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https://www.readbyqxmd.com/read/28208338/synchronization-and-long-time-memory-in-neural-networks-with-inhibitory-hubs-and-synaptic-plasticity
#1
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/28203142/development-and-feasibility-assessment-of-a-rotational-orthosis-for-walking-with-arm-swing
#2
Juan Fang, Qing Xie, Guo-Yuan Yang, Le Xie
Interlimb neural coupling might underlie human bipedal locomotion, which is reflected in the fact that people swing their arms synchronously with leg movement in normal gait. Therefore, arm swing should be included in gait training to provide coordinated interlimb performance. The present study aimed to develop a Rotational Orthosis for Walking with Arm Swing (ROWAS), and evaluate its feasibility from the perspectives of implementation, acceptability and responsiveness. We developed the mechanical structures of the ROWAS system in SolidWorks, and implemented the concept in a prototype...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28202572/differential-regulation-of-nmda-receptors-by-d-serine-and-glycine-in-mammalian-spinal-locomotor-networks
#3
David Acton, Gareth Brian Miles
Activation of N-methyl-D-aspartate receptors (NMDARs) requires the binding of a co-agonist, either D-serine or glycine, in addition to glutamate. Changes in occupancy of the co-agonist binding site are proposed to modulate neural networks including those controlling swimming in frog tadpoles. Here, we characterize regulation of the NMDAR co-agonist binding site in mammalian spinal locomotor networks. Blockade of NMDARs by D(-)-2-amino-5-phosphonopentanoic acid (D-APV) or 5,7-dichlorokynurenic acid reduced the frequency and amplitude of pharmacologically induced locomotor-related activity recorded from the ventral roots of spinal-cord preparations from neonatal mice...
February 15, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28197088/synchronization-and-inter-layer-interactions-of-noise-driven-neural-networks
#4
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
#5
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/28192762/neural-mass-models-describing-possible-origin-of-the-excessive-beta-oscillations-correlated-with-parkinsonian-state
#6
Chen Liu, Yulin Zhu, Fei Liu, Jiang Wang, Huiyan Li, Bin Deng, Chris Fietkiewicz, Kenneth A Loparo
In Parkinson's disease, the enhanced beta rhythm is closely associated with akinesia/bradykinesia and rigidity. An increase in beta oscillations (12-35 Hz) within the basal ganglia (BG) nuclei does not proliferate throughout the cortico-basal ganglia loop in uniform fashion; rather it can be subdivided into two distinct frequency bands, i.e. the lower beta (12-20 Hz) and upper beta (21-35 Hz). A computational model of the excitatory and inhibitory neural network that focuses on the population properties is proposed to explore the mechanism underlying the pathological beta oscillations...
January 30, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28187128/neural-mechanisms-of-rhythm-based-temporal-prediction-delta-phase-locking-reflects-temporal-predictability-but-not-rhythmic-entrainment
#7
Assaf Breska, Leon Y Deouell
Predicting the timing of upcoming events enables efficient resource allocation and action preparation. Rhythmic streams, such as music, speech, and biological motion, constitute a pervasive source for temporal predictions. Widely accepted entrainment theories postulate that rhythm-based predictions are mediated by synchronizing low-frequency neural oscillations to the rhythm, as indicated by increased phase concentration (PC) of low-frequency neural activity for rhythmic compared to random streams. However, we show here that PC enhancement in scalp recordings is not specific to rhythms but is observed to the same extent in less periodic streams if they enable memory-based prediction...
February 2017: PLoS Biology
https://www.readbyqxmd.com/read/28185093/altered-spontaneous-brain-activity-in-adolescent-boys-with-pure-conduct-disorder-revealed-by-regional-homogeneity-analysis
#8
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
#9
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/28169987/theta-and-beta-synchrony-coordinate-frontal-eye-fields-and-anterior-cingulate-cortex-during-sensorimotor-mapping
#10
Sahand Babapoor-Farrokhran, Martin Vinck, Thilo Womelsdorf, Stefan Everling
The frontal eye fields (FEFs) and the anterior cingulate cortex (ACC) are commonly coactivated for cognitive saccade tasks, but whether this joined activation indexes coordinated activity underlying successful guidance of sensorimotor mapping is unknown. Here we test whether ACC and FEF circuits coordinate through phase synchronization of local field potential and neural spiking activity in macaque monkeys performing memory-guided and pro- and anti-saccades. We find that FEF and ACC showed prominent synchronization at a 3-9 Hz theta and a 12-30 Hz beta frequency band during the delay and preparation periods with a strong Granger-causal influence from ACC to FEF...
