Global ETD Search

61	Organisation anatomique et rôle du couplage astrocytaire dans l’activité rythmique du noyau sensoriel du trijumeau Condamine, Steven 12 1900 (has links) No description available. Mastication Générateurs de patrons centraux Noyau sensoriel principal du trijumeau S100β Réseaux astrocytaires Connexines Analyse vectorielle Central pattern generator Trigeminal main sensory nucleus Astrocyte networks Connexin Vectorial analysis
62	Organisation anatomique et rôle du couplage astrocytaire dans l’activité rythmique du noyau sensoriel du trijumeau Couillard-Larocque, Marc 04 1900 (has links) De nombreuses fonctions cérébrales dépendent de la capacité de réseaux de neurones à générer une activité rythmique. Les réseaux neuronaux, nommés générateurs de patron centraux (GPCs), contrôlant les patrons de mouvements répétitifs comme la locomotion, la respiration et la mastication en sont un exemple important. Des travaux antérieurs ont montré que le noyau sensoriel principal du trijumeau (NVsnpr), qui fait partie du GPC de la mastication, contient des neurones qui peuvent décharger de façon rythmique et que les astrocytes et leur protéine S100ß étaient nécessaires pour cette rythmogénèse neuronale. Cependant, l’effet de l’activation directe des astrocytes sur la décharge des neurones du NVsnpr n’a jamais été investigué. De plus, comme les astrocytes forment des réseaux bien définis dans le NVsnpr, nous avons émis l’hypothèse que l’activation de ces réseaux pourrait contribuer à synchroniser l’activité rythmique de groupes de neurones. Pour investiguer ces deux questions, nous avons utilisé des enregistrements en mode cellules entières de neurones et d’astrocytes du NVsnpr lors de stimulations optogénétiques des astrocytes chez des souris transgéniques. Différentes lignées de souris transgéniques ont été utilisées pour exprimer des protéines photosensibles comme la channelrhodopsin (ChR2) ou le récepteur adrénergique α-1 dans les astrocytes du NVsnpr dans le but de pouvoir les stimuler par l’exposition à la lumière. De ces lignées, seul le croisement de souris S100β-Cre à des souris ChR2-lox donna des réponses significatives. Ces résultats démontrent que la stimulation optogénétique des astrocytes du NVsnpr cause divers effets sur la décharge neuronale, dont la genèse de bouffées rythmiques. Cependant, l’enregistrement de paires de neurones n’a pas permis de confirmer l’implication des astrocytes dans la synchronisation de l’activité rythmique des neurones de NVsnpr. Ces résultats permettent d’affiner les méthodes d’études des astrocytes dans le système trigéminal ainsi que de confirmer l’implication des astrocytes dans une activité rythmique, une implication qui pourrait potentiellement être observée dans d’autres structures du système nerveux central comme les GPCs de la locomotion ou de la respiration. / Several cerebral functions depend on the capacity of neural network to generate a rhythmic activity. One prominent example of this is the neural networks, named central pattern generators (CPGs), controlling repetitive movements patterns like locomotion, breathing and chewing. Previous studies have shown that the trigeminal main sensory nucleus (NVsnpr), which is part of the masticatory CPG, contains neurons that can rhythmically discharge and that the astrocytes and their protein, S100β, were essential for this neuronal rhythmogenesis. However, the effect of the activation of astrocytes on neuronal discharge of the NVsnpr remains uninvestigated. Additionally, since astrocytes form well-defined networks in the NVsnpr, we hypothesized that the activation of these networks could help synchronize the rhythmic activity of groups of neurons. To investigate these questions, we used whole cell recordings of neurons and astrocytes of the NVsnpr during optogenetic stimulation of astrocytes in transgenic mice. Different mice strains have been used to express photosensitive proteins such as channelrhodopsin (ChR2) or the α-1 adrenegic receptor in NVsnpr astrocytes to enable their stimulation with light. Of all these strains, only the S100β-Cre X ChR2-lox hybrids provided significant responses. Optogenetic stimulation of NVsnpr astrocytes produced various effects on neuronal discharge, including the genesis of rhythmic bursts. However, the recording of pairs of neurons did not confirm the involvement of astrocytes in the synchronization of the rhythmic activity of NVsnpr neurons. These results contribute to the refinement of methods used to study astrocytes in the trigeminal system and confirm the involvement of astrocytes in rhythmogenesis, an involvement that could be observed in other structures of the central nervous system such as the CPGs for respiration or locomotion. Mastication Générateurs de patrons centraux Communication neurone-glie Noyau sensoriel principal du trijumeau S100β Optogénétique Central pattern generator Neuron-Glia Communication Trigeminal main sensory nucleus Optogenetic
