Search results for "Neurons"
showing 10 items of 1969 documents
Chemical fingerprints suggest direct familiarisation rather than phenotype matching during olfactory recognition in Australian sea lions (Neophoca ci…
2019
International audience; Olfaction is one of the most commonly used senses for communication among animals and is of particular importance to mother-offspring recognition in mammals. The use of smell in offspring recognition has been well studied, however, we often lack information about the underlying mechanistic basis for olfactory recognition. Using gas chromatography–mass spectrometry (GC–MS), we examine chemical profiles of two different colonies of Australian sea lions (Neophoca cinerea) and assess similarity of chemical fingerprints in mother-pup pairs. This analysis allows us to examine whether a chemical base for phenotype matching exists in this species. Our results showed no GC-de…
Oxidation in wine: Does expertise influence the perception?
2019
International audience; Wines can develop off-odours that depreciate their quality. Among them, oxidation is one of the most prevalent. The main objective of this work was to study the perception of wine oxidation through the categorization of oxidized wines perceived as not-faulty/faulty depending on the expertise of participants. For this purpose, one white wine and one red wine were spiked with three volatile oxidation compounds (acetaldehyde, phenylacetaldehyde and methional) in order to recreate twelve levels of oxidation in a controlled way. Samples were submitted to orthonasal tasting for being categorized by wine experts and novices and coupled to a free description task. Results de…
Acoustic communication in the Kittiwake Rissa tridactyla: potential cues for sexual and individual signatures in long calls
2007
International audience; Sex and individual recognition systems vary among species and can have various functions in different contexts. In order to determine the basis of identification by voice in the Kittiwake (Rissa tridactyla), the greeting calls of 32 individuals (18 males and 14 females) were recorded in May–June 2004 on the Kittiwake colony of Hornøya island (Barents sea) and analysed. On the basis of coefficient of variation calculations and discriminant analyses, we show (1) that calls are sexually dimorphic and that the dimorphism is mainly based on the value of the fundamental frequency, and (2) that calls are individually distinct, individuality being due to a complex of tempora…
Extreme Learning Machines for Data Classification Tuning by Improved Bat Algorithm
2018
Single hidden layer feed forward neural networks are widely used for various practical problems. However, the training process for determining synaptic weights of such neural networks can be computationally very expensive. In this paper we propose a new learning algorithm for learning the synaptic weights of the single hidden layer feedforward neural networks in order to reduce the learning time. We propose combining the upgraded bat algorithm with the extreme learning machine. The proposed approach reduces the number of evaluations needed to train a neural network and efficiently finds optimal input weights and the hidden biases. The proposed algorithm was tested on standard benchmark clas…
Graph-theoretical derivation of brain structural connectivity
2020
Brain connectivity at the single neuron level can provide fundamental insights into how information is integrated and propagated within and between brain regions. However, it is almost impossible to adequately study this problem experimentally and, despite intense efforts in the field, no mathematical description has been obtained so far. Here, we present a mathematical framework based on a graph-theoretical approach that, starting from experimental data obtained from a few small subsets of neurons, can quantitatively explain and predict the corresponding full network properties. This model also changes the paradigm with which large-scale model networks can be built, from using probabilisti…
Analysis of Activity States of Local Neuronal Microcircuits in Mouse Brain
2018
Time series of neuronal activity corresponding to different activity states in mouse brain are analyzed in the time domain and the time-frequency domain. The signals are associated with either a slow wave brain state or a persistent brain state. For both states, characteristic spectral features are identified and a simple detector is proposed that is able to identify the brain state with low latency and high accuracy. In practice, being able to monitor the brain state online and in real time is crucial for improved in vivoexperiments and, ultimately, for a causal understanding of brain dynamics.
Bifunctional poly(acrylamide) hydrogels through orthogonal coupling chemistries
2019
Biomaterials for cell culture allowing simple and quantitative presentation of instructive cues enable rationalization of the interplay between cells and their surrounding microenvironment. Poly(acrylamide) (PAAm) hydrogels are popular 2D-model substrates for this purpose. However, quantitative and reproducible biofunctionalization of PAAm hydrogels with multiple ligands in a trustable, controlled, and independent fashion is not trivial. Here, we describe a method for bifunctional modification of PAAm hydrogels with thiol- and amine- containing biomolecules with controlled densities in an independent, orthogonal manner. We developed copolymer networks of AAm with 9% acrylic acid and 2% N-(4…
AMPA receptor complex constituents: Control of receptor assembly, membrane trafficking and subcellular localization
2018
Fast excitatory transmission at synapses of the central nervous system is mainly mediated by AMPA receptors (AMPARs). Synaptic AMPAR number and function correlates with synaptic strength. AMPARs are thus key proteins of activity-dependent plasticity in neuronal communication. Up- or down-regulation of synaptic AMPAR number is a tightly controlled dynamic process that involves export of receptors from the endoplasmic reticulum (ER) and Golgi apparatus, exocytosis and endocytosis as well as lateral diffusion of the receptors in the cell membrane. The four AMPAR subunits are embedded into a dynamic network of more than 30 interacting proteins. Many of these proteins are known to modulate recep…
Synergistic activation of AMPK prevents from polyglutamine-inducedtoxicity inCaenorhabditis elegans
2020
11 páginas, 4 figuras. Supplementary material related to this article can be found, in the online version, at doi: https://doi.org/10.1016/j.phrs.2020.105105.
Positive Controls in Adults and Children Support That Very Few, If Any, New Neurons Are Born in the Adult Human Hippocampus.
2020
Adult hippocampal neurogenesis was originally discovered in rodents. Subsequent studies identified the adult neural stem cells and found important links between adult neurogenesis and plasticity, behavior, and disease. However, whether new neurons are produced in the human dentate gyrus (DG) during healthy aging is still debated. We and others readily observe proliferating neural progenitors in the infant hippocampus near immature cells expressing doublecortin (DCX), but the number of such cells decreases in children and few, if any, are present in adults. Recent investigations using dual antigen retrieval find many cells stained by DCX antibodies in adult human DG. This has been interprete…