Aperiodic neural activity distinguishes between phasic and tonic REM sleep.

Traditionally categorized as a uniform sleep phase, rapid eye movement sleep exhibits substantial heterogeneity with its phasic and tonic constituents showing marked differences regarding many characteristics. Here, we investigate how tonic and phasic states differ with respect to aperiodic neural activity, a marker of arousal and sleep. Rapid eye movement sleep heterogeneity was assessed using either binary phasic-tonic (n = 97) or continuous (in 60/97 participants) approach.

The influence of relative pubertal maturity on executive function development in adolescent girls.

A positive association between pubertal maturity as assessed by skeletal development, and specific cognitive abilities has recently been demonstrated in a cohort of adolescent girls. The current study explores the impact of chronological age and relative pubertal maturity on executive function within the same cohort. Relative maturity, determined by the difference between chronological age and skeletal age, establishes the criteria for enrolling participants into average, advanced, or delayed relative maturity subgroups.

Navigating Pubertal Goldilocks: The Optimal Pace for Hierarchical Brain Organization.

Adolescence is a timed process with an onset, tempo, and duration. Nevertheless, the temporal dimension, especially the pace of maturation, remains an insufficiently studied aspect of developmental progression. The primary objective is to estimate the precise influence of pubertal maturational tempo on the configuration of associative brain regions.

Analysis of slow and fast sleep spindle properties in Parkinson's disease - A comparative EEG study.

Study Objectives: Sleep disturbances and altered sleep macrostructure are common in Parkinson's disease (PD). Few studies have addressed the changes in sleep spindle (SS) properties in this movement disorder so far. SS seem to be fundamental of both sleep architecture and memory consolidation.

Overnight dynamics in scale-free and oscillatory spectral parameters of NREM sleep EEG.

Unfolding the overnight dynamics in human sleep features plays a pivotal role in understanding sleep regulation. Studies revealed the complex reorganization of the frequency composition of sleep electroencephalogram (EEG) during the course of sleep, however the scale-free and the oscillatory measures remained undistinguished and improperly characterized before. By focusing on the first four non-rapid eye movement (NREM) periods of night sleep records of 251 healthy human subjects (4-69 years), here we reveal the flattening of spectral slopes and decrease in several measures of the spectral intercepts during consecutive sleep cycles.

Scale-free and oscillatory spectral measures of sleep stages in humans.

Power spectra of sleep electroencephalograms (EEG) comprise two main components: a decaying power-law corresponding to the aperiodic neural background activity, and spectral peaks present due to neural oscillations. "Traditional" band-based spectral methods ignore this fundamental structure of the EEG spectra and thus are susceptible to misrepresenting the underlying phenomena. A fitting method that attempts to separate and parameterize the aperiodic and periodic spectral components called "fitting oscillations and one over f" (FOOOF) was applied to a set of annotated whole-night sleep EEG recordings of 251 subjects from a wide age range (4-69 years).

Maturation-dependent vulnerability of emotion regulation as a response to COVID-19 related stress in adolescents.

Background: The COVID-19 pandemic created unpredictable circumstances resulting in increased psychological strain. Here we investigate pandemic-related alterations in emotion regulation in adolescents assessed before and during the pandemic. We also take biological age into account in the response to the pandemic.

Visual imagery vividness declines across the lifespan.

The capacity to elicit vivid visual mental images varies within an extensive range across individuals between hyper- and aphantasia. It is not clear, however, whether imagery vividness is constant across the lifespan or changes during development and later in life. Without enforcing the constraints of strict experimental procedures and representativity across the entire population, our purpose was to explore the self-reported level of imagery vividness and determine the relative proportions of aphantasic/hyperphantasic participants in different age groups.

Musical training improves fine motor function in adolescents.

Background: Adolescence is a sensitive period in motor development but little is known about how long-term learning dependent processes shape hand function in tasks of different complexity.

