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https://www.readbyqxmd.com/read/29666978/spike-timing-precision-of-neuronal-circuits
#1
Deniz Kilinc, Alper Demir
Spike timing is believed to be a key factor in sensory information encoding and computations performed by the neurons and neuronal circuits. However, the considerable noise and variability, arising from the inherently stochastic mechanisms that exist in the neurons and the synapses, degrade spike timing precision. Computational modeling can help decipher the mechanisms utilized by the neuronal circuits in order to regulate timing precision. In this paper, we utilize semi-analytical techniques, which were adapted from previously developed methods for electronic circuits, for the stochastic characterization of neuronal circuits...
April 17, 2018: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/29664887/%C3%AE-aminobutyric-acid-type-a-receptor-potentiation-inhibits-learning-in-a-computational-network-model
#2
Kingsley P Storer, George N Reeke
BACKGROUND: Propofol produces memory impairment at concentrations well below those abolishing consciousness. Episodic memory, mediated by the hippocampus, is most sensitive. Two potentially overlapping scenarios may explain how γ-aminobutyric acid receptor type A (GABAA) potentiation by propofol disrupts episodic memory-the first mediated by shifting the balance from excitation to inhibition while the second involves disruption of rhythmic oscillations. We use a hippocampal network model to explore these scenarios...
April 17, 2018: Anesthesiology
https://www.readbyqxmd.com/read/29662089/time-rescaling-reproduces-eeg-behavior-during-transition-from-propofol-anesthesia-induced-unconsciousness-to-consciousness
#3
S Boussen, A Spiegler, C Benar, M Carrère, F Bartolomei, P Metellus, R Voituriez, L Velly, N Bruder, A Trébuchon
General anesthesia (GA) is a reversible manipulation of consciousness whose mechanism is mysterious at the level of neural networks leaving space for several competing hypotheses. We recorded electrocorticography (ECoG) signals in patients who underwent intracranial monitoring during awake surgery for the treatment of cerebral tumors in functional areas of the brain. Therefore, we recorded the transition from unconsciousness to consciousness directly on the brain surface. Using frequency resolved interferometry; we studied the intermediate ECoG frequencies (4-40 Hz)...
April 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29659572/a-computational-study-of-astrocytic-glutamate-influence-on-post-synaptic-neuronal-excitability
#4
Bronac Flanagan, Liam McDaid, John Wade, KongFatt Wong-Lin, Jim Harkin
The ability of astrocytes to rapidly clear synaptic glutamate and purposefully release the excitatory transmitter is critical in the functioning of synapses and neuronal circuits. Dysfunctions of these homeostatic functions have been implicated in the pathology of brain disorders such as mesial temporal lobe epilepsy. However, the reasons for these dysfunctions are not clear from experimental data and computational models have been developed to provide further understanding of the implications of glutamate clearance from the extracellular space, as a result of EAAT2 downregulation: although they only partially account for the glutamate clearance process...
April 16, 2018: PLoS Computational Biology
https://www.readbyqxmd.com/read/29656873/vision-and-locomotion-shape-the-interactions-between-neuron-types-in-mouse-visual-cortex
#5
Mario Dipoppa, Adam Ranson, Michael Krumin, Marius Pachitariu, Matteo Carandini, Kenneth D Harris
Cortical computation arises from the interaction of multiple neuronal types, including pyramidal (Pyr) cells and interneurons expressing Sst, Vip, or Pvalb. To study the circuit underlying such interactions, we imaged these four types of cells in mouse primary visual cortex (V1). Our recordings in darkness were consistent with a "disinhibitory" model in which locomotion activates Vip cells, thus inhibiting Sst cells and disinhibiting Pyr cells. However, the disinhibitory model failed when visual stimuli were present: locomotion increased Sst cell responses to large stimuli and Vip cell responses to small stimuli...
