Sleep and dreaming in the light of reactive and predictive homeostasis.

Dreams are often viewed as fascinating but irrelevant mental epihenomena of the sleeping mind with questionable functional relevance. Despite long hours of oneiric activity, and high individual differences in dream recall, dreams are lost into oblivion. Here, we conceptualize dreaming and dream amnesia as inherent aspects of the reactive and predictive homeostatic functions of sleep. Mental activity during sleep conforms to the interplay of restorative processes and future anticipation, and particularly during the second half of the night, it unfolds as a special form of non-constrained, self-referent, and future-oriented cognitive process. Awakening facilitates constrained, goal-directed prospection that competes for shared neural resources with dream production and dream recall, and contributes to dream amnesia. We present the neurophysiological aspects of reactive and predictive homeostasis during sleep, highlighting the putative role of cortisol in predictive homeostasis and forgetting dreams. The theoretical and methodological aspects of our proposal are discussed in relation to the study of dreaming, dream recall, and sleep-related cognitive processes.

An ecological approach to clinically assess nightmares in military service members with severe PTSD.

BACKGROUND: Trauma-related nightmares (TRNs) are distressing events which contribute to insomnia severity, chronicity and treatment resistance of PTSD. Therefore, recording TRNs is a crucial technical challenge in order to understand their physiopathological patterns and their impact on sleep. However, TRNs are difficult to record during a single night in a sleep laboratory, which, moreover, is likely to be considered by patients as a protective sleep environment that is therefore not representative of home sleep conditions. METHOD: In the present study, we investigate if objective sleep measures acquired at-home using two ambulatory devices is of clinical value by correlating with PTSD patients' complaints about sleep and nightmares. A secondary objective is to relate awakenings associated with TRNs to sleep stages and to provide new insights into the use of electrodermal activity (EDA) as a potential physiological marker of TRNs. Sixty veterans and active-duty service members were assessed by questionnaires and recorded for 5 consecutive nights in their homes. RESULTS: Our approach firstly identified positive correlations between subjective and objective sleep parameters (total sleep time, sleep-onset latency and TRNs frequency). We also developed a method of synchronization between the two ambulatory devices that allowed us to match 200 TRNs (reported by event marker push button) with sleep stages corresponding to 91 nights and 37 patients. Most awakenings associated with TRNs occurred during NREM sleep (65.5% versus 34.5% during REM sleep). Our results also reveal significant differences in the frequency of EDA peaks 10 min before the reported events, with a lower frequency in REM (13.7 peaks) than in NREM (24.8 peaks) awakenings associated with TRNs. This EDA peaks frequency in REM sleep is not statistically different from that in REM sleep preceding awakenings that are not associated with TRNs. CONCLUSION: The development of wearable devices to collect physiological parameters is of interest in clinical practice to improve our knowledge of sleep and trauma-related nightmares in patients with PTSD.

Balloon Shaft Fracture: A Nightmare Scenario in the Setting of Percutaneous Coronary Intervention.

These images illustrate an attempt to pull back the balloon of an implanted proximal stent swiftly (before it was completely deflated) just following unplanned disengagement of the guiding catheter from the right coronary ostium. This maneuver resulted in abrupt balloon shaft fracture (outside the guiding catheter), leading to a freely swinging shaft appearance in the descending aorta. Unfortunately, several attempts to retrieve the swinging fragment of the shaft failed. Moreover, intracoronary snare technique in an effort to grasp the distal portion of the shaft also failed. Finally, the shaft fragment was surgically removed along with a bypass graft operation for the severely stenotic circumflex artery.

The nightmare of obstetricians - the placenta accreta spectrum in primiparous pregnant women.

OBJECTIVES: The incidence of PAS is increasing day by day as a life-threatening condition. The purpose of the present study was to determine the factors affecting PAS formation in primiparous pregnant women and to define possible risk factors for the mother and the baby. MATERIAL AND METHODS: Bursa Yüksek Ihtisas Training and Research Hospital, department of obstetrics and gynecology, Bursa, Turkey, between June 2016 and December 2020. A total of 58,895 patients were included in the study. After the exclusion criteria, the study was continued with 27 primiparous PAS and 54 non-primiparous PAS patients. The primary purpose is to evaluate PAS risk factors. The secondary aim is to examine maternal and neonatal characteristics. RESULTS: When the parameters that are significant in terms of PAS risk factors were analyzed by Logistic Regression Analysis, it was found that the increase in age also increased the development of PAS 1.552 times (95% CI: 1.236-1.948) and a history of abortion was 7.928. times (95% CI: 1.408-44.654) and 11,007 times (95% CI: 2.059-58.832) with history of myomectomy; postoperative HB values (p < 0.001), an estimated amount of bleeding (p < 0.001), need for transfusion (p = 0.002), and use of drains ( < 0.001) were statistically significant different between two groups. When the neonatal results between patients with and without PAS were examined, birth weight (p < 0.001) and gestational week ( < 0.001) were statistically significant. CONCLUSIONS: PAS does not occur only in multiparous patients who have a history of previous cesarean section. It may also occur in primiparous patients and is a life-threatening condition.

