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https://www.readbyqxmd.com/read/28227907/understanding-the-role-of-astrocytic-gaba-in-simulated-neural-networks
#1
Kerstin Lenk, Eero Raisanen, Jari A K Hyttinen, Kerstin Lenk, Eero Raisanen, Jari A K Hyttinen, Kerstin Lenk, Jari Ak Hyttinen, Eero Raisanen
Astrocytes actively influence the behavior of the surrounding neuronal network including changes of the synaptic plasticity and neuronal excitability. These dynamics are altered in diseases like Alzheimer's, where the release of the gliotransmitter GABA is increased by affected, so called reactive astrocytes. In this paper, we aim to simulate a neural network with altered astrocytic GABA release. Therefore, we use our developed neuron-astrocyte model, called INEXA, which includes astrocyte controlled tripartite synapses and the astrocyte-astrocyte interaction...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226670/computational-modeling-of-high-frequency-oscillations-recorded-with-clinical-intracranial-macroelectrodes
#2
M Shamas, P Benquet, I Merlet, W El Falou, M Khalil, F Wendling, M Shamas, P Benquet, I Merlet, W El Falou, M Khalil, F Wendling, M Khalil, P Benquet, I Merlet, W El Falou, M Shamas, F Wendling
High Frequency Oscillations (HFOs) are a potential biomarker of epileptogenic regions. They have been extensively investigated in terms of automatic detection, classification and feature extraction. However, the mechanisms governing the generation of HFOs as well as the observability conditions on clinical intracranial macroelectrodes remain elusive. In this paper, we propose a novel physiologically-relevant macroscopic model for accurate simulation of HFOs as invasively recorded in epileptic patients. This model accounts for both the temporal and spatial properties of the cortical patch at the origin of epileptiform activity...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226655/use-of-local-field-potentials-of-dissociated-cultures-grown-on-multi-electrode-arrays-for-pharmacological-assays
#3
G D C Mendis, E Morrisroe, C A Reid, S K Halgamuge, S Petrou, G D C Mendis, E Morrisroe, C A Reid, S K Halgamuge, S Petrou, S K Halgamuge, S Petrou, E Morrisroe, C A Reid, G D C Mendis
In vitro Multi-Electrode Arrays (MEA) are an extracellular recording technology that enables the analysis of networks of neurons in vitro. Neurons in culture exhibit a range of behavioral dynamics, which can be measured in terms of individual action potentials, network-wide synchronized firing and a host of other features that characterize network activity. MEA data analysis was historically focused on high frequency spike data forgoing the low frequency content of the signal. In this study, we use local field potentials, which are low frequency components of MEA signals, to differentiate between two types of antiepileptic drugs (p<;0...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28220891/nmda-receptor-expression-in-the-thalamus-of-the-stargazer-model-of-absence-epilepsy
#4
Z Barad, D R Grattan, B Leitch
In the stargazer mouse model of absence epilepsy, altered corticothalamic excitation of reticular thalamic nucleus (RTN) neurons has been suggested to contribute to abnormal synchronicity in the corticothalamic-thalamocortical circuit, leading to spike-wave discharges, the hallmark of absence seizures. AMPA receptor expression and function are decreased in stargazer RTN, due to a mutation of AMPAR auxiliary subunit stargazin. It is unresolved and debated, however, if decreased excitation of RTN is compatible with epileptogenesis...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220877/impact-of-bounded-noise-on-the-formation-and-instability-of-spiral-wave-in-a-2d-lattice-of-neurons
#5
Yuangen Yao, Haiyou Deng, Ming Yi, Jun Ma
Spiral waves in the neocortex may provide a spatial framework to organize cortical oscillations, thus help signal communication. However, noise influences spiral wave. Many previous theoretical studies about noise mainly focus on unbounded Gaussian noise, which contradicts that a real physical quantity is always bounded. Furthermore, non-Gaussian noise is also important for dynamical behaviors of excitable media. Nevertheless, there are no results concerning the effect of bounded noise on spiral wave till now...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28213155/high-frequency-stimulation-of-afferent-fibers-generates-asynchronous-firing-in-the-downstream-neurons-in-hippocampus-through-partial-block-of-axonal-conduction
#6
Zhouyan Feng, Zhaoxiang Wang, Zheshan Guo, Wenjie Zhou, Ziyan Cai, Dominique M Durand
Deep brain stimulation (DBS) is effective for treating neurological disorders in clinic. However, the therapeutic mechanisms of high-frequency stimulation (HFS) of DBS have not yet been elucidated. Previous studies have suggested that HFS-induced changes in axon conduction could have important contributions to the DBS effects and desiderate further studies. To investigate the effects of prolonged HFS of afferent axons on the firing of downstream neurons, HFS trains of 100 and 200 Hz were applied on the Schaffer collaterals of the hippocampal CA1 region in anaesthetized rats...