April 11, 2018: Neuron
https://www.readbyqxmd.com/read/29656872/the-medial-prefrontal-cortex-shapes-dopamine-reward-prediction-errors-under-state-uncertainty
#6
Clara Kwon Starkweather, Samuel J Gershman, Naoshige Uchida
Animals make predictions based on currently available information. In natural settings, sensory cues may not reveal complete information, requiring the animal to infer the "hidden state" of the environment. The brain structures important in hidden state inference remain unknown. A previous study showed that midbrain dopamine neurons exhibit distinct response patterns depending on whether reward is delivered in 100% (task 1) or 90% of trials (task 2) in a classical conditioning task. Here we found that inactivation of the medial prefrontal cortex (mPFC) affected dopaminergic signaling in task 2, in which the hidden state must be inferred ("will reward come or not?"), but not in task 1, where the state was known with certainty...
April 9, 2018: Neuron
https://www.readbyqxmd.com/read/29656800/dopaminergic-disturbances-in-tourette-syndrome-an-integrative-account
#7
REVIEW
Tiago V Maia, Vasco A Conceição
Tourette syndrome (TS) is thought to involve dopaminergic disturbances, but the nature of those disturbances remains controversial. Existing hypotheses suggest that TS involves 1) supersensitive dopamine receptors, 2) overactive dopamine transporters that cause low tonic but high phasic dopamine, 3) presynaptic dysfunction in dopamine neurons, or 4) dopaminergic hyperinnervation. We review evidence that contradicts the first two hypotheses; we also note that the last two hypotheses have traditionally been considered too narrowly, explaining only small subsets of findings...
March 9, 2018: Biological Psychiatry
https://www.readbyqxmd.com/read/29651458/differential-expression-of-voltage-gated-sodium-channels-in-afferent-neurons-renders-selective-neural-block-by-ionic-direct-current
#8
Fei Yang, Michael Anderson, Shaoqiu He, Kimberly Stephens, Yu Zheng, Zhiyong Chen, Srinivasa N Raja, Felix Aplin, Yun Guan, Gene Fridman
The assertion that large-diameter nerve fibers have low thresholds and small-diameter fibers have high thresholds in response to electrical stimulation has been held in a nearly axiomatic regard in the field of neuromodulation and neuroprosthetics. In contrast to the short pulses used to evoke action potentials, long-duration ionic direct current has been shown to block neural activity. We propose that the main determinant of the neural sensitivity to direct current block is not the size of the axon but the types of voltage-gated sodium channels prevalent in its neural membrane...
April 2018: Science Advances
https://www.readbyqxmd.com/read/29642837/approximate-inference-of-gene-regulatory-network-models-from-rna-seq-time-series-data
#9
Thomas Thorne
BACKGROUND: Inference of gene regulatory network structures from RNA-Seq data is challenging due to the nature of the data, as measurements take the form of counts of reads mapped to a given gene. Here we present a model for RNA-Seq time series data that applies a negative binomial distribution for the observations, and uses sparse regression with a horseshoe prior to learn a dynamic Bayesian network of interactions between genes. We use a variational inference scheme to learn approximate posterior distributions for the model parameters...
April 11, 2018: BMC Bioinformatics
https://www.readbyqxmd.com/read/29642483/drawing-inspiration-from-human-brain-networks-construction-of-interconnected-virtual-networks
#10
Masaya Murakami, Daichi Kominami, Kenji Leibnitz, Masayuki Murata
Virtualization of wireless sensor networks (WSN) is widely considered as a foundational block of edge/fog computing, which is a key technology that can help realize next-generation Internet of things (IoT) networks. In such scenarios, multiple IoT devices and service modules will be virtually deployed and interconnected over the Internet. Moreover, application services are expected to be more sophisticated and complex, thereby increasing the number of modifications required for the construction of network topologies...
