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Granger causality

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https://www.readbyqxmd.com/read/28729831/investigating-focal-connectivity-deficits-in-alzheimer-s-disease-using-directional-brain-networks-derived-from-resting-state-fmri
#1
Sinan Zhao, D Rangaprakash, Archana Venkataraman, Peipeng Liang, Gopikrishna Deshpande
Connectivity analysis of resting-state fMRI has been widely used to identify biomarkers of Alzheimer's disease (AD) based on brain network aberrations. However, it is not straightforward to interpret such connectivity results since our understanding of brain functioning relies on regional properties (activations and morphometric changes) more than connections. Further, from an interventional standpoint, it is easier to modulate the activity of regions (using brain stimulation, neurofeedback, etc.) rather than connections...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28713396/system-level-and-granger-network-analysis-of-integrated-proteomic-and-metabolomic-dynamics-identifies-key-points-of-grape-berry-development-at-the-interface-of-primary-and-secondary-metabolism
#2
Lei Wang, Xiaoliang Sun, Jakob Weiszmann, Wolfram Weckwerth
Grapevine is a fruit crop with worldwide economic importance. The grape berry undergoes complex biochemical changes from fruit set until ripening. This ripening process and production processes define the wine quality. Thus, a thorough understanding of berry ripening is crucial for the prediction of wine quality. For a systemic analysis of grape berry development we applied mass spectrometry based platforms to analyse the metabolome and proteome of Early Campbell at 12 stages covering major developmental phases...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28713237/behavioral-and-neural-correlates-of-executive-function-interplay-between-inhibition-and-updating-processes
#3
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/28708870/assessment-of-resampling-methods-for-causality-testing-a-note-on-the-us-inflation-behavior
#4
Angeliki Papana, Catherine Kyrtsou, Dimitris Kugiumtzis, Cees Diks
Different resampling methods for the null hypothesis of no Granger causality are assessed in the setting of multivariate time series, taking into account that the driving-response coupling is conditioned on the other observed variables. As appropriate test statistic for this setting, the partial transfer entropy (PTE), an information and model-free measure, is used. Two resampling techniques, time-shifted surrogates and the stationary bootstrap, are combined with three independence settings (giving a total of six resampling methods), all approximating the null hypothesis of no Granger causality...
2017: PloS One
https://www.readbyqxmd.com/read/28705767/common-and-distinct-dysfunctional-patterns-contribute-to-triple-network-model-in-schizophrenia-and-depression-a-preliminary-study
#5
Yuchao Jiang, Mingjun Duan, Xi Chen, Xin Chang, Hui He, YingJia Li, Cheng Luo, Dezhong Yao
BACKGROUND: Schizophrenia (SCH) and depression (DEP) are prevalent psychiatric disorders and share common and distinguished elements in their pathophysiology. A triple network model composed of the default mode network (DMN), salience network (SN) and central executive network (CEN) may represent a major abnormality across several psychiatric disorders including SCH and DEP. However, common and distinct dysfunctional patterns between SCH and DEP across three core networks remain unclear...
July 10, 2017: Progress in Neuro-psychopharmacology & Biological Psychiatry
https://www.readbyqxmd.com/read/28698376/frequency-specific-directed-interactions-in-the-human-brain-network-for-language
#6
Jan-Mathijs Schoffelen, Annika Hultén, Nietzsche Lam, André F Marquand, Julia Uddén, Peter Hagoort
The brain's remarkable capacity for language requires bidirectional interactions between functionally specialized brain regions. We used magnetoencephalography to investigate interregional interactions in the brain network for language while 102 participants were reading sentences. Using Granger causality analysis, we identified inferior frontal cortex and anterior temporal regions to receive widespread input and middle temporal regions to send widespread output. This fits well with the notion that these regions play a central role in language processing...
July 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28698280/glycemic-control-after-metabolic-surgery-a-granger-causality-and-graph-analysis
#7
Elena Previti, Serenella Salinari, Alessandro Bertuzzi, Esmeralda Capristo, Stefan Bornstein, Geltrude Mingrone
To examine the contribution of Non-Esterified Fatty-Acids (NEFA) and incretin to insulin-resistance and diabetes amelioration after malabsorptive metabolic-surgery that dramatically reduces circulating NEFA. In fact, NEFA infusion reduces glucose-stimulated insulin secretion and high-fat diets predict diabetes development. Six healthy-controls, 11 obese and 10 Type-2-Diabetic (T2D) subjects were studied before and 1 month after Bilio-Pancreatic Diversion (BPD). Twenty-four hours plasma glucose, NEFA, insulin, C-peptide, glucagon-like peptide-1 (GLP1) and gastric-inhibitory-polypeptide (GIP) time courses were obtained and analyzed by Granger causality and graph analyses...
