scholarly journals Oscillatory default mode network coupling in concussion

2017 ◽  
Author(s):  
B.T Dunkley ◽  
K. Urban ◽  
L. Da Costa ◽  
S. Wong ◽  
E.W. Pang ◽  
...  
Keyword(s):  
Large Scale ◽  
Critical Role ◽  
Network Connectivity ◽  
Permutation Testing ◽  
Default Mode ◽  
Spectrum Density ◽  
Intrinsic Connectivity Networks ◽  
Time Courses ◽  
Band Limited ◽  
The Impact

AbstractBackgroundConcussion is a common form of mild traumatic brain injury (mTBI). Despite the descriptor ‘mild’, a single injury can leave long-lasting and sustained alterations to brain function, including changes to localised activity and large-scale interregional communication. Cognitive complaints are thought to arise from such functional deficits. We investigated the impact of injury on neurophysiological and functionally-specialised resting networks, known as intrinsic connectivity networks (ICNs), using MEG.MethodsWe assessed neurophysiological connectivity in 40 males, 20 with concussion, 20 without, using MEG. Regions-of-interest that comprise nodes of ICNs were defined, and their time courses derived using a beamformer approach. Pairwise fluctuations and covariations in band-limited amplitude envelopes were computed reflecting measures of functional connectivity. Intra-network connectivity was compared between groups using permutation testing, and correlated with symptoms.ResultsWe observed increased resting spectral connectivity in the default mode and motor networks in our concussion group when compared with controls, across alpha through gamma ranges. Moreover, these differences were not explained by power spectrum density (absolute changes in the spectral profiles within the ICNs). Furthermore, this increased coupling was significantly associated with symptoms in the DMN and MOT networks – but once accounting for comorbid symptoms (including, depression, anxiety, and ADHD) only the DMN continued to be associated with symptoms.ConclusionThe DMN network plays a critical role in shifting between cognitive tasks. These data suggest even a single concussion can perturb the intrinsic coupling of functionally-specialised networks in the brain and may explain persistent and wide-ranging symptomatology.

Revisiting default mode network function in major depression: evidence for disrupted subsystem connectivity

2013 ◽  
Vol 44 (10) ◽  
pp. 2041-2051 ◽  
Author(s):  
F. Sambataro ◽  
N. D. Wolf ◽  
M. Pennuto ◽  
N. Vasic ◽  
R. C. Wolf
Keyword(s):  
Default Mode Network ◽  
Resting State ◽  
Large Scale ◽  
Critical Role ◽  
Low Frequency ◽  
Network Connectivity ◽  
Brain Regions ◽  
Default Mode ◽  
Network Function ◽  
Functional Relevance

BackgroundMajor depressive disorder (MDD) is characterized by alterations in brain function that are identifiable also during the brain's ‘resting state’. One functional network that is disrupted in this disorder is the default mode network (DMN), a set of large-scale connected brain regions that oscillate with low-frequency fluctuations and are more active during rest relative to a goal-directed task. Recent studies support the idea that the DMN is not a unitary system, but rather is composed of smaller and distinct functional subsystems that interact with each other. The functional relevance of these subsystems in depression, however, is unclear.MethodHere, we investigated the functional connectivity of distinct DMN subsystems and their interplay in depression using resting-state functional magnetic resonance imaging.ResultsWe show that patients with MDD exhibit increased within-network connectivity in posterior, ventral and core DMN subsystems along with reduced interplay from the anterior to the ventral DMN subsystems.ConclusionsThese data suggest that MDD is characterized by alterations of subsystems within the DMN as well as of their interactions. Our findings highlight a critical role of DMN circuitry in the pathophysiology of MDD, thus suggesting these subsystems as potential therapeutic targets.

scholarly journals Sex differences in brain correlates of STEM anxiety

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Ariel A. Gonzalez ◽  
Katherine L. Bottenhorn ◽  
Jessica E. Bartley ◽  
Timothy Hayes ◽  
Michael C. Riedel ◽  
...  
Keyword(s):  
Sex Differences ◽  
Academic Performance ◽  
Large Scale ◽  
Math Anxiety ◽  
Brain Connectivity ◽  
Learning Experience ◽  
Network Connectivity ◽  
Male Students ◽  
Stem Learning ◽  
Default Mode

Abstract Anxiety is known to dysregulate the salience, default mode, and central executive networks of the human brain, yet this phenomenon has not been fully explored across the STEM learning experience, where anxiety can impact negatively academic performance. Here, we evaluated anxiety and large-scale brain connectivity in 101 undergraduate physics students. We found sex differences in STEM-related and clinical anxiety, with longitudinal increases in science anxiety observed for both female and male students. Sex-specific relationships between STEM anxiety and brain connectivity emerged, with male students exhibiting distinct inter-network connectivity for STEM and clinical anxiety, and female students demonstrating no significant within-sex correlations. Anxiety was negatively correlated with academic performance in sex-specific ways at both pre- and post-instruction. Moreover, math anxiety in male students mediated the relation between default mode-salience connectivity and course grade. Together, these results reveal complex sex differences in the neural mechanisms driving how anxiety is related to STEM learning.