63	Distinct Modulatory Actions Enable Network Neuron Recruitment and Regulation Fahoum, Savanna-Rae Hakam 21 July 2023 (has links) No description available. Biology Neurosciences recruitment neuronal switching reconfiguration intrinsic properties ion channels synaptic properties synapses modulation neuromodulation central pattern generator CPG rhythmic circuits rhythmic motor system regulation entrainment Gly1-SIFamide crustacean stomatogastric STG STNS electrophysiology current clamp voltage clamp
64	Pharmacological studies on the contribution of the neuropeptide proctolin to the cephalic control of singing behavior in grasshopper Chorthippus biguttulus (L.1758) / Pharmakologische Untersuchungen zu der Beteiligung des Neuropeptides Proctolin an der Cephalen Kontrolle der Stridulation bei der Heuschreke Chorthippus biguttulus (L.1758) / Фарамакологично изследване на ролята на невропептида проктолин в мозъчния контрол на стридулацията (пеенето) при скакалеца Chorthippus biguttulus (L.1758) Vezenkov, Stoyan Raykov 02 November 2004 (has links) No description available. 570 Biowissenschaften, Biologie Mathematics and Computer Science neuropeptide proctolin singing behavior stridulation Chorthippus biguttulus insect brain neuronal circuit phonotactic approach step-wise making decision mAChR nAChR co-transmission modulation oscillation glutamate central pattern generator signal transduction glycine GABA histamine dopamine AC PLC PKC Ca2+ signaling Li+ pharma neuropeptide proctolin singing behavior stridulation Chorthippus biguttulus insect brain neuronal circuit phonotactic approach step-wise making decision mAChR nAChR co-transmission modulation oscillation glutamate central pattern generator signal transduction glycine GABA histamine dopamine AC PLC PKC Ca2+ signaling Li+ pharma 42.63 Tierphysiologie
65	Regulation of mammalian spinal locomotor networks by glial cells Acton, David January 2017 (has links) Networks of interneurons within the spinal cord coordinate the rhythmic activation of muscles during locomotion. These networks are subject to extensive neuromodulation, ensuring appropriate behavioural output. Astrocytes are proposed to detect neuronal activity via Gαq-linked G-protein coupled receptors and to secrete neuromodulators in response. However, there is currently a paucity of evidence that astrocytic information processing of this kind is important in behaviour. Here, it is shown that protease-activated receptor-1 (PAR1), a Gαq-linked receptor, is preferentially expressed by glia in the spinal cords of postnatal mice. During ongoing locomotor-related network activity in isolated spinal cords, PAR1 activation stimulates release of adenosine triphosphate (ATP), which is hydrolysed to adenosine extracellularly. Adenosine then activates A1 receptors to reduce the frequency of locomotor-related bursting recorded from ventral roots. This entails inhibition of D1 dopamine receptors, activation of which enhances burst frequency. The effect of A1 blockade scales with network activity, consistent with activity-dependent production of adenosine by glia. Astrocytes also regulate activity by controlling the availability of D-serine or glycine, both of which act as co-agonists of glutamate at N-methyl-D-aspartate receptors (NMDARs). The importance of NMDAR regulation for locomotor-related activity is demonstrated by blockade of NMDARs, which reduces burst frequency and amplitude. Bath-applied D-serine increases the frequency of locomotor-related bursting but not intense synchronous bursting produced by blockade of inhibitory transmission, implying activity-dependent regulation of co-agonist availability. Depletion of endogenous D-serine increases the frequency of locomotor-related but not synchronous bursting, indicating that D-serine is required at a subset of NMDARs expressed by inhibitory interneurons. Blockade of the astrocytic glycine transporter GlyT1 increases the frequency of locomotor-related activity, but application of glycine has no effect, indicating that GlyT1 regulates glycine at excitatory synapses. These results indicate that glia play an important role in regulating the output of spinal locomotor networks.
