scholarly journals Beta Rhythms (15–20 Hz) Generated by Nonreciprocal Communication in Hippocampus

2007 ◽  
Vol 97 (4) ◽  
pp. 2812-2823 ◽  
Author(s):  
Andrea Bibbig ◽  
Steven Middleton ◽  
Claudia Racca ◽  
Martin J. Gillies ◽  
Helen Garner ◽  
...  
Keyword(s):  
Local Population ◽  
Neuronal Firing ◽  
Principal Cell ◽  
Cell Recruitment ◽  
Basket Cells ◽  
Stratum Oriens ◽  
Area Ca1 ◽  
Gamma Rhythm ◽  
Gamma Rhythms

Generation of gamma rhythms in reciprocally connected areas of cortex produces synchronous neuronal firing, although little is known about the consequences of gamma rhythms when generated in nonreciprocally connected regions. This nonreciprocity exists in hippocampus, where gamma rhythms are generated in area CA3 in vitro and in vivo and nonreciprocally projected to area CA1 by the Schaffer collateral pathway. Here we demonstrate how this CA3 gamma rhythm generates two different patterns of local CA1 oscillation dependent on the degree of output from area CA1. 1) In conditions where activity projected to area CA1 produces only very low principal cell recruitment the local population rhythm mimics the gamma rhythm projected from CA3. This activity is generated predominantly by recruitment of CA1 basket cells in a manner dependent on phasic, feedforward excitation of this interneuron subclass. Interneurons in stratum oriens, not receiving CA3 feedforward input, fired at theta frequencies. 2) In the presence of serotonin CA1 principal cell recruitment was appreciably enhanced, resulting in dual activation of CA1 basket cells through both feedforward and feedback excitations. Feedback excitation to CA1 stratum oriens interneurons was also enhanced. The resulting change in interneuron network dynamics generated a beta-frequency CA1 rhythm (as a near-subharmonic of the gamma rhythm projected from CA3). These findings demonstrate that in nonreciprocally connected networks, the frequency of population rhythms in target areas serves to code for degree of principal cell recruitment by afferent input.

CONSERVATION OF RARE SPECIES PLANTS AND LICHENS IN SITU WITH PLANNED ANTHROPOGENIC ACTIVITIES: BASIC APPROACHES AND IMPLEMENTATION PRINCIPLES

2018 ◽  
Vol 12 (7-8) ◽  
pp. 38-45
Author(s):  
A. N. EFREMOV ◽  
N. V. PLIKINA ◽  
T. ABELI
Keyword(s):  
Rare Species ◽  
Technology Implementation ◽  
Technology Development ◽  
Anthropogenic Activities ◽  
Natural Habitat ◽  
Local Population ◽  
Main Stage ◽  
Social Risks

Rare species are most vulnerable to man-made impacts, due to their biological characteristics or natural resource management. As a rule, the economic impact is associated with the destruction and damage of individual organisms, the destruction or alienation of habitats. Unfortunately, the conservation of habitat integrity is an important protection strategy, which is not always achievable in the implementation of industrial and infrastructural projects. The aim of the publication is to summarize the experience in the field of protection of rare species in the natural habitat (in situ), to evaluate and analyze the possibility of using existing methods in design and survey activities. In this regard, the main methodological approaches to the protection of rare species in the natural habitat (in situ) during the proposed economic activity were reflected. The algorithm suggested by the authors for implementing the in situ project should include a preparatory stage (initial data collection, preliminary risk assessments, technology development, obtaining permitting documentation), the main stage, the content of which is determined by the selected technology and a long monitoring stage, which makes it possible to assess the effectiveness of the taken measures. Among the main risks of in situ technology implementation, the following can be noted: the limited resources of the population that do not allow for the implementation of the procedure without prior reproduction of individuals in situ (in vitro); limited knowledge of the biology of the species; the possibility of invasion; the possibility of crossing for closely related species that сo-exist in the same habitat; social risks and consequences, target species or population may be important for the local population; financial risks during the recovery of the population. The available experience makes it possible to consider the approach to the conservation of rare species in situ as the best available technology that contributes to reducing negative environmental risks.

scholarly journals Development of rice pre-breeding resources with blast resistance

2020 ◽  
Vol 224 ◽  
pp. 04020
Author(s):  
Zh M Mukhina ◽  
E G Savenko ◽  
T L Korotenko ◽  
I I Suprun ◽  
O. A. Bragina ◽  
...  
Keyword(s):  
Magnaporthe Grisea ◽  
Blast Resistance ◽  
Local Population ◽  
Rice Varieties ◽  
Germplasm Exchange ◽  
Yield Structure ◽  
Rice Samples ◽  
Breeding Resources

