scholarly journals Unraveling why we sleep: Quantitative analysis reveals abrupt transition from neural reorganization to repair in early development

2020 ◽  
Vol 6 (38) ◽  
pp. eaba0398 ◽  
Author(s):  
Junyu Cao ◽  
Alexander B. Herman ◽  
Geoffrey B. West ◽  
Gina Poe ◽  
Van M. Savage
Keyword(s):  
Quantitative Analysis ◽  
Early Development ◽  
Rem Sleep ◽  
Early Ontogeny ◽  
Evolutionary Constraints ◽  
Relative Importance ◽  
Complex Interplay ◽  
Neural Repair ◽  
Abrupt Transition ◽  
Metabolite Clearance

Sleep serves disparate functions, most notably neural repair, metabolite clearance and circuit reorganization. Yet the relative importance remains hotly debated. Here, we create a novel mechanistic framework for understanding and predicting how sleep changes during ontogeny and across phylogeny. We use this theory to quantitatively distinguish between sleep used for neural reorganization versus repair. Our findings reveal an abrupt transition, between 2 and 3 years of age in humans. Specifically, our results show that differences in sleep across phylogeny and during late ontogeny (after 2 or 3 years in humans) are primarily due to sleep functioning for repair or clearance, while changes in sleep during early ontogeny (before 2 or 3 years) primarily support neural reorganization and learning. Moreover, our analysis shows that neuroplastic reorganization occurs primarily in REM sleep but not in NREM. This developmental transition suggests a complex interplay between developmental and evolutionary constraints on sleep.

scholarly journals Unraveling Why We Sleep: Quantitative Analysis Reveals Abrupt Transition from Neural Reorganization to Repair in Early Development

2019 ◽  
Author(s):  
Junyu Cao ◽  
Alexander B. Herman ◽  
Geoffrey B. West ◽  
Gina Poe ◽  
Van M. Savage
Keyword(s):  
Quantitative Analysis ◽  
Rem Sleep ◽  
Brain Size ◽  
Nrem Sleep ◽  
Sleep Time ◽  
Early Ontogeny ◽  
Neural Repair ◽  
Abrupt Transition ◽  
Metabolite Clearance

Sleep serves disparate functions, most notably neural repair, metabolite clearance and circuit reorganization, yet the relative importance of these functions remains hotly debated. Here, we create a novel mechanistic framework for understanding and predicting how sleep changes during ontogeny (why babies sleep twice as long as adults) and across phylogeny (why mice sleep roughly five times that of whales). We use this theory to quantitatively distinguish between sleep used for neural reorganization versus repair. We conduct a comprehensive, quantitative analysis of human sleep using total sleep time, cerebral metabolic rate, brain size, synaptic density, and REM sleep (used here to also refer to Active Sleep in infants and children). Our findings reveal an abrupt transition, between 2 and 3 years of age in humans. Specifically, our results show that differences in sleep across phylogeny and during late ontogeny (after 2 or 3 years in humans) are primarily due to sleep functioning for repair or clearance, while changes in sleep during early ontogeny (before 2 - 3 years in humans) primarily support neural reorganization and learning. Moreover, our analysis shows that neuroplastic reorganization occurs primarily in REM sleep but not in NREM. In accordance with the developmental role of neuroplasticity, the percent of time spent in REM sleep is independent of brain size across species but decreases dramatically as brain size grows through development. Furthermore, the ratio of NREM sleep time to awake time emerges as a new invariant across development. This developmental transition and fundamental shift across ontogeny and phylogeny suggests a complex interplay between developmental and evolutionary constraints on sleep.