July 11, 2017: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28690507/the-relationship-between-intrinsic-couplings-of-the-visual-word-form-area-with-spoken-language-network-and-reading-ability-in-children-and-adults
#8
Yu Li, Linjun Zhang, Zhichao Xia, Jie Yang, Hua Shu, Ping Li
Reading plays a key role in education and communication in modern society. Learning to read establishes the connections between the visual word form area (VWFA) and language areas responsible for speech processing. Using resting-state functional connectivity (RSFC) and Granger Causality Analysis (GCA) methods, the current developmental study aimed to identify the difference in the relationship between the connections of VWFA-language areas and reading performance in both adults and children. The results showed that: (1) the spontaneous connectivity between VWFA and the spoken language areas, i...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28687605/alterations-in-functional-cortical-hierarchy-in-hemiparkinsonian-rats
#9
B N Jávor-Duray, M Vinck, M van der Roest, E Bezard, H W Berendse, T Boraud, P Voorn
Parkinson's disease and experimentally induced hemiparkinsonism are characterized by increased beta-synchronization between cortical and subcortical areas. This change in beta-connectivity might reflect either a symmetric increase in interareal influences or asymmetric changes in directed influences among brain areas. We assessed patterns of functional and directed connectivity within and between striatum and six cortical sites in each hemisphere of the hemiparkinsonian rat model. Local field potentials were recorded in resting and walking states, before and after unilateral 6-hydroxydopamine lesion...
July 7, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28687522/dimension-reduction-of-frequency-based-direct-granger-causality-measures-on-short-time-series
#10
Elsa Siggiridou, Vasilios K Kimiskidis, Dimitris Kugiumtzis
BACKGROUND: The mainstream in the estimation of effective brain connectivity relies on Granger causality measures in the frequency domain. If the measure is meant to capture direct causal effects accounting for the presence of other observed variables, as in multi-channel electroencephalograms (EEG), typically the fit of a vector autoregressive (VAR) model on the multivariate time series is required. For short time series of many variables, the estimation of VAR may not be stable requiring dimension reduction resulting in restricted or sparse VAR models...
July 4, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28674507/impaired-coupling-between-the-dorsomedial-prefrontal-cortex-and-the-amygdala-in-schizophrenia-smokers-viewing-anti-smoking-images
#11
Stéphane Potvin, Andràs Tikàsz, Ovidiu Lungu, Emmanuel Stip, Vesséla Zaharieva, Pierre Lalonde, Olivier Lipp, Adrianna Mendrek
BACKGROUND: Cigarette smoking is highly prevalent in schizophrenia and is one of the main factors contributing to the significantly decreased life expectancy in this population. Schizophrenia smokers, compared to their counterparts with no comorbid psychiatric disorder, are largely unaware and indifferent to the long-term negative consequences of cigarette smoking. The objective of this study was to determine, for the first time, if these meta-cognitive deficits are associated with neuro-functional alterations in schizophrenia smokers...
2017: Frontiers in Psychiatry
https://www.readbyqxmd.com/read/28660667/pivotal-role-of-hmt-in-long-range-disambiguation-of-interhemispheric-bistable-surface-motion
#12
João Valente Duarte, Gabriel Nascimento Costa, Ricardo Martins, Miguel Castelo-Branco
It remains an open question whether long-range disambiguation of ambiguous surface motion can be achieved in early visual cortex or instead in higher level regions, which concerns object/surface segmentation/integration mechanisms. We used a bistable moving stimulus that can be perceived as a pattern comprehending both visual hemi-fields moving coherently downward or as two widely segregated nonoverlapping component objects (in each visual hemi-field) moving separately inward. This paradigm requires long-range integration across the vertical meridian leading to interhemispheric binding...
June 28, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28654771/trajectories-of-social-anxiety-cognitive-reappraisal-and-mindfulness-during-an-rct-of-cbgt-versus-mbsr-for-social-anxiety-disorder
#13
Philippe R Goldin, Amanda S Morrison, Hooria Jazaieri, Richard G Heimberg, James J Gross
Cognitive-Behavioral Group Therapy (CBGT) and Mindfulness-Based Stress Reduction (MBSR) are efficacious in treating social anxiety disorder (SAD). It is not yet clear, however, whether they share similar trajectories of change and underlying mechanisms in the context of SAD. This randomized controlled study of 108 unmedicated adults with generalized SAD investigated the impact of CBGT vs. MBSR on trajectories of social anxiety, cognitive reappraisal, and mindfulness during 12 weeks of treatment. CBGT and MBSR produced similar trajectories showing decreases in social anxiety and increases in reappraisal (changing the way of thinking) and mindfulness (mindful attitude)...
June 3, 2017: Behaviour Research and Therapy
https://www.readbyqxmd.com/read/28639013/revisiting-the-environmental-kuznets-curve-and-pollution-haven-hypotheses-mikta-sample
#14
Ibrahim Bakirtas, Mumin Atalay Cetin
This study aims to examine the validity of the environmental Kuznets curve (EKC) and pollution haven hypotheses in Mexico, Indonesia, South Korea, Turkey, and Australia (MIKTA) countries from 1982 to 2011 by using a panel vector auto regressive (PVAR) model. Empirical findings imply that the EKC hypothesis is rejected by the MIKTA sample. However, PVAR estimations reveal Granger causality from income level, foreign direct investment (FDI) inward, and energy consumption to CO2 emissions. Orthogonalized impulse-response functions are derived from PVAR estimations...
