Spectral Slope and Lempel–Ziv Complexity as Robust Markers of Brain States during Sleep and Wakefulness

eNeuro, Journal Year: 2024, Volume and Issue: 11(3), P. ENEURO.0259 - 23.2024

Published: March 1, 2024

Nonoscillatory measures of brain activity such as the spectral slope and Lempel–Ziv complexity are affected by many neurological disorders modulated sleep. A multitude frequency ranges, particularly a broadband (encompassing full spectrum) narrowband approach, have been used especially for estimating slope. However, effects choosing different ranges not yet explored in detail. Here, we evaluated impact sleep stage task engagement (resting, attention, memory) on (30–45 Hz) (1–45 range 28 healthy male human subjects (21.54 ± 1.90 years) using within-subject design over 2 weeks with three recording nights days per subject. We strived to determine how states affect two perform comparison. In range, steepened, decreased continuously from wakefulness N3 REM sleep, however, was best discriminated Importantly, also differed between tasks during wakefulness. While engagement, flattened both ranges. Interestingly, only positively correlated performance. Our results show that sensitive indices state variations yields more information could be greater variety research questions than complexity, when is used.

Language: Английский

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Human REM sleep recalibrates neural activity in support of memory formation

Science Advances, Journal Year: 2023, Volume and Issue: 9(34)

Published: Aug. 25, 2023

The proposed mechanisms of sleep-dependent memory consolidation involve the overnight regulation neural activity at both synaptic and whole-network levels. Now, there is a lack in vivo data humans elucidating if, how, sleep its varied stages balance activity, if such recalibration benefits memory. We combined electrophysiology with two-photon calcium imaging rodents as well intracranial scalp electroencephalography (EEG) to reveal key role for non-oscillatory brain during rapid eye movement (REM) mediate population dynamics. extent this REM predicted success consolidation, expressly modulation hippocampal-neocortical favoring remembering rather than forgetting. findings describe mechanism how human modulates enhance long-term

Language: Английский

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Fundamentals of sleep regulation: Model and benchmark values for fractal and oscillatory neurodynamics

Progress in Neurobiology, Journal Year: 2024, Volume and Issue: 234, P. 102589 - 102589

Published: March 1, 2024

Homeostatic, circadian and ultradian mechanisms play crucial roles in the regulation of sleep. Evidence suggests that ratios low-to-high frequency power electroencephalogram (EEG) spectrum indicate instantaneous level sleep pressure, influenced by factors such as individual sleep-wake history, current stage, age-related differences brain topography characteristics. These effects are well captured reflected spectral exponent, a composite measure constant ratio periodogram, which is scale-free exhibits lower interindividual variability compared to slow wave activity, potentially serving suitable standardization reference measure. Here we propose an index homeostasis based on reflecting membrane hyperpolarization and/or network bistability central nervous system humans. In addition, advance idea U-shaped overnight deceleration oscillatory fast spindle frequencies marks biological night, providing somnologists with EEG-index regulation. supporting this assertion comes from studies replacement, forced desynchrony protocols high-resolution analyses spindles. Finally, regulatory indicated recurrent, abrupt shifts dominant frequencies, ranges signifying non-rapid eye movement non-spindle oscillations – rapid phases cycles. Reconsidering indicators fundamental processes framework new Fractal Oscillatory Adjustment Model (FOAM) offers appealing opportunity bridge gap between two-process model clinical somnology.

Language: Английский

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The Temporal Dynamics of Aperiodic Neural Activity Track Changes in Sleep Architecture

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 26, 2024

Abstract The aperiodic (1/f-like) component of electrophysiological data - whereby power systematically decreases with increasing frequency, as quantified by the exponent has been shown to differentiate sleep stages. Earlier work, however, typically focused on measuring across a narrow frequency range. In this we sought further investigate activity during extending these analyses broader ranges and considering alternate model definitions. This included ‘knees’ in component, which reflect bends spectrum, indicating change exponent. We also evaluate temporal dynamics sleep. To do so, analyzed from two sources: intracranial EEG (iEEG) 106 epilepsy patients high-density 17 healthy individuals, measured activity, explicitly comparing different forms. doing find that fitting broadband models incorporating ‘knee’ feature effectively captures sleep-stage-dependent differences well relate stage transitions responses external stimuli. particular, knee parameter shows stage-specific variation, suggesting an interpretation varying timescales These results demonstrate examining more complex reveals novel insights interpretations for understanding neural

