scholarly journals Theta oscillations decrease spike synchrony in the hippocampus and entorhinal cortex

2014 ◽  
Vol 369 (1635) ◽  
pp. 20120530 ◽  
Author(s):  
Kenji Mizuseki ◽  
György Buzsaki
Keyword(s):  
Entorhinal Cortex ◽  
Slow Wave Sleep ◽  
Temporal Distribution ◽  
Theta Oscillations ◽  
Spike Synchrony ◽  
Wide Range ◽  
Multiple Cell ◽  
Theta Phase ◽  
Oscillatory Mechanisms ◽  
Phase Preference

Oscillations and synchrony are often used synonymously. However, oscillatory mechanisms involving both excitation and inhibition can generate non-synchronous yet coordinated firing patterns. Using simultaneous recordings from multiple layers of the entorhinal–hippocampal loop, we found that coactivation of principal cell pairs (synchrony) was lowest during exploration and rapid-eye-movement (REM) sleep, associated with theta oscillations, and highest in slow wave sleep. Individual principal neurons had a wide range of theta phase preference. Thus, while theta oscillations reduce population synchrony, they nevertheless coordinate the phase (temporal) distribution of neurons. As a result, multiple cell assemblies can nest within the period of the theta cycle.

scholarly journals Theta phase synchronization between the human hippocampus and the prefrontal cortex supports learning of unexpected information

2017 ◽  
Author(s):  
Matthias J. Gruber ◽  
Liang-Tien Hsieh ◽  
Bernhard P. Staresina ◽  
Christian E. Elger ◽  
Juergen Fell ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Phase Synchronization ◽  
Theta Oscillations ◽  
Presurgical Evaluation ◽  
Human Hippocampus ◽  
Electrophysiological Recordings ◽  
Rhinal Cortex ◽  
Theta Phase ◽  
Oscillatory Mechanisms ◽  
Rare Opportunity

AbstractEvents that violate predictions are thought to not only modulate activity within the hippocampus and prefrontal cortex, but also to enhance communication between the two regions. Several studies in rodents have shown that synchronized theta oscillations facilitate communication between the prefrontal cortex and hippocampus during salient events, but it remains unclear whether similar oscillatory mechanisms support interactions between the two regions in humans. Here, we had the rare opportunity to conduct simultaneous electrophysiological recordings from the human hippocampus and prefrontal cortex from two patients undergoing presurgical evaluation for pharmaco-resistant epilepsy. Recordings were conducted during a task that involved encoding of contextually expected and unexpected visual stimuli. Across both patients, hippocampal-prefrontal theta phase synchronization was significantly higher during encoding of unexpected study items, compared to contextually expected study items. In contrast, we did not find increased theta synchronization between the prefrontal cortex and rhinal cortex. Our findings are consistent with the idea that theta oscillations orchestrate communication between the hippocampus and prefrontal cortex during the processing of contextually salient information.

scholarly journals Sounding It Out: Auditory Stimulation and Overnight Memory Processing

2021 ◽  
Author(s):  
Marcus O. Harrington ◽  
Scott A. Cairney
Keyword(s):  
Rem Sleep ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Auditory Stimulation ◽  
Theta Oscillations ◽  
Neural Oscillations ◽  
Healthy Children ◽  
Factors Affecting ◽  
Memory Processing ◽  
Eeg Recordings

Abstract Purpose of Review Auditory stimulation is a technique that can enhance neural oscillations linked to overnight memory consolidation. In this review, we evaluate the impacts of auditory stimulation on the neural oscillations of sleep and associated memory processes in a variety of populations. Recent Findings Cortical EEG recordings of slow-wave sleep (SWS) are characterised by two cardinal oscillations: slow oscillations (SOs) and sleep spindles. Auditory stimulation delivered in SWS enhances SOs and phase-coupled spindle activity in healthy children and adults, children with ADHD, adults with mild cognitive impairment and patients with major depression. Under certain conditions, auditory stimulation bolsters the benefits of SWS for memory consolidation, although further work is required to fully understand the factors affecting stimulation-related memory gains. Recent work has turned to rapid eye movement (REM) sleep, demonstrating that auditory stimulation can be used to manipulate REM sleep theta oscillations. Summary Auditory stimulation enhances oscillations linked to overnight memory processing and shows promise as a technique for enhancing the memory benefits of sleep.

