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Dynamic functional connectivity

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https://www.readbyqxmd.com/read/28729938/abnormal-resting-state-effective-connectivity-within-the-default-mode-network-in-major-depressive-disorder-a-spectral-dynamic-causal-modeling-study
#1
Liang Li, Baojuan Li, Yuanhan Bai, Wenlei Liu, Huaning Wang, Hoi-Chung Leung, Ping Tian, Linchuan Zhang, Fan Guo, Long-Biao Cui, Hong Yin, Hongbing Lu, Qingrong Tan
INTRODUCTION: Understanding the neural basis underlying major depressive disorder (MDD) is essential for the diagnosis and treatment of this mental disorder. Aberrant activation and functional connectivity of the default mode network (DMN) have been consistently found in patients with MDD. It is not known whether effective connectivity within the DMN is altered in MDD. OBJECTS: The primary object of this study is to investigate the effective connectivity within the DMN during resting state in MDD patients before and after eight weeks of antidepressant treatment...
July 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28727850/hybrid-cubature-kalman-filtering-for-identifying-nonlinear-models-from-sampled-recording-estimation-of-neuronal-dynamics
#2
Mahmoud K Madi, Fadi N Karameh
Kalman filtering methods have long been regarded as efficient adaptive Bayesian techniques for estimating hidden states in models of linear dynamical systems under Gaussian uncertainty. Recent advents of the Cubature Kalman filter (CKF) have extended this efficient estimation property to nonlinear systems, and also to hybrid nonlinear problems where by the processes are continuous and the observations are discrete (continuous-discrete CD-CKF). Employing CKF techniques, therefore, carries high promise for modeling many biological phenomena where the underlying processes exhibit inherently nonlinear, continuous, and noisy dynamics and the associated measurements are uncertain and time-sampled...
2017: PloS One
https://www.readbyqxmd.com/read/28726769/activity-dependent-feedback-inhibition-may-maintain-head-direction-signals-in-mouse-presubiculum
#3
Jean Simonnet, Mérie Nassar, Federico Stella, Ivan Cohen, Bertrand Mathon, Charlotte N Boccara, Richard Miles, Desdemona Fricker
Orientation in space is represented in specialized brain circuits. Persistent head direction signals are transmitted from anterior thalamus to the presubiculum, but the identity of the presubicular target neurons, their connectivity and function in local microcircuits are unknown. Here, we examine how thalamic afferents recruit presubicular principal neurons and Martinotti interneurons, and the ensuing synaptic interactions between these cells. Pyramidal neuron activation of Martinotti cells in superficial layers is strongly facilitating such that high-frequency head directional stimulation efficiently unmutes synaptic excitation...
July 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28725185/reticular-formation-and-pain-the-past-and-the-future
#4
REVIEW
Isabel Martins, Isaura Tavares
The involvement of the reticular formation (RF) in the transmission and modulation of nociceptive information has been extensively studied. The brainstem RF contains several areas which are targeted by spinal cord afferents conveying nociceptive input. The arrival of nociceptive input to the RF may trigger alert reactions which generate a protective/defense reaction to pain. RF neurons located at the medulla oblongata and targeted by ascending nociceptive information are also involved in the control of vital functions that can be affected by pain, namely cardiovascular control...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/28724928/on-wakefulness-fluctuations-as-a-source-of-bold-functional-connectivity-dynamics
#5
Ariel Haimovici, Enzo Tagliazucchi, Pablo Balenzuela, Helmut Laufs
Human brain dynamics and functional connectivity fluctuate over a range of temporal scales in coordination with internal states and environmental demands. However, the neurobiological significance and consequences of functional connectivity dynamics during rest have not yet been established. We show that the coarse-grained clustering of whole-brain dynamic connectivity measured with magnetic resonance imaging reveals discrete patterns (dynamic connectivity states) associated with wakefulness and sleep. We validate this using EEG in healthy subjects and patients with narcolepsy and by matching our results with previous findings in a large collaborative database...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28721673/gas-flow-in-the-capillary-of-the-atmosphere-to-vacuum-interface-of-mass-spectrometers
#6
Michael Skoblin, Alexey Chudinov, Ilia Soulimenkov, Vladimir Brusov, Viacheslav Kozlovskiy
Numerical simulations of a gas flow through a capillary being a part of mass spectrometer atmospheric interface were performed using a detailed laminar flow model. The simulated interface consisted of atmospheric and forevacuum volumes connected via a thin capillary. The pressure in the forevacuum volume where the gas was expanding after passing through the capillary was varied in the wide range from 10 to 900 mbar in order to study the volume flow rate as well as the other flow parameters as functions of the pressure drop between the atmospheric and forevacuum volumes...
July 18, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28716967/contextual-and-developmental-differences-in-the-neural-architecture-of-cognitive-control
#7
Raluca Petrican, Cheryl L Grady
Since both development and context impact functional brain architecture, the neural connectivity signature of a cognitive or affective predisposition may similarly vary across different ages and circumstances. To test this hypothesis, we investigated the effects of age and cognitive versus social-affective context on the stable and time-varying neural architecture of inhibition, the putative core cognitive control component, in a subsample (N= 359 [22-36 yrs], 174 men) of the Human Connectome Project. Among younger individuals, a neural signature of superior inhibition emerged in both stable and dynamic connectivity analyses...