scholarly journals Sex differences in brain correlates of STEM anxiety

2019 ◽  
Author(s):  
Ariel A. Gonzalez ◽  
Katherine L. Bottenhorn ◽  
Jessica E. Bartley ◽  
Timothy Hayes ◽  
Michael C. Riedel ◽  
...  
Keyword(s):  
Sex Differences ◽  
Academic Performance ◽  
Large Scale ◽  
Math Anxiety ◽  
Brain Connectivity ◽  
Learning Experience ◽  
Network Connectivity ◽  
Male Students ◽  
Stem Learning ◽  
Default Mode

ABSTRACTAnxiety is known to dysregulate the salience, default mode, and central executive networks of the human brain, yet this phenomenon has not been fully explored across the STEM learning experience, where anxiety can impact negatively academic performance. Here, we evaluated anxiety and large-scale brain connectivity in 101 undergraduate physics students. We found sex differences in STEM-related but not clinical anxiety, with longitudinal increases in science anxiety observed for both female and male students. Sex-specific impacts of STEM anxiety on brain connectivity emerged, with male students exhibiting distinct inter-network connectivity for STEM and clinical anxiety and female students demonstrating no significant within-sex correlations. Anxiety was negatively correlated with academic performance in sex-specific ways at both pre-and post-instruction. Moreover, math anxiety in male students mediated the relation between default mode-salience connectivity and course grade. Together, these results reveal complex sex differences in the neural mechanisms driving how anxiety impacts STEM learning.

scholarly journals Docosahexaenoic fatty acid-containing phospholipids affect plasma membrane susceptibility to disruption by bacterial toxin-induced macroapertures

2020 ◽  
Author(s):  
Meng-Chen Tsai ◽  
Lucile Fleuriot ◽  
Sébastien Janel ◽  
David Gonzalez-Rodriguez ◽  
Camille Morel ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Large Scale ◽  
Umbilical Vein ◽  
Critical Role ◽  
Membrane Dynamics ◽  
Bacterial Toxin ◽  
Rhoa Gtpase ◽  
Docosahexaenoic Fatty Acid ◽  
Umbilical Vein Endothelial Cells ◽  
The Impact

AbstractMetabolic studies and animal knockout models point to the critical role of polyunsaturated docosahexaenoic acid (22:6, DHA)-containing phospholipids (PLs) in physiology. Here, we study the impact of DHA-PLs on the dynamics of transendothelial cell macroapertures (TEMs) tunnels triggered by the RhoA GTPase inhibitory exotoxin C3 from Clostridium botulinum. Through lipidomic analyses, we show that primary human umbilical vein endothelial cells (HUVECs) subjected to DHA-diet undergo a 6-fold DHA-PLs enrichment in plasma membrane at the expense of monounsaturated OA-PLs. In contrast, OA-diet had almost no effect on PLs composition. Consequently, DHA treatment increases the nucleation rate of TEMs by 2-fold that we ascribe to a reduction of cell thickness. We reveal that the global transcellular area of cells remains conserved through a reduction of the width and lifetime of TEMs. Altogether, we reveal a homeostasis between plasma membrane DHA-PLs content and large-scale membrane dynamics.

scholarly journals Disaster management and humanitarian logistics – A South African perspective

2011 ◽  
Vol 5 (1) ◽  
Author(s):  
Wilna L. Bean ◽  
Nadia M. Viljoen ◽  
Hans W. Ittmann ◽  
Elza Kekana
Keyword(s):  
South Africa ◽  
South African ◽  
Large Scale ◽  
Critical Role ◽  
Humanitarian Logistics ◽  
Future Research ◽  
The South ◽  
Management Context ◽  
African Perspective ◽  
The Impact

Disasters are becoming an unavoidable part of everyday life throughout the world, including South Africa. Even though South Africa is not a country affected by large-scale disasters such as earthquakes, the impact of disasters in South Africa is aggravated significantly by the vulnerability of people living in informal settlements. Humanitarian logistics, as a ‘new’ sub-field in the supply chain management context, has developed significantly recently to assist in disaster situations. This paper provides an overview of the South African humanitarian logistics context. Even though humanitarian logistics plays a critical role in the aftermath of disasters, it extends far beyond events that can typically be classified as ‘disasters’. Therefore the implication of the South African humanