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https://www.readbyqxmd.com/read/29782993/generalized-recurrent-neural-network-accommodating-dynamic-causal-modeling-for-functional-mri-analysis
#1
Yuan Wang, Yao Wang, Yvonne W Lui
Dynamic Causal Modeling (DCM) is an advanced biophysical model which explicitly describes the entire process from experimental stimuli to functional magnetic resonance imaging (fMRI) signals via neural activity and cerebral hemodynamics. To conduct a DCM study, one needs to represent the experimental stimuli as a compact vector-valued function of time, which is hard in complex tasks such as book reading and natural movie watching. Deep learning provides the state-of-the-art signal representation solution, encoding complex signals into compact dense vectors while preserving the essence of the original signals...
May 18, 2018: NeuroImage
https://www.readbyqxmd.com/read/29780313/network-dynamics-of-attention-during-a-naturalistic-behavioral-paradigm
#2
René Weber, Bradly Alicea, Richard Huskey, Klaus Mathiak
This study investigates the dynamics of attention during continuous, naturalistic interactions in a video game. Specifically, the effect of repeated distraction on a continuous primary task is related to a functional model of network connectivity. We introduce the Non-linear Attentional Saturation Hypothesis (NASH), which predicts that effective connectivity within attentional networks increases non-linearly with decreasing distraction over time, and exhibits dampening at critical parameter values. Functional magnetic resonance imaging (fMRI) data collected using a naturalistic behavioral paradigm coupled with an interactive video game is used to test the hypothesis...
2018: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29758883/challenges-in-coupling-lter-with-environmental-assessments-an-insight-from-potential-and-reality-of-the-chinese-ecological-research-network-in-servicing-environment-assessments
#3
Shaoxia Xia, Yu Liu, Xiubo Yu, Bojie Fu
Environmental assessments estimate, evaluate and predict the consequences of natural processes and human activities on the environment. Long-term ecosystem observation and research networks (LTERs) are potentially valuable infrastructure to support environmental assessments. However, very few environmental assessments have successfully incorporated them. In this study, we try to reveal the current status of coupling LTERs with environmental assessments and look at the challenges involved in improving this coupling through exploring the role that Chinese Ecological Research Network (CERN), the LTER of China, currently plays in regional environment assessments...
August 15, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29758729/neural-field-theory-of-perceptual-echo-and-implications-for-estimating-brain-connectivity
#4
P A Robinson, J C Pagès, N C Gabay, T Babaie, K N Mukta
Neural field theory is used to predict and analyze the phenomenon of perceptual echo in which random input stimuli at one location are correlated with electroencephalographic responses at other locations. It is shown that this echo correlation (EC) yields an estimate of the transfer function from the stimulated point to other locations. Modal analysis then explains the observed spatiotemporal structure of visually driven EC and the dominance of the alpha frequency; two eigenmodes of similar amplitude dominate the response, leading to temporal beating and a line of low correlation that runs from the crown of the head toward the ears...
April 2018: Physical Review. E
https://www.readbyqxmd.com/read/29758234/a-validation-of-dynamic-causal-modelling-for-7t-fmri
#5
S Tak, J Noh, C Cheong, P Zeidman, A Razi, W D Penny, K J Friston
BACKGROUND: There is growing interest in ultra-high field magnetic resonance imaging (MRI) in cognitive and clinical neuroscience studies. However, the benefits offered by higher field strength have not been evaluated in terms of effective connectivity and dynamic causal modelling (DCM). NEW METHOD: In this study, we address the validity of DCM for 7T functional MRI data at two levels. First, we evaluate the predictive validity of DCM estimates based upon 3T and 7T in terms of reproducibility...
May 11, 2018: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29753842/extracting-orthogonal-subject-and-condition-specific-signatures-from-fmri-data-using-whole-brain-effective-connectivity
#6
Vicente Pallarés, Andrea Insabato, Ana Sanjuán, Simone Kühn, Dante Mantini, Gustavo Deco, Matthieu Gilson
The study of brain communication based on fMRI data is often limited because such measurements are a mixture of session-to-session variability with subject- and condition-related information. Disentangling these contributions is crucial for real-life applications, in particular when only a few recording sessions are available. The present study aims to define a reliable standard for the extraction of multiple signatures from fMRI data, while verifying that they do not mix information about the different modalities (e...
