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https://www.readbyqxmd.com/read/28804744/reduced-rich-club-connectivity-is-related-to-disability-in-primary-progressive-ms
#1
Jan-Patrick Stellmann, Sibylle Hodecker, Bastian Cheng, Nadine Wanke, Kim Lea Young, Claus Hilgetag, Christian Gerloff, Christoph Heesen, Götz Thomalla, Susanne Siemonsen
OBJECTIVE: To investigate whether the structural connectivity of the brain's rich-club organization is altered in patients with primary progressive MS and whether such changes to this fundamental network feature are associated with disability measures. METHODS: We recruited 37 patients with primary progressive MS and 21 healthy controls for an observational cohort study. Structural connectomes were reconstructed based on diffusion-weighted imaging data using probabilistic tractography and analyzed with graph theory...
September 2017: Neurology® Neuroimmunology & Neuroinflammation
https://www.readbyqxmd.com/read/28799862/disrupted-topologic-efficiency-of-white-matter-structural-connectome-in-individuals-with-subjective-cognitive-decline
#2
Ni Shu, Xiaoni Wang, Qiuhui Bi, Tengda Zhao, Ying Han
Purpose To determine whether individuals with subjective cognitive decline (SCD), which is defined by memory complaints with normal performance at objective neuropsychologic examinations, exhibit disruptions of white matter (WM) connectivity and topologic alterations of the brain structural connectome. Materials and Methods Diffusion-tensor magnetic resonance imaging and graph theory approaches were used to investigate the topologic organization of the brain structural connectome in 36 participants with SCD (21 women: mean age, 62...
August 11, 2017: Radiology
https://www.readbyqxmd.com/read/28795168/changes-in-brain-behavior-relationships-following-a-3-month-pilot-cognitive-intervention-program-for-adults-with-traumatic-brain-injury
#3
S Porter, I J Torres, W Panenka, Z Rajwani, D Fawcett, A Hyder, N Virji-Babul
Facilitating functional recovery following brain injury is a key goal of neurorehabilitation. Direct, objective measures of changes in the brain are critical to understanding how and when meaningful changes occur, however, assessing neuroplasticity using brain based results remains a significant challenge. Little is known about the underlying changes in functional brain networks that correlate with cognitive outcomes in traumatic brain injury (TBI). The purpose of this pilot study was to assess the feasibility of an intensive three month cognitive intervention program in individuals with chronic TBI and to evaluate the effects of this intervention on brain-behavioral relationships...
August 2017: Heliyon
https://www.readbyqxmd.com/read/28789772/mean-square-consensus-of-leader-following-multi-agent-systems-with-measurement-noises-and-time-delays
#4
Hongwei Ren, Feiqi Deng
This paper investigates the mean square consensus problem of dynamical networks of leader-following multi-agent systems with measurement noises and time-varying delays. We consider that the fixed undirected communication topologies are connected. A neighbor-based tracking algorithm together with distributed estimators are presented. Using tools of algebraic graph theory and the Gronwall-Bellman-Halanay type inequality, we establish sufficient conditions to reach consensus in mean square sense via the proposed consensus protocols...