February 7, 2017: Nature Communications
https://www.readbyqxmd.com/read/28161319/biophysical-and-neural-basis-of-resting-state-functional-connectivity-evidence-from-non-human-primates
#11
REVIEW
Li Min Chen, Pai-Feng Yang, Feng Wang, Arabinda Mishra, Zhaoyue Shi, Ruiqi Wu, Tung-Lin Wu, George H Wilson, Zhaohua Ding, John C Gore
Functional MRI (fMRI) has evolved from simple observations of regional changes in MRI signals caused by cortical activity induced by a task or stimulus, to task-free acquisitions of images in a resting state. Such resting state signals contain low frequency fluctuations which may be correlated between voxels, and strongly correlated regions are deemed to reflect functional connectivity within synchronized circuits. Resting state functional connectivity (rsFC) measures have been widely adopted by the neuroscience community, and are being used and interpreted as indicators of intrinsic neural circuits and their functional states in a broad range of applications, both basic and clinical...
February 2, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28159688/altered-regional-connectivity-reflecting-effects-of-different-anaesthesia-protocols-in-the-mouse-brain
#12
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
#13
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
#14
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/28155864/aberrant-neuronal-dynamics-during-working-memory-operations-in-the-aging-hiv-infected-brain
#15
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
https://www.readbyqxmd.com/read/28149963/reveal-consistent-spatial-temporal-patterns-from-dynamic-functional-connectivity-for-autism-spectrum-disorder-identification
#16
Yingying Zhu, Xiaofeng Zhu, Han Zhang, Wei Gao, Dinggang Shen, Guorong Wu
Functional magnetic resonance imaging (fMRI) provides a non-invasive way to investigate brain activity. Recently, convergent evidence shows that the correlations of spontaneous fluctuations between two distinct brain regions dynamically change even in resting state, due to the condition-dependent nature of brain activity. Thus, quantifying the patterns of functional connectivity (FC) in a short time period and changes of FC over time can potentially provide valuable insight into both individual-based diagnosis and group comparison...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/28147496/exponential-synchronization-of-generalized-neural-networks-with-mixed-time-varying-delays-and-reaction-diffusion-terms-via-aperiodically-intermittent-control
#17
Qintao Gan
In this paper, the exponential synchronization problem of generalized reaction-diffusion neural networks with mixed time-varying delays is investigated concerning Dirichlet boundary conditions in terms of p-norm. Under the framework of the Lyapunov stability method, stochastic theory, and mathematical analysis, some novel synchronization criteria are derived, and an aperiodically intermittent control strategy is proposed simultaneously. Moreover, the effects of diffusion coefficients, diffusion space, and stochastic perturbations on the synchronization process are explicitly expressed under the obtained conditions...
January 2017: Chaos
https://www.readbyqxmd.com/read/28147492/patterns-of-synchrony-for-feed-forward-and-auto-regulation-feed-forward-neural-networks
#18
Manuela A D Aguiar, Ana Paula S Dias, Flora Ferreira
We consider feed-forward and auto-regulation feed-forward neural (weighted) coupled cell networks. In feed-forward neural networks, cells are arranged in layers such that the cells of the first layer have empty input set and cells of each other layer receive only inputs from cells of the previous layer. An auto-regulation feed-forward neural coupled cell network is a feed-forward neural network where additionally some cells of the first layer have auto-regulation, that is, they have a self-loop. Given a network structure, a robust pattern of synchrony is a space defined in terms of equalities of cell coordinates that is flow-invariant for any coupled cell system (with additive input structure) associated with the network...
January 2017: Chaos
https://www.readbyqxmd.com/read/28147488/finite-time-synchronization-for-recurrent-neural-networks-with-discontinuous-activations-and-time-varying-delays
#19
Lian Duan, Lihong Huang, Xianwen Fang
In this paper, we study the finite-time synchronization problem for recurrent neural networks with discontinuous activations and time-varying delays. Based on the finite-time convergence theory and by using the nonsmooth analysis technique, some finite-time synchronization criteria for the considered neural network model are established, which are new and complement some existing ones. The feasibility and effectiveness of the proposed synchronization method are supported by two examples with numerical simulations...
January 2017: Chaos
https://www.readbyqxmd.com/read/28146472/gamma-oscillations-organize-top-down-signalling-to-hypothalamus-and-enable-food-seeking
#20
Marta Carus-Cadavieco, Maria Gorbati, Li Ye, Franziska Bender, Suzanne van der Veldt, Christin Kosse, Christoph Börgers, Soo Yeun Lee, Charu Ramakrishnan, Yubin Hu, Natalia Denisova, Franziska Ramm, Emmanouela Volitaki, Denis Burdakov, Karl Deisseroth, Alexey Ponomarenko, Tatiana Korotkova
Both humans and animals seek primary rewards in the environment, even when such rewards do not correspond to current physiological needs. An example of this is a dissociation between food-seeking behaviour and metabolic needs, a notoriously difficult-to-treat symptom of eating disorders. Feeding relies on distinct cell groups in the hypothalamus, the activity of which also changes in anticipation of feeding onset. The hypothalamus receives strong descending inputs from the lateral septum, which is connected, in turn, with cortical networks, but cognitive regulation of feeding-related behaviours is not yet understood...
February 9, 2017: Nature
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