Nightmares and psychiatric symptoms: A systematic review of longitudinal, experimental, and clinical trial studies.

Nightmares occur across a wide range of psychiatric disorders, but outside of PTSD presentations are infrequently considered a treatment priority. We aimed to assess evidence for a contributory causal role of nightmares to the occurrence of psychiatric disorders, and vice versa. A systematic review was conducted of longitudinal, experimental, and clinical trial studies. Twenty-four longitudinal, sixteen trials, and no experimental studies were identified. Methodological shortcomings were common, especially the use of single-item nightmare assessment. Thirty-five studies assessed the path from nightmares to psychiatric symptoms. Depression (n = 10 studies), PTSD (n = 10) and anxiety (n = 5) were the most commonly assessed outcomes in trials. Most were not designed to assess the effect of nightmare treatment on psychiatric symptoms. Treating nightmares led to moderate reductions in PTSD and depression, small to moderate reductions in anxiety, and potentially moderate reductions in paranoia. Nightmares increased the risk of later suicide outcomes (n = 10), but two small pilot trials indicated that treating nightmares might potentially prevent recovery of suicidal ideation. PTSD treatment led to large reductions in trauma-related nightmares (n = 3). The limited literature suggests that treating nightmares may be one route to lessening threat-based disorders in particular, suggestive of a causal relationship. Overall, however, nightmares in most disorders are greatly understudied.

Chain mediating effect of insomnia, depression, and anxiety on the relationship between nightmares and cognitive deficits in adolescents.

BACKGROUND: The study explored the differences in nightmare, insomnia, depression, anxiety, and cognitive deficits among adolescents and the chain mediating effects of insomnia, depression, and anxiety on the relationship between nightmares and cognitive deficits in adolescents. METHODS: An online survey was used to collect demographic data of 6014 adolescents and assess nightmare, insomnia, depression, anxiety, and cognitive deficits using the Chinese Version of Nightmare Distress Questionnaire, Insomnia Severity Index, Patient Health Questionnaire 9, Generalized Anxiety Disorder 7, and Perceived Deficits Questionnaire-Depression. Spearman correlation analysis and the SPSS function "PROCESS macro" were used for correlation and mediation analyses, respectively. RESULTS: Female adolescents, senior high school, and poor academic performance had higher nightmare, insomnia, and cognitive deficit scores; those living in the city had higher depression and anxiety scores. Cognitive deficits were positively correlated with nightmares, insomnia, depression, and anxiety. Further, insomnia, depression, and anxiety had a chain mediating effect between nightmares and cognitive deficits in adolescents. Nightmares indirectly affect cognition deficits by affecting insomnia and then depression and anxiety symptoms. LIMITATIONS: As this was a cross-sectional study, the causal relationship between the variables could not be determined. Moreover, reporting bias and volunteer bias might be present. CONCLUSIONS: These findings suggest that clinicians should identify adolescents with frequent nightmares early and provide timely treatment to minimize negative outcomes and possibly limit the chronicity of nightmare disorder. It is significant to maintain the physical and mental health development of adolescents to reduce the risk of insomnia, depression, anxiety, and cognitive deficits.

Georges Perec's Zeit-Raum: Creating a Space of Remembrance.