Within the framework of this study, the first Russian-Chinese joint program for development of rice varieties with long-term blast resistance was launched on the basis of rice germplasm exchange and the subsequent comprehensive study of the obtained breeding samples, hybridization of Russian and Chinese varieties with specified traits. The genetic diversity of the Chinese rice samples obtained by exchange was studied by biological and morphological traits of plants, taxonomic belonging to a botanical variety, elements of the yield structure, and resistance to lodging. 31 hybrid combinations (F1) from the crossing of Russian and Chinese varieties were used to obtain the BC1 generation. The technologies of cultivation of isolated rice anthers in vitro have been optimized in relation to Chinese genotypes in order to accelerate the genetic stabilization of breeding material obtained from crossing. Phenotyping of Russian and Chinese breeding samples was carried out on the basis of resistance to the local population of the blast pathogen (Magnaporthe grisea (T.T. Hebert) M.E. Barr)), on natural and artificial infectious backgrounds. DNA identification of genes for blast resistance was carried out for the same breeding samples. Based on the experimental data obtained, promising samples were selected - prototypes of new rice varieties.

Deciphering how interneuron specific 3 cells control oriens lacunosum-moleculare cells to contribute to circuit function

2021 ◽  
Author(s):  
Alexandre Guet-McCreight ◽  
Frances K Skinner
Keyword(s):  
Pyramidal Cell ◽  
Inhibitory Interneuron ◽  
Cell Type ◽  
Cell Recruitment ◽  
External Modulation ◽  
Theta Frequency ◽  
Cell Firing ◽  
Circuit Function

The wide diversity of inhibitory cells across the brain makes them suitable to contribute to network dynamics in specialized fashions. However, the contributions of a particular inhibitory cell type in a behaving animal are challenging to untangle as one needs to both record cellular activities and identify the cell type being recorded. Thus, using computational modeling and theory to predict and hypothesize cell-specific contributions is desirable. Here, we examine potential contributions of interneuron-specific 3 (I-S3) cells - an inhibitory interneuron found in CA1 hippocampus that only targets other inhibitory interneurons - during simulated theta rhythms. We use previously developed multi-compartment models of oriens lacunosum-moleculare (OLM) cells, the main target of I-S3 cells, and explore how I-S3 cell inputs during in vitro and in vivo scenarios contribute to theta. We find that I-S3 cells suppress OLM cell spiking, rather than engender its spiking via post-inhibitory rebound mechanisms, and contribute to theta frequency spike resonance during simulated in vivo scenarios. To elicit recruitment similar to in vitro experiments, inclusion of disinhibited pyramidal cell inputs is necessary, implying that I-S3 cell firing broadens the window for pyramidal cell disinhibition. Using in vivo virtual networks, we show that I-S3 cells contribute to a sharpening of OLM cell recruitment at theta frequencies. Further, shifting the timing of I-S3 cell spiking due to external modulation shifts the timing of the OLM cell firing and thus disinhibitory windows. We propose a specialized contribution of I-S3 cells to create temporally precise coordination of modulation pathways.

Characterisation of fibrous ferrierite in the rhyolitic tuffs at Lovelock, Nevada, USA

2019 ◽  
Vol 83 (4) ◽  
pp. 577-586 ◽  
Author(s):  
Alessandro Zoboli ◽  
Dario Di Giuseppe ◽  
Cecilia Baraldi ◽  
Maria Cristina Gamberini ◽  
Daniele Malferrari ◽  
...  
Keyword(s):  
Thermal Analyses ◽  
Local Population ◽  
Crystal Habit ◽  
X Ray Diffraction ◽  
Mining Operations ◽  
Precautionary Approach ◽  
Mineral Fibre ◽  
Fibrous Morphology