August 5, 2017: ISA Transactions
https://www.readbyqxmd.com/read/28769858/dedifferentiation-does-not-account-for-hyperconnectivity-after-traumatic-brain-injury
#5
Rachel Anne Bernier, Arnab Roy, Umesh Meyyappan Venkatesan, Emily C Grossner, Einat K Brenner, Frank Gerard Hillary
OBJECTIVE: Changes in functional network connectivity following traumatic brain injury (TBI) have received increasing attention in recent neuroimaging literature. This study sought to understand how disrupted systems adapt to injury during resting and goal-directed brain states. Hyperconnectivity has been a common finding, and dedifferentiation (or loss of segregation of networks) is one possible explanation for this finding. We hypothesized that individuals with TBI would show dedifferentiation of networks (as noted in other clinical populations) and these effects would be associated with cognitive dysfunction...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28763447/braph-a-graph-theory-software-for-the-analysis-of-brain-connectivity
#6
Mite Mijalkov, Ehsan Kakaei, Joana B Pereira, Eric Westman, Giovanni Volpe
The brain is a large-scale complex network whose workings rely on the interaction between its various regions. In the past few years, the organization of the human brain network has been studied extensively using concepts from graph theory, where the brain is represented as a set of nodes connected by edges. This representation of the brain as a connectome can be used to assess important measures that reflect its topological architecture. We have developed a freeware MatLab-based software (BRAPH-BRain Analysis using graPH theory) for connectivity analysis of brain networks derived from structural magnetic resonance imaging (MRI), functional MRI (fMRI), positron emission tomography (PET) and electroencephalogram (EEG) data...
2017: PloS One
https://www.readbyqxmd.com/read/28760438/elucidating-functional-differences-between-cortical-gyri-and-sulci-via-sparse-representation-hcp-grayordinate-fmri-data
#7
Huan Liu, Xi Jiang, Tuo Zhang, Yudan Ren, Xintao Hu, Lei Guo, Junwei Han, Tianming Liu
The highly convoluted cerebral cortex is characterized by two different topographic structures: convex gyri and concave sulci. Increasing studies have demonstrated that cortical gyri and sulci exhibit different structural connectivity patterns. Inspired by the intrinsic structural differences between gyri and sulci, in this paper, we present a data-driven framework based on sparse representation of fMRI data for functional network inferences, then examine the interactions within and across gyral and sulcal functional networks and finally elucidate possible functional differences using graph theory based properties...
July 28, 2017: Brain Research
https://www.readbyqxmd.com/read/28751865/breakdown-of-modularity-in-complex-networks
#8
Sergi Valverde
The presence of modular organization is a common property of a wide range of complex systems, from cellular or brain networks to technological graphs. Modularity allows some degree of segregation between different parts of the network and has been suggested to be a prerequisite for the evolvability of biological systems. In technology, modularity defines a clear division of tasks and it is an explicit design target. However, many natural and artificial systems experience a breakdown in their modular pattern of connections, which has been associated with failures in hub nodes or the activation of global stress responses...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28744955/cortical-connectivity-modulation-during-sleep-onset-a-study-via-graph-theory-on-eeg-data
#9
Fabrizio Vecchio, Francesca Miraglia, Maurizio Gorgoni, Michele Ferrara, Francesco Iberite, Placido Bramanti, Luigi De Gennaro, Paolo Maria Rossini
Sleep onset is characterized by a specific and orchestrated pattern of frequency and topographical EEG changes. Conventional power analyses of electroencephalographic (EEG) and computational assessments of network dynamics have described an earlier synchronization of the centrofrontal areas rhythms and a spread of synchronizing signals from associative prefrontal to posterior areas. Here, we assess how "small world" characteristics of the brain networks, as reflected in the EEG rhythms, are modified in the wakefulness-sleep transition comparing the pre- and post-sleep onset epochs...
July 26, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28743886/the-minimum-resting-state-fnirs-imaging-duration-for-accurate-and-stable-mapping-of-brain-connectivity-network-in-children
#10
Jingyu Wang, Qi Dong, Haijing Niu
Resting-state functional near-infrared spectroscopy (fNIRS) is a potential technique for the study of brain functional connectivity (FC) and networks in children. However, the necessary fNIRS scanning duration required to map accurate and stable functional brain connectivity and graph theory metrics in the resting-state brain activity remains largely unknown. Here, we acquired resting-state fNIRS imaging data from 53 healthy children to provide the first empirical evidence for the minimum imaging time required to obtain accurate and stable FC and graph theory metrics of brain network activity (e...