May 10, 2018: NeuroImage
https://www.readbyqxmd.com/read/29752589/novelty-modulates-human-striatal-activation-and-prefrontal-striatal-effective-connectivity-during-working-memory-encoding
#7
Lena S Geiger, Carolin Moessnang, Axel Schäfer, Zhenxiang Zang, Maria Zangl, Hengyi Cao, Tamar R van Raalten, Andreas Meyer-Lindenberg, Heike Tost
The functional role of the basal ganglia (BG) in the gating of suitable motor responses to the cortex is well established. Growing evidence supports an analogous role of the BG during working memory encoding, a task phase in which the "input-gating" of relevant materials (or filtering of irrelevant information) is an important mechanism supporting cognitive capacity and the updating of working memory buffers. One important aspect of stimulus relevance is the novelty of working memory items, a quality that is understudied with respect to its effects on corticostriatal function and connectivity...
May 11, 2018: Brain Structure & Function
https://www.readbyqxmd.com/read/29744884/the-interplay-between-cytokinins-and-light-during-senescence-in-detached-arabidopsis-leaves
#8
Helena Janečková, Alexandra Husičková, Ursula Ferretti, Maroš Prčina, Eva Pilařová, Lenka Plačková, Pavel Pospíšil, Karel Doležal, Martina Špundová
Light and cytokinins are known to be the key players in the regulation of plant senescence. In detached leaves, the retarding effect of light on senescence is well described; however, it is not clear to what extent is this effect connected with changes in endogenous cytokinin levels. We have performed a detailed analysis of changes in endogenous content of 29 cytokinin forms in detached leaves of Arabidopsis thaliana (wild-type and three cytokinin receptor double-mutants). Leaves were kept under different light conditions and changes in cytokinin content were correlated with changes in chlorophyll content, efficiency of photosystem II photochemistry and lipid peroxidation...
May 9, 2018: Plant, Cell & Environment
https://www.readbyqxmd.com/read/29735557/decomposing-gratitude-representation-and-integration-of-cognitive-antecedents-of-gratitude-in-the-brain
#9
Hongbo Yu, Xiaoxue Gao, Yuanyuan Zhou, Xiaolin Zhou
Gratitude is a typical social-moral emotion that plays a crucial role in maintaining human cooperative interpersonal relationship. Although neural correlates of gratitude have been investigated, the neurocognitive processes that lead to gratitude, namely the representation and integration of its cognitive antecedents, remain largely unknown. Here, we combined fMRI and a human social interaction task to investigate how benefactor's cost and beneficiary's benefit, two critical antecedents of gratitude, are encoded and integrated in beneficiary's brain, and how the neural processing of gratitude is converted to reciprocity...
May 7, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29700893/action-and-semantic-tool-knowledge-effective-connectivity-in-the-underlying-neural-networks
#10
Nina N Kleineberg, Anna Dovern, Ellen Binder, Christian Grefkes, Simon B Eickhoff, Gereon R Fink, Peter H Weiss
Evidence from neuropsychological and imaging studies indicate that action and semantic knowledge about tools draw upon distinct neural substrates, but little is known about the underlying interregional effective connectivity. With fMRI and dynamic causal modeling (DCM) we investigated effective connectivity in the left-hemisphere (LH) while subjects performed (i) a function knowledge and (ii) a value knowledge task, both addressing semantic tool knowledge, and (iii) a manipulation (action) knowledge task. Overall, the results indicate crosstalk between action nodes and semantic nodes...
April 26, 2018: Human Brain Mapping
https://www.readbyqxmd.com/read/29698732/dopamine-substitution-alters-effective-connectivity-of-cortical-prefrontal-premotor-and-motor-regions-during-complex-bimanual-finger-movements-in-parkinson-s-disease
#11
Felix Sebastian Nettersheim, Philipp Alexander Loehrer, Immo Weber, Fabienne Jung, Till Anselm Dembek, Esther Annegret Pelzer, Haidar Salimi Dafsari, Carlo Andreas Huber, Marc Tittgemeyer, Lars Timmermann
Bimanual coordination is impaired in Parkinson's disease (PD), affecting patients' quality of life. Besides dysfunction of the basal ganglia network, alterations of cortical oscillatory coupling, particularly between prefrontal and (pre-)motoric areas, are thought to underlie this impairment. Here, we studied 16 PD patients OFF and ON medication and age-matched healthy controls recording high-resolution electroencephalography (EEG) during performance of spatially coupled and uncoupled bimanual finger movements...