Quantitative analysis of wake and REM sleep EEG in dementia of the Alzheimer type

1993 ◽  
Vol 87 (2) ◽  
pp. S76
Author(s):  
K. Nakagawa ◽  
H. Furuta ◽  
S. Yamamori ◽  
Y. Maeda ◽  
N. Ishiguro ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Rem Sleep ◽  
Sleep Eeg ◽  
Alzheimer Type

Propanidid, a useful anaesthetic for studying blood circulation in early development of fish

1987 ◽  
Vol 65 (5) ◽  
pp. 1286-1289
Author(s):  
Ronald S. Veenstra ◽  
Eugene K. Balon ◽  
Christine Flegler-Balon
Keyword(s):  
Blood Flow ◽  
Early Development ◽  
Blood Circulation ◽  
Salvelinus Fontinalis ◽  
Early Ontogeny ◽  
The Other ◽  
Brook Charr ◽  
Cocaine Hydrochloride ◽  
The Times ◽  
Blood Elements

The effectiveness of propanidid was tested by comparing it with cocaine hydrochloride, urethane, and traicaine methanesulfonate, anaesthetics already established for studies of early ontogeny in fishes. Free embryos of the brook charr, Salvelinus fontinalis, and 7-day-old amargosa pupfish, Cyprinodon nevadensis amargosae, were anaesthetized with dilute solutions of these drugs. The times taken until the blood elements ceased moving through the capillary loops of the developing caudal fin were compared. Propanidid was found to be superior to the other drugs tested in maintaining the longest duration of unaltered blood flow.

Habitats of circumboreal–subarctic sphagna: I. A quantitative analysis and review of species in the Caribou Mountains, northern Alberta

1979 ◽  
Vol 57 (20) ◽  
pp. 2283-2317 ◽  
Author(s):  
Diana G. Horton ◽  
Dale H. Vitt ◽  
Nancy G. Slack
Keyword(s):  
Quantitative Analysis ◽  
Picea Mariana ◽  
Water Channel ◽  
Bottom Layer ◽  
Relative Importance ◽  
Habitat Types ◽  
Sphagnum Fuscum ◽  
Dense Zone ◽  
Caribou Mountains ◽  
Northern Alberta

A quantitative analysis of the habitats of 14 species of Sphagnum found in the Caribou Mountains of northern Alberta and a literature review are the basis for a discussion of the habitats of these species as they occur in circumboreal–subarctic regions. Despite the implication inherent in the name, the Caribou Mountains are not mountains; the formation is an extensive, elevated plateau, which is underlain by more-or-less continuous permafrost. Three habitat types predominated in our study area: an upland "treed-tundra" (which is dominant over much of the plateau) with scattered Picea mariana and a hummocky bottom layer of sphagna; rounded "thaw-pocket" depressions dominated by carpets of Sphagnum and some carices; and streams defined by a dense zone of shrubs with the narrow water channel bordered by more-or-less firm lawns of Sphagnum species. Three gradients, which are considered to have a predominant influence on the occurrence of Sphagnum species, are wet to dry, ombrotrophic to minerotrophic, and shaded to exposed. The relative importance of each of these factors varies with each species of Sphagnum. Sphagnum jensenii, S. majus, S. riparium, and S. lindbergii occur exclusively in weakly minerotrophic to ombrotrophic, aquatic habitats where populations form loose, floating carpets. Such habitats are generally not much shaded. Such species as S. angustifolium, S. teres, and S. russowii are characteristic of somewhat less moist conditions, but all have a broad amplitude along the ombrotrophic to minerotrophic gradient. However, S. angustifolium is most abundant under poorly minerotrophic conditions where there is less shade, while S. teres predominates under highly minerotrophic conditions and is more-or-less equally tolerant of shade and exposure. Sphagnum warnstorfii apparently is restricted to habitats which are highly minerotrophic, but is tolerant of both shade and exposure. The sphagna most characteristic of densely shaded, woodland habitats where there is little peat development are S. squarrosum, S. wulfianum, and S. girgensohnii. All three species generally form low mounds. Sphagnum fuscum and S. nemoreum form well-defined hummocks and are most prevalent under ombrotrophic conditions.

scholarly journals How Phagocytic Cells Kill Different Bacteria: a Quantitative Analysis Using Dictyostelium discoideum

