scholarly journals Aspects of tree shrew consolidated sleep structure resemble human sleep

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marta M. Dimanico ◽  
Arndt-Lukas Klaassen ◽  
Jing Wang ◽  
Melanie Kaeser ◽  
Michael Harvey ◽  
...  
Keyword(s):  
Tree Shrew ◽  
Nrem Sleep ◽  
Intermediate Stage ◽  
Sleep Stages ◽  
Sleep Structure ◽  
Tree Shrews ◽  
Delta Waves ◽  
Human Sleep ◽  
Electrophysiological Recordings ◽  
Considerable Homology

AbstractUnderstanding human sleep requires appropriate animal models. Sleep has been extensively studied in rodents, although rodent sleep differs substantially from human sleep. Here we investigate sleep in tree shrews, small diurnal mammals phylogenetically close to primates, and compare it to sleep in rats and humans using electrophysiological recordings from frontal cortex of each species. Tree shrews exhibited consolidated sleep, with a sleep bout duration parameter, τ, uncharacteristically high for a small mammal, and differing substantially from the sleep of rodents that is often punctuated by wakefulness. Two NREM sleep stages were observed in tree shrews: NREM, characterized by high delta waves and spindles, and an intermediate stage (IS-NREM) occurring on NREM to REM transitions and consisting of intermediate delta waves with concomitant theta-alpha activity. While IS-NREM activity was reliable in tree shrews, we could also detect it in human EEG data, on a subset of transitions. Finally, coupling events between sleep spindles and slow waves clustered near the beginning of the sleep period in tree shrews, paralleling humans, whereas they were more evenly distributed in rats. Our results suggest considerable homology of sleep structure between humans and tree shrews despite the large difference in body mass between these species.

scholarly journals Improved sleep scoring in mice reveals human-like stages

2018 ◽  
Author(s):  
Marie Masako Lacroix ◽  
Gaetan de Lavilléon ◽  
Julie Lefort ◽  
Karim El Kanbi ◽  
Sophie Bagur ◽  
...  
Keyword(s):  
Sleep Onset ◽  
Nrem Sleep ◽  
Oscillatory Activity ◽  
Sleep Stages ◽  
New Approach ◽  
Firing Rates ◽  
Sleep Scoring ◽  
Delta Waves ◽  
Night Terrors

AbstractRodents are the main animal model to study sleep. Yet, in spite of a large consensus on the distinction between rapid-eye-movements sleep (REM) and non-REM sleep (NREM) in both humans and rodent, there is still no equivalent in mice of the NREM subdivision classically described in humans.Here we propose a classification of sleep stages in mice, inspired by human sleep scoring. By using chronic recordings in medial prefrontal cortex (mPFC) and hippocampus we can classify three NREM stages with a stage N1 devoid of any low oscillatory activity and N3 with a high density of delta waves. These stages displayed the same evolution observed in human during the whole sleep or within sleep cycles. Importantly, as in human, N1 in mice is the first stage observed at sleep onset and is increased after sleep fragmentation in Orexin-/- mice, a mouse model of narcolepsy.We also show that these substages are associated to massive modification of neuronal activity. Moreover, considering these stages allows to predict mPFC neurons evolution of firing rates across sleep period. Notably, neurons preferentially active within N3 decreased their activity over sleep while the opposite is seen for those preferentially active in N1 and N2.Overall this new approach shows the feasibility of NREM sleep sub-classification in rodents, and, in regard to the similarity between sleep in both species, will pave the way for further studies in sleep pathologies given the perturbation of specific sleep substages in human pathologies such as insomnia, somnambulism, night terrors, or fibromyalgia.

Dose-dependent effects of endotoxin on human sleep

2000 ◽  
Vol 278 (4) ◽  
pp. R947-R955 ◽  
Author(s):  
Janet Mullington ◽  
Carsten Korth ◽  
Dirk M. Hermann ◽  
Armin Orth ◽  
Chris Galanos ◽  
...  
Keyword(s):  
Heart Rate ◽  
Host Defense ◽  
Rectal Temperature ◽  
Host Response ◽  
Defense Mechanisms ◽  
Nrem Sleep ◽  
Sleep Stages ◽  
Nocturnal Sleep ◽  
Human Sleep ◽  
Sleep Amount