July 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28714584/oscillations-during-observations-dynamic-oscillatory-networks-serving-visuospatial-attention
#8
Alex I Wiesman, Elizabeth Heinrichs-Graham, Amy L Proskovec, Timothy J McDermott, Tony W Wilson
The dynamic allocation of neural resources to discrete features within a visual scene enables us to react quickly and accurately to salient environmental circumstances. A network of bilateral cortical regions is known to subserve such visuospatial attention functions; however the oscillatory and functional connectivity dynamics of information coding within this network are not fully understood. Particularly, the coding of information within prototypical attention-network hubs and the subsecond functional connections formed between these hubs have not been adequately characterized...
July 17, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28713261/age-related-decline-in-the-variation-of-dynamic-functional-connectivity-a-resting-state-analysis
#9
Yuanyuan Chen, Weiwei Wang, Xin Zhao, Miao Sha, Ya'nan Liu, Xiong Zhang, Jianguo Ma, Hongyan Ni, Dong Ming
Normal aging is typically characterized by abnormal resting-state functional connectivity (FC), including decreasing connectivity within networks and increasing connectivity between networks, under the assumption that the FC over the scan time was stationary. In fact, the resting-state FC has been shown in recent years to vary over time even within minutes, thus showing the great potential of intrinsic interactions and organization of the brain. In this article, we assumed that the dynamic FC consisted of an intrinsic dynamic balance in the resting brain and was altered with increasing age...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28713237/behavioral-and-neural-correlates-of-executive-function-interplay-between-inhibition-and-updating-processes
#10
Na Young Kim, Ellen Wittenberg, Chang S Nam
This study investigated the interaction between two executive function processes, inhibition and updating, through analyses of behavioral, neurophysiological, and effective connectivity metrics. Although, many studies have focused on behavioral effects of executive function processes individually, few studies have examined the dynamic causal interactions between these two functions. A total of twenty participants from a local university performed a dual task combing flanker and n-back experimental paradigms, and completed the Operation Span Task designed to measure working memory capacity...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28713174/fusing-multiple-neuroimaging-modalities-to-assess-group-differences-in-perception-action-coupling
#11
Jordan Muraskin, Jason Sherwin, Gregory Lieberman, Javier O Garcia, Timothy Verstynen, Jean M Vettel, Paul Sajda
In the last few decades, non-invasive neuroimaging has revealed macro-scale brain dynamics that underlie perception, cognition and action. Advances in non-invasive neuroimaging target two capabilities; 1) increased spatial and temporal resolution of measured neural activity, and 2) innovative methodologies to extract brain-behavior relationships from evolving neuroimaging technology. We target the second. Our novel methodology integrated three neuroimaging methodologies and elucidated expertise-dependent differences in functional (fused EEG-fMRI) and structural (dMRI) brain networks for a perception-action coupling task...
January 2017: Proceedings of the IEEE
https://www.readbyqxmd.com/read/28712995/investigations-into-within-and-between-subject-resting-state-amplitude-variations
#12
Janine Bijsterbosch, Samuel Harrison, Eugene Duff, Fidel Alfaro-Almagro, Mark Woolrich, Stephen Smith
The amplitudes of spontaneous fluctuations in brain activity may be a significant source of within-subject and between-subject variability, and this variability is likely to be carried through into functional connectivity (FC) estimates (whether directly or indirectly). Therefore, improving our understanding of amplitude fluctuations over the course of a resting state scan and variation in amplitude across individuals is of great relevance to the interpretation of FC findings. We investigate resting state amplitudes in two large-scale studies (HCP and UK Biobank), with the aim of determining between-subject and within-subject variability...
July 13, 2017: NeuroImage
https://www.readbyqxmd.com/read/28709361/entanglement-and-its-relationship-to-classical-dynamics
#13
Joshua B Ruebeck, Jie Lin, Arjendu K Pattanayak
We present an analysis of the entangling quantum kicked top focusing on the few qubit case and the initial condition dependence of the time-averaged entanglement S_{Q} for spin-coherent states. We show a very strong connection between the classical phase space and the initial condition dependence of S_{Q} even for the extreme case of two spin-1/2 qubits. This correlation is not related directly to chaos in the classical dynamics. We introduce a measure of the behavior of a classical trajectory which correlates far better with the entanglement and show that the maps of classical and quantum initial-condition dependence are both organized around the symmetry points of the Hamiltonian...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28709330/backward-renormalization-group-inference-of-cortical-dipole-sources-and-neural-connectivity-efficacy
#14
Selene da Rocha Amaral, Luiz A Baccalá, Leonardo S Barbosa, Nestor Caticha
Proper neural connectivity inference has become essential for understanding cognitive processes associated with human brain function. Its efficacy is often hampered by the curse of dimensionality. In the electroencephalogram case, which is a noninvasive electrophysiological monitoring technique to record electrical activity of the brain, a possible way around this is to replace multichannel electrode information with dipole reconstructed data. We use a method based on maximum entropy and the renormalization group to infer the position of the sources, whose success hinges on transmitting information from low- to high-resolution representations of the cortex...