July 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28731567/integration-of-white-matter-network-is-associated-with-interindividual-differences-in-psychologically-mediated-placebo-response-in-migraine-patients
#11
Jixin Liu, Shaohui Ma, Junya Mu, Tao Chen, Qing Xu, Wanghuan Dun, Jie Tian, Ming Zhang
Individual differences of brain changes of neural communication and integration in the modular architecture of the human brain network exist for the repeated migraine attack and physical or psychological stressors. However, whether the interindividual variability in the migraine brain connectome predicts placebo response to placebo treatment is still unclear. Using DTI and graph theory approaches, we systematically investigated the topological organization of white matter networks in 71 patients with migraine without aura (MO) and 50 matched healthy controls at three levels: global network measure, nodal efficiency, and nodal intramodule/intermodule efficiency...
July 21, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28731453/topological-alterations-and-symptom-relevant-modules-in-the-whole-brain-structural-network-in-semantic-dementia
#12
Junhua Ding, Keliang Chen, Weibin Zhang, Ming Li, Yan Chen, Qing Yang, Yingru Lv, Qihao Guo, Zaizhu Han
BACKGROUND: Semantic dementia (SD) is characterized by a selective decline in semantic processing. Although the neuropsychological pattern of this disease has been identified, its topological global alterations and symptom-relevant modules in the whole-brain anatomical network have not been fully elucidated. OBJECTIVE: This study aims to explore the topological alteration of anatomical network in SD and reveal the modules associated with semantic deficits in this disease...
2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28705239/nap-the-network-analysis-profiler-a-web-tool-for-easier-topological-analysis-and-comparison-of-medium-scale-biological-networks
#13
Theodosios Theodosiou, Georgios Efstathiou, Nikolas Papanikolaou, Nikos C Kyrpides, Pantelis G Bagos, Ioannis Iliopoulos, Georgios A Pavlopoulos
OBJECTIVE: Nowadays, due to the technological advances of high-throughput techniques, Systems Biology has seen a tremendous growth of data generation. With network analysis, looking at biological systems at a higher level in order to better understand a system, its topology and the relationships between its components is of a great importance. Gene expression, signal transduction, protein/chemical interactions, biomedical literature co-occurrences, are few of the examples captured in biological network representations where nodes represent certain bioentities and edges represent the connections between them...
July 14, 2017: BMC Research Notes
https://www.readbyqxmd.com/read/28695358/retained-executive-abilities-in-mild-cognitive-impairment-are-associated-with-increased-white-matter-network-connectivity
#14
Danielle C Farrar, Asim Z Mian, Andrew E Budson, Mark B Moss, Bang Bon Koo, Ronald J Killiany
PURPOSE: To describe structural network differences in individuals with mild cognitive impairment (MCI) with high versus low executive abilities, as reflected by measures of white matter connectivity using diffusion tensor imaging (DTI). MATERIALS AND METHODS: This was a retrospective, cross-sectional study. Of the 128 participants from the Alzheimer's Disease Neuroimaging Initiative database who had both a DTI scan as well as a diagnosis of MCI, we used an executive function score to classify the top 15 scoring patients as high executive ability, and the bottom-scoring 16 patients as low executive ability...
July 10, 2017: European Radiology
https://www.readbyqxmd.com/read/28675389/topologically-convergent-and-divergent-functional-connectivity-patterns-in-unmedicated-unipolar-depression-and-bipolar-disorder
#15
Y Wang, J Wang, Y Jia, S Zhong, M Zhong, Y Sun, M Niu, L Zhao, L Zhao, J Pan, L Huang, R Huang
Bipolar disorder (BD), particularly BD II, is frequently misdiagnosed as unipolar depression (UD), leading to inappropriate treatment and poor clinical outcomes. Although depressive symptoms may be expressed similarly in UD and BD, the similarities and differences in the architecture of brain functional networks between the two disorders are still unknown. In this study, we hypothesized that UD and BD II patients would show convergent and divergent patterns of disrupted topological organization of the functional connectome, especially in the default mode network (DMN) and the limbic network...
