in Bipolar Disorders - Feasibility of the Central Image Method: A Prospective Controlled Trial.

Background: Emotions play an important role in the emergence, formation, and experience of dreams. The Central Image (CI) in a dream refers to the dream's dominant or underlying emotion, and it is the best-remembered part of a dream. Bipolar disorders are characterized by strong emotions, particularly during manic and depressive episodes. In these patients, dreams and CIs may serve as a helpful diagnostic and therapeutic tool. This study aims to evaluate the feasibility of the CI Method and to check for differences concerning dreams and CI emotions between healthy controls and patients with bipolar disorder. Methods: Over a period of 3 weeks, 61 participants were asked to maintain a daily record of all dreams remembered. Dream reports were rated using the Central Image Method (CIM) by two independent, blinded raters. We assessed for interrater agreement on the CIM and for within and between group differences related to negative and positive CI emotions. Results: Mean agreement rates (weighted Cohen's kappa) for the CI emotion ratings could be classified as very good: For primary CI emotion ratings, the mean weighted Cohen's kappa was 0.99 (± 0.02), and for secondary CI emotions, it was 0.90 (± 0.17). Regarding the CI intensities, the mean agreement rate (Spearman's correlation) was also strong. Evaluation of differences within the groups showed that there were more negative CI emotions than positive CI emotions in healthy controls and currently depressive patients; however, in the latter, the difference was statistically not significant. Analyses of differences between groups indicated that patients who were currently depressed recorded more negative CI emotions in dreams than those who were euthymic or healthy controls. Discussion: The findings support the feasibility of the CIM. Our results might indicate different emotion regulation and defense mechanisms across bipolar disorder states, as reflected by the occurrence of negative and positive CI emotions.

In the attic of dreams. The personal archives of the father of paradoxical sleep.

Michel Jouvet (1925-2017) is one of the most important figures in the contemporary history of the neuroscience of sleep and dreams, and one of the most awarded French researchers of the last century. Yet this former CNRS gold medalist and winner of the Cino Del Duca World Prize remains little known-not to say unknown-outside the field of sleep medicine, especially in non-French-speaking countries, where the name of his American counterpart, William C. Dement, is more familiar. Often reduced to his experiments on cats and the discovery of what he called "paradoxical sleep," Jouvet left behind a rather unique body of work that includes not only countless publications on sleep and dreams-neurophysiological as well as ethnological and psychological-but also major contributions to clinical medicine, two novels and an impressive collection of personal dream accounts and drawings, which now make it possible to explore the nocturnal side of the last 50 years of his life. This article draws on unpublished archives to illuminate all these little-known and unknown aspects of Jouvet's life and work, highlighting his hidden links with 19th-century scientific oneirology and bringing to light its paradoxes.

Spiral 3DREAM sequence for fast whole-brain B1 mapping.

PURPOSE: This work demonstrates a new variant of the 3DREAM sequence for whole-brain B 1 + $$ {\mathrm{B}}_1^{+} $$ mapping employing a three-dimensional (3D) stack-of-spirals readout. The spiral readout reduces the echo train length after the STEAM preparation in order to overcome the significant blurring in STE* images due to the decreasing STE* signal with each excitation pulse. METHODS: The 3DREAM sequence rapidly acquires two contrasts to calculate whole-brain flip angle maps. In the proposed spiral 3DREAM sequence, the Cartesian readout scheme is replaced by an accelerated 3D stack-of-spirals readout with a CAIPIRINHA sampling scheme. Phantom experiments were conducted to compare flip angle maps of the spiral 3DREAM sequence to a Cartesian 3DREAM sequence, an actual flip-angle-imaging (AFI) sequence, the dual-angle method, and the Bloch-Siegert shift method. Afterwards, the results were validated in vivo acquiring flip angle maps from five subjects. RESULTS: Flip angle maps of the spiral 3DREAM sequences showed high agreement with the reference methods both in phantom and in vivo experiments. Blurring in STE* images and flip angle maps was reduced compared to the Cartesian 3DREAM sequence. CONCLUSION: The spiral 3DREAM sequence utilizes a fast readout minimizing the echo train length of the imaging train. This reduces blurring in STE* images as well as the total acquisition time and increases the effective resolution of B 1 + $$ {\mathrm{B}}_1^{+} $$ maps.

Polysomnographic features prior to dream enactment behaviors in isolated rapid eye movement sleep behavior disorder.