scholarly journals Composition, Sources, and Distribution of PM2.5 Saccharides in a Coastal Urban Site of China

Atmosphere ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 274 ◽  
Author(s):  
Mengxin Xiao ◽  
Qiongzhen Wang ◽  
Xiaofei Qin ◽  
Guangyuan Yu ◽  
Congrui Deng
Keyword(s):  
Biomass Burning ◽  
Biological Activities ◽  
Process Analysis ◽  
Fungal Spores ◽  
Temporal Distribution ◽  
Urban Site ◽  
Pollution Levels ◽  
Haze Pollution ◽  
Wide Range ◽  
High Level

The characteristics of biogenic aerosols in an urban area were explored by determining the composition and temporal distribution of saccharides in PM2.5 in Shanghai. The total saccharides showed a wide range of 9.4 ng/m3 to 1652.9 ng/m3, with the averaged concentrations of 133.1 ng/m3, 267.5 ng/m3, 265.1 ng/m3, and 674.4 ng/m3 in spring, summer, autumn, and winter, respectively. The saccharides include anhydrosaccharides (levoglucosan and mannosan), which were higher in cold seasons due to the increased biomass burning; saccharide alcohols (mannitol, arabitol, sorbitol); and monosaccharides (fructose, glucose), which were more abundant in warm seasons and attributed to the biological emissions. Through positive matrix factorization (PMF) analysis, four emission sources of saccharides were resolved, including biomass burning, fungal spores, plant decomposition, and pollen. Moreover, the process analysis of high concentrations of leveglucosan was conducted by backward trajectory and fire points. We found that concentrations of anhydrosaccharides were relatively stable under different pollution levels, while saccharide alcohols exhibited an obvious decrease with the concentration of PM2.5, indicating that biomass burning was not the core reason for heavy haze pollution. However, high level PM2.5 pollution might inhibit the effects of biological activities.

scholarly journals A50 Whole-genome sequencing of African swine fever isolates from Sardinia

2019 ◽  
Vol 5 (Supplement_1) ◽  
Author(s):  
C Torresi ◽  
F Granberg ◽  
L Bertolotti ◽  
A Oggiano ◽  
B Colitti ◽  
...  
Keyword(s):  
Amino Acid ◽  
Sequence Data ◽  
Temporal Distribution ◽  
African Swine Fever ◽  
Amino Acid Identity ◽  
Genotype I ◽  
Acid Identity ◽  
Wide Range ◽  
Intergenic Sequences ◽  
Genes Encoding

Abstract In order to assess the molecular epidemiology of African swine fever (ASF) in Sardinia, we analyzed a wide range of isolates from wild and domestic pigs over a 31-year period (1978–2009) by genotyping sequence data from the genes encoding the p54 and the p72 proteins and the CVR. On this basis, the analysis of the B602L gene revealed a minor difference, placing the Sardinian isolates into two clusters according to their temporal distribution. As an extension of this study, in order to achieve a higher level of discrimination, three further variable genome regions, namely p30, CD2v, and I73R/I329L, of a large number of isolates collected from outbreaks in the years 2002–14 have been investigated. Sequence analysis of the CD2v region revealed a temporal subdivision of the viruses into two subgroups. These data, together with those from the B602L gene analysis, demonstrated that the viruses circulating in Sardinia belong to p72/genotype I, but since 1990 have undergone minor genetic variations in respect to its ancestor, thus making it impossible to trace isolates, enabling a more accurate assessment of the origin of outbreaks, and extending knowledge of virus evolution. To solve this problem, we have sequenced and annotated the complete genome of nine ASF isolates collected in Sardinia between 1978 and 2012. This was achieved using sequence data determined by next-generation sequencing. The results showed a very high identity with range of nucleotide similarity among isolates of 99.5 per cent to 99.9 per cent. The ASF virus (ASFV) genomes were composed of terminal inverted repeats and conserved and non-conserved ORFs. Among the conserved ORFs, B385R, H339R, and O61R-p12 showed 100 per cent amino acid identity. The same was true for the hypervariable ORFs, with regard to X69R, DP96R, DP60R, EP153R, B407L, I10L, and L60L genes. The EP402R and B602L genes showed, as expected, an amino acid identity range of 98.5 per cent to 100 per cent and 91 per cent to 100 per cent, respectively. In addition, all of the isolates displayed variable intergenic sequences. As a whole, the results from our studies confirmed a remarkable genetic stability of the ASFV/p72 genotype I viruses circulating in Sardinia.