July 4, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/28667481/disrupted-topological-organization-of-brain-structural-network-associated-with-prior-overt-hepatic-encephalopathy-in-cirrhotic-patients
#16
Hua-Jun Chen, Hai-Bin Shi, Long-Feng Jiang, Lan Li, Rong Chen
OBJECTIVES: To investigate structural brain connectome alterations in cirrhotic patients with prior overt hepatic encephalopathy (OHE). METHODS: Seventeen cirrhotic patients with prior OHE (prior-OHE), 18 cirrhotic patients without prior OHE (non-prior-OHE) and 18 healthy controls (HC) underwent diffusion tensor imaging. Neurocognitive functioning was assessed with Psychometric Hepatic Encephalopathy Score (PHES). Using a probabilistic fibre tracking approach, we depicted the whole-brain structural network as a connectivity matrix of 90 regions (derived from the Automated Anatomic Labeling atlas)...
June 30, 2017: European Radiology
https://www.readbyqxmd.com/read/28666351/brain-networks-predict-metabolism-diagnosis-and-prognosis-at-the-bedside-in-disorders-of-consciousness
#17
Srivas Chennu, Jitka Annen, Sarah Wannez, Aurore Thibaut, Camille Chatelle, Helena Cassol, Géraldine Martens, Caroline Schnakers, Olivia Gosseries, David Menon, Steven Laureys
Recent advances in functional neuroimaging have demonstrated novel potential for informing diagnosis and prognosis in the unresponsive wakeful syndrome and minimally conscious states. However, these technologies come with considerable expense and difficulty, limiting the possibility of wider clinical application in patients. Here, we show that high density electroencephalography, collected from 104 patients measured at rest, can provide valuable information about brain connectivity that correlates with behaviour and functional neuroimaging...
June 27, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28657774/integrative-structural-brain-network-analysis-in-diffusion-tensor-imaging
#18
Moo K Chung, Jamie L Hanson, Nagesh Adluru, Andrew L Alexander, Richard J Davidson, Seth D Pollak
In diffusion tensor imaging, structural connectivity between brain regions is often measured by the number of white matter fiber tracts connecting them. Other features such as the length of tracts or fractional anisotropy (FA) are also used in measuring the strength of connectivity. In this study, we investigated the effects of incorporating the number of tracts, the tract length, and FA values into the connectivity model. Using various node-degree-based graph theory features, the three connectivity models are compared...
June 28, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28657334/large-scale-network-analysis-of-whole-brain-resting-state-functional-connectivity-in-spinal-cord-injury-a-comparative-study
#19
Mayank Kaushal, Akinwunmi Oni-Orisan, Gang Chen, Wenjun Li, Jack Leschke, Doug Ward, Benjamin Kalinosky, Matthew Budde, Brain Schmit, Shi-Jiang Li, Vaishnavi Muqeet, Shekar Kurpad
BACKGROUND: Network analysis based on graph theory depicts the brain as a complex network that allows for inspection of overall brain connectivity pattern and calculation of quantifiable network metrics. To date, large-scale network analysis has not been applied to resting-state functional networks in complete spinal cord injury (SCI) patients. OBJECTIVE: To characterize modular reorganization of whole brain into constituent nodes and compare network metrics between SCI and control subjects...
June 28, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28645844/modeling-and-interpreting-mesoscale-network-dynamics
#20
REVIEW
Ankit N Khambhati, Ann E Sizemore, Richard F Betzel, Danielle S Bassett
Recent advances in brain imaging techniques, measurement approaches, and storage capacities have provided an unprecedented supply of high temporal resolution neural data. These data present a remarkable opportunity to gain a mechanistic understanding not just of circuit structure, but also of circuit dynamics, and its role in cognition and disease. Such understanding necessitates a description of the raw observations, and a delineation of computational models and mathematical theories that accurately capture fundamental principles behind the observations...
June 20, 2017: NeuroImage
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