June 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28629720/exploring-connectivity-with-large-scale-granger-causality-on-resting-state-functional-mri
#15
Adora M DSouza, Anas Z Abidin, Lutz Leistritz, Axel Wismüller
BACKGROUND: Large-scale Granger causality (lsGC) is a recently developed, resting-state functional MRI (fMRI) connectivity analysis approach that estimates multivariate voxel-resolution connectivity. Unlike most commonly used multivariate approaches, which establish coarse-resolution connectivity by aggregating voxel time-series avoiding an underdetermined problem, lsGC estimates voxel-resolution, fine-grained connectivity by incorporating an embedded dimension reduction. NEW METHOD: We investigate application of lsGC on realistic fMRI simulations, modeling smoothing of neuronal activity by the hemodynamic response function and repetition time (TR), and empirical resting-state fMRI data...
August 1, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28627420/distinct-neural-processes-support-post-success-and-post-error-slowing-in-the-stop-signal-task
#16
Yihe Zhang, Jaime S Ide, Sheng Zhang, Sien Hu, Nikola S Valchev, Xiaoying Tang, Chiang-Shan R Li
Executive control requires behavioral adaptation to environmental contingencies. In the stop signal task (SST), participants exhibit slower go trial reaction time (RT) following a stop trial, whether or not they successfully interrupt the motor response. In previous fMRI studies, we demonstrated activation of the right-hemispheric ventrolateral prefrontal cortex, in the area of inferior frontal gyrus, pars opercularis (IFGpo) and anterior insula (AI), during post-error slowing (PES). However, in similar analyses we were not able to identify regional activities during post-success slowing (PSS)...
June 13, 2017: Neuroscience
https://www.readbyqxmd.com/read/28620297/racial-differences-in-insular-connectivity-and-thickness-and-related-cognitive-impairment-in-hypertension
#17
Ganesh B Chand, Junjie Wu, Deqiang Qiu, Ihab Hajjar
Hypertensive African-Americans have a greater risk of cognitive impairment than hypertensive Caucasian-Americans. The neural basis of this increased risk is yet unknown. Neuroimaging investigations suggest that the normal neural activity comprises complex interactions between brain networks. Recent studies consistently demonstrate that the insula, part of the salience network, provides modulation effects (information flow) over the default-mode and central-executive networks in cognitively normal subjects, and argue that the modulation effect is declined in cognitive impairment...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28614420/the-degree-of-cardiac-baroreflex-involvement-during-active-standing-is-associated-with-the-quality-of-life-in-fibromyalgia-patients
#18
Antonio Roberto Zamunér, Alberto Porta, Carolina Pieroni Andrade, Meire Forti, Andrea Marchi, Raffaello Furlan, Franca Barbic, Aparecida Maria Catai, Ester Silva
Fibromyalgia syndrome (FMS) is a rheumatologic disorder characterized by chronic widespread pain, fatigue and other symptoms. Baroreflex dysfunction has been observed in women with FMS. However, it is unknown whether the limited involvement of the baroreflex control during an orthostatic stimulus has some impact on the quality of life of the FMS patient. Therefore, the aim of the study is evaluate the relationship between the quality of life of the FMS patient and indexes of the cardiovascular autonomic control as estimated from spontaneous fluctuations of heart period (HP) and systolic arterial pressure (SAP)...
2017: PloS One
https://www.readbyqxmd.com/read/28600253/robust-granger-analysis-in-lp-norm-space-for-directed-eeg-network-analysis
#19
PeiYang Li, Xiaoye Huang, Fali Li, Xurui Wang, Weiwei Zhou, Huan Liu, Teng Ma, Tao Zhang, Daqing Guo, Dezhong Yao, Peng Xu
Granger analysis (GA) is widely used to construct directed brain networks based on various physiological recordings, such as functional magnetic resonance imaging (fMRI), electroencephalogram (EEG), etc. However, in real applications, EEGs are inevitably contaminated by unexpected artifacts that may distort the networks because of the L2 norm structure utilized in GAs when estimating directed links. Compared with the L2 norm, the Lp (p ≤ 1) norm can compress outlier effects. In this study, an extended GA is constructed by applying the Lp (p ≤ 1) norm strategy to estimate robust causalities under outlier conditions, and a feasible iteration procedure is utilized to solve the new GA model...
June 5, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28597846/single-trial-effective-brain-connectivity-patterns-enhance-discriminability-of-mental-imagery-tasks
#20
Dheeraj Rathee, Hubert Cecotti, Girijesh Prasad
The majority of the current approaches of connectivity based BCI systems focus on distinguishing between different motor imagery (MI) tasks. Brain regions associated with MI are anatomically close to each other, hence these BCI systems suffer from low performances. Our objective is to introduce single-trial connectivity feature based BCI system for cognition imagery (CI) based tasks wherein the associated brain regions are located relatively far away as compared to those for MI...
June 9, 2017: Journal of Neural Engineering
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