Language: Английский

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The National Sleep Research Resource: making data findable, accessible, interoperable, reusable and promoting sleep science

SLEEP, Journal Year: 2024, Volume and Issue: 47(7)

Published: April 30, 2024

This paper presents a comprehensive overview of the National Sleep Research Resource (NSRR), Heart Lung and Blood Institute-supported repository developed to share data from clinical studies focused on evaluation sleep disorders. The NSRR addresses challenges presented by heterogeneity sleep-related data, leveraging innovative strategies optimize quality accessibility available datasets. It provides authorized users with secure centralized access large quantity including polysomnography, actigraphy, demographics, patient-reported outcomes, other data. In developing NSRR, we have implemented processing protocols that ensure de-identification compliance FAIR (Findable, Accessible, Interoperable, Reusable) principles. Heterogeneity stemming intrinsic variation in collection, annotation, definition, interpretation has proven be one primary obstacles efficient sharing Approaches employed address this include (1) development standardized terminologies utilizing compositional coding scheme, (2) specification metadata, (3) harmonization commonly used variables, computational tools standardize signal processing. We also leveraged external resources engineer domain-specific approach harmonization. describe scope within its role promoting circadian research through sharing, datasets analytical tools. Finally, identify opportunities for approaches field medicine further support standardization sharing.

Language: Английский

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The spectral slope as a marker of excitation/inhibition ratio and cognitive functioning in multiple sclerosis

Human Brain Mapping, Journal Year: 2023, Volume and Issue: 44(17), P. 5784 - 5794

Published: Sept. 6, 2023

Multiple sclerosis (MS) is a neurodegenerative disease characterized by neuronal and synaptic loss, resulting in an imbalance of excitatory inhibitory transmission potentially cognitive impairment. Current methods for measuring the excitation/inhibition (E/I) ratio are mostly invasive, but recent research combining neurocomputational modeling with measurements local field potentials has indicated that slope which power spectrum activity captured electro- and/or magnetoencephalography rolls off, non-invasive biomarker E/I ratio. A steeper roll-off associated stronger inhibition. This novel method can be applied to assess people multiple (pwMS), detect effect medication such as benzodiazepines, explore its utility cognition. We recruited 44 healthy control subjects 95 pwMS who underwent resting-state magnetoencephalographic recordings. The 1/f spectral neural spectra was calculated each subject brain region. As expected, significantly treated benzodiazepines (BZDs) compared not receiving BZDs (p = .01). In sub-cohort BZDs, we observed cognitively impaired preserved .01) .02). Furthermore, significant correlation between verbal spatial working memory functioning regions located prefrontal parietal cortex. this study, highlighted value MS quantifying putting it forward potential deficits pwMS.

Language: Английский

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Neural complexity and the spectral slope characterise auditory processing in wakefulness and sleep

European Journal of Neuroscience, Journal Year: 2023, Volume and Issue: 59(5), P. 822 - 841

Published: Dec. 15, 2023

Auditory processing and the complexity of neural activity can both indicate residual consciousness levels differentiate states arousal. However, how measures signal manifest in following environmental stimulation and, more generally, electrophysiological characteristics auditory responses change reduced remain under-explored. Here, we tested hypothesis that spectral slope would discriminate stages sleep wakefulness not only baseline electroencephalography (EEG) but also EEG signals stimulation. High-density was recorded 21 participants to determine spatial relationship between these pre- post-auditory Results showed 2-20 Hz range discriminated had a high correlation sleep. In wakefulness, strongly correlated 20-40 slope. resulted compared pre-stimulation modulated wakefulness. These findings confirm our markers arousal are sensitive sleep/wake during Our results have direct applications studies using probe functions consciousness.

