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https://www.readbyqxmd.com/read/27902865/small-world-properties-changes-in-mild-traumatic-brain-injury
#1
Yongxia Zhou
PURPOSE: To investigate local and global efficiency changes characterized by small-world properties based on resting-state functional MRI, such as centrality and clustering coefficient, in mild traumatic brain injury (MTBI) patients; and to associate these findings with axonal injury as measured by diffusion tensor imaging (DTI) as well as with post-concussive symptom (PCS). MATERIALS AND METHODS: Thirty patients (mean age 35 ± 13 years) with clinically defined MTBI and 45 age-matched healthy controls (mean age 37 ± 10 years) participated in the experiments...
November 30, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27892501/a-social-contagious-model-of-the-obesity-epidemic
#2
He Huang, Zhijun Yan, Yahong Chen, Fangyan Liu
Obesity has been recognized as a global epidemic by WHO, followed by many empirical evidences to prove its infectiousness. However, the inter-person spreading dynamics of obesity are seldom studied. A distinguishing feature of the obesity epidemic is that it is driven by a social contagion process which cannot be perfectly described by the infectious disease models. In this paper, we propose a novel belief decision model based on the famous Dempster-Shafer theory of evidence to model obesity epidemic as the competing spread of two obesity-related behaviors: physical inactivity and physical activity...
November 28, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27873413/six-degrees-of-separation-the-small-world-of-medical-education
#3
Wolf E Hautz, Gert Krummrey, Aristomenis Exadaktylos, Stefanie C Hautz
CONTEXT: Conventional wisdom has it that everyone on earth is on average only six steps away from knowing any other person through 'a friend of a friend'. On a local level, however, many people experience that most of their acquaintances know each other. It is thus hard to imagine how such a highly clustered group could be so well connected to the rest of the world. In this paper, we investigate how co-authorship connects scholars in medical education and whether the six degrees of separation hypothesis also applies to the network of authors in the field...
December 2016: Medical Education
https://www.readbyqxmd.com/read/27867033/differences-in-a%C3%AE-brain-networks-in-alzheimer-s-disease-and-healthy-controls
#4
Huoqiang Duan, Jiehui Jiang, Jun Xu, Hucheng Zhou, Zhemin Huang, Zhihua Yu, Zhuangzhi Yan
The prevailing β-amyloid (Aβ)-cascade hypothesis is the most classical Alzheimer's disease (AD) pathogenesis. In this hypothesis, excessive Aβ plaque deposition in human brain is considered to be the cause of AD. Carbon 11-labeled Pittsburgh compound B Positron emission tomography (11C-PiB PET) is the latest technology to detect Aβ plaques in vivo. Thus, it is possible to investigate the difference of Aβ brain networks between AD patients and Health Controls (HC) by analyzing 11C-PiB PET images. In this study, a graph-theoretical method was employed to investigate the topological properties of Aβ networks in 18 Chinese AD patients and 16 HC subjects from Huashan Hospital, Shanghai...
November 17, 2016: Brain Research
https://www.readbyqxmd.com/read/27856276/the-complex-hierarchical-topology-of-eeg-functional-connectivity
#5
Keith Smith, Javier Escudero
BACKGROUND: Understanding the complex hierarchical topology of functional brain networks is a key aspect of functional connectivity research. Such topics are obscured by the widespread use of sparse binary network models which are fundamentally different to the complete weighted networks derived from functional connectivity. NEW METHODS: We introduce two techniques to probe the hierarchical complexity of topologies. Firstly, a new metric to measure hierarchical complexity; secondly, a Weighted Complex Hierarchy (WCH) model...
November 14, 2016: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/27853301/trade-offs-between-robustness-and-small-world-effect-in-complex-networks
#6
Guan-Sheng Peng, Suo-Yi Tan, Jun Wu, Petter Holme
Robustness and small-world effect are two crucial structural features of complex networks and have attracted increasing attention. However, little is known about the relation between them. Here we demonstrate that, there is a conflicting relation between robustness and small-world effect for a given degree sequence. We suggest that the robustness-oriented optimization will weaken the small-world effect and vice versa. Then, we propose a multi-objective trade-off optimization model and develop a heuristic algorithm to obtain the optimal trade-off topology for robustness and small-world effect...
November 17, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27843396/network-rewiring-dynamics-with-convergence-towards-a-star-network
#7
P A Whigham, G Dick, M Parry
Network rewiring as a method for producing a range of structures was first introduced in 1998 by Watts & Strogatz (Nature393, 440-442. (doi:10.1038/30918)). This approach allowed a transition from regular through small-world to a random network. The subsequent interest in scale-free networks motivated a number of methods for developing rewiring approaches that converged to scale-free networks. This paper presents a rewiring algorithm (RtoS) for undirected, non-degenerate, fixed size networks that transitions from regular, through small-world and scale-free to star-like networks...