66	Studies of Spinal Motor Control Networks in Genetically Modified Mouse Models Gezelius, Henrik January 2009 (has links) Spinal neurons are important in several aspects motor control. For example, the neurons essential for locomotor movements reside in the ventral spinal cord. In this thesis, different motor control functions are being related to neuronal populations defined by their common expression of a gene. First, a targeted disruption of the gene for vesicular glutamate transporter 2 (Vglut2/ Slc17a6) is described. The mutant animals die at birth because of their inability to breathe. The neuronal network in the brainstem, responsible for inspiration, was shown to become non-functional by the targeted deletion of Vglut2. To our surprise, it was still possible to induce rhythmic activity with normal left/right alternation in spinal cords isolated from VGLUT2-null embryos. Inconsistent reports of Vglut1 expression in the spinal cord made us re-evaluate the Vglut1 and Vglut2 expressions. While Vglut2 expression was widespread in the spinal cord, Vglut1 expression was restricted to a few cells dorsal to the central canal. Taken together, the data suggest that, glutamatergic signaling is mandatory to drive the bilateral breathing, but not needed for coordination of basal alternating spinal locomotor rhythm. Next, a screen for genes with restricted ventral expression was made. Some of the genes found could be connected to the characteristics of specific neuronal cell populations. For example, fast motor neurons were shown to express the genes Calca and Chodl. Further, we found the Chrna2 expression selectively in putative Renshaw cells. It seems likely that the gene product, the alpha2 subunit of the nicotinergic receptor, could be linked to the unique connection of motor neurons to Renshaw cells. We used the Chrna2 promoter to drive expression of Cre recombinase in a transgenic mouse. The Cre activity was present in most neurons labeled with Renshaw cell markers, which should make it a useful tool for functional studies of this population. The studies presented here show how the genes expressed in subsets of neurons can be used to target populations of neurons for functional studies of neuronal systems. acetyl choline central nervous system central pattern generator Cre recombinase development genetic screen glutamate interneuron motor neuron mouse mouse genetics movement network neuronal network nicotinic receptors physiology Renshaw cell rhythm spinal cord transmitter Neuroscience Neurovetenskap Neurobiology Neurobiologi Molecular neurobiology Molekylär neurobiologi Neurophysiology Neurofysiologi Neurobiology Neurobiologi
67	Détermination des facteurs bénéfiques et néfastes à la récupération locomotrice à la suite d’une section spinale complète chez la souris Jeffrey-Gauthier, Renaud 12 1900 (has links) No description available. moelle épinière section hémisection locomotion plasticité générateur de patron central sérotonine inflammation réflexe de Hoffmann dépression post-activation désinhibition afférences sensorielles nociception Spinal cord Transection Plasticity Central pattern generator Serotonin Neuromodulation Hoffmann reflex Frequency-dependent depression Sensory afferents
68	Les cantates de Nicolaus Bruhns (1665-1697) / The cantatas of Nicolaus Bruhns (1665-1697) Fructus, Michel 03 December 2009 (has links) Nicolaus Bruhns (1665-1697) fut organiste à la Marienkirche de Husum (Schleswig-Holstein), et Kapellmeister au service des ducs de Schleswig-Holstein-Gottorf. Si nous ne possédons aujourd’hui qu’une poignée de ses pièces pour orgue (quatre praeludia et un choral-fantaisie), nous pouvons apprécier l’ingéniosité de cet auteur à travers sa production d’œuvres sacrées, douze cantates où règne une énergie comparable à celle de son professeur Dietrich Buxtehude.Soucieux de mieux cerner les enjeux de l’identité créatrice, nous proposerons une approche contradictoire, fondée sur deux conceptions opposées de l’œuvre d’art : elle est par voie de conséquence le produit d’une culture (parce qu’elle est liée au contexte artistique qui la précède, au regard des éléments qui la constituent et qui sont facilement identifiables dans les œuvres du passé, toute œuvre peut être perçue et pensée comme une synthèse de différents modèles, une forme d’aboutissement culturel), mais aussi le fruit d’une individualité (une œuvre d’art est une élaboration unique, indépendante de toute autre production, au regard des facteurs d’unité qui la structurent ; toute œuvre peut alors être perçue et pensée comme une entité autonome).Cette étude nous permettra de mettre à jour un soubassement de l’activité psychique : l’estimation de la distance entre le fixe et le muable. / Nicolaus Bruhns (1665-1697) was an organist at the Marienkirche in Husum (Schleswig-Holstein), and Kapellmeister to the dukes of Schleswig-Holstein-Gottorf. If we own today only a handful of his pieces for organ (four praeludia and a chorale-fantasia), we can appreciate the cleverness of this author through his production of sacred works, twelve cantatas where the energy which appears is similar to that of his professor Dietrich Buxtehude.With the