OBJECTIVE: This study aimed to identify electroencephalogram correlates of dream enactment behaviors (DEBs) and elucidate their cortical dynamics in patients with isolated/idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD). METHODS: This cross-sectional study included 15 patients with iRBD. Two REM sleep periods in routine polysomnography were compared: the 60 s preceding the DEBs ("pre-representative behavior" [preR]), and the 60 s with the least submental electromyogram activity ("background" [BG]). Six EEG frequency bands and electrooculogram were analyzed; power spectra, coherence and phase-locking values in four 15-s periods were examined to assess trends. These indices were also compared between preR and BG. RESULTS: Compared with BG, significantly higher delta power in the F3 channel and gamma power in the F4 and O2 channels were observed during preR. For functional connectivity, the widespread beta-band connectivity was significantly increased during preR than BG. CONCLUSION: Before notable REM sleep behaviors, uneven distributed higher EEG spectral power in both very low and high frequencies, and increased wide-range beta band functional connectivity, were observed over 60 s, suggesting cortical correlates to subsequent DEBs. SIGNIFICANCE: This study may shed light on the pathological mechanisms underlies RBD through the routine vPSG analysis, leading to detection of DEBs.

REM sleep in narcolepsy.

Narcolepsy is mainly associated with excessive daytime sleepiness, but the characteristic feature is abnormal rapid eye movement (REM) sleep phenomena. REM sleep disturbances can manifest as cataplexy (in narcolepsy type 1), sleep paralysis, sleep-related hallucinations, REM sleep behavior disorder, abnormal dreams, polysomnographic evidence of REM sleep disruption with sleep-onset REM periods, and fragmented REM sleep. Characterization of REM sleep and related symptoms facilitates the differentiation of narcolepsy from other central hypersomnolence disorders and aids in distinguishing between narcolepsy types 1 and 2. A circuit comprising regions within the brainstem, forebrain, and hypothalamus is involved in generating and regulating REM sleep, which is influenced by changes in monoamines, acetylcholine, and neuropeptides. REM sleep is associated with brainstem functions, including autonomic control, and REM sleep disturbances may be associated with increased cardiovascular risk. Medications used to treat narcolepsy (and REM-related symptoms of narcolepsy) include stimulants/wake-promoting agents, pitolisant, oxybates, and antidepressants; hypocretin agonists are a potential new class of therapeutics. The role of REM sleep disturbances in narcolepsy remains an area of active research in pathophysiology, symptom management, and treatment. This review summarizes the current understanding of the role of REM sleep and its dysfunction in narcolepsy.

Practicable strategies parents can apply in their daily routine to successfully implement the 50/50-split-model of paid work, childcare, and housework: a qualitative content analysis.

BACKGROUND: Many young couples are planning to share paid work, childcare, and housework equally between each other. But implementing such a 50/50-split-model is difficult and parents often return to traditional gender role distributions after the birth of a child. This return has potential negative effects on mental health, physical health, and relationship satisfaction. Therefore, this study aims to find practicable strategies on a behavioral-level which new parents can apply in their daily routine to successfully implement the 50/50-split-model if they wish to do so. METHODS: This qualitative study, DREAMTALK, is part of the multi-method, prospective Dresden Study on Parenting, Work, and Mental Health (DREAM). For DREAMTALK, N = 25 parents implementing a 50/50-split-model were selected based on quantitative data regarding time use, which participants had provided in questionnaires. In DREAMTALK, problem-centered interviews were conducted with the selected sample at 17 months postpartum. Those were analyzed via qualitative content analysis, which is systematic, rule-guided, and based on the criteria of validity and reliability. RESULTS: The qualitative content analysis revealed a catalog of 38 practicable strategies to manage daily routine, which can help parents to successfully implement a 50/50-split-model. Individual participants used 23 success strategies on average. Examples include having a regular coordination appointment with the other parent, planning foresightedly, flexibility, reducing cleaning, optimization of routes, or moderate split-shift parenting. Some of these strategies seem opposing, e.g., planning foresightedly, and at the same time, meeting unpredicted changes with flexibility. Those seemingly opposing strategies were well balanced by the participants, which was an additional strategy. CONCLUSIONS: Parents can use the success strategies relatively independently of external circumstances. This behavioral perspective extends prior theories, which have focused on explaining unequal gender role distributions with external circumstances. A behavioral perspective can be a gateway to assist more parents to pioneer in implementing the 50/50-split-model, which might in turn lead to a healthier and more satisfied public population.

A New Way of Analysing Dreams on Its Profoundest Level: The Development of Motif Analysis and Phase Model (MAP) as an Extension of Structural Dream Analysis (SDA).