April 23, 2018: NeuroImage
https://www.readbyqxmd.com/read/29698695/neural-mechanisms-associated-with-treatment-decision-making-an-fmri-study
#12
Malek Abidi, Jared Bruce, Alain Le Blanche, Amanda Bruce, David P Jarmolowicz, Antonia Csillik, N Jade Thai, Seung-Lark Lim, Olivier Heinzlef, Giovanni de Marco
Great progress has been made in understanding how people make financial decisions. However, there is little research on how people make health and treatment choices. Our study aimed to examine how participants weigh benefits (reduction in disease progression) and probability of risk (medications' side effects) when making hypothetical treatment decisions, and to identify the neural networks implicated in this process. Fourteen healthy participants were recruited to perform a treatment decision probability discounting task using MRI...
April 23, 2018: Behavioural Brain Research
https://www.readbyqxmd.com/read/29695280/shaping-neuroplasticity-by-using-powered-exoskeletons-in-patients-with-stroke-a-randomized-clinical-trial
#13
Rocco Salvatore Calabrò, Antonino Naro, Margherita Russo, Placido Bramanti, Luigi Carioti, Tina Balletta, Antonio Buda, Alfredo Manuli, Serena Filoni, Alessia Bramanti
BACKGROUND: The use of neurorobotic devices may improve gait recovery by entraining specific brain plasticity mechanisms, which may be a key issue for successful rehabilitation using such approach. We assessed whether the wearable exoskeleton, Ekso™, could get higher gait performance than conventional overground gait training (OGT) in patients with hemiparesis due to stroke in a chronic phase, and foster the recovery of specific brain plasticity mechanisms. METHODS: We enrolled forty patients in a prospective, pre-post, randomized clinical study...
April 25, 2018: Journal of Neuroengineering and Rehabilitation
https://www.readbyqxmd.com/read/29688392/challenge-to-unity-relationship-between-hemispheric-asymmetry-of-the-default-mode-network-and-mind-wandering
#14
Shogo Kajimura, Takanori Kochiyama, Nobuhito Abe, Michio Nomura
The default mode network (DMN) is considered a unified core brain function for generating subjective mental experiences, such as mind wandering. We propose a novel cognitive framework for understanding the unity of the DMN from the perspective of hemispheric asymmetry. Using transcranial direct current stimulation (tDCS), effective connectivity estimation, and machine learning, we show that the bilateral angular gyri (AG), which are core regions of the DMN, exhibit heterogeneity in both inherent network organization and mind wandering regulation...
April 21, 2018: Cerebral Cortex
https://www.readbyqxmd.com/read/29678734/polymeric-micelle-mediated-delivery-of-half-sandwich-ruthenium-ii-complexes-with-phosphanes-derived-from-fluoroloquinolones-for-lung-adenocarcinoma-treatment
#15
Przemysław Kołoczek, Agnieszka Skórska-Stania, Agnieszka Cierniak, Victor Sebastian, Urszula K Komarnicka, Michał Płotek, Agnieszka Kyzioł
Novel half-sandwich ruthenium(II) complexes with aminomethyl(diphenyl)phosphine derived from fluoroloquinolones (RuPCp, RuPSf, RuPLm, RuPNr) were being investigated as alternatives to well-established metal-based chemotherapeutics. All compounds were characterized by elemental analysis, selected spectroscopic methods (i.e., absorption and fluorescence spectroscopy, ESI-MS, NMR, circular dichroizm), X-ray diffractometry, ICP-MS, and electrochemical techniques. To overcome low solubility, serious side effects connected with systemic cytotoxicity of ruthenium complexes, and acquiring the resistance of cancer cells, polymeric nanoformulations based on Pluronic P-123 micelles loaded with selected Ru(II) complexes were prepared and characterized...