AbstractFerrierite is the name for a series of zeolite-group of minerals which includes three species with the same ferrierite framework (FER) crystal structure but different extra-framework cations. Recent studies have shown that ferrierite can exhibit a fibrous-asbestiform crystal habit and may possess the same properties as carcinogenic fibrous erionite. Characterisation of the ferrierite in and around a mine location will be helpful in assessing the potential for toxic outcomes of exposure in the mine and any local population.The zeolite-rich tuff deposit of Lovelock, Nevada, USA is the largest occurrence of diagenetic ferrierite-Mg. A previous survey reported that ferrierite hosted in these rocks displays a fibrous morphology. However, these observations concerned a limited number of samples and until now there has been little evidence of widespread occurrence of fibrous ferrierite in the Lovelock deposit.The main goal of this study was to perform a mineralogical and morphometric characterisation of the tuff deposit at Lovelock and evaluate the distribution of fibrous ferrierite in the outcrop. For this purpose, a multi-analytical approach including powder X-ray diffraction, scanning and transmission microscopies, micro-Raman spectroscopy, thermal analyses, and surface-area determination was applied.The results prove fibrous ferrierite is widespread and intermixed with mordenite and orthoclase, although there are variations in the spatial distribution in the bedrock. The crystal habit of the ferrierite ranges from prismatic to asbestiform (elongated, thin and slightly flexible) and fibres are aggregated in bundles. According to the WHO counting criteria, most of the ferrierite fibres can be classified as breathable. While waiting for confirmatory in vitro and in vivo tests to assess the actual toxicity/pathogenicity potential of this mineral fibre, it is recommended to adopt a precautionary approach for mining operations in this area to reduce the risk of exposure.

scholarly journals KCC2 antagonism increases neuronal network excitability but disrupts ictogenesis in vitro

2019 ◽  
Vol 122 (3) ◽  
pp. 1163-1173 ◽  
Author(s):  
Li-Yuan Chen ◽  
Maxime Lévesque ◽  
Massimo Avoli
Keyword(s):  
Potassium Chloride ◽  
Entorhinal Cortex ◽  
Single Unit ◽  
Neuronal Excitability ◽  
Cell Activity ◽  
Principal Cell ◽  
Cell Firing ◽  
Interictal Discharges ◽  
Tetrode Recordings

The potassium-chloride cotransporter 2 (KCC2) plays a role in epileptiform synchronization, but it remains unclear how it influences such a process. Here, we used tetrode recordings in the in vitro rat entorhinal cortex (EC) to analyze the effects of the KCC2 antagonist VU0463271 on 4-aminopyridine (4AP)-induced ictal and interictal activity. During 4AP application, ictal events were associated with significant increases in interneurons and principal cells activities. VU0463271 application transformed ictal discharges to shorter ictal-like events that were not accompanied by significant increases in interneuron or principal cell firing. Interictal events persisted during VU0463271 application at an accelerated frequency of occurrence with significant increases in interneuron and principal cell activity. Further analysis revealed that interneuron and principal cell firing rate during 4AP-induced interictal events were increased after VU0463271 application without changes in synchronicity. Overall, our results demonstrate that in the EC, KCC2 antagonism enhances both interneuron and principal cell excitability, while paradoxically decreasing the ability of neuronal networks to generate structured ictal events. NEW & NOTEWORTHY We are the first to use tetrode recordings in the entorhinal cortex to demonstrate that antagonizing potassium-chloride cotransporter 2 (KCC2) function abolishes ictal discharges and the associated, dynamic changes in single-unit firing in the in vitro 4-aminopyrine model of epileptiform synchronization. Interictal discharges were, however, shorter and more frequent during KCC2 antagonism, while the associated single-unit activity increased, suggesting augmented neuronal excitability. Our findings highlight the complex role of KCC2 in disease pathology.

scholarly journals L-type voltage-gated calcium channel regulation of in vitro human cortical neuronal networks

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
William Plumbly ◽  
Nick Brandon ◽  
Tarek Z. Deeb ◽  
Jeremy Hall ◽  
Adrian J. Harwood
Keyword(s):  
Calcium Channel ◽  
Neuronal Networks ◽  
Gene Mutations ◽  
Synaptic Function ◽  
Neuronal Firing ◽  
Network Activity ◽  
Electrode Arrays ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channel

Abstract The combination of in vitro multi-electrode arrays (MEAs) and the neuronal differentiation of stem cells offers the capability to study human neuronal networks from patient or engineered human cell lines. Here, we use MEA-based assays to probe synaptic function and network interactions of hiPSC-derived neurons. Neuronal network behaviour first emerges at approximately 30 days of culture and is driven by glutamate neurotransmission. Over a further 30 days, inhibitory GABAergic signalling shapes network behaviour into a synchronous regular pattern of burst firing activity and low activity periods. Gene mutations in L-type voltage gated calcium channel subunit genes are strongly implicated as genetic risk factors for the development of schizophrenia and bipolar disorder. We find that, although basal neuronal firing rate is unaffected, there is a dose-dependent effect of L-type voltage gated calcium channel inhibitors on synchronous firing patterns of our hiPSC-derived neural networks. This demonstrates that MEA assays have sufficient sensitivity to detect changes in patterns of neuronal interaction that may arise from hypo-function of psychiatric risk genes. Our study highlights the utility of in vitro MEA based platforms for the study of hiPSC neural network activity and their potential use in novel compound screening.