Dream research today assumes that there is a connection between dreams and waking life. However, the structural alteration of dream motifs in connection with the psychotherapeutic process and waking life has not yet been researched extensively. This study depicts the development of the new Motif Analysis and Phase Model (MAP), a dynamic method which allows research on the previous aspects. The following question was investigated as an accompanying key issue: can a connection be established between the course of the dream patterns and the agency of the dream ego as well as the dream contents and the course of the psychotherapies of the dreaming person as a whole? Four hypotheses were formulated and tested. The data material consists of 217 dreams of a male test subject. The motifs were analysed using Structural Dream Analysis (SDA) at first. Thereafter, the content was linked to the test subject's waking life in a guided interview. The findings show a strong connection between the dream content and the psychotherapies as well as the test subject's waking life. Five motifs with structural changes were found, through which the Phase Model with four phases was developed. At turning points, the transformative child motif also appears in the dreams. The course of the dream patterns and agency of the dream ego, however, has not changed. The results, the method and the generalisability were critically discussed and recommendations for future research were formulated.

Consciousness in non-REM-parasomnia episodes.

Sleepwalking and related parasomnias are thought to result from incomplete awakenings out of non-rapid eye movement (non-REM) sleep. Non-REM parasomnia behaviours have been described as unconscious and automatic, or related to vivid, dream-like conscious experiences. Similarly, some observations have suggested that patients are unresponsive during episodes, while others that they can interact with their surroundings. To better grasp and characterise the full spectrum of consciousness and environmental (dis)connection associated with behavioural episodes, 35 adult patients with non-REM sleep parasomnias were interviewed in-depth about their experiences. The level of consciousness during parasomnia episodes was reported to be variable both within and between individuals, ranging from minimal or absent consciousness and largely automatic behaviours (frequently/always present in 36% of patients) to preserved conscious experiences characterised by delusional thinking to varying degrees of specificity (65%), often about impending danger, variably formed, uni- or multisensory hallucinations (53%), impaired insight (77%), negative emotions (75%), and variable, but often pronounced, amnesia (30%). Patients described their experiences as a dream scene during which they felt awake ("awake dreaming"). The surroundings were either realistically perceived, misinterpreted (in the form of perceptual illusions or misidentifications of people), or entirely hallucinated as a function of the prevailing delusion. These observations suggest that the level of consciousness, amnesia and sensory disconnection during non-REM parasomnia episodes is variable and graded. In their full-fledged expression, non-REM parasomnia experiences feature several core features of dreams. They therefore represent a valuable model for the study of consciousness, sleep-related sensory disconnection and dreaming.

The Persistent Paradox of Rapid Eye Movement Sleep (REMS): Brain Waves and Dreaming.

The original conceptualization of REM sleep as paradoxical sleep was based on its EEG resembling wakefulness and its association with dreaming. Over time, the concept of paradox was expanded to include various associations with REM sleep, such as dream exclusivity, high recall, and pathophysiology. However, none of these associations are unique to REM sleep; they can also occur in other sleep states. Today, after more than fifty years of focused research, two aspects of REMS clearly retain paradoxical exclusivity. Despite the persistent contention that the EEG of human REMS consists of wake-like, low-voltage, non-synchronous electrical discharges, REMS is based on and defined by the intracranial electrical presence of 5-8 Hz. theta, which has always been the marker of REMS in other animals. The wake-like EEG used to define REMS on human polysomnography is secondary to a generalized absence of electrophysiological waveforms because the strong waves of intracranial theta do not propagate to scalp electrodes placed outside the skull. It is a persistent paradox that the theta frequency is restricted to a cyclical intracranial dynamic that does not extend beyond the lining of the brain. REMS has a persistent association with narratively long and salient dream reports. However, the extension of this finding to equate REMS with dreaming led to a foundational error in neuroscientific logic. Major theories and clinical approaches were built upon this belief despite clear evidence that dreaming is reported throughout sleep in definingly different physiologic and phenomenological forms. Few studies have addressed the differences between the dreams reported from the different stages of sleep so that today, the most paradoxical aspect of REMS dreaming may be how little the state has actually been studied. An assessment of the differences in dreaming between sleep stages could provide valuable insights into how dreaming relates to the underlying brain activity and physiological processes occurring during each stage. The brain waves and dreams of REMS persist as being paradoxically unique and different from waking and the other states of sleep consciousness.

Impact of Pre-Sleep Visual Media Exposure on Dreams: A Scoping Review.