Procedure: We mapped two fundamental aspects of hand function: simple repetitive and complex sequential finger movements, as a function of the length of musical instrumental training. We controlled maturational factors such as chronological and biological age of adolescent female participants (11 to 15 years of age, n = 114).

Topographical relocation of adolescent sleep spindles reveals a new maturational pattern in the human brain.

Current theories of human neural development emphasize the posterior-to-anterior pattern of brain maturation. However, this scenario leaves out significant brain areas not directly involved with sensory input and behavioral control. Suggesting the relevance of cortical activity unrelated to sensory stimulation, such as sleep, we investigated adolescent transformations in the topography of sleep spindles.

The adolescent pattern of sleep spindle development revealed by HD-EEG.

Sleep spindles are developmentally relevant cortical oscillatory patterns; however, they have mostly been studied by considering the entire spindle frequency range (11-15 Hz) without a distinction between the functionally and topographically different slow and fast spindles, using relatively few electrodes and analysing wide age-ranges. Here, we employ high-density night sleep electroencephalography in three age-groups between 12 and 20 years of age (30 females and 30 males) and analyse the adolescent developmental pattern of the four major parameters of slow and fast sleep spindles. Most of our findings corroborate those very few previous studies that also make a distinction between slow and fast spindles in their developmental analysis.

Ultrasonic bone age fractionates cognitive abilities in adolescence.

Adolescent development is not only shaped by the mere passing of time and accumulating experience, but it also depends on pubertal timing and the cascade of maturational processes orchestrated by gonadal hormones. Although individual variability in puberty onset confounds adolescent studies, it has not been efficiently controlled for. Here we introduce ultrasonic bone age assessment to estimate biological maturity and disentangle the independent effects of chronological and biological age on adolescent cognitive abilities.

Sleep alterations are related to cognitive symptoms in Parkinson's disease: A 24-hour ambulatory polygraphic EEG study.

Background: Sleep disorders are frequent and early non-motor symptoms of Parkinson's disease (PD). As a consequence of histopathological changes, the regulation of rapid eye movement (REM) sleep is affected in PD causing REM sleep behaviour disorder in about half of the patients. Considering the well-known role of sleep in memory formation processes, our aim was to investigate the relationship between sleep alterations and cognitive performance to elucidate the possible association between sleep, and especially REM sleep changes and cognitive dysfunction in PD.

Sleep-spindle frequency: Overnight dynamics, afternoon nap effects, and possible circadian modulation.

Homeostatic and circadian processes play a pivotal role in determining sleep structure, timing, and quality. In sharp contrast with the wide accessibility of the electroencephalogram (EEG) index of sleep homeostasis, an electrophysiological measure of the circadian modulation of sleep is still unavailable. Evidence suggests that sleep-spindle frequencies decelerate during biological night.

REM Sleep Microstates in the Human Anterior Thalamus.

Rapid eye movement (REM) sleep is an elusive neural state that is associated with a variety of functions from physiological regulatory mechanisms to complex cognitive processing. REM periods consist of the alternation of phasic and tonic REM microstates that differ in spontaneous and evoked neural activity. Although previous studies indicate, that cortical and thalamocortical activity differs across phasic and tonic microstates, the characterization of neural activity, particularly in subcortical structures that are critical in the initiation and maintenance of REM sleep is still limited in humans.

A set of composite, non-redundant EEG measures of NREM sleep based on the power law scaling of the Fourier spectrum.

Features of sleep were shown to reflect aging, typical sex differences and cognitive abilities of humans. However, these measures are characterized by redundancy and arbitrariness. Our present approach relies on the assumptions that the spontaneous human brain activity as reflected by the scalp-derived electroencephalogram (EEG) during non-rapid eye movement (NREM) sleep is characterized by arrhythmic, scale-free properties and is based on the power law scaling of the Fourier spectra with the additional consideration of the rhythmic, oscillatory waves at specific frequencies, including sleep spindles.

The laminar profile of sleep spindles in humans.