October 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/27830974/modeling-of-synchronization-behavior-of-bursting-neurons-at-nonlinearly-coupled-dynamical-networks
#8
Yüksel Çakir
Synchronization behaviors of bursting neurons coupled through electrical and dynamic chemical synapses are investigated. The Izhikevich model is used with random and small world network of bursting neurons. Various currents which consist of diffusive electrical and time-delayed dynamic chemical synapses are used in the simulations to investigate the influences of synaptic currents and couplings on synchronization behavior of bursting neurons. The effects of parameters, such as time delay, inhibitory synaptic strengths, and decay time on synchronization behavior are investigated...
November 10, 2016: Network: Computation in Neural Systems
https://www.readbyqxmd.com/read/27824356/altered-gray-matter-organization-in-children-and-adolescents-with-adhd-a-structural-covariance-connectome-study
#9
K R Griffiths, S M Grieve, M R Kohn, S Clarke, L M Williams, M S Korgaonkar
Although multiple studies have reported structural deficits in multiple brain regions in attention-deficit hyperactivity disorder (ADHD), we do not yet know if these deficits reflect a more systematic disruption to the anatomical organization of large-scale brain networks. Here we used a graph theoretical approach to quantify anatomical organization in children and adolescents with ADHD. We generated anatomical networks based on covariance of gray matter volumes from 92 regions across the brain in children and adolescents with ADHD (n=34) and age- and sex-matched healthy controls (n=28)...
November 8, 2016: Translational Psychiatry
https://www.readbyqxmd.com/read/27824149/coevolution-of-cooperation-and-partner-rewiring-range-in-spatial-social-networks
#10
Tommy Khoo, Feng Fu, Scott Pauls
In recent years, there has been growing interest in the study of coevolutionary games on networks. Despite much progress, little attention has been paid to spatially embedded networks, where the underlying geographic distance, rather than the graph distance, is an important and relevant aspect of the partner rewiring process. It thus remains largely unclear how individual partner rewiring range preference, local vs. global, emerges and affects cooperation. Here we explicitly address this issue using a coevolutionary model of cooperation and partner rewiring range preference in spatially embedded social networks...
November 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27811962/an-investigation-of-the-differences-and-similarities-between-generated-small-world-networks-for-right-and-left-hand-motor-imageries
#11
Jiang Zhang, Yuyao Li, Huafu Chen, Jurong Ding, Zhen Yuan
In this study, small-world network analysis was performed to identify the similarities and differences between functional brain networks for right- and left-hand motor imageries (MIs). First, Pearson correlation coefficients among the nodes within the functional brain networks from healthy subjects were calculated. Then, small-world network indicators, including the clustering coefficient, the average path length, the global efficiency, the local efficiency, the average node degree, and the small-world index, were generated for the functional brain networks during both right- and left-hand MIs...
November 4, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27809275/estimation-of-anonymous-email-network-characteristics-through-statistical-disclosure-attacks
#12
Javier Portela, Luis Javier García Villalba, Alejandra Guadalupe Silva Trujillo, Ana Lucila Sandoval Orozco, Tai-Hoon Kim
Social network analysis aims to obtain relational data from social systems to identify leaders, roles, and communities in order to model profiles or predict a specific behavior in users' network. Preserving anonymity in social networks is a subject of major concern. Anonymity can be compromised by disclosing senders' or receivers' identity, message content, or sender-receiver relationships. Under strongly incomplete information, a statistical disclosure attack is used to estimate the network and node characteristics such as centrality and clustering measures, degree distribution, and small-world-ness...
November 1, 2016: Sensors
https://www.readbyqxmd.com/read/27804899/disrupted-resting-state-brain-network-properties-in-obesity-decreased-global-and-putaminal-cortico-striatal-network-efficiency
#13
K Baek, L S Morris, P Kundu, V Voon
BACKGROUND: The efficient organization and communication of brain networks underlie cognitive processing and their disruption can lead to pathological behaviours. Few studies have focused on whole-brain networks in obesity and binge eating disorder (BED). Here we used multi-echo resting-state functional magnetic resonance imaging (rsfMRI) along with a data-driven graph theory approach to assess brain network characteristics in obesity and BED. METHOD: Multi-echo rsfMRI scans were collected from 40 obese subjects (including 20 BED patients) and 40 healthy controls and denoised using multi-echo independent component analysis (ME-ICA)...
November 2, 2016: Psychological Medicine
https://www.readbyqxmd.com/read/27799906/structure-and-topology-dynamics-of-hyper-frequency-networks-during-rest-and-auditory-oddball-performance
#14
Viktor Müller, Dionysios Perdikis, Timo von Oertzen, Rita Sleimen-Malkoun, Viktor Jirsa, Ulman Lindenberger
Resting-state and task-related recordings are characterized by oscillatory brain activity and widely distributed networks of synchronized oscillatory circuits. Electroencephalographic recordings (EEG) were used to assess network structure and network dynamics during resting state with eyes open and closed, and auditory oddball performance through phase synchronization between EEG channels. For this assessment, we constructed a hyper-frequency network (HFN) based on within- and cross-frequency coupling (WFC and CFC, respectively) at 10 oscillation frequencies ranging between 2 and 20 Hz...