June 2017: Physical Review. E
https://www.readbyqxmd.com/read/28708874/the-enigma-of-the-near-symmetry-of-proteins-domain-swapping
#15
Maayan Bonjack-Shterengartz, David Avnir
The majority of proteins form oligomers which have rotational symmetry. Literature has suggested many functional advantages that the symmetric packing offers. Yet, despite these advantages, the vast majority of protein oligomers are only nearly symmetric. A key question in the field of proteins structure is therefore, if symmetry is so advantageous, why do oligomers settle for aggregates that do not maximize that structural property? The answer to that question is apparently multi-parametric, and involves distortions at the interaction zones of the monomer units of the oligomer in order to minimize the free energy, the dynamics of the protein, the effects of surroundings parameters, and the mechanism of oligomerization...
2017: PloS One
https://www.readbyqxmd.com/read/28707959/interactions-of-the-salience-network-and-its-subsystems-with-the-default-mode-and-the-central-executive-networks-in-normal-aging-and-mild-cognitive-impairment
#16
Ganesh Chand, Junjie Wu, Ihab Hajjar, Deqiang Qiu
Previous functional MRI (fMRI) investigations suggest that the intrinsically organized large-scale networks and the interaction between them might be crucial for cognitive activities. A triple network model, which consists of the default-mode network, salience network, and central-executive network, has been recently employed to understand the connectivity patterns of the cognitively normal brains versus the brains with disorders. This model suggests that the salience network dynamically controls the default-mode and central-executive networks in healthy young individuals...
July 14, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28707887/full-characterization-of-localization-diversity-in-human-protein-interactome
#17
Lixin Cheng, Kaili Fan, Yan Huang, Dong Wang, Kwong-Sak Leung
Spatial-temporal regulation amongst proteins forms dynamic networks in cells. Co-existence in common cell compartments can improve biological reliability of the protein-protein interactions. However, this is usually overlooked by most proteomic studies and leads to unrealistic discoveries. In this paper, we systematically characterize the interaction localization diversity in human protein interactome using localization coefficient, a novel metric proposed for assessing how diversely the interactions localize among cell compartments...
July 14, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28707166/altered-dynamic-functional-connectivity-in-the-default-mode-network-in-patients-with-cirrhosis-and-minimal-hepatic-encephalopathy
#18
Hua-Jun Chen, Hai-Long Lin, Qiu-Feng Chen, Peng-Fei Liu
PURPOSE: Abnormal brain intrinsic functional connectivity (FC) has been documented in minimal hepatic encephalopathy (MHE) by static connectivity analysis. However, changes in dynamic FC (dFC) remain unknown. We aimed to identify altered dFC within the default mode network (DMN) associated with MHE. METHODS: Resting-state functional MRI data were acquired from 20 cirrhotic patients with MHE and 24 healthy controls. DMN seed regions were defined using seed-based FC analysis (centered on the posterior cingulate cortex (PCC))...
July 13, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28706851/a-joint-time-frequency-analysis-of-resting-state-functional-connectivity-reveals-novel-patterns-of-connectivity-shared-between-or-unique-to-schizophrenia-patients-and-healthy-controls
#19
Maziar Yaesoubi, Robyn L Miller, Juan Bustillo, Kelvin O Lim, Jatin Vaidya, Vince D Calhoun
Functional connectivity of the resting-state (RS) brain is a vehicle to study brain dysconnectivity aspects of diseases such as schizophrenia and bipolar. Methods that are developed to measure functional connectivity are based on the underlying hypotheses regarding the actual nature of RS-connectivity including evidence of temporally dynamic versus static RS-connectivity and evidence of frequency-specific versus hemodynamically-driven connectivity over a wide frequency range. This study is derived by these observations of variation of RS-connectivity in temporal and frequency domains and evaluates such characteristics of RS-connectivity in clinical population and jointly in temporal and frequency domains (the spectro-temporal domain)...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28706303/memristive-neural-network-for-on-line-learning-and-tracking-with-brain-inspired-spike-timing-dependent-plasticity
#20
G Pedretti, V Milo, S Ambrogio, R Carboni, S Bianchi, A Calderoni, N Ramaswamy, A S Spinelli, D Ielmini
Brain-inspired computation can revolutionize information technology by introducing machines capable of recognizing patterns (images, speech, video) and interacting with the external world in a cognitive, humanlike way. Achieving this goal requires first to gain a detailed understanding of the brain operation, and second to identify a scalable microelectronic technology capable of reproducing some of the inherent functions of the human brain, such as the high synaptic connectivity (~10(4)) and the peculiar time-dependent synaptic plasticity...
July 13, 2017: Scientific Reports
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