Georges Perec's memoir of his analysis, "The Scene of a Stratagem" (1977), is part of a literary oeuvre characterized by innovative forms addressing the paradoxical task of telling a story that cannot be told. His life history was constructed from memory traces, veiled behind the untimely death of his parents in World War II. The memoir tells the story of his analysis in adulthood with Jean-Bertrand Pontalis, at a time when Perec was struggling with depression and writer's block. Beneath doubts and the tedious analytic routine, Perec presents analysis as a space in which memory traces can be given new life. The historical past takes place in a space Walter Benjamin calls time-space (Zeit-raum), or time-dream (Zeit-traum). This space is created in a flash of co-incidence between dreaming and waking. History, then, is created in a space where archived memory traces are transformed into present experience. Perec creates a kind of Benjaminian dream-space of the past to deal with the fragmentation of memory that follows traumatic loss. The significance of this distinct space is discussed in relation to the challenge of representing traumatic experiences while remaining faithful to the dreamlike and fragmented nature of the space.

Pre-deployment threat learning predicts increased risk for post-deployment insomnia: Evidence from the Marine Resiliency Study.

Insomnia is a common and impairing consequence of military deployment, but little is known about pre-deployment risk factors for post-deployment insomnia. Abnormal threat learning tendencies are commonly observed in individuals with insomnia and maladaptive responses to stress have been implicated in the development of insomnia, suggesting that threat learning could be an important risk factor for post-deployment insomnia. Here, we examined pre-deployment threat learning as a predictor of post-deployment insomnia and the potential mechanisms underlying this effect. Male servicemembers (N = 814) completed measures of insomnia, psychiatric symptoms, and a threat learning task before and after military deployment. Threat learning indices that differentiated participants with versus withoutinsomnia at post-deployment were tested as pre-deployment predictors of post-deployment insomnia. Post-deployment insomnia was linked to elevations on several threat learning indices at post-deployment, but only higher threat conditioning, as indexed by higher threat expectancy ratings to the danger cue, emerged as a pre-deployment predictor of post-deployment insomnia. This effect was independent of combat exposure levels and partially mediated by greater post-deployment nightmares. The tendency to acquire stronger expectations of aversive events following encounters with danger cues may increase risk for post-deployment insomnia, in part due to the development of more severe nightmares.

Dark feet and dark wings: penetrating the depths of the Earth.

The author, although an analyst, is an initiate into the topic of environmental destruction. Following Wendell Berry, she enters the dark and begins a journey of dream-like reflection, weaving images from her own dream and drawing on the work of Vaughan, Bernstein, Soloveitchik and Sacks. She asks, 'not if but where does climate change enter the room?'. The second half of the paper focuses on the manifestations of environmental destruction in dreams and sandplay from three patients and one dream group participant. The paper argues that the analyst must see and intuit before our patients can access the objective layer of environmental destruction in dreams and symbolic material. In this way, the climate becomes the wounded patient, and the analyst as wounded healer must first access his/her own relationship to the wounds inside. Finally, using an ancient Jewish mythological story of Rabbi Shimon bar Yochai, the author argues that Jungian analysts must work to find balance between the inner world of depth psychology and the outer world with its challenges and problems that include environmental destruction.

L'auteur, bien qu'étant analyste, est une initiée du sujet de la destruction de l'environnement. Inspirée par Wendell Berry, elle entre dans le noir et commence un voyage de réflexion en tissant des images provenant de son propre rêve et utilisant les travaux de Vaughan, Bernstein, Soloveitchik et Sacks. Pour elle la question est non pas si mais où est-ce que le changement climatique entre dans la pièce ? La deuxième moitié de l'article s'intéresse aux manifestations de destruction de l'environnement dans les rêves et la thérapie par le jeu de sable de trois patients et d'une personne participant à un groupe de rêves. L'article soutient que l'analyste doit voir et suivre son intuition avant que les patients aient accès à la couche objective de la destruction de l'environnement dans les rêves et le matériel symbolique. De cette manière, le climat devient le patient blessé, et l'analyste, en tant que guérisseur blessé, doit tout d'abord accéder à sa propre relation aux blessures intérieures. Enfin, s'appuyant sur une ancienne histoire mythologique Juive, celle de Rabbi Shimon bar Yochai - qui se retira dans une caverne pendant 13 années - l'auteur soutient que les analystes Jungiens doivent œuvrer à trouver l'équilibre entre le monde intérieur de la psychologie des profondeurs et le monde extérieur avec ses défis et ses problèmes, qui incluent la destruction de l'environnement.