A body of experimental research has aimed to investigate processes underlying dream formation by examining the effects of a range of pre-sleep stimuli and events on subsequent dream content. Given its ever-growing presence and salience in people's everyday lives, pre-sleep media consumption stands out as a key variable that could influence people's dreams. We conducted a scoping review to evaluate the experimental evidence of the effects of pre-sleep exposure to visual media on dream content. A systematic search on PubMed, PsycInfo, and Web of Science using terms related to moving visual media and dreams yielded 29 studies meeting the inclusion criteria. Overall, we found modest yet varied effects of pre-sleep exposure to visual media on dream content, with rates of stimulus-related incorporation ranging from 3% to 43% for REM dream reports, 4% to 30% for NREM sleep mentation reports, and between 11% and 35% for home dream reports. Our review highlights the large methodological heterogeneity and gaps across studies, the general difficulty in influencing dream content using pre-sleep exposure to visual media, and suggests promising venues for future research to advance our understanding of how and why digital media may impact people's dreams.

Sensational Dreams: The Prevalence of Sensory Experiences in Dreaming.

Dreaming, a widely researched aspect of sleep, often mirrors waking-life experiences. Despite the prevalence of sensory perception during wakefulness, sensory experiences in dreams remain relatively unexplored. Free recall dream reports, where individuals describe their dreams freely, may not fully capture sensory dream experiences. In this study, we developed a dream diary with direct questions about sensory dream experiences. Participants reported sensory experiences in their dreams upon awakening, over multiple days, in a home-based setting (n = 3476 diaries). Our findings show that vision was the most common sensory dream experience, followed by audition and touch. Olfaction and gustation were reported at equally low rates. Multisensory dreams were far more prevalent than unisensory dreams. Additionally, the prevalence of sensory dream experiences varied across emotionally positive and negative dreams. A positive relationship was found between on the one hand sensory richness and, on the other emotional intensity of dreams and clarity of dream recall, for both positive and negative dreams. These results underscore the variety of dream experiences and suggest a link between sensory richness, emotional content and dream recall clarity. Systematic registration of sensory dream experiences offers valuable insights into dream manifestation, aiding the understanding of sleep-related memory consolidation and other aspects of sleep-related information processing.

Artificial Intelligence on The Couch. Staying Human Post-AI.

This paper examines the human relationship to technology, and AI in particular, including the proposition that algorithms are the new unconscious. Key is the question of how much human ability will be duplicated and transcended by general machine intelligence. More and more people are seeking connection via social media and interaction with artificial beings. The paper examines what it means to be human and which of these traits are already or will be replicated by AI. Therapy bots already exist. It is easier to envision AI therapy guided by CBT manuals than psychoanalytic techniques. Yet, a demonstration of how AI can already perform dream analysis reaching beyond a dream's manifest content is presented. The reader is left to consider whether these findings demand a new role for psychoanalysis in supporting, sustaining, and reframing our humanity as we create technology that transcends our abilities.

Enhancing and advancing the understanding and study of dreaming and memory consolidation: Reflections, challenges, theoretical clarity, and methodological considerations.

Empirical investigations that search for a link between dreaming and sleep-dependent memory consolidation have focused on testing for an association between dreaming of what was learned, and improved memory performance for learned material. Empirical support for this is mixed, perhaps owing to the inherent challenges presented by the nature of dreams, and methodological inconsistencies. The purpose of this paper is to address critically prevalent assumptions and practices, with the aim of clarifying and enhancing research on this topic, chiefly by providing a theoretical synthesis of existing models and evidence. Also, it recommends the method of Targeted Memory Reactivation (TMR) as a means for investigating if dream content can be linked to specific cued activations. Other recommendations to enhance research practice and enquiry on this subject are also provided, focusing on the HOW and WHY we search for memory sources in dreams, and what purpose (if any) they might serve.

DREAM On, DREAM Off: A Review of the Estrogen Paradox in Luminal A Breast Cancers.

It is generally assumed that all estrogen-receptor-positive (ER+) breast cancers proliferate in response to estrogen and, therefore, examples of the estrogen-induced regression of ER+ cancers are paradoxical. This review re-examines the estrogen regression paradox for the Luminal A subtype of ER+ breast cancers. The proliferative response to estrogen is shown to depend on the level of ER. Mechanistically, a window of opportunity study of pre-operative estradiol suggested that with higher levels of ER, estradiol could activate the DREAM-MMB (Dimerization partner, Retinoblastoma-like proteins, E2F4, and MuvB-MYB-MuvB) pathway to decrease proliferation. The response of breast epithelium and the incidence of breast cancers during hormonal variations that occur during the menstrual cycle and at the menopausal transition, respectively, suggest that a single hormone, either estrogen, progesterone or androgen, could activate the DREAM pathway, leading to reversible cell cycle arrest. Conversely, the presence of two hormones could switch the DREAM-MMB complex to a pro-proliferative pathway. Using publicly available data, we examine the gene expression changes after aromatase inhibitors and ICI 182,780 to provide support for the hypothesis. This review suggests that it might be possible to integrate all current hormonal therapies for Luminal A tumors within a single theoretical schema.