April 17, 2018: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/29663927/encapsulation-of-5-flurouracil-into-plga-nanofibers-and-enhanced-anticancer-effect-in-combination-with-ajwa-dates-extract-phoenix-dactylifera-l
#16
Fazal Khan, Musab Aldhahri, Mohammad Asif Hussain, Kalamegam Gauthaman, Adnan Memic, Adel Abuzenadah, Taha Kumosani, Elie Barbour, Nazeeh Shuja Alothmany, Rabah Wasil Aldhaheri
Side effects connected with chemotherapeutic agents used in cancer treatment has led to alternative modalities of combinatorial therapies in an attempt to reduce the drug dosage and associated risks. In the current study we evaluated the potential use of Ajwa Dates Extract (ADE), reported to have anti-cancer effects, as an adjuvant therapy in combination with 5-flurouracil (5FU) against the human-breast-adenocarcinoma cell line (MFC-7) in vitro. The effects of ADE alone and in combination with 5-FU were evaluated in terms of cell viability and cytotoxicity...
March 1, 2018: Journal of Biomedical Nanotechnology
https://www.readbyqxmd.com/read/29660102/psychopathic-traits-influence-amygdala-anterior-cingulate-cortex-connectivity-during-facial-emotion-processing
#17
Michael P Ewbank, Luca Passamonti, Cindy C Hagan, Ian M Goodyer, Andrew J Calder, Graeme Fairchild
There is accumulating evidence that youths with antisocial behavior or psychopathic traits show deficits in facial emotion recognition, but little is known about the neural mechanisms underlying these impairments. A number of neuroimaging studies have investigated brain activity during facial emotion processing in youths with Conduct Disorder (CD) and adults with psychopathy, but few of these studies tested for group differences in effective connectivity - i.e., changes in connectivity during emotion processing...
April 12, 2018: Social Cognitive and Affective Neuroscience
https://www.readbyqxmd.com/read/29659125/extremely-preterm-children-exhibit-increased-interhemispheric-connectivity-for-language-findings-from-fmri-constrained-meg-analysis
#18
Maria E Barnes-Davis, Stephanie L Merhar, Scott K Holland, Darren S Kadis
Children born extremely preterm are at significant risk for cognitive impairment, including language deficits. The relationship between preterm birth and neurological changes that underlie cognitive deficits is poorly understood. We use a stories-listening task in fMRI and MEG to characterize language network representation and connectivity in children born extremely preterm (n = 15, <28 weeks gestation, ages 4-6 years), and in a group of typically developing control participants (n = 15, term birth, 4-6 years)...
April 16, 2018: Developmental Science
https://www.readbyqxmd.com/read/29658519/biomechanical-evaluation-of-tendon-connection-with-novel-suture-techniques
#19
Zhe Chen, Jun Wang, Jia-Sen Wei, Zhao-Yang Hou, Min Li, Qi-Xin Chen
PURPOSE: Achilles tendon rupture is a severe injury with poor curative effect due to its anatomical characteristic and mechanical peculiarity. Internal fixation of limited loop (IFLL) with steel-wire has been applied on patients with tendon rupture to fix the broken ends before physical rehabilitation. The purpose of this study is to investigate the biomechanical property and radiological characteristic of such suture technique for the repairment of tendon rupture. METHODS: Tendons of pigs' hint feet were separated for the biomechanical study...
2018: Acta of Bioengineering and Biomechanics
https://www.readbyqxmd.com/read/29655936/dynamic-causal-modelling-on-infant-fnirs-data-a-validation-study-on-a-simultaneously-recorded-fnirs-fmri-dataset
#20
Chiara Bulgarelli, Anna Blasi, Simon Arridge, Samuel Powell, Carina C J M de Klerk, Victoria Southgate, Sabrina Brigadoi, William Penny, Sungho Tak, Antonia Hamilton
Tracking the connectivity of the developing brain from infancy through childhood is an area of increasing research interest, and fNIRS provides an ideal method for studying the infant brain as it is compact, safe and robust to motion. However, data analysis methods for fNIRS are still underdeveloped compared to those available for fMRI. Dynamic causal modelling (DCM) is an advanced connectivity technique developed for fMRI data, that aims to estimate the coupling between brain regions and how this might be modulated by changes in experimental conditions...
April 12, 2018: NeuroImage
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