scholarly journals Inositol phosphates: health implications, methods of analysis, and occurrence in plant foods

2018 ◽  
Vol 1 ◽  
Author(s):  
Quynh H. Duong ◽  
Karen G. Lapsley ◽  
Ronald B. Pegg
Keyword(s):  
Inositol Phosphates ◽  
Negative Effects ◽  
Plant Foods ◽  
Plant Seeds ◽  
Cell Functions ◽  
Wide Range ◽  
Multiple Cell ◽  
The Relationship

Inositol phosphates (InsPs), especially myo-inositol hexakisphosphate (InsP6), are important binders of phosphorus and minerals in plant seeds. However, they have long been considered as anti-nutritional components of plant foods due to their possible negative effects on the absorption of minerals and proteins in mammals. On the other hand, recent findings have found InsPs to be ubiquitous in eukaryote cells and actively participating in multiple cell functions. In vivo and in vitro studies have also documented the preventive potential of these compounds against the development of a wide range of diseases. In light of these findings, interest in the relationship between these compounds and human health has been renewed. It is suggested that the interactions of InsPs with other nutrients in the gut are complex, that the absorption of dietary InsPs might be implied but is not certain, and that the disease fighting capabilities of InsPs hold both promises and limitations. At the same time, the analysis of these compounds in foods and biological samples still faces many challenges, calling for more advanced modification and developments in the future.

scholarly journals The DBL-1/TGF-β signaling pathway regulates pathogen-specific innate immune responses in C. elegans

2021 ◽  
Author(s):  
Bhoomi Madhu ◽  
Tina L. Gumienny
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Defense Responses ◽  
C Elegans ◽  
Host Immune Responses ◽  
Wide Range ◽  
Independent Functions ◽  
Multiple Cell

Innate immunity in animals is orchestrated by multiple cell signaling pathways, including the TGF-β; superfamily pathway. While the role of TGF-β signaling in innate immunity has been clearly identified, the requirement for this pathway in generating specific, robust responses to different bacterial challenges has not been characterized. Here, we address the role of DBL-1/TGF-β in regulating signature host defense responses to a wide range of bacteria in C. elegans. This work reveals a role of DBL-1/TGF-β in animal survival, organismal behaviors, and molecular responses in different environments. Additionally, we identify a novel role for SMA-4/Smad that suggests both DBL-1/TGF-β-dependent and -independent functions in host avoidance responses. RNA-seq analyses and immunity reporter studies indicate DBL-1/TGF-β differentially regulates target gene expression upon exposure to different bacteria. Furthermore, the DBL-1/TGF-β pathway is itself differentially affected by the bacteria exposure. Collectively, these findings demonstrate bacteria-specific host immune responses regulated by the DBL-1/TGF-β signaling pathway.

scholarly journals A versatile automated high-throughput drug screening platform for zebrafish embryos

2020 ◽  
Author(s):  
Alexandra Lubin ◽  
Jason Otterstrom ◽  
Yvette Hoade ◽  
Ivana Bjedov ◽  
Eleanor Stead ◽  
...  
Keyword(s):  
High Throughput ◽  
Drug Screening ◽  
Imaging System ◽  
Cell Types ◽  
Wide Range ◽  
Stem And Progenitor Cells ◽  
Multiple Cell ◽  
Flexible Imaging ◽  
Automated Screening ◽  
Screening Platform

AbstractZebrafish provide a unique opportunity for drug screening in living animals, with the fast developing, transparent embryos allowing for relatively high throughput, microscopy-based screens. However, the limited availability of rapid, flexible imaging and analysis platforms has limited the use of zebrafish in drug screens. We have developed a easy-to-use, customisable automated screening procedure suitable for high-throughput phenotype-based screens of live zebrafish. We utilised the WiScan®Hermes High Content Imaging System to rapidly acquire brightfield and fluorescent images of embryos, and the WiSoft®Athena Zebrafish Application for analysis, which harnesses an Artificial Intelligence-driven algorithm to automatically detect fish in brightfield images, identify anatomical structures, partition the animal into regions, and exclusively select the desired side-oriented fish. Our initial validation combined structural analysis with fluorescence images to enumerate GFP-tagged haematopoietic stem and progenitor cells in the tails of embryos, which correlated with manual counts. We further validated this system to assess the effects of genetic mutations and x-ray irradiation in high content using a wide range of assays. Further, we performed simultaneous analysis of multiple cell types using dual fluorophores in high throughput. In summary, we demonstrate a broadly applicable and rapidly customisable platform for high content screening in zebrafish.

