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https://www.readbyqxmd.com/read/29232386/on-the-calculation-of-betweenness-centrality-in-marine-connectivity-studies-using-transfer-probabilities
#1
Andrea Costa, Anne A Petrenko, Katell Guizien, Andrea M Doglioli
Betweenness has been used in a number of marine studies to identify portions of sea that sustain the connectivity of whole marine networks. Herein we highlight the need of methodological exactness in the calculation of betweenness when graph theory is applied to marine connectivity studies based on transfer probabilities. We show the inconsistency in calculating betweeness directly from transfer probabilities and propose a new metric for the node-to-node distance that solves it. Our argumentation is illustrated by both simple theoretical examples and the analysis of a literature data set...
2017: PloS One
https://www.readbyqxmd.com/read/29225064/intracranial-high-%C3%AE-connectivity-distinguishes-wakefulness-from-sleep
#2
Ezequiel Mikulan, Eugenia Hesse, Lucas Sedeño, Tristán Bekinschtein, Mariano Sigman, María Del Carmen García, Walter Silva, Carlos Ciraolo, Adolfo M García, Agustín Ibáñez
Neural synchrony in the γ-band is considered a fundamental process in cortical computation and communication and it has also been proposed as a crucial correlate of consciousness. However, the latter claim remains inconclusive, mainly due to methodological limitations, such as the spectral constraints of scalp-level electroencephalographic recordings or volume-conduction confounds. Here, we circumvented these caveats by comparing γ-band connectivity between two global states of consciousness via intracranial electroencephalography (iEEG), which provides the most reliable measurements of high-frequency activity in the human brain...
December 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/29224969/aberrant-development-of-the-asymmetry-between-hemispheric-brain-white-matter-networks-in-autism-spectrum-disorder
#3
Long Wei, Suyu Zhong, Shengdong Nie, Gaolang Gong
Atypical brain asymmetry/lateralization has long been hypothesized for autism spectrum disorder (ASD), and this model has been repeatedly supported by various neuroimaging studies. Recently, hemispheric network topologies have been found to be asymmetric, thereby providing a new avenue for investigating brain asymmetries under various conditions. To date, however, how network topological asymmetries are altered in ASD remains largely unexplored. To clarify this, the present study included ASD individuals from the newly released Autism Brain Imaging Data Exchange II database (58 right-handed male ASD individuals aged 5 to 26 years and 70 age- and IQ-matched typically developing (TD) individuals)...
December 7, 2017: European Neuropsychopharmacology: the Journal of the European College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/29223742/network-analysis-reveals-disrupted-functional-brain-circuitry-in-drug-naive-social-anxiety-disorder
#4
REVIEW
Xun Yang, Jin Liu, Yajing Meng, Mingrui Xia, Zaixu Cui, Xi Wu, Xinyu Hu, Wei Zhang, Gaolang Gong, Qiyong Gong, John A Sweeney, Yong He
Social anxiety disorder (SAD) is a common and disabling condition characterized by excessive fear and avoidance of public scrutiny. Neuroimaging studies have suggested that the emotional and behavior deficits in SAD are associated with abnormalities in regional brain function and functional connectivity. However, little is known about whether intrinsic functional brain networks in patients with SAD are topologically disrupted. Here, we collected resting-state fMRI data from 33 drug-naive patients with SAD and 32 healthy controls (HC), constructed functional networks with 34 predefined regions based on previous meta-analytic research with task-based fMRI in SAD, and performed network-based statistic and graph-theory analyses...
December 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/29218416/stability-and-donor-acceptor-bond-in-dinuclear-organometallics-cpm1-m2cl3-m1-m2%C3%A2-%C3%A2-b-al-ga-in-cp%C3%A2-%C3%A2-%C3%AE-5-c5h5
#5
Yaru Dang, Lingpeng Meng, Mei Qin, Qingzhong Li, Xiaoyan Li
The geometries and stabilities of the dinuclear organometallics CpM1-M2Cl3 (M1, M2 = B, Al, Ga, In; Cp = η 5-C5H5) have been investigated by density functional theory (DFT) at M06 L/6-311G(d, p) levels. The nature of the donor-acceptor M1 → M2 bond was also studied based on the atoms in molecules (AIM) theory, energy decomposition analysis (EDA) and natural bond orbital (NBO) analysis. The results show that the electronegativity of the M atom determines the stability and covalent character of the dinuclear organometallics CpM1-M2Cl3...
