Neurosci Biobehav Rev
December 2024
Disorders of Arousal (DOA) are non-rapid eye movement (NREM) parasomnias traditionally regarded as unconscious states. However, recent research challenges this assumption. This narrative review aims to explore the presence and qualitative features of conscious experiences in patients with DOA during their episodes.
View Article and Find Full Text PDFDreaming, a common yet mysterious cognitive phenomenon, is an involuntary process experienced by individuals during sleep. Although the fascination with dreams dates back to ancient times and gained therapeutic significance through psychoanalysis in the early twentieth century, its scientific investigation only gained momentum with the discovery of rapid eye movement (REM) sleep in the 1950s. This review synthesises current research on the neurobiological and psychological aspects of dreaming, including factors influencing dream recall and content, neurophysiological correlates, and experimental models, and discusses the implications for clinical practice.
View Article and Find Full Text PDFSleepwalking 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.
View Article and Find Full Text PDFSleepwalking and related parasomnias result from incomplete awakenings out of non-rapid eye movement sleep. Behavioral episodes can occur without consciousness or recollection, or in relation to dream-like experiences. To understand what accounts for these differences in consciousness and recall, here we recorded parasomnia episodes with high-density electroencephalography (EEG) and interviewed participants immediately afterward about their experiences.
View Article and Find Full Text PDFWhole-night sleep electroencephalogram (EEG) is plagued by several types of large-amplitude artifacts. Common approaches to remove them are fraught with issues: channel interpolation, rejection of noisy intervals, and independent component analysis are time-consuming, rely on subjective user decisions, and result in signal loss. Artifact Subspace Reconstruction (ASR) is an increasingly popular approach to rapidly and automatically clean wake EEG data.
View Article and Find Full Text PDFIt is currently unclear which patients with obstructive sleep apnea (OSA) are at increased cardiovascular risk. To investigate the value of pulse wave amplitude drops (PWADs), reflecting sympathetic activations and vasoreactivity, as a biomarker of cardiovascular risk in OSA. PWADs were derived from pulse oximetry-based photoplethysmography signals in three prospective cohorts: HypnoLaus ( = 1,941), the Pays-de-la-Loire Sleep Cohort (PLSC; = 6,367), and "Impact of Sleep Apnea syndrome in the evolution of Acute Coronary syndrome.
View Article and Find Full Text PDFStudy Objectives: Although recent investigations combining noradrenergic and antimuscarinic drugs have shown promising short-term results to treat obstructive sleep apnea (OSA), the mid-term effect and optimal dosage remain uncertain. The present study aimed to evaluate the effect of 1 week of 5 mg oxybutynin and 6 mg reboxetine (oxy-reb) on OSA versus placebo.
Methods: We performed a randomized, placebo-controlled, double-blind, crossover trial comparing the effect of 1 week of oxy-reb versus 1 week of placebo on OSA severity.
Background Poor sleep quality is associated with increased incident hypertension. However, few studies have investigated the impact of objective sleep structure parameters on hypertension. This study investigated the association between sleep macrostructural and microstructural parameters and incident hypertension in a middle- to older-aged sample.
View Article and Find Full Text PDFStudy Objectives: Sleepwalking, confusional arousals, and sleep terrors are parasomnias occurring out of non-rapid eye movement (NREM) sleep. Several previous studies have described EEG changes associated with NREM parasomnia episodes, but it remains unclear whether these changes are specific to parasomnia episodes or whether they are part of the normal awakening process. Here we directly compared regional brain activity, measured with high-density (hd-) EEG, between parasomnia episodes and normal awakenings (without behavioral manifestations of parasomnia).
View Article and Find Full Text PDFWhat accounts for feeling deeply asleep? Standard sleep recordings only incompletely reflect subjective aspects of sleep and some individuals with so-called sleep misperception frequently feel awake although sleep recordings indicate clear-cut sleep. To identify the determinants of sleep perception, we performed 787 awakenings in 20 good sleepers and 10 individuals with sleep misperception and interviewed them about their subjective sleep depth while they underwent high-density EEG sleep recordings. Surprisingly, in good sleepers, sleep was subjectively lightest in the first 2 h of non-rapid eye movement (NREM) sleep, generally considered the deepest sleep, and deepest in rapid eye movement (REM) sleep.