April 8, 2018: Sensors
https://www.readbyqxmd.com/read/29626009/the-nurr1-ligand-1-1-bis-3-indolyl-1-p-chlorophenyl-methane-modulates-glial-reactivity-and-is-neuroprotective-in-mptp-induced-parkinsonism
#11
Sean L Hammond, Katriana A Popichak, Xi Li, Lindsay G Hunt, Evan H Richman, Pranav Damale, Edwin Chong, Donald S Backos, Stephen Safe, Ronald B Tjalkens
The orphan nuclear receptor, Nurr1 (NR4A2), regulates inflammatory gene expression in glial cells, as well as genes associated with homeostatic and trophic function in dopaminergic neurons. Despite these known functions of Nurr1, an endogenous ligand has not been discovered. We postulated that activation of Nurr1 would suppress activation of glia and thereby protect against loss of dopamine (DA) neurons following subacute lesioning with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our previous studies have shown that a synthetic Nurr1 ligand, 1,1-bis(3'-indolyl)-1-(p-chlorophenyl)methane (C-DIM12), suppresses inflammatory gene expression in primary astrocytes and induces a dopaminergic phenotype in neurons...
April 6, 2018: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/29617218/computational-model-of-brainstem-circuit-for-state-dependent-control-of-hypoglossal-motoneurons
#12
Mohsen Naji, Maxim Komarov, Giri P Krishnan, Atul Malhotra, Frank L Powell, Irma Rukhadze, Victor B Fenik, Maxim Bazhenov
In patients with obstructive sleep apnea (OSA) the pharyngeal muscles become relaxed during sleep, which leads to a partial or complete closure of upper airway. Experimental studies suggest that withdrawal of noradrenergic and serotonergic drives importantly contribute to depression of hypoglossal motoneurons and, therefore, may contribute to OSA pathophysiology; however, specific cellular and synaptic mechanisms remain unknown. In this new study, we developed a biophysical network model to test the hypothesis that, in order to explain experimental observations, the neuronal network for monoaminergic control of excitability of hypoglossal motoneurons needs to include excitatory and inhibitory perihypoglossal interneurons that mediate noradrenergic and serotonergic drives to hypoglossal motoneurons...
April 4, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29615797/a-statistical-method-for-analyzing-and-comparing-spatiotemporal-cortical-activation-patterns
#13
Patrick Krauss, Claus Metzner, Achim Schilling, Konstantin Tziridis, Maximilian Traxdorf, Andreas Wollbrink, Stefan Rampp, Christo Pantev, Holger Schulze
Information in the cortex is encoded in spatiotemporal patterns of neuronal activity, but the exact nature of that code still remains elusive. While onset responses to simple stimuli are associated with specific loci in cortical sensory maps, it is completely unclear how the information about a sustained stimulus is encoded that is perceived for minutes or even longer, when discharge rates have decayed back to spontaneous levels. Using a newly developed statistical approach (multidimensional cluster statistics (MCS)) that allows for a comparison of clusters of data points in n-dimensional space, we here demonstrate that the information about long-lasting stimuli is encoded in the ongoing spatiotemporal activity patterns in sensory cortex...
April 3, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29615366/ongoing-brain-rhythms-shape-i-wave-properties-in-a-computational-model
#14
Natalie Schaworonkow, Jochen Triesch
BACKGROUND: Responses to transcranial magnetic stimulation (TMS) are notoriously variable. Previous studies have observed a dependence of TMS-induced responses on ongoing brain activity, for instance sensorimotor rhythms. This suggests an opportunity for the development of more effective stimulation protocols through closed-loop TMS-EEG. However, it is not yet clear how features of ongoing activity affect the responses of cortical circuits to TMS. OBJECTIVE/HYPOTHESIS: Here we investigate the dependence of TMS-responses on power and phase of ongoing oscillatory activity in a computational model of TMS-induced I-waves...
March 20, 2018: Brain Stimulation
https://www.readbyqxmd.com/read/29610104/a-copula-based-granger-causality-measure-for-the-analysis-of-neural-spike-train-data
#15
Meng Hu, Wu Li, Hualou Liang
In systems neuroscience, it is becoming increasingly common to record the activity of hundreds of neurons simultaneously via electrode arrays. The ability to accurately measure the causal interactions among multiple neurons in the brain is crucial to understanding how neurons work in concert to generate specific brain functions. The development of new statistical methods for assessing causal influence between spike trains is still an active field of neuroscience research. Here, we suggest a copula-based Granger causality measure for the analysis of neural spike train data...