scholarly journals Hyaluronic acid, HAS1, and HAS2 are significantly upregulated during muscle hypertrophy

2012 ◽  
Vol 303 (5) ◽  
pp. C577-C588 ◽  
Author(s):  
Sarah Calve ◽  
Jahdonna Isaac ◽  
Jonathan P. Gumucio ◽  
Christopher L. Mendias
Keyword(s):  
Skeletal Muscle ◽  
Hyaluronic Acid ◽  
Type I Collagen ◽  
Muscle Growth ◽  
Type I ◽  
Muscle Adaptation ◽  
Cell Recruitment ◽  
Regeneration In Vitro ◽  
Muscle Progenitor Cell

Hyaluronic acid (HA) is a component of the extracellular matrix (ECM) in most vertebrate tissues and is thought to play a significant role during development, wound healing, and regeneration. In vitro studies have shown that HA enhances muscle progenitor cell recruitment and inhibits premature myotube fusion, implicating a role for this glycosaminoglycan in functional repair. However, the spatiotemporal distribution of HA during muscle growth and repair was unknown. We hypothesized that inducing hypertrophy via synergist ablation would increase the expression of HA and the HA synthases (HAS1–HAS3). We found that HA and HAS1–HAS3 were significantly upregulated within the plantaris muscle in response to Achilles tenectomy. HA concentration significantly increased 2.8-fold after 2 days but decreased towards levels comparable to age-matched controls by 14 days. Using immunohistochemistry, we found the colocalization of HAS1–HAS3 with macrophages, blood vessel epithelia, and fibroblasts varied in response to time and/or tenectomy. At the level of gene expression, only HAS1 and HAS2 significantly increased with respect to both time and tenectomy. The profiles of additional genes that influence ECM composition during muscle repair, tenascin-C, type I collagen, the HA-degrading hyaluronidases (Hyal) and matrix metalloproteinases (MMP) were also investigated. Hyal1 and Hyal2 were highly expressed in skeletal muscle but did not change after tenectomy; however, indicators of hypertrophy, MMP-2 and MMP-14, were significantly upregulated from 2 to 14 days. These results indicate that HA levels dynamically change in response to a hypertrophic stimulus and various cells may participate in this mechanism of skeletal muscle adaptation.

Serotoninergic modulation of excitability in area CA1 of the in vitro rat hippocampus

1995 ◽  
Vol 199 (3) ◽  
pp. 211-214 ◽  
Author(s):  
Richard J. Siarey ◽  
Mogens Andreasen ◽  
John D.C. Lambert
Keyword(s):  
Rat Hippocampus ◽  
Area Ca1

Cross-fostering in rodents causes region-specific alterations in entorhinal cortical gamma rhythms associated with NMDA receptor dysfunction

2018 ◽  
Author(s):  
Stephen Hall ◽  
Karen Hawkins ◽  
Grace Laws ◽  
Thomas Akitt ◽  
Anna Simon ◽  
...  
Keyword(s):  
Social Cognition ◽  
Foster Care ◽  
Social Interaction ◽  
Nmda Receptor ◽  
Life Stress ◽  
Early Life ◽  
The United States ◽  
Gamma Rhythm ◽  
Gamma Rhythms ◽  
Cross Fostering

ABSTRACTThere has recently been a large increase in the number of children placed in foster care in the United States and Europe. While this is ‘the least worst scenario’ for those with a lack of appropriate biological care, it is recognised that these children are exposed to major stressors correlated with behavioural changes, particularly in the realm of social cognition into adulthood. Here we model foster care in rodents: rat pups are removed from their biological mother and placed with a non-genetically related dam. This prevented the entorhinal cortex from generating patterns of gamma rhythms required for normal parahippocampal function relevant to social interaction. These changes correlated with a reduction in NMDA receptor-mediated excitation, and changes in parvalbumin expression in interneurons. These data suggest that early life care delivered by a non-biological parent may disrupt social behaviour but, in contrast, generate neurobiological changes antagonistic to those currently associated with psychosis.Significance StatementCross fostering is an effective approach for delineating the effect of environment from genetic influences upon behavior. This involves removal of pups from one mother and transfer to another lactating dam. This manipulation is considered as a mild form of early life stress, producing neurobehavioral changes such as alterations in social interaction. We demonstrate that cross fostering produces changes in the ability of cortical microcircuits to generate oscillatory rhythms, in particular the gamma rhythm, in brain regions important for social cognition. This reduction in gamma rhythmogenesis is related to a reduction in synaptic drive provided by the NMDA receptor. One implication of this work is that the modulation of NMDA receptors offers a potential therapeutic strategy for disorders involving impaired sociability.

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