February 14, 2017: Brain Research
https://www.readbyqxmd.com/read/28212785/the-role-of-driver-nodes-in-managing-epileptic-seizures-application-of-kuramoto-model
#7
Ali Mohseni, Shahriar Gharibzadeh, Fatemeh Bakouie
Synchronization is an important global phenomenon which could be found in a wide range of complex systems such as brain or electronic devices. However, in some circumstances the synchronized states are not desirable for the system and should be suppressed. For example, excessively synchronized activities in the brain network could be the root of neuronal disorders like epileptic seizures. According to the controllability theory of the complex networks, a minimum set of driver nodes has the ability to control the entire system...
February 15, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28208338/synchronization-and-long-time-memory-in-neural-networks-with-inhibitory-hubs-and-synaptic-plasticity
#8
Elena Bertolotti, Raffaella Burioni, Matteo di Volo, Alessandro Vezzani
We investigate the dynamical role of inhibitory and highly connected nodes (hub) in synchronization and input processing of leaky-integrate-and-fire neural networks with short term synaptic plasticity. We take advantage of a heterogeneous mean-field approximation to encode the role of network structure and we tune the fraction of inhibitory neurons f_{I} and their connectivity level to investigate the cooperation between hub features and inhibition. We show that, depending on f_{I}, highly connected inhibitory nodes strongly drive the synchronization properties of the overall network through dynamical transitions from synchronous to asynchronous regimes...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28203147/astrocyte-dependent-slow-inward-currents-sics-participate-in-neuromodulatory-mechanisms-in-the-pedunculopontine-nucleus-ppn
#9
Adrienn Kovács, Balázs Pál
Slow inward currents (SICs) are known as excitatory events of neurons caused by astrocytic glutamate release and consequential activation of neuronal extrasynaptic NMDA receptors. In the present article we investigate the role of these astrocyte-dependent excitatory events on a cholinergic nucleus of the reticular activating system (RAS), the pedunculopontine nucleus (PPN). It is well known about this and other elements of the RAS, that they do not only give rise to neuromodulatory innervation of several areas, but also targets neuromodulatory actions from other members of the RAS or factors providing the homeostatic drive for sleep...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28202729/synchronous-spikes-are-necessary-but-not-sufficient-for-a-synchrony-code-in-populations-of-spiking-neurons
#10
Jan Grewe, Alexandra Kruscha, Benjamin Lindner, Jan Benda
Synchronous activity in populations of neurons potentially encodes special stimulus features. Selective readout of either synchronous or asynchronous activity allows formation of two streams of information processing. Theoretical work predicts that such a synchrony code is a fundamental feature of populations of spiking neurons if they operate in specific noise and stimulus regimes. Here we experimentally test the theoretical predictions by quantifying and comparing neuronal response properties in tuberous and ampullary electroreceptor afferents of the weakly electric fish Apteronotus leptorhynchus These related systems show similar levels of synchronous activity, but only in the more irregularly firing tuberous afferents a synchrony code is established, whereas in the more regularly firing ampullary afferents it is not...