Sleep spindles are functionally important NREM sleep EEG oscillations which are generated in thalamocortical, corticothalamic and possibly cortico-cortical circuits. Previous hypotheses suggested that slow and fast spindles or spindles with various spatial extent may be generated in different circuits with various cortical laminar innervation patterns. We used NREM sleep EEG data recorded from four human epileptic patients undergoing presurgical electrophysiological monitoring with subdural electrocorticographic grids (ECoG) and implanted laminar microelectrodes penetrating the cortex (IME).

First report on parasites of European beavers in the Slovak Republic.

European beaver (Castor fiber L. 1758) is the biggest rodent living in Europe. It is a semi-aquatic animal known for building dams and burrows.

REM versus Non-REM sleep disturbance specifically affects inter-specific emotion processing in family dogs (Canis familiaris).

Dogs have outstanding capabilities to read human emotional expressions, both vocal and facial. It has also been shown that positively versus negatively valenced dog-human social interactions substantially affect dogs' subsequent sleep. In the present study, we manipulated dogs' (N = 15, in a within subject design) sleep structure by specifically disrupting REM versus Non-REM sleep, while maintaining equal sleep efficiency (monitored via non-invasive polysomnography).

Reliability of Family Dogs' Sleep Structure Scoring Based on Manual and Automated Sleep Stage Identification.

Non-invasive polysomnography recording on dogs has been claimed to produce data comparable to those for humans regarding sleep macrostructure, EEG spectra and sleep spindles. While functional parallels have been described relating to both affective (e.g.

Repeated afternoon sleep recordings indicate first-night-effect-like adaptation process in family dogs.

The importance of dogs (Canis familiaris) in sleep research is primarily based on their comparability with humans. In spite of numerous differences, dogs' comparable sleep pattern, as well as several phenotypic similarities on both the behavioural and neural levels, make this species a most feasible model in many respects. Our aim was to investigate whether the so-called first-night effect, which in humans manifests as a marked macrostructure difference between the first and second sleep occasions, can be observed in family dogs.

Hyperarousal captured in increased number of arousal events during pre-REM periods in individuals with frequent nightmares.

The aim of this study was to investigate hyperarousal in individuals with frequent nightmares (NM participants) by calculating arousal events during nocturnal sleep. We hypothesized an increased number of arousals in NM participants compared with controls, especially during those periods where the probability of spontaneous arousal occurrence is already high, such as non-rapid eye movement to rapid eye movement transitions (pre-rapid eye movement periods). Twenty-two NM participants and 23 control participants spent two consecutive nights in our sleep laboratory, monitored by polysomnography.

Cortical hyperarousal in NREM sleep normalizes from pre- to post- REM periods in individuals with frequent nightmares.

Study Objectives: Frequent nightmares have a high prevalence and constitute a risk factor for psychiatric conditions, but their pathophysiology is poorly understood. Our aim was to examine sleep architecture and electroencephalographic markers-with a specific focus on state transitions-related to sleep regulation and hyperarousal in participants with frequent nightmares (NM participants) versus healthy controls.

Methods: Healthy controls and NM participants spent two consecutive nights in the sleep laboratory.

The paradox of rapid eye movement sleep in the light of oscillatory activity and cortical synchronization during phasic and tonic microstates.

Rapid Eye Movement (REM) sleep is a peculiar neural state showing a combination of muscle atonia and intense cortical activity. REM sleep is usually considered as a unitary state in neuroscientific research; however, it is composed of two different microstates: phasic and tonic REM. These differ in awakening thresholds, sensory processing, and cortical oscillations.

Sleep EEG functional connectivity varies with age and sex, but not general intelligence.

Variations in the anatomical and functional connectivity between brain areas underlie both healthy and pathological variation in psychological measures. Largely independent from external stimuli, the sleep EEG is particularly well suited to measure individual variations in functional brain connectivity. In this study of 172 healthy individuals (17-69 years old), we show that functional connectivity between distant brain areas-reflected by the weighted phase lag index of the sleep EEG-is strongly affected by the age and sex of participants.