scholarly journals Learning to synchronize: Midfrontal theta dynamics during rule switching

2020 ◽  
Author(s):  
Pieter Verbeke ◽  
Kate Ergo ◽  
Esther De Loof ◽  
Tom Verguts
Keyword(s):  
Negative Feedback ◽  
Human Subjects ◽  
Learning Task ◽  
Theta Oscillations ◽  
Prediction Errors ◽  
Hierarchical Learning ◽  
Theta Power ◽  
Negative Prediction ◽  
Theta Phase ◽  
The Brain

AbstractIn recent years, several hierarchical extensions of well-known learning algorithms have been proposed. For example, when stimulus-action mappings vary across time or context, the brain may learn two or more stimulus-action mappings in separate modules, and additionally (at a hierarchically higher level) learn to appropriately switch between those modules. However, how the brain mechanistically coordinates neural communication to implement such hierarchical learning, remains unknown. Therefore, the current study tests a recent computational model that proposed how midfrontal theta oscillations implement such hierarchical learning via the principle of binding by synchrony (Sync model). More specifically, the Sync model employs bursts at theta frequency to flexibly bind appropriate task modules by synchrony. 64-channel EEG signal was recorded while 27 human subjects (Female: 21, Male: 6) performed a probabilistic reversal learning task. In line with the Sync model, post-feedback theta power showed a linear relationship with negative prediction errors, but not with positive prediction errors. This relationship was especially pronounced for subjects with better behavioral fit (measured via AIC) of the Sync model. Also consistent with Sync model simulations, theta phase-coupling between midfrontal electrodes and temporo-parietal electrodes was stronger after negative feedback. Our data suggest that the brain uses theta power and synchronization for flexibly switching between task rule modules, as is useful for example when multiple stimulus-action mappings must be retained and used.Significance StatementEveryday life requires flexibility in switching between several rules. A key question in understanding this ability is how the brain mechanistically coordinates such switches. The current study tests a recent computational framework (Sync model) that proposed how midfrontal theta oscillations coordinate activity in hierarchically lower task-related areas. In line with predictions of this Sync model, midfrontal theta power was stronger when rule switches were most likely (strong negative prediction error), especially in subjects who obtained a better model fit. Additionally, also theta phase connectivity between midfrontal and task-related areas was increased after negative feedback. Thus, the data provided support for the hypothesis that the brain uses theta power and synchronization for flexibly switching between rules.

scholarly journals Alternating sequences of future and past behavior encoded within hippocampal theta oscillations

Science ◽  
2020 ◽  
Vol 370 (6513) ◽  
pp. 247-250 ◽  
Author(s):  
Mengni Wang ◽  
David J. Foster ◽  
Brad E. Pfeiffer
Keyword(s):  
Activity Patterns ◽  
Place Cells ◽  
Theta Oscillations ◽  
Retrospective Evaluation ◽  
Past Behavior ◽  
Hippocampal Ca1 ◽  
Ongoing Behavior ◽  
Theta Phase ◽  
Hippocampal Theta ◽  
And Storage

Neural networks display the ability to transform forward-ordered activity patterns into reverse-ordered, retrospective sequences. The mechanisms underlying this transformation remain unknown. We discovered that, during active navigation, rat hippocampal CA1 place cell ensembles are inherently organized to produce independent forward- and reverse-ordered sequences within individual theta oscillations. This finding may provide a circuit-level basis for retrospective evaluation and storage during ongoing behavior. Theta phase procession arose in a minority of place cells, many of which displayed two preferred firing phases in theta oscillations and preferentially participated in reverse replay during subsequent rest. These findings reveal an unexpected aspect of theta-based hippocampal encoding and provide a biological mechanism to support the expression of reverse-ordered sequences.

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