scholarly journals Standing Sentinel during Human Sleep: Continued Evaluation of Environmental Stimuli in the Absence of Consciousness

2017 ◽  
Author(s):  
Christine Blume ◽  
Renata del Giudice ◽  
Malgorzata Wislowska ◽  
Dominik P. J. Heib ◽  
Manuel Schabus
Keyword(s):  
Information Processing ◽  
Rem Sleep ◽  
Nrem Sleep ◽  
Negative Slope ◽  
Sleep Stages ◽  
Sleep Spindles ◽  
Environmental Stimuli ◽  
Stimulus Salience ◽  
The Mind ◽  
Austrian Science Fund

AbstractWhile it is a well-established finding that subject’s own names (SON) or familiar voices are salient during wakefulness, we here investigated processing of environmental stimuli during sleep including deep N3 and REM sleep. Besides the effects of sleep depth we investigated how sleep-specific EEG patterns (i.e. sleep spindles and slow oscillations [SOs]) relate to stimulus processing. Using 256-channel EEG we studied processing of auditory stimuli by means of event-related oscillatory responses (de-/ synchronisation, ERD/ERS) and potentials (ERPs) in N = 17 healthy sleepers. We varied stimulus salience by manipulating subjective (SON vs. unfamiliar name) and paralinguistic emotional relevance (familiar vs. unfamiliar voice, FV/UFV). Results reveal that evaluation of voice familiarity continues during all NREM sleep stages and even REM sleep suggesting a ‘sentinel processing mode’ of the human brain in the absence of wake-like consciousness. Especially UFV stimuli elicit larger responses in a 1-15 Hz range suggesting they continue being salient. Beyond this, we find that sleep spindles and the negative slope of SOs attenuate information processing. However, unlike previously suggested they do not uniformly inhibit information processing, but inhibition seems to be scaled to stimulus salience.FundingCB is supported by the Konrad-Adenauer-Stiftung e.V. and CB, MW and DPJH are supported by a grant from the Austrian Science Fund FWF (Y-777). CB, RdG, MW and DPJH are also supported by the Doctoral College “Imaging the Mind” (FWF; W1233-G17).

scholarly journals Contribution of REM sleep and N2 sleep spindles to procedural memory consolidation in Vipassana meditators and non-meditating controls.

2017 ◽  
Author(s):  
Elizaveta Solomonova ◽  
Simon Dubé ◽  
Cloé Blanchette-Carrière ◽  
Arnaud Samson-Richer ◽  
Michelle Carr ◽  
...  
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Memory Consolidation ◽  
Nrem Sleep ◽  
Procedural Memory ◽  
Sleep Stages ◽  
Sleep Spindles ◽  
Meditation Practice ◽  
Rapid Eye Movement ◽  
Vipassana Meditation

Study objectives: Rapid eye movement (REM) sleep, non-rapid eye movement (NREM) sleep, and sleep spindles are all implicated in the consolidation of procedural memories. The relative contributions of sleep stages and sleep spindles was previously shown to depend on individual differences in task processing. Experience with Vipassana meditation is one such individual difference that has not been investigated in relation to sleep. Vipassana meditation is a form of mental training that enhances proprioceptive and somatic awareness and alters attentional style. The goal was thus to examine a potential moderating role for Vipassana meditation experience on sleep-dependent procedural memory consolidation.Methods: Groups of Vipassana meditation practitioners (N=20) and matched meditation-naïve controls (N=20) slept for a single daytime nap in the laboratory. Before and after the nap they completed a procedural task on the Wii Fit balance platform.Results: Meditators performed slightly better on the task before the nap, but the two groups improved similarly after sleep. The groups showed different patterns of sleep-dependent procedural memory consolidation: in meditators task learning was negatively correlated with density of fast and positively correlated with density of slow occipital spindles, while in controls task improvement was associated with increases in REM sleep. Meditation practitioners had a lower density of sleep spindles, especially in occipital regions.Conclusions: Results suggest that neuroplastic changes associated with sustained meditation practice may alter overall sleep architecture and reorganize sleep-dependent patterns of memory consolidation. The lower density of spindles in meditators may mean that meditation practice compensates for some of the memory functions of sleep.