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tania Jauslin ◽  
Otmane Lamrabet ◽  
Xenia Crespo-Yañez ◽  
Anna Marchetti ◽  
Imen Ayadi ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Dictyostelium Discoideum ◽  
Human Body ◽  
Relative Importance ◽  
Phagocytic Cells ◽  
Bacterial Killing ◽  
Content Type ◽  
Individual Gene ◽  
Genetic Manipulations ◽  
High Degree

ABSTRACT Ingestion and killing of bacteria by phagocytic cells protect the human body against infections. While many mechanisms have been proposed to account for bacterial killing in phagosomes, their relative importance, redundancy, and specificity remain unclear. In this study, we used the Dictyostelium discoideum amoeba as a model phagocyte and quantified the requirement of 11 individual gene products, including nine putative effectors, for the killing of bacteria. This analysis revealed that radically different mechanisms are required to kill Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. AlyL, a lysozyme-like protein equipped with a distinct bacteriolytic region, plays a specific role in the intracellular killing of K. pneumoniae, with assistance from BpiC and Aoah, two lipopolysaccharide (LPS)-binding proteins. Rapid killing of E. coli and P. aeruginosa requires the presence of BpiC and of the NoxA NADPH oxidase. No single effector tested is essential for rapid killing of S. aureus or B. subtilis. Overall, our observations reveal an unsuspected degree of specificity in the elimination of bacteria in phagosomes. IMPORTANCE Phagocytic cells ingest and kill bacteria, a process essential for the defense of the human body against infections. Many potential killing mechanisms have been identified in phagocytic cells, including free radicals, toxic ions, enzymes, and permeabilizing peptides. Yet fundamental questions remain unanswered: what is the relative importance of these mechanisms, how redundant are they, and are different mechanisms used to kill different species of bacteria? We addressed these questions using Dictyostelium discoideum, a model phagocytic cell amenable to genetic manipulations and quantitative analysis. Our results reveal that vastly different mechanisms are required to kill different species of bacteria. This very high degree of specificity was unexpected and indicates that a lot remains to be discovered about how phagocytic cells eliminate bacteria.

scholarly journals The relationship between fasting-induced torpor, sleep and wakefulness in the laboratory mouse

2020 ◽  
Author(s):  
Yi G. Huang ◽  
Sarah J. Flaherty ◽  
Carina A. Pothecary ◽  
Russell G. Foster ◽  
Stuart N. Peirson ◽  
...  
Keyword(s):  
Body Temperature ◽  
Rem Sleep ◽  
Brain Activity ◽  
Mammalian Species ◽  
Laboratory Mouse ◽  
Nrem Sleep ◽  
Early Ontogeny ◽  
State Classification ◽  
The Relationship ◽  
Electroencephalogram Eeg

AbstractTorpor is a regulated reversible state of metabolic suppression used by many mammalian species to conserve energy. Although torpor has been studied extensively in terms of general physiology, metabolism and neuroendocrinology, the effects of hypometabolism and associated hypothermia on brain activity and states of vigilance have received little attention. Here we performed continuous monitoring of electroencephalogram (EEG), electromyogram (EMG) and peripheral body temperature in adult, male C57BL/6 mice over consecutive days of scheduled restricted feeding. All animals showed prominent bouts of hypothermia that became progressively deeper and longer as fasting progressed. EEG and EMG were markedly affected by hypothermia, although the typical electrophysiological signatures of NREM sleep, REM sleep and wakefulness allowed us to perform vigilance-state classification in all cases. Invariably, hypothermia bouts were initiated from a state indistinguishable from NREM sleep, with EEG power decreasing gradually in parallel with decreasing body temperature. Furthermore, during deep hypothermia REM sleep was largely abolished, but we observed brief and intense bursts of muscle activity, which resembled the regular motor discharges seen during early ontogeny associated with immature sleep patterns. We conclude that torpor and sleep are electrophysiologically on a continuum, and that, in order for torpor to occur, mice need to first transition through euthermic sleep.

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