December 7, 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/29205593/identifying-apparent-local-stable-isotope-equilibrium-in-a-complex-non-equilibrium-system
#6
Yuyang He, Xiaobin Cao, Jianwei Wang, Huiming Bao
RATIONALE: Although being out of equilibrium, biomolecules in organisms have the potential to approach isotope equilibrium locally because enzymatic reactions are intrinsically reversible. A rigorous approach that can describe isotope distribution among biomolecules and their apparent deviation from equilibrium state is lacking, however. METHODS: Applying the concept of distance matrix in graph theory, we propose that apparent local isotope equilibrium among a subset of biomolecules can be assessed using an apparent fractionation difference (|Δα|) matrix, in which the differences between the observed isotope composition (δ') and the calculated equilibrium fractionation factor (1000lnβ) can be more rigorously evaluated than by using a previous approach for multiple biomolecules...
December 5, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/29203874/the-posterior-insula-shows-disrupted-brain-functional-connectivity-in-female-migraineurs-without-aura-based-on-brainnetome-atlas
#7
Jilei Zhang, Jingjing Su, Mengxing Wang, Ying Zhao, Qi-Ting Zhang, Qian Yao, Haifeng Lu, Hui Zhang, Ge-Fei Li, Yi-Lan Wu, Yi-Sheng Liu, Feng-Di Liu, Mei-Ting Zhuang, Yan-Hui Shi, Tian-Yu Hou, Rong Zhao, Yuan Qiao, Jianqi Li, Jian-Ren Liu, Xiaoxia Du
Long-term headache attacks may cause human brain network reorganization in patients with migraine. In the current study, we calculated the topologic properties of functional networks based on the Brainnetome atlas using graph theory analysis in 29 female migraineurs without aura (MWoA) and in 29 female age-matched healthy controls. Compared with controls, female MWoA exhibited that the network properties altered, and the nodal centralities decreased/increased in some brain areas. In particular, the right posterior insula and the left medial superior occipital gyrus of patients exhibited significantly decreased nodal centrality compared with healthy controls...
December 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29196672/network-properties-in-transitions-of-consciousness-during-propofol-induced-sedation
#8
Minji Lee, Robert D Sanders, Seul-Ki Yeom, Dong-Ok Won, Kwang-Suk Seo, Hyun Jeong Kim, Giulio Tononi, Seong-Whan Lee
Reliable electroencephalography (EEG) signatures of transitions between consciousness and unconsciousness under anaesthesia have not yet been identified. Herein we examined network changes using graph theoretical analysis of high-density EEG during patient-titrated propofol-induced sedation. Responsiveness was used as a surrogate for consciousness. We divided the data into five states: baseline, transition into unresponsiveness, unresponsiveness, transition into responsiveness, and recovery. Power spectral analysis showed that delta power increased from responsiveness to unresponsiveness...
December 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29193654/technology-experience-of-solid-organ-transplant-patients-and-their-overall-willingness-to-use-interactive-health-technology
#9
Jasper M M Vanhoof, Bert Vandenberghe, David Geerts, Pieter Philippaerts, Patrick De Mazière, Annette DeVito Dabbs, Sabina De Geest, Fabienne Dobbels
BACKGROUND: The use of interactive health technology (IHT) is a promising pathway to tackle self-management problems experienced by many chronically ill patients, including solid organ transplant (Tx) patients. Yet, to ensure that the IHT is accepted and used, a human-centered design process is needed, actively involving end users in all steps of the development process. A first critical, predevelopment step involves understanding end users' characteristics. This study therefore aims to (a) select an IHT platform to deliver a self-management support intervention most closely related to Tx patients' current use of information and communication technologies (ICTs), (b) understand Tx patients' overall willingness to use IHT for self-management support, and investigate associations with relevant technology acceptance variables, and (c) explore Tx patients' views on potential IHT features...
November 28, 2017: Journal of Nursing Scholarship
https://www.readbyqxmd.com/read/29190759/graph-based-analysis-of-brain-connectivity-in-schizophrenia
#10
Elzbieta Olejarczyk, Wojciech Jernajczyk
The present study evaluated brain connectivity using electroencephalography (EEG) data from 14 patients with schizophrenia and 14 healthy controls. Phase-Locking Value (PLV), Phase-Lag Index (PLI) and Directed Transfer Function (DTF) were calculated for the original EEG data and following current source density (CSD) transformation, re-referencing using the average reference electrode (AVERAGE) and reference electrode standardization techniques (REST). The statistical analysis of adjacency matrices was carried out using indices based on graph theory...