Neuropsychopharmacological Induction of (Lucid) Dreams: A Narrative Review.

Lucid dreaming (LD) is a physiological state of consciousness that occurs when dreamers become aware that they are dreaming, and may also control the oneiric content. In the general population, LD is spontaneously rare; thus, there is great interest in its induction. Here, we aim to review the literature on neuropsychopharmacological induction of LD. First, we describe the circadian and homeostatic processes of sleep regulation and the mechanisms that control REM sleep with a focus on neurotransmission systems. We then discuss the neurophysiology and phenomenology of LD to understand the main cortical oscillations and brain areas involved in the emergence of lucidity during REM sleep. Finally, we review possible exogenous substances-including natural plants and artificial drugs-that increase metacognition, REM sleep, and/or dream recall, thus with the potential to induce LD. We found that the main candidates are substances that increase cholinergic and/or dopaminergic transmission, such as galantamine. However, the main limitation of this technique is the complexity of these neurotransmitter systems, which challenges interpreting results in a simple way. We conclude that, despite these promising substances, more research is necessary to find a reliable way to pharmacologically induce LD.

Personality Functioning Improvement during Psychotherapy Is Associated with an Enhanced Capacity for Affect Regulation in Dreams: A Preliminary Study.

BACKGROUND: Clinical case illustrations of patients with an impairment of personality functioning (IPF) have repeatedly reported that progress during psychotherapy is reflected by alterations in dream content. However, quantitative studies based on samples of psychotherapy patients are scarce. As a core component of both personality functioning and contemporary psychodynamic dream theory, the construct of affect regulation is of specific significance in this context. AIMS: To test if improvement in personality functioning in the course of psychotherapy is associated with an increasing ability to regulate affects in dreams. METHOD: In a longitudinal design, affect regulation was compared in N = 94 unsolicited dream reports from the first vs. last third of long term psychotherapy of ten patients with initial IPF. Dream reports were transcribed from recordings of the sessions. Expert ratings of the level of personality functioning were obtained using the Scales of Psychological Capacities. The capacity for affect regulation was assessed using the Zurich Dream Process Coding System. Group differences were assessed using linear mixed models, controlling for dream length as well as the nested structure of this data set. RESULTS: Patients demonstrated an increased capacity for affect regulation in dreams that was primarily evident in three core features: the complexity of dream elements (cf., e.g., parameter attributes, p = 0.024); the extent of affective involvement in the dream ego (cf., e.g., parameter subject feeling, p = 0.014); and the flexibility to regulate the dynamics of safety/involvement processes (p ≤ 0.001). This pattern was especially prominent in a subgroup (n = 7) of patients with more pronounced improvements in personality functioning. CONCLUSION: These findings support the hypotheses that decreasing IPF during psychotherapy is associated with increases in the capacity for affect regulation in dreams. Thus, researchers and therapists can utilize dream reports to illuminate the important aspects of treatment progress in clinical practice.

REM sleep behaviour disorder (RBD): Personal perspectives and research priorities.

The formal identification and naming of rapid eye movement (REM) sleep behaviour disorder (RBD) in 1985-1987 is described; the historical background of RBD from 1966 to 1985 is briefly discussed; and RBD milestones are presented. Current knowledge on RBD is identified with reference to recent comprehensive reviews, allowing for a focus on research priorities for RBD: factors and predictors of neurodegenerative phenoconversion from isolated RBD and patient enrolment in neuroprotective trials; isolated RBD clinical research cohorts; epidemiology of RBD; traumatic brain injury, post-traumatic stress disorder, RBD and neurodegeneration; depression, RBD and synucleinopathy; evolution of prodromal RBD to neurodegeneration; gut microbiome dysbiosis and colonic synuclein histopathology in isolated RBD; other alpha-synuclein research in isolated RBD; narcolepsy-RBD; dreams and nightmares in RBD; phasic REM sleep in isolated RBD; RBD, periodic limb movements, periodic limb movement disorder pseudo-RBD; other neurophysiology research in RBD; cardiac scintigraphy (123I-MIBG) in isolated RBD; brain magnetic resonance imaging biomarkers in isolated RBD; microRNAs as biomarkers in isolated RBD; actigraphic, other automated digital monitoring and machine learning research in RBD; prognostic counselling and ethical considerations in isolated RBD; and REM sleep basic science research. RBD research is flourishing, and is strategically situated at an ever-expanding crossroads of clinical (sleep) medicine, neurology, psychiatry and neuroscience.