concern to better define the stakes of creative identity, we shall put forward a contradictory approach based on two opposite conceptions of the work of art : it is in essence the product of a culture (since it is linked to the artistic context which precedes it, according to the elements which constitute it and which are easily identifiable in the works of the past, any work can be perceived and thought as a synthesis of various models, a form of cultural achievement), but also the result of individuality (a work of art is a unique construction, independent from any other production according to the factors of unity which structure it ; any work may then be perceived and thought as an autonomous entity).This study will enable us to bring to light a basis of the psychic activity : the appraisal of the distance between the fixed and the changing. Baroque Basse continue Bokemeyer (Heinrich) Buxtehude (Dietrich) Cantate Chiffrages Continuo Figures musicales Fixe Héritage Husum Identité Kapellmeiter Luther Luthéranisme Motif générateur Muable Musique allemande Musique luthérienne Musique sacrée Œuvres vocales Organiste Orgue Protestantisme Réduction mélodique Réduction harmonique Ritornello Schleswig-Holstein Sinfonia Baroque Basso continuo Bokemeyer (Heinrich) Buxtehude (Dietrich) Cantate Figuring Continuo Musical figure Fixed Heritage Husum Identity Kapellmeiter Luther Lutheranism Pattern generator Changing German music Lutheran music Sacred music Vocal works Organist Organ Protestantism Melodic reduction Harmonic reduction Ritornello Schleswig-Holstein Sinfonia
69	Modeling, Simulation, and Injection of Camera Images/Video to Automotive Embedded ECU : Image Injection Solution for Hardware-in-the-Loop Testing Lind, Anton January 2023 (has links) Testing, verification and validation of sensors, components and systems is vital in the early-stage development of new cars with computer-in-the-car architecture. This can be done with the help of the existing technique, hardware-in-the-loop (HIL) testing which, in the close loop testing case, consists of four main parts: Real-Time Simulation Platform, Sensor Simulation PC, Interface Unit (IU), and unit under test which is, for instance, a Vehicle Computing Unit (VCU). The purpose of this degree project is to research and develop a proof of concept for in-house development of an image injection solution (IIS) on the IU in the HIL testing environment. A proof of concept could confirm that editing, customizing, and having full control of the IU is a possibility. This project was initiated by Volvo Cars to optimize the use of the HIL testing environment currently available, making the environment more changeable and controllable while the IIS remains a static system. The IU is an MPSoC/FPGA based design that uses primarily Xilinx hardware and software (Vivado/Vitis) to achieve the necessary requirements for image injection in the HIL testing environment. It consists of three stages in series: input, image processing, and output. The whole project was divided in three parts based on the three stages and carried out at Volvo Cars in cooperation by three students, respectively. The author of this thesis was responsible for the output stage, where the main goal was to find a solution for converting, preferably, AXI4 RAW12 image data into data on CSI2 format. This CSI2 data can then be used as input to serializers, which in turn transmit the data via fiber-optic cable on GMSL2 format to the VCU. Associated with the output stage, extensive simulations and hardware tests have been done on a preliminary solution that partially worked on the hardware, producing signals in parts of the design that could be read and analyzed. However, a final definite solution that fully functions on the hardware has not been found, because the work is at the initial phase of an advanced and very complex project. Presented in this thesis is: important theory regarding, for example, protocols CSI2, AXI4, GMSL2, etc., appropriate hardware selection for an IIS in HIL (FPGA, MPSoC, FMC, etc.), simulations of AXI4 and CSI2 signals, comparisons of those simulations with the hardware signals of an implemented design, and more. The outcome was heavily dependent on getting a certain hardware (TEF0010) to transmit the GMSL2 data. Since the wrong card was provided, this was the main problem that hindered the thesis from reaching a fully functioning implementation. However, these results provide a solid foundation for future work related to image injection in a HIL environment. ADAS AD ADS HIL Hardware in the loop Hardware-in-the-loop ECU VCU Automotive Embedded System Systems Camera Image Video Injection FPGA MPSoC Vivado Vitis VHDL Volvo Cars FMC HPC LPC MIPI CSI2 GMSL2 AMBA AXI4 Xilinx RTL Implementation Synthesis Intelectual Property IP Vehicle computing unit Electronic control unit TEB0911 TEF0007 TEF0010 CSI2 Tx CSI2 Tx Subsystem Zynq SerDes AXI4 AXI4-Lite Programmable Logic PL Processor System PS C C++ Video test pattern generator VTPG Axi traffic generator ATG Ultrascale+ Virtual input/output VIO Integrated logic analyzer ILA Interface Unit Embedded Systems Inbäddad systemteknik

Search results