scholarly journals Shining a Light on the Mechanisms of Sleep for Memory Consolidation

2021 ◽  
Author(s):  
Michelle A. Frazer ◽  
Yesenia Cabrera ◽  
Rockelle S. Guthrie ◽  
Gina R. Poe
Keyword(s):  
Rem Sleep ◽  
Neural Activity ◽  
Memory Consolidation ◽  
Strong Support ◽  
Nrem Sleep ◽  
Future Research ◽  
Sleep Spindles ◽  
Slow Oscillations ◽  
Theta Waves ◽  
Learning Tasks

Abstract Purpose of review This paper reviews all optogenetic studies that directly test various sleep states, traits, and circuit-level activity profiles for the consolidation of different learning tasks. Recent findings Inhibiting or exciting neurons involved either in the production of sleep states or in the encoding and consolidation of memories reveals sleep states and traits that are essential for memory. REM sleep, NREM sleep, and the N2 transition to REM (characterized by sleep spindles) are integral to memory consolidation. Neural activity during sharp-wave ripples, slow oscillations, theta waves, and spindles are the mediators of this process. Summary These studies lend strong support to the hypothesis that sleep is essential to the consolidation of memories from the hippocampus and the consolidation of motor learning which does not necessarily involve the hippocampus. Future research can further probe the types of memory dependent on sleep-related traits and on the neurotransmitters and neuromodulators required.

scholarly journals Nonrapid eye movement sleep electroencephalographic oscillations in idiopathic rapid eye movement sleep behavior disorder: a study of sleep spindles and slow oscillations

SLEEP ◽  
2020 ◽  
Author(s):  
Jun-Sang Sunwoo ◽  
Kwang Su Cha ◽  
Jung-Ick Byun ◽  
Jin-Sun Jun ◽  
Tae-Joon Kim ◽  
...  
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
Rem Sleep Behavior Disorder ◽  
Behavior Disorder ◽  
Nrem Sleep ◽  
Sleep Spindles ◽  
Rapid Eye Movement ◽  
Sleep Behavior ◽  
Slow Oscillations ◽  
Lower Amplitude

Abstract Study Objectives We investigated electroencephalographic (EEG) slow oscillations (SOs), sleep spindles (SSs), and their temporal coordination during nonrapid eye movement (NREM) sleep in patients with idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD). Methods We analyzed 16 patients with video-polysomnography-confirmed iRBD (age, 65.4 ± 6.6 years; male, 87.5%) and 10 controls (age, 62.3 ± 7.5 years; male, 70%). SSs and SOs were automatically detected during stage N2 and N3. We analyzed their characteristics, including density, frequency, duration, and amplitude. We additionally identified SO-locked spindles and examined their phase distribution and phase locking with the corresponding SO. For inter-group comparisons, we used the independent samples t-test or Wilcoxon rank-sum test, as appropriate. Results The SOs of iRBD patients had significantly lower amplitude, longer duration (p = 0.005 for both), and shallower slope (p < 0.001) than those of controls. The SS power of iRBD patients was significantly lower than that of controls (p = 0.002), although spindle density did not differ significantly. Furthermore, SO-locked spindles of iRBD patients prematurely occurred during the down-to-up-state transition of SOs, whereas those of controls occurred at the up-state peak of SOs (p = 0.009). The phase of SO-locked spindles showed a positive correlation with delayed recall subscores (p = 0.005) but not with tonic or phasic electromyography activity during REM sleep. Conclusions In this study, we found abnormal EEG oscillations during NREM sleep in patients with iRBD. The impaired temporal coupling between SOs and SSs may reflect early neurodegenerative changes in iRBD.

scholarly journals Vigilance and behavioral state-dependent modulation of cortical neuronal activity throughout the sleep/wake cycle