The role of the central nervous system in the host response to infection and inflammation and modulation of these responses by the hypothalamic-pituitary-adrenal system are well established. In animals, activation of host defense mechanisms increases non-rapid eye movement (NREM) sleep amount and intensity, which, in turn, are thought to support host defense, or the body's ability to defend itself against challenges to its immune system. In humans, the evidence is conflicting. Therefore, we investigated the effects of three placebo-controlled doses of endotoxin on host response, including nocturnal sleep in healthy volunteers. Administered before nocturnal sleep onset, endotoxin dose dependently increased rectal temperature, heart rate, and the plasma levels of tumor necrosis factor (TNF)-α, soluble TNF receptors, interleukin (IL)-1 receptor antagonist, IL-6, and cortisol. The lowest dose reliably increased circulating levels of cytokines and soluble cytokine receptors, but it did not affect rectal temperature, heart rate, or cortisol. This subtle host defense activation increased deep NREM sleep amount, often referred to as slow-wave sleep (stages 3 and 4), and intensity (delta power). Conversely, the highest dose of endotoxin disrupted sleep. Whereas it is well established that the endocrine and thermoregulatory systems are very sensitive to endotoxin, this study shows that human sleep-wake behavior is even more sensitive to activation of host defense mechanisms.

Morphological Examination of a Herpes-type Virus Indigenous for Tree Shrews

1970 ◽  
Vol 28 ◽  
pp. 160-161
Author(s):  
J. P. Brunschwig ◽  
R. M. McCombs ◽  
R. Mirkovic ◽  
M. Benyesh-Melnick
Keyword(s):  
Electron Microscopy ◽  
Soft Tissue ◽  
Chick Embryo ◽  
Soft Tissue Sarcoma ◽  
Cell Cultures ◽  
Tree Shrew ◽  
Type Virus ◽  
Morphological Examination ◽  
Tree Shrews ◽  
Embryo Cells

A new virus, established as a member of the herpesvirus group by electron microscopy, was isolated from spontaneously degenerating cell cultures derived from the kidneys and lungs of two normal tree shrews. The virus was found to replicate best in cells derived from the homologous species. The cells used were a tree shrew cell line, T-23, which was derived from a spontaneous soft tissue sarcoma. The virus did not multiply or did so poorly for a limited number of passages in human, monkey, rodent, rabbit or chick embryo cells. In the T-23 cells, the virus behaved as members of the subgroup B of herpesvirus, in that the virus remained primarily cell associated.

scholarly journals Capturing the Development of Internal Representations in a High-Performing Deep Network for Sleep Stage Classification

2021 ◽  
Vol 2 (4) ◽  
Author(s):  
Sarun Paisarnsrisomsuk ◽  
Carolina Ruiz ◽  
Sergio A. Alvarez
Keyword(s):  
Input Data ◽  
Single Channel ◽  
Sleep Stage ◽  
Quantitative Measure ◽  
Classification Performance ◽  
Sleep Stages ◽  
Layer Depth ◽  
Human Sleep ◽  
Stage Classification ◽  
Sleep Stage Classification

AbstractDeep neural networks can provide accurate automated classification of human sleep signals into sleep stages that enables more effective diagnosis and treatment of sleep disorders. We develop a deep convolutional neural network (CNN) that attains state-of-the-art sleep stage classification performance on input data consisting of human sleep EEG and EOG signals. Nested cross-validation is used for optimal model selection and reliable estimation of out-of-sample classification performance. The resulting network attains a classification accuracy of $$84.50 \pm 0.13\%$$ 84.50 ± 0.13 % ; its performance exceeds human expert inter-scorer agreement, even on single-channel EEG input data, therefore providing more objective and consistent labeling than human experts demonstrate as a group. We focus on analyzing the learned internal data representations of our network, with the aim of understanding the development of class differentiation ability across the layers of processing units, as a function of layer depth. We approach this problem visually, using t-Stochastic Neighbor Embedding (t-SNE), and propose a pooling variant of Centered Kernel Alignment (CKA) that provides an objective quantitative measure of the development of sleep stage specialization and differentiation with layer depth. The results reveal a monotonic progression of both of these sleep stage modeling abilities as layer depth increases.