February 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28197088/synchronization-and-inter-layer-interactions-of-noise-driven-neural-networks
#11
Anis Yuniati, Te-Lun Mai, Chi-Ming Chen
In this study, we used the Hodgkin-Huxley (HH) model of neurons to investigate the phase diagram of a developing single-layer neural network and that of a network consisting of two weakly coupled neural layers. These networks are noise driven and learn through the spike-timing-dependent plasticity (STDP) or the inverse STDP rules. We described how these networks transited from a non-synchronous background activity state (BAS) to a synchronous firing state (SFS) by varying the network connectivity and the learning efficacy...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28193862/differential-modulation-of-global-and-local-neural-oscillations-in-rem-sleep-by-homeostatic-sleep-regulation
#12
Bowon Kim, Bernat Kocsis, Eunjin Hwang, Youngsoo Kim, Robert E Strecker, Robert W McCarley, Jee Hyun Choi
Homeostatic rebound in rapid eye movement (REM) sleep normally occurs after acute sleep deprivation, but REM sleep rebound settles on a persistently elevated level despite continued accumulation of REM sleep debt during chronic sleep restriction (CSR). Using high-density EEG in mice, we studied how this pattern of global regulation is implemented in cortical regions with different functions and network architectures. We found that across all areas, slow oscillations repeated the behavioral pattern of persistent enhancement during CSR, whereas high-frequency oscillations showed progressive increases...
February 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28185093/altered-spontaneous-brain-activity-in-adolescent-boys-with-pure-conduct-disorder-revealed-by-regional-homogeneity-analysis
#13
Qiong Wu, Xiaocui Zhang, Daifeng Dong, Xiang Wang, Shuqiao Yao
Functional magnetic resonance imaging (fMRI) studies have revealed abnormal neural activity in several brain regions of adolescents with conduct disorder (CD) performing various tasks. However, little is known about the spontaneous neural activity in people with CD in a resting state. The aims of this study were to investigate CD-associated regional activity abnormalities and to explore the relationship between behavioral impulsivity and regional activity abnormalities. Resting-state fMRI (rs-fMRI) scans were administered to 28 adolescents with CD and 28 age-, gender-, and IQ-matched healthy controls (HCs)...
February 9, 2017: European Child & Adolescent Psychiatry
https://www.readbyqxmd.com/read/28174614/weak-electric-fields-detectability-in-a-noisy-neural-network
#14
Jia Zhao, Bin Deng, Yingmei Qin, Cong Men, Jiang Wang, Xile Wei, Jianbing Sun
We investigate the detectability of weak electric field in a noisy neural network based on Izhikevich neuron model systematically. The neural network is composed of excitatory and inhibitory neurons with similar ratio as that in the mammalian neocortex, and the axonal conduction delays between neurons are also considered. It is found that the noise intensity can modulate the detectability of weak electric field. Stochastic resonance (SR) phenomenon induced by white noise is observed when the weak electric field is added to the network...
February 2017: Cognitive Neurodynamics
https://www.readbyqxmd.com/read/28166220/neuronal-activity-modifies-the-chromatin-accessibility-landscape-in-the-adult-brain
#15
Yijing Su, Jaehoon Shin, Chun Zhong, Sabrina Wang, Prith Roychowdhury, Jongseuk Lim, David Kim, Guo-Li Ming, Hongjun Song
Neuronal activity-induced gene expression modulates the function and plasticity of the nervous system. It is unknown whether and to what extent neuronal activity may trigger changes in chromatin accessibility, a major mode of epigenetic regulation of gene expression. Here we compared chromatin accessibility landscapes of adult mouse dentate granule neurons in vivo before and after synchronous neuronal activation using an assay for transposase-accessible chromatin using sequencing (ATAC-seq). We found genome-wide changes 1 h after activation, with enrichment of gained-open sites at active enhancer regions and at binding sites for AP1-complex components, including c-Fos...