2021 ◽  
Author(s):  
Aurelie Brecier ◽  
Melodie Borel ◽  
Nadia Urbain ◽  
Luc J Gentet
Keyword(s):  
Neuronal Activity ◽  
Rem Sleep ◽  
Barrel Cortex ◽  
Field Potential ◽  
Nrem Sleep ◽  
Inhibitory Neurons ◽  
Sleep Stages ◽  
Theta Waves ◽  
Physiological Diversity ◽  
Activity Dynamics

GABAergic inhibitory neurons, through their molecular, anatomic and physiological diversity, provide a substrate for the modulation of ongoing cortical circuit activity throughout the sleep-wake cycle. Here, we investigated neuronal activity dynamics of parvalbumin (PV), vasoactive intestinal polypeptide (VIP) and somatostatin (SST) neurons in naturally-sleeping head-restrained mice at the level of layer 2/3 of the primary somatosensory barrel cortex of mice. Through calcium-imaging and targeted single-unit loose-patch or whole-cell recordings, we found that PV action potential (AP) firing activity was largest during both NREM (non-rapid eye movement) and REM sleep stages, that VIP neurons were activated during REM sleep and that the overall activity of SST neurons remained stable throughout the sleep/wake cycle. Analysis of neuronal activity dynamics uncovered rapid decreases in PV cell firing at wake onset followed by a progressive recovery during wake. Simultaneous local field potential (LFP) recordings further revealed that, except for SST neurons, a large proportion of neurons were modulated by ongoing delta and theta waves. During NREM sleep spindles, PV and SST activity increased and decreased, respectively. Finally, we uncovered the presence of whisking behavior in mice during REM sleep and show that the activity of VIP and SST is differentially modulated during awake and sleeping whisking bouts, which may provide a neuronal substrate for internal brain representations occurring during sleep.

scholarly journals Don't count your chickens before they're hatched: Elaborative encoding in REM dreaming in face of the physiology of sleep stages

2013 ◽  
Vol 36 (6) ◽  
pp. 613-614
Author(s):  
Gaétane Deliens ◽  
Sophie Schwartz ◽  
Philippe Peigneux
Keyword(s):  
Eye Movement ◽  
Rem Sleep ◽  
De Novo ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Rapid Eye Movement ◽  
Hidden Patterns ◽  
Episodic Memories ◽  
Novel Associations

AbstractLlewellyn suggests that episodic memories undergo “elaborative encoding” during rapid eye movement (REM) dreams, generating novel associations between recent and remote memories that are then instantiated during non-REM (NREM) sleep. This hypothesis conflicts with our knowledge of the physiology of NREM and then REM sleep stages and their ordered succession. Moreover, associations during sleep might also involve the extraction of hidden patterns rather than de novo associations.

scholarly journals Does Obstructive Sleep Apnea Worsen During REM Sleep?

2013 ◽  
pp. 569-575 ◽  
Author(s):  
I. PEREGRIM ◽  
S. GREŠOVÁ ◽  
M. PALLAYOVÁ ◽  
B. L. FULTON ◽  
J. ŠTIMMELOVÁ ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Rem Sleep ◽  
Body Position ◽  
Statistical Significance ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Lateral Body ◽  
Obstructive Sleep ◽  
Significant Difference

Although it is thought that obstructive sleep apnea (OSA) is worse during rapid eye movement (REM) sleep than in non-REM (NREM) sleep there are some uncertainties, especially about apnoe-hypopnoe-index (AHI). Several studies found no significant difference in AHI between both sleep stages. However, REM sleep is associated more with side sleeping compared to NREM sleep, which suggests that body position is a possible confounding factor. The main purpose of this study was to compare the AHI in REM and NREM sleep in both supine and lateral body position. A retrospective study was performed on 422 consecutive patients who underwent an overnight polysomnography. Women had higher AHI in REM sleep than NREM sleep in both supine (46.05±26.26 vs. 23.91±30.96, P<0.01) and lateral (18.16±27.68 vs. 11.30±21.09, P<0.01) body position. Men had higher AHI in REM sleep than NREM sleep in lateral body position (28.94±28.44 vs. 23.58±27.31, P<0.01), however, they did not reach statistical significance in supine position (49.12±32.03 in REM sleep vs. 45.78±34.02 in NREM sleep, P=0.50). In conclusion, our data suggest that REM sleep is a contributing factor for OSA in women as well as in men, at least in lateral position.