2017: PloS One
https://www.readbyqxmd.com/read/29187817/predicting-long-term-cognitive-outcome-following-breast-cancer-with-pre-treatment-resting-state-fmri-and-random-forest-machine-learning
#11
Shelli R Kesler, Arvind Rao, Douglas W Blayney, Ingrid A Oakley-Girvan, Meghan Karuturi, Oxana Palesh
We aimed to determine if resting state functional magnetic resonance imaging (fMRI) acquired at pre-treatment baseline could accurately predict breast cancer-related cognitive impairment at long-term follow-up. We evaluated 31 patients with breast cancer (age 34-65) prior to any treatment, post-chemotherapy and 1 year later. Cognitive testing scores were normalized based on data obtained from 43 healthy female controls and then used to categorize patients as impaired or not based on longitudinal changes. We measured clustering coefficient, a measure of local connectivity, by applying graph theory to baseline resting state fMRI and entered these metrics along with relevant patient-related and medical variables into random forest classification...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29184896/formative-evaluation-on-cultural-tailoring-breathing-awareness-meditation-smartphone-apps-to-reduce-stress-and-blood-pressure
#12
John C Sieverdes, Zachary W Adams, Lynne Nemeth, Brenda Brunner-Jackson, Martina Mueller, Ashley Anderson, Sachin Patel, Luke Sox, Frank A Treiber
Background: Chronic stress is an independent risk factor for essential hypertension (EH), cardiovascular disease (CVD), and is sometimes confronted by mal-adaptive coping behaviors (e.g., stress eating, excessive alcohol consumption, etc.). Pre-essential hypertension (preEH) is the leading predictor of future EH status. Breathing awareness meditation (BAM) can result in clinically beneficial blood pressure (BP) reductions, though face-to-face sessions presents barriers to reach those in need...
2017: MHealth
https://www.readbyqxmd.com/read/29167724/analysis-of-resting-state-fmri-topological-graph-theory-properties-in-methamphetamine-drug-users-applying-box-counting-fractal-dimension
#13
Meysam Siyah Mansoory, Mohammad Ali Oghabian, Amir Homayoun Jafari, Alireza Shahbabaie
Introduction: Graph theoretical analysis of functional Magnetic Resonance Imaging (fMRI) data has provided new measures of mapping human brain in vivo. Of all methods to measure the functional connectivity between regions, Linear Correlation (LC) calculation of activity time series of the brain regions as a linear measure is considered the most ubiquitous one. The strength of the dependence obligatory for graph construction and analysis is consistently underestimated by LC, because not all the bivariate distributions, but only the marginals are Gaussian...
September 2017: Basic and Clinical Neuroscience
https://www.readbyqxmd.com/read/29164774/task-related-changes-in-degree-centrality-and-local-coherence-of-the-posterior-cingulate-cortex-after-major-cardiac-surgery-in-older-adults
#14
Jeffrey N Browndyke, Miles Berger, Patrick J Smith, Todd B Harshbarger, Zachary A Monge, Viral Panchal, Tiffany L Bisanar, Donald D Glower, John H Alexander, Roberto Cabeza, Kathleen Welsh-Bohmer, Mark F Newman, Joseph P Mathew
OBJECTIVES: Older adults often display postoperative cognitive decline (POCD) after surgery, yet it is unclear to what extent functional connectivity (FC) alterations may underlie these deficits. We examined for postoperative voxel-wise FC changes in response to increased working memory load demands in cardiac surgery patients and nonsurgical controls. EXPERIMENTAL DESIGN: Older cardiac surgery patients (n = 25) completed a verbal N-back working memory task during MRI scanning and cognitive testing before and 6 weeks after surgery; nonsurgical controls with cardiac disease (n = 26) underwent these assessments at identical time intervals...