February 6, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/28159688/altered-regional-connectivity-reflecting-effects-of-different-anaesthesia-protocols-in-the-mouse-brain
#16
Tong Wu, Joanes Grandjean, Simone C Bosshard, Markus Rudin, David Reutens, Tianzi Jiang
Studies in mice using resting-state functional magnetic resonance imaging (rs-fMRI) have provided opportunities to investigate the effects of pharmacological manipulations on brain function and map the phenotypes of mouse models of human brain disorders. Mouse rs-fMRI is typically performed under anaesthesia, which induces both regional suppression of brain activity and disruption of large-scale neural networks. Previous comparative studies using rodents investigating various drug effects on long-distance functional connectivity (FC) have reported agent-specific FC patterns, however, effects of regional suppression are sparsely explored...
February 1, 2017: NeuroImage
https://www.readbyqxmd.com/read/28159382/the-putative-role-of-neuronal-network-synchronization-as-a-potential-biomarker-for-bipolar-disorder-a-review-of-eeg-studies
#17
REVIEW
E Maggioni, A M Bianchi, A C Altamura, Jair C Soares, P Brambilla
Impaired intra-hemispheric and inter-hemispheric communication play a major role in the pathophysiology and cognitive disturbances of bipolar disorder (BD). Brain connectivity in BD has been largely investigated using magnetic resonance imaging (MRI) techniques, which have found alterations in prefronto-limbic coupling. In contrast, evidence for functional neural circuitry abnormalities in BD is less consistent. Indeed, just a few studies employing the electroencephalographic (EEG) technique, enabling the exploration of oscillatory brain dynamics, addressed this issue...
January 3, 2017: Journal of Affective Disorders
https://www.readbyqxmd.com/read/28157557/elimination-of-spiral-waves-in-a-locally-connected-chaotic-neural-network-by-a-dynamic-phase-space-constraint
#18
Yang Li, Makito Oku, Guoguang He, Kazuyuki Aihara
In this study, a method is proposed that eliminates spiral waves in a locally connected chaotic neural network (CNN) under some simplified conditions, using a dynamic phase space constraint (DPSC) as a control method. In this method, a control signal is constructed from the feedback internal states of the neurons to detect phase singularities based on their amplitude reduction, before modulating a threshold value to truncate the refractory internal states of the neurons and terminate the spirals. Simulations showed that with appropriate parameter settings, the network was directed from a spiral wave state into either a plane wave (PW) state or a synchronized oscillation (SO) state, where the control vanished automatically and left the original CNN model unaltered...
January 16, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28155916/dual-origins-of-the-intracellular-circadian-calcium-rhythm-in-the-suprachiasmatic-nucleus
#19
Ryosuke Enoki, Daisuke Ono, Shigeru Kuroda, Sato Honma, Ken-Ichi Honma
In mammals, the master circadian clock is located in the suprachiasmatic nucleus (SCN), where most neurons show circadian rhythms of intracellular Ca(2+) levels. However, the origin of these Ca(2+) rhythms remains largely unknown. In this study, we successfully monitored the intracellular circadian Ca(2+) rhythms together with the circadian PER2 and firing rhythms in a single SCN slice ex vivo, which enabled us to explore the origins. The phase relation between the circadian PER2 and Ca(2+) rhythms, but not between the circadian PER2 and firing rhythms, was significantly altered in Cry1/Cry2 double knockout mice, which display a loss of intercellular synchronization in the SCN...
February 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28155864/aberrant-neuronal-dynamics-during-working-memory-operations-in-the-aging-hiv-infected-brain
#20
Tony W Wilson, Amy L Proskovec, Elizabeth Heinrichs-Graham, Jennifer O'Neill, Kevin R Robertson, Howard S Fox, Susan Swindells
Impairments in working memory are among the most prevalent features of HIV-associated neurocognitive disorders (HAND), yet their origins are unknown, with some studies arguing that encoding operations are disturbed and others supporting deficits in memory maintenance. The current investigation directly addresses this issue by using a dynamic mapping approach to identify when and where processing in working memory circuits degrades. HIV-infected older adults and a demographically-matched group of uninfected controls performed a verbal working memory task during magnetoencephalography (MEG)...
February 3, 2017: Scientific Reports
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