scholarly journals Opponent neurochemical and functional processing in NREM and REM sleep in visual learning

2019 ◽  
Author(s):  
Masako Tamaki ◽  
Zhiyan Wang ◽  
Tyler Barnes-Diana ◽  
Aaron V. Berard ◽  
Edward Walsh ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Visual Learning ◽  
Nrem Sleep ◽  
Visual Task ◽  
Sleep Stages ◽  
Learning Facilitation ◽  
Visual Areas ◽  
Specific Manner ◽  
Performance Gains ◽  
First Time

AbstractSleep is beneficial for learning. However, whether NREM or REM sleep facilitates learning, whether the learning facilitation results from plasticity increases or stabilization and whether the facilitation results from learning-specific processing are all controversial. Here, after training on a visual task we measured the excitatory and inhibitory neurochemical (E/I) balance, an index of plasticity in human visual areas, for the first time, while subjects slept. Off-line performance gains of presleep learning were associated with the E/I balance increase during NREM sleep, which also occurred without presleep training. In contrast, increased stabilization was associated with decreased E/I balance during REM sleep only after presleep training. These indicate that the above-mentioned issues are not matters of controversy but reflect opposite neurochemical processing for different roles in learning during different sleep stages: NREM sleep increases plasticity leading to performance gains independently of learning, while REM sleep decreases plasticity to stabilize learning in a learning-specific manner.

Increased Chin Muscle Tone during All Sleep Stages in Children Taking SSRI Antidepressants and in Children with Narcolepsy Type 1

SLEEP ◽  
2021 ◽  
Author(s):  
Raffaele Ferri ◽  
Maria P Mogavero ◽  
Oliviero Bruni ◽  
Giuseppe Plazzi ◽  
Carlos H Schenck ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Serotonin Reuptake ◽  
Treatment Duration ◽  
Muscle Tone ◽  
Sleep Stage ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Pharmacological Properties ◽  
Age And Sex

Abstract Study Objectives To assess if selective serotonin reuptake inhibitor (SSRI) antidepressants are able to modify the chin EMG tone during sleep also in children. Methods Twenty-three children and adolescents (12 girls, mean age 14.1 years, SD 2.94) under therapy with antidepressant for their mood disorder were consecutively recruited and had a PSG recording. Twenty-one were taking were taking SSRI and treatment duration was 2-12 months. An age- and sex matched group of 33 control children (17 girls, mean age 14.2 years, SD 2.83) and 24 children with narcolepsy type 1 (12 girls, mean age 13.7 years, SD 2.80) were also included. The Atonia Index was then computed for each NREM sleep stage and for REM sleep, also all EMG activations were counted. Results Atonia Index in all sleep stages was found to be significantly reduced in children with narcolepsy followed by the group taking SSRI antidepressants and the number of EMG activations was also increased in both groups. Fluoxetine, in particular, was found to be significantly associated with reduced Atonia index during NREM sleep stages N1, N2, and N3, and with increased number of EMG activations/hour during sleep stage N3. Conclusions Similarly to adults, SSRI antidepressants are able to modify the chin EMG tone also in children during REM sleep, as well as during NREM sleep stages. Different pharmacological properties of the different SSRI might explain the differential effect on chin tone during sleep found in this study.

scholarly journals Sleep in disorders of consciousness: behavioral and polysomnographic recording

BMC Medicine ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Isabella Mertel ◽  
Yuri G. Pavlov ◽  
Christine Barner ◽  
Friedemann Müller ◽  
Susanne Diekelmann ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Minimally Conscious State ◽  
Conscious State ◽  
Disorders Of Consciousness ◽  
Hospital Environment ◽  
Sleep Stages ◽  
Sleep Spindles ◽  
Video Recordings ◽  
Clinical Control ◽  
Minimally Conscious