Automatic real-time analysis of human sleep stages by an interval histogram method

1988 ◽  
Vol 70 (3) ◽  
pp. 220-229 ◽  
Author(s):  
H. Kuwahara ◽  
H. Higashi ◽  
Y. Mizuki ◽  
S. Matsunari ◽  
M. Tanaka ◽  
...  
Keyword(s):  
Real Time ◽  
Sleep Stages ◽  
Time Analysis ◽  
Histogram Method ◽  
Human Sleep ◽  
Real Time Analysis ◽  
Interval Histogram

scholarly journals Susceptibility of tree shrew to SARS-CoV-2 infection

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuan Zhao ◽  
Junbin Wang ◽  
Dexuan Kuang ◽  
Jingwen Xu ◽  
Mengli Yang ◽  
...  
Keyword(s):  
Asymptomatic Carrier ◽  
Tree Shrew ◽  
Age Groups ◽  
Clinical Signs ◽  
Economic Losses ◽  
Global Public Health ◽  
Young Tree ◽  
Virus Shedding ◽  
Tree Shrews ◽  
Scientific Questions

Abstract Since severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became a pandemic event in the world, it has not only caused huge economic losses, but also a serious threat to global public health. Many scientific questions about SARS-CoV-2 and Coronavirus disease (COVID-19) were raised and urgently need to be answered, including the susceptibility of animals to SARS-CoV-2 infection. Here we tested whether tree shrew, an emerging experimental animal domesticated from wild animal, is susceptible to SARS-CoV-2 infection. No clinical signs were observed in SARS-CoV-2 inoculated tree shrews during this experiment except the increasing body temperature particularly in female animals. Low levels of virus shedding and replication in tissues occurred in all three age groups. Notably, young tree shrews (6 months to 12 months) showed virus shedding at the earlier stage of infection than adult (2 years to 4 years) and old (5 years to 7 years) animals that had longer duration of virus shedding comparatively. Histopathological examine revealed that pulmonary abnormalities were the main changes but mild although slight lesions were also observed in other tissues. In summary, tree shrew is less susceptible to SARS-CoV-2 infection compared with the reported animal models and may not be a suitable animal for COVID-19 related researches. However, tree shrew may be a potential intermediate host of SARS-CoV-2 as an asymptomatic carrier.

Sleep structure in sleep bruxism: A polysomnographic study including bruxism activity phenotypes across sleep stages

2020 ◽  
Vol 29 (6) ◽  
Author(s):  
Tomasz Wieczorek ◽  
Mieszko Wieckiewicz ◽  
Joanna Smardz ◽  
Anna Wojakowska ◽  
Monika Michalek‐Zrabkowska ◽  
...  
Keyword(s):  
Sleep Bruxism ◽  
Sleep Stages ◽  
Sleep Structure

scholarly journals 0074 Inhibitory Neurons in the Dorsomedial Medulla Promote REM Sleep

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A30-A30
Author(s):  
J Stucynski ◽  
A Schott ◽  
J Baik ◽  
J Hong ◽  
F Weber ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Nrem Sleep ◽  
Inhibitory Neurons ◽  
Brain State ◽  
Sleep Regulation ◽  
Optogenetic Stimulation ◽  
Electrophysiological Recordings ◽  
Stimulation Of

Abstract Introduction The neural circuits controlling rapid eye movement (REM) sleep, and in particular the role of the medulla in regulating this brain state, remains an active area of study. Previous electrophysiological recordings in the dorsomedial medulla (DM) and electrical stimulation experiments suggested an important role of this area in the control of REM sleep. However the identity of the involved neurons and their precise role in REM sleep regulation are still unclear. Methods The properties of DM GAD2 neurons in mice were investigated through stereotaxic injection of CRE-dependent viruses in conjunction with implantation of electrodes for electroencephalogram (EEG) and electromyogram (EMG) recordings and optic fibers. Experiments included in vivo calcium imaging (fiber photometry) across sleep and wake states, optogenetic stimulation of cell bodies, chemogenetic excitation and suppression (DREADDs), and connectivity mapping using viral tracing and optogenetics. Results Imaging the calcium activity of DM GAD2 neurons in vivo indicates that these neurons are most active during REM sleep. Optogenetic stimulation of DM GAD2 neurons reliably triggered transitions into REM sleep from NREM sleep. Consistent with this, chemogenetic activation of DM GAD2 neurons increased the amount of REM sleep while inhibition suppressed its occurrence and enhanced NREM sleep. Anatomical tracing revealed that DM GAD2 neurons project to several areas involved in sleep / wake regulation including the wake-promoting locus coeruleus (LC) and the REM sleep-suppressing ventrolateral periaquaductal gray (vlPAG). Optogenetic activation of axonal projections from DM to LC, and DM to vlPAG was sufficient to induce REM sleep. Conclusion These experiments demonstrate that DM inhibitory neurons expressing GAD2 powerfully promote initiation of REM sleep in mice. These findings further characterize the dorsomedial medulla as a critical structure involved in REM sleep regulation and inform future investigations of the REM sleep circuitry. Support R01 HL149133

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