November 21, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29163343/data-driven-sequence-of-changes-to-anatomical-brain-connectivity-in-sporadic-alzheimer-s-disease
#15
Neil P Oxtoby, Sara Garbarino, Nicholas C Firth, Jason D Warren, Jonathan M Schott, Daniel C Alexander
Model-based investigations of transneuronal spreading mechanisms in neurodegenerative diseases relate the pattern of pathology severity to the brain's connectivity matrix, which reveals information about how pathology propagates through the connectivity network. Such network models typically use networks based on functional or structural connectivity in young and healthy individuals, and only end-stage patterns of pathology, thereby ignoring/excluding the effects of normal aging and disease progression. Here, we examine the sequence of changes in the elderly brain's anatomical connectivity over the course of a neurodegenerative disease...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/29163072/altered-functional-brain-connectomes-between-sporadic-and-familial-parkinson-s-patients
#16
Yan Tang, Xue Xiao, Hua Xie, Chang-Min Wan, Li Meng, Zhen-Hua Liu, Wei-Hua Liao, Bei-Sha Tang, Ji-Feng Guo
Familial Parkinson's disease (PD) is often caused by mutation of a certain gene, while sporadic PD is associated with variants of genes which can influence the susceptibility to PD. The goal of this study was to investigate the difference between the two forms of PD in terms of brain abnormalities using resting-state functional MRI and graph theory. Thirty-one familial PD patients and 36 sporadic PD patients underwent resting-state functional MRI scanning. Frequency-dependent functional connectivity was calculated for each subject using wavelet-based correlations of BOLD signal over 246 brain regions from Brainnetome Atlas...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/29141589/reconstructing-cancer-karyotypes-from-short-read-data-the-half-empty-and-half-full-glass
#17
Rami Eitan, Ron Shamir
BACKGROUND: During cancer progression genomes undergo point mutations as well as larger segmental changes. The latter include, among others, segmental deletions duplications, translocations and inversions.The result is a highly complex, patient-specific cancer karyotype. Using high-throughput technologies of deep sequencing and microarrays it is possible to interrogate a cancer genome and produce chromosomal copy number profiles and a list of breakpoints ("jumps") relative to the normal genome...
November 15, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/29139161/cognitive-abilities-brain-white-matter-hyperintensity-volume-and-structural-network-connectivity-in-older-age
#18
Stewart J Wiseman, Tom Booth, Stuart J Ritchie, Simon R Cox, Susana Muñoz Maniega, Maria Del C Valdés Hernández, David Alexander Dickie, Natalie A Royle, John M Starr, Ian J Deary, Joanna M Wardlaw, Mark E Bastin
OBJECTIVE: To assess brain structural connectivity in relation to cognitive abilities in healthy ageing, and the mediating effects of white matter hyper-intensity (WMH) volume. METHODS: MRI data were analysed in 558 members of the Lothian Birth Cohort 1936. Brains were segmented into 85 regions and combined with tractography to generate structural connectomes. WMH volume was quantified. Relationships between whole-brain connectivity, assessed using graph theory metrics, and four major domains of cognitive ability (visuospatial reasoning, verbal memory, information processing speed and crystallized ability) were investigated, as was the mediating effects of WMH volume on these relationships...
November 14, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29137126/carbon-nanotubes-effect-on-mitochondrial-oxygen-flux-dynamics-polarography-experimental-study-and-machine-learning-models-using-star-graph-trace-invariants-of-raman-spectra
#19
Michael González-Durruthy, Jose M Monserrat, Bakhtiyor Rasulev, Gerardo M Casañola-Martín, José María Barreiro Sorrivas, Sergio Paraíso-Medina, Víctor Maojo, Humberto González-Díaz, Alejandro Pazos, Cristian R Munteanu
This study presents the impact of carbon nanotubes (CNTs) on mitochondrial oxygen mass flux (Jm) under three experimental conditions. New experimental results and a new methodology are reported for the first time and they are based on CNT Raman spectra star graph transform (spectral moments) and perturbation theory. The experimental measures of Jm showed that no tested CNT family can inhibit the oxygen consumption profiles of mitochondria. The best model for the prediction of Jm for other CNTs was provided by random forest using eight features, obtaining test R-squared (R²) of 0...
November 11, 2017: Nanomaterials
https://www.readbyqxmd.com/read/29136123/amyloid-network-topology-characterizes-the-progression-of-alzheimer-s-disease-during-the-predementia-stages
#20
Joana B Pereira, Tor Olof Strandberg, Sebastian Palmqvist, Giovanni Volpe, Danielle van Westen, Eric Westman, Oskar Hansson
There is increasing evidence showing that the accumulation of the amyloid-β (Aβ) peptide into extracellular plaques is a central event in Alzheimer's disease (AD). These abnormalities can be detected as lowered levels of Aβ42 in the cerebrospinal fluid (CSF) and are followed by increased amyloid burden on positron emission tomography (PET) several years before the onset of dementia. The aim of this study was to assess amyloid network topology in nondemented individuals with early stage Aβ accumulation, defined as abnormal CSF Aβ42 levels and normal Florbetapir PET (CSF+/PET-), and more advanced Aβ accumulation, defined as both abnormal CSF Aβ42 and Florbetapir PET (CSF+/PET+)...
November 9, 2017: Cerebral Cortex
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