March 2018: IEEE/ACM Transactions on Computational Biology and Bioinformatics
https://www.readbyqxmd.com/read/29606961/a-pruning-neural-network-model-in-credit-classification-analysis
#16
Yajiao Tang, Junkai Ji, Shangce Gao, Hongwei Dai, Yang Yu, Yuki Todo
Nowadays, credit classification models are widely applied because they can help financial decision-makers to handle credit classification issues. Among them, artificial neural networks (ANNs) have been widely accepted as the convincing methods in the credit industry. In this paper, we propose a pruning neural network (PNN) and apply it to solve credit classification problem by adopting the well-known Australian and Japanese credit datasets. The model is inspired by synaptic nonlinearity of a dendritic tree in a biological neural model...
2018: Computational Intelligence and Neuroscience
https://www.readbyqxmd.com/read/29604967/an-improved-measurement-of-the-ca-2-binding-affinity-of-fluorescent-ca-2-indicators
#17
Van Tran, Michael C H Park, Christian Stricker
Fluorescent Ca2+ indicators are widely used to measure the intracellular Ca2+ concentration ([Ca2+ ]i ) in living cells, including neurons. By calibrating an indicator in solutions that mimic the main ionic constituents of the actual cytoplasm, [Ca2+ ]i can be determined from the measured fluorescence intensity. However, different studies have reported considerably different Ca2+ -binding affinities (Kd ) for the same indicator, even though they used calibrating solutions with similar compositions. In this paper, we present a method to accurately determine the Kd values of non-ratiometric Ca2+ indicators in solutions that mimicked a standard patch-clamp internal solution...
May 2018: Cell Calcium
https://www.readbyqxmd.com/read/29604459/subcortical-sources-dominate-the-neuroelectric-auditory-frequency-following-response-to-speech
#18
Gavin M Bidelman
Frequency-following responses (FFRs) are neurophonic potentials that provide a window into the encoding of complex sounds (e.g., speech/music), auditory disorders, and neuroplasticity. While the neural origins of the FFR remain debated, renewed controversy has reemerged after demonstration that FFRs recorded via magnetoencephalography (MEG) are dominated by cortical rather than brainstem structures as previously assumed. Here, we recorded high-density (64 ch) FFRs via EEG and applied state-of-the art source imaging techniques to multichannel data (discrete dipole modeling, distributed imaging, independent component analysis, computational simulations)...
March 28, 2018: NeuroImage
https://www.readbyqxmd.com/read/29602186/molecular-mechanisms-underlying-striatal-synaptic-plasticity-relevance-to-chronic-alcohol-consumption-and-seeking
#19
Kim T Blackwell, Armando G Salinas, Parul Tewatia, Brad English, Jeanette Hellgren Kotaleski, David M Lovinger
The striatum, the input structure of the basal ganglia, is a major site of learning and memory for goal-directed actions and habit formation. Spiny projection neurons of the striatum integrate cortical, thalamic, and nigral inputs to learn associations, with cortico-striatal synaptic plasticity as a learning mechanism. Signaling molecules implicated in synaptic plasticity are altered in alcohol withdrawal, which may contribute to overly strong learning and increased alcohol seeking and consumption. To understand how interactions among signaling molecules produce synaptic plasticity, we implemented a mechanistic model of signaling pathways activated by dopamine D1 receptors, acetylcholine receptors, and glutamate...
March 30, 2018: European Journal of Neuroscience
https://www.readbyqxmd.com/read/29601053/implications-of-information-theory-for-computational-modeling-of-schizophrenia
#20
Steven M Silverstein, Michael Wibral, William A Phillips
Information theory provides a formal framework within which information processing and its disorders can be described. However, information theory has rarely been applied to modeling aspects of the cognitive neuroscience of schizophrenia. The goal of this article is to highlight the benefits of an approach based on information theory, including its recent extensions, for understanding several disrupted neural goal functions as well as related cognitive and symptomatic phenomena in schizophrenia. We begin by demonstrating that foundational concepts from information theory-such as Shannon information, entropy, data compression, block coding, and strategies to increase the signal-to-noise ratio-can be used to provide novel understandings of cognitive impairments in schizophrenia and metrics to evaluate their integrity...
October 2017: Computational psychiatry
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