La autora, es analista, y también iniciada en el tópico de la destrucción medioambiental. Siguiendo a Wendell Berry, ella entra en la oscuridad y comienza una travesía reflexiva hilvanando imágenes de sus propios sueños y apoyándose en los trabajos de Vaughan, Bernstein, Soloveitchik y Sacks. Ella pregunta, '¿sino dónde el cambio climático entra en la sala? La segunda parte del trabajo se focaliza en manifestaciones de la destrucción del medioambiente en sueños y en la caja de arena de tres pacientes y de un participante de un grupo de sueños. El trabajo argumenta que el/la analista debe poder ver e intuir antes que nuestros pacientes puedan acceder la dimensión objetiva de la destrucción medioambiental en sueños y material simbólico. De este modo, el clima deviene el/la paciente herido, y el/la analista como curador herido debe primero poder acceder su propia relación con su herida interior. Finalmente, utilizando una antigua historia mitológica de la tradición Judía del Rabino Shimon bar Yochai, quien se retiró a una cueva durante trece años, ella argumenta que analistas Junguianos deben trabajar para encontrar un balance entre el mundo interno de la psicología profunda y el mundo externo con sus desafíos y problemas como el de la destrucción ambiental.

Bad Dreams and Nightmares Preceding Suicidal Behaviors.

Objective: Nightmares seem to predict suicidal behaviors, and the aim of this study is to explore the chronology and trajectories of alterations in dream contents before a suicidal crisis, distinguishing 3 different experiences: bad dreams, nightmares, and suicidal scenarios during dreams.Methods: This naturalistic study included individuals hospitalized between January 2021 and May 2021 in a psychiatric post-emergency room unit for suicidal crisis (thoughts and attempts).Results: The study observed that 80% (n = 32/40) of patients had altered dreams (AD) before the suicidal crisis, including 27 (67.5%) with bad dreams, 21 (52.5%) with nightmares (bad dreams that awaken the sleeper), and 9 (22.5%) with suicidal scenarios during dreams. No differences were observed between the AD group versus patients with no altered dreams (ND) regarding sociodemographic characteristics. We observed a progression of dream content alterations: bad dreams appear 111 days (4 months) before the suicidal crisis, then nightmares appear 87.3 days before (3 months), and suicidal scenarios during dreams were reported 45.2 days before (1.5 months). For the AD and ND populations in suicidal crisis, 80% had at least 1 subtype of dream alterations, 40% had bad dreams and nightmares, and 17.5% had all 3 subtypes. The AD group, compared to the ND group, had significantly more family history of insomnia (P = .046). Almost all patients (97.5%) had depressive symptoms (Montgomery-Asberg Depression Rating Scale [MADRS] score ≥ 7; 82.5% had moderate to severe symptoms, MADRS ≥ 20), 60% had insomnia (Insomnia Severity Index > 14), 92.5% had altered sleep quality (Pittsburgh Sleep Quality Index > 5), and 57.5% reported sleepiness (Epworth Sleepiness Scale > 10).Conclusions: Dream alterations and their progression can be readily assessed and may help to better identify prodromal signs of suicidal behaviors.

Mapping dreams in a computational space: A phrase-level model for analyzing Fight/Flight and other typical situations in dream reports.

This article demonstrates that an automated system of linguistic analysis can be developed - the Oneirograph - to analyze large collections of dreams and computationally map their contents in terms of typical situations involving an interplay of characters, activities, and settings. Focusing the analysis first on the twin situations of fighting and fleeing, the results provide densely detailed empirical evidence of the underlying semantic structures of typical dreams. The results also indicate that the Oneirograph analytic system can be applied to other typical dream situations as well (e.g., flying, falling), each of which can be computationally mapped in terms of a distinctive constellation of characters, activities, and settings.

Dissociation between dreams and wakefulness: Insights from body and action representations of rare individuals with massive somatosensory deafferentation.

The realism of body and actions in dreams is thought to be induced by simulations based on internal representations used during wakefulness. As somatosensory signals contribute to the updating of body and action representations, these are impaired when somatosensory signals are lacking. Here, we tested the hypothesis that individuals with somatosensory deafferentation have impaired body and actions in their dreams, as in wakefulness. We questioned three individuals with a severe, acquired sensory neuropathy on their dreams. While deafferented participants were impaired in daily life, they could dream of themselves as able-bodied, with some sensations (touch, proprioception) and actions (such as running or jumping) which had not been experienced in physical life since deafferentation. We speculate that simulation in dreams could be based on former, "healthy" body and action representations. Our findings are consistent with the idea that distinct body and action representations may be used during dreams and wakefulness.

Enhancing imagery rehearsal therapy for nightmares with targeted memory reactivation.