Abstract Background Sleep-wakefulness cycles are an essential diagnostic criterion for disorders of consciousness (DOC), differentiating prolonged DOC from coma. Specific sleep features, like the presence of sleep spindles, are an important marker for the prognosis of recovery from DOC. Based on increasing evidence for a link between sleep and neuronal plasticity, understanding sleep in DOC might facilitate the development of novel methods for rehabilitation. Yet, well-controlled studies of sleep in DOC are lacking. Here, we aimed to quantify, on a reliable evaluation basis, the distribution of behavioral and neurophysiological sleep patterns in DOC over a 24-h period while controlling for environmental factors (by recruiting a group of conscious tetraplegic patients who resided in the same hospital). Methods We evaluated the distribution of sleep and wakefulness by means of polysomnography (EEG, EOG, EMG) and video recordings in 32 DOC patients (16 unresponsive wakefulness syndrome [UWS], 16 minimally conscious state [MCS]), and 10 clinical control patients with severe tetraplegia. Three independent raters scored the patients’ polysomnographic recordings. Results All but one patient (UWS) showed behavioral and electrophysiological signs of sleep. Control and MCS patients spent significantly more time in sleep during the night than during daytime, a pattern that was not evident in UWS. DOC patients (particularly UWS) exhibited less REM sleep than control patients. Forty-four percent of UWS patients and 12% of MCS patients did not have any REM sleep, while all control patients (100%) showed signs of all sleep stages and sleep spindles. Furthermore, no sleep spindles were found in 62% of UWS patients and 21% of MCS patients. In the remaining DOC patients who had spindles, their number and amplitude were significantly lower than in controls. Conclusions The distribution of sleep signs in DOC over 24 h differs significantly from the normal sleep-wakefulness pattern. These abnormalities of sleep in DOC are independent of external factors such as severe immobility and hospital environment.

Altered heart rate variability during sleep in mild cognitive impairment

SLEEP ◽  
2020 ◽  
Author(s):  
Shawn D X Kong ◽  
Camilla M Hoyos ◽  
Craig L Phillips ◽  
Andrew C McKinnon ◽  
Pinghsiu Lin ◽  
...  
Keyword(s):  
Older Adults ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Eye Movement ◽  
Rem Sleep ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Rapid Eye Movement

Abstract Study Objectives Cardiovascular autonomic dysfunction, as measured by short-term diurnal heart rate variability (HRV), has been reported in older adults with mild cognitive impairment (MCI). However, it is unclear whether this impairment also exists during sleep in this group. We, therefore, compared overnight HRV during sleep in older adults with MCI and those with subjective cognitive impairment (SCI). Methods Older adults (n = 210) underwent overnight polysomnography. Eligible participants were characterized as multi-domain MCI or SCI. The multi-domain MCI group was comprised of amnestic and non-amnestic subtypes. Power spectral analysis of HRV was conducted on the overnight electrocardiogram during non-rapid eye movement (NREM), rapid eye movement (REM), N1, N2, N3 sleep stages, and wake periods. High-frequency HRV (HF-HRV) was employed as the primary measure to estimate parasympathetic function. Results The MCI group showed reduced HF-HRV during NREM sleep (p = 0.018), but not during wake or REM sleep (p &gt; 0.05) compared to the SCI group. Participants with aMCI compared to SCI had the most pronounced reduction in HF-HRV across all NREM sleep stages—N1, N2, and N3, but not during wake or REM sleep. The naMCI sub-group did not show any significant differences in HF-HRV during any sleep stage compared to SCI. Conclusions Our study showed that amnestic MCI participants had greater reductions in HF-HRV during NREM sleep, relative to those with SCI, suggesting potential vulnerability to sleep-related parasympathetic dysfunction. HF-HRV, especially during NREM sleep, may be an early biomarker for dementia detection.

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