2016: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/27798379/changes-in-structural-connectivity-following-a-cognitive-intervention-in-children-with-traumatic-brain-injury-a-pilot-study
#15
Weihong Yuan, Amery Treble-Barna, McKay M Sohlberg, Beth Harn, Shari L Wade
Objective Structural connectivity analysis based on graph theory and diffusion tensor imaging tractography is a novel method that quantifies the topological characteristics in the brain network. This study aimed to examine structural connectivity changes following the Attention Intervention and Management (AIM) program designed to improve attention and executive function (EF) in children with traumatic brain injury (TBI). Methods Seventeen children with complicated mild to severe TBI (13.66 ± 2.68 years; >12 months postinjury) completed magnetic resonance imaging (MRI) and neurobehavioral measures at time 1, 10 of whom completed AIM and assessment at time 2...
October 25, 2016: Neurorehabilitation and Neural Repair
https://www.readbyqxmd.com/read/27781444/discrimination-of-coupling-structures-using-causality-networks-from-multivariate-time-series
#16
Christos Koutlis, Dimitris Kugiumtzis
Measures of Granger causality on multivariate time series have been used to form the so-called causality networks. A causality network represents the interdependence structure of the underlying dynamical system or coupled dynamical systems, and its properties are quantified by network indices. In this work, it is investigated whether network indices on networks generated by an appropriate Granger causality measure can discriminate different coupling structures. The information based Granger causality measure of partial mutual information from mixed embedding (PMIME) is used to form causality networks, and a large number of network indices are ranked according to their ability to discriminate the different coupling structures...
September 2016: Chaos
https://www.readbyqxmd.com/read/27779449/anatomic-insights-into-disrupted-small-world-networks-in-pediatric-posttraumatic-stress-disorder
#17
Xueling Suo, Du Lei, Fuqin Chen, Min Wu, Lei Li, Ling Sun, Xiaoli Wei, Hongyan Zhu, Lingjiang Li, Graham J Kemp, Qiyong Gong
Purpose To use diffusion-tensor (DT) imaging and graph theory approaches to explore the brain structural connectome in pediatric posttraumatic stress disorder (PTSD). Materials and Methods This study was approved by the relevant research ethics committee, and all participants' parents or guardians provided informed consent. Twenty-four pediatric patients with PTSD and 23 control subjects exposed to trauma but without PTSD were recruited after the 2008 Sichuan earthquake. The structural connectome was constructed by using DT imaging tractography and thresholding the mean fractional anisotropy of 90 brain regions to yield 90 × 90 partial correlation matrixes...
October 25, 2016: Radiology
https://www.readbyqxmd.com/read/27776135/top-down-network-effective-connectivity-in-abstinent-substance-dependent-individuals
#18
Michael F Regner, Naomi Saenz, Keeran Maharajh, Dorothy J Yamamoto, Brianne Mohl, Korey Wylie, Jason Tregellas, Jody Tanabe
OBJECTIVE: We hypothesized that compared to healthy controls, long-term abstinent substance dependent individuals (SDI) will differ in their effective connectivity between large-scale brain networks and demonstrate increased directional information from executive control to interoception-, reward-, and habit-related networks. In addition, using graph theory to compare network efficiencies we predicted decreased small-worldness in SDI compared to controls. METHODS: 50 SDI and 50 controls of similar sex and age completed psychological surveys and resting state fMRI...
2016: PloS One
https://www.readbyqxmd.com/read/27774721/altered-brain-network-integrity-after-childhood-maltreatment-a-structural-connectomic-dti-study
#19
V B Puetz, D Parker, N Kohn, B Dahmen, R Verma, K Konrad
Childhood maltreatment is associated with alterations in neural architecture that potentially put these children at increased risk for psychopathology. Alterations in white matter (WM) tracts have been reported, however no study to date has investigated WM connectivity in brain networks in maltreated children to quantify global and local abnormalities through graph theoretical analyses of DTI data. We aimed for a multilevel investigation examining the DTI-based structural connectome and its associations with basal cortisol levels of 25 children with documented maltreatment experiences before age 3, and 24 matched controls (age: 10...
October 24, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27760177/discriminating-the-difference-between-remote-and-close-association-with-relation-to-white-matter-structural-connectivity
#20
Chinglin Wu, Suyu Zhong, Hsuehchih Chen
Remote association is a core ability that influences creative output. In contrast to close association, remote association is commonly agreed to be connected with more original and unique concepts. However, although existing studies have discovered that creativity is closely related to the white-matter structure of the brain, there are no studies that examine the relevance between the connectivity efficiencies and creativity of the brain regions from the perspective of networks. Consequently, this study constructed a brain white matter network structure that consisted of cerebral tissues and nerve fibers and used graph theory to analyze the connection efficiencies among the network nodes, further illuminating the differences between remote and close association in relation to the connectivity of the brain network...
2016: PloS One
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