Nightmare disorder (ND) is characterized by dreams with strong negative emotions occurring during rapid eye movement (REM) sleep. ND is mainly treated by imagery rehearsal therapy (IRT), where the patients are asked to change the negative story line of their nightmare to a more positive one. We here used targeted memory reactivation (TMR) during REM sleep to strengthen IRT-related memories and accelerate remission of ND. Thirty-six patients with ND were asked to perform an initial IRT session and, while they generated a positive outcome of their nightmare, half of the patients were exposed to a sound (TMR group), while no such pairing took place for the other half (control group). During the next 2 weeks, all patients performed IRT every evening at home and were exposed to the sound during REM sleep with a wireless headband, which automatically detected sleep stages. The frequency of nightmares per week at 2 weeks was used as the primary outcome measure. We found that the TMR group had less frequent nightmares and more positive dream emotions than the control group after 2 weeks of IRT and a sustained decrease of nightmares after 3 months. By demonstrating the effectiveness of TMR during sleep to potentiate therapy, these results have clinical implications for the management of ND, with relevance to other psychiatric disorders too. Additionally, these findings show that TMR applied during REM sleep can modulate emotions in dreams.

An examination of volumetric and cortical thickness correlates of posttraumatic nightmares in male active duty service members.

Posttraumatic nightmares commonly occur after a traumatic experience. Despite significant deleterious effects on well-being and their role in posttraumatic stress disorder, posttraumatic nightmares remain understudied. The neuroanatomical structures of the amygdala, medial prefrontal cortex, hippocampus, and anterior cingulate cortex constitute the AMPHAC model (Levin and Nielsen, 2007), which is implicated in the neurophysiology of disturbing dreams of which posttraumatic nightmares is a part. However, this model has not been investigated using neuroimaging data. The present study sought to determine whether there are structural differences in the AMPHAC regions in relation to the occurrence of posttraumatic nightmares. Data were obtained from treatment-seeking male active duty service members (N = 351). Posttraumatic nightmares were not significantly related to gray matter volume, cortical surface area, or cortical thickness of any the AMPHAC regions when controlling for age and history of mild traumatic brain injury. Although the present analyses do not support an association between structural measures of AMPHAC regions and posttraumatic nightmares, we suggest that functional differences within and/or between these brain regions may be related to the occurrence of posttraumatic nightmares because functional and structural associations are distinct. Future research should examine whether functional differences may be associated with posttraumatic nightmares.

The functions of sleep: A cognitive neuroscience perspective.

This Special Feature explores the various purposes served by sleep, describing current attempts to understand how the many functions of sleep are instantiated in neural circuits and cognitive structures. Our feature reflects current experts' opinions about, and insights into, the dynamic processes of sleep. In the last few decades, technological advances have supported the updated view that sleep plays an active role in both cognition and health. However, these roles are far from understood. This collection of articles evaluates the dynamic nature of sleep, how it evolves across the lifespan, becomes a competitive arena for memory systems through the influence of the autonomic system, supports the consolidation and integration of new memories, and how lucid dreams might originate. This set of papers highlights new approaches and insights that will lay the groundwork to eventually understand the full range of functions supported by sleep.

Predictive coding, multisensory integration, and attentional control: A multicomponent framework for lucid dreaming.

Lucid dreaming (LD) is a mental state in which we realize not being awake but are dreaming while asleep. It often involves vivid, perceptually intense dream images as well as peculiar kinesthetic sensations, such as flying, levitating, or out-of-body experiences. LD is in the cross-spotlight of cognitive neuroscience and sleep research as a particular case to study consciousness, cognition, and the neural background of dream experiences. Here, we present a multicomponent framework for the study and understanding of neurocognitive mechanisms and phenomenological aspects of LD. We propose that LD is associated with prediction error signals arising during sleep and occurring at higher or lower levels of the processing hierarchy. Prediction errors are resolved by generating a superordinate self-model able to integrate ambiguous stimuli arriving from sensory periphery and higher-order cortical regions. While multisensory integration enables lucidity maintenance and contributes to peculiar kinesthetic experiences, attentional control facilitates multisensory integration by dynamically regulating the balance between the influence of top-down mental models and the precision weighting of bottom-up sensory inputs. Our novel framework aims to link neural correlates of LD with current concepts of sleep and arousal regulation and provide testable predictions on interindividual differences in LD as well as neurocognitive mechanisms inducing lucid dreams.