Language: Английский

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Spontaneous oxycodone withdrawal disrupts sleep, diurnal, and electrophysiological dynamics in rats

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(1), P. e0312794 - e0312794

Published: Jan. 17, 2025

Opioid dependence is defined by an aversive withdrawal syndrome upon drug cessation that can motivate continued drug-taking, development of opioid use disorder, and precipitate relapse. An understudied but common symptom disrupted sleep, reported as both insomnia daytime sleepiness. Despite the prevalence severity sleep disturbances during withdrawal, there a gap in our understanding their interactions. The goal this study was to establish in-depth, temporal signature spontaneous oxycodone effects on diurnal composition discrete stages dynamic spectral properties electroencephalogram (EEG) signal male rats. We continuously recorded EEG electromyography (EMG) signals for 8 d after 14-d escalating-dose regimen (0.5–8.0 mg/kg, 2×d; SC). During profound loss (peaking days 2–3) gradual return structure body temperature, locomotor activity, well decreased wake bout durations dependent lights on/off. Withdrawal associated with significant alterations slope aperiodic 1/f component power spectrum, established biomarker arousal level. Early NREM exhibited acute flattening baseline low (1–4 Hz) high (15–50 frequency components spectrum. These findings suggest temporally reflecting complex way which allostatic forces impinge processes. foundational data based continuous tracking vigilance state, stage composition, provide detailed construct form test hypotheses mechanisms opioid-sleep

Language: Английский

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Age-related changes in “cortical” 1/f dynamics are linked to cardiac activity

Published: April 14, 2025

The power of electrophysiologically measured cortical activity decays with an approximately 1/f X function. slope this decay (i.e. the spectral exponent, ) is modulated by various factors such as age, cognitive states or psychiatric/neurological disorders. Interestingly, a mostly parallel line research has also uncovered similar effects for in electrocardiogram (ECG). This raises question whether these bodywide changes slopes are (in-)dependent. Focusing on well-established age-related we analyzed total 1282 recordings magnetoencephalography (MEG) resting state measurements concurrent ECG age-diverse sample (18-88 years). Using diverse array analytical approaches, demonstrate that aperiodic signal recorded via surface electrodes/sensors originates from multiple physiological sources. Furthermore, our results suggest common “artifact” rejection approaches ICA) may not be sufficient to separate cardiac neural activity. In particular, significant parts normally interpreted origin can explained Moreover, (flattening/steepening) age dependent recording site and investigated frequency range. Our highlight complexity while raising concerns when interpreting “cortical“ without considering influences.

Language: Английский

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Rényi entropy-complexity causality space: a novel neurocomputational tool for detecting scale-free features in EEG/iEEG data

Frontiers in Computational Neuroscience, Journal Year: 2024, Volume and Issue: 18

Published: July 15, 2024

Scale-free brain activity, linked with learning, the integration of different time scales, and formation mental models, is correlated a metastable cognitive basis. The spectral slope, key aspect scale-free dynamics, was proposed as potential indicator to distinguish between sleep stages. Studies suggest that networks maintain consistent structure across wakefulness, anesthesia, recovery. Although differences in anesthetic sensitivity sexes are recognized, these variations not evident clinical electroencephalographic recordings cortex. Recently, changes slope power law exponent neural activity were found correlate Rényi entropy, an extended concept Shannon's information entropy. These findings establish quantifiers promising tool for study dynamics brain. Our presents novel visual representation called entropy-complexity causality space, which encapsulates complexity, permutation parameter q. main goal this define space classical dynamical systems within theoretical bounds. In addition, aims investigate how well series mimicking can be discriminated. Finally, used detect dynamic features intracranial electroencephalography (iEEG) signals. To achieve goals, implementse Bandt Pompe method ordinal patterns. process, each signal associated probability distribution, causal measures entropy complexity computed based on This valuable analyzing simulated series. It effectively distinguishes elements noise provides straightforward means examining behaviors, characteristics, classifications. For iEEG experimental data, REM state showed greater number significant sex-based differences, while supramarginal gyrus region most variation modes analyzes. Exploring framework could provide insights into cognition neurological disorders. results may have implications understanding function their possible relevance

Language: Английский

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