View Article and Find Full Text PDFBenzodiazepines have proven to be highly effective for treating insomnia and anxiety. Although considered safe when taken for a short period of time, a major risk-benefit dilemma arises in the context of long-term use, relating to addiction, withdrawal symptoms, and potential side effects. For these reasons, benzodiazepines are not recommended for treating chronic sleep disorders, anxiety disorders, nor for people over the age of 65, and withdrawal among long-term users is a public health issue.
View Article and Find Full Text PDFSleep spindles of non-REM sleep are transient, waxing-and-waning 10-16 Hz EEG oscillations, whose cortical synchronization depends on the engagement of thalamo-cortical loops. However, previous studies in animal models lacking the corpus callosum due to agenesis or total callosotomy and in humans with agenesis of the corpus callosum suggested that cortico-cortical connections may also have a relevant role in cortical (inter-hemispheric) spindle synchronization. Yet, most of these works did not provide direct quantitative analyses to support their observations.
View Article and Find Full Text PDFObjectives: Existing data suggest that smoking may be associated with sleep disturbances. This study aimed to determine the association between smoking and both subjective and objective sleep quality.
Methods: Cross-sectional analysis of sleep characteristics in 3233 participants from the population-based CoLaus-HypnoLaus cohort (52.
EEG slow waves, the hallmarks of NREM sleep are thought to be crucial for the regulation of several important processes, including learning, sensory disconnection and the removal of brain metabolic wastes. Animal research indicates that slow waves may involve complex interactions within and between cortical and subcortical structures. Conventional EEG in humans, however, has a low spatial resolution and is unable to accurately describe changes in the activity of subcortical and deep cortical structures.
View Article and Find Full Text PDFFunctional connectivity (FC) metrics describe brain inter-regional interactions and may complement information provided by common power-based analyses. Here, we investigated whether the FC-metrics weighted Phase Lag Index (wPLI) and weighted Symbolic Mutual Information (wSMI) may unveil functional differences across four stages of vigilance-wakefulness (W), NREM-N2, NREM-N3, and REM sleep-with respect to each other and to power-based features. Moreover, we explored their possible contribution in identifying differences between stages characterized by distinct levels of consciousness (REM+W vs.
View Article and Find Full Text PDFDreams are internally generated experiences that occur independently of current sensory input. Here we argue, based on cortical anatomy and function, that dream experiences are tightly related to the workings of a specific part of cortical pyramidal neurons, the apical integration zone (AIZ). The AIZ receives and processes contextual information from diverse sources and could constitute a major switch point for transitioning from externally to internally generated experiences such as dreams.
View Article and Find Full Text PDFDreams are experiences that occur during sleep, while we are disconnected from the environment. Thanks to recent progress in neuroimaging techniques, it is now becoming possible to relate dream features to specific patterns of brain activity. Some conditions occurring in patients with neurological disorders, such as lucid dreams and parasomnias, not only have diagnostic value, but also offer a window into the dream process.
View Article and Find Full Text PDFIt has been known for some time that the brain can react selectively to meaningful sensory stimuli during sleep. A recent study shows that this ability may be selectively suppressed during rapid eye movements of sleep.
View Article and Find Full Text PDFThe slow waves of non-rapid eye movement (NREM) sleep reflect experience-dependent plasticity and play a direct role in the restorative functions of sleep. Importantly, slow waves behave as traveling waves, and their propagation is assumed to occur through cortico-cortical white matter connections. In this light, the corpus callosum (CC) may represent the main responsible for cross-hemispheric slow-wave propagation.
View Article and Find Full Text PDFAlthough excessive daytime sleepiness is commonly evaluated in clinical and research settings using the Epworth Sleepiness Scale, few studies have assessed the factors associated with its incidence in the general population. We prospectively investigated the predictors of incident and persistent excessive daytime sleepiness in 2,751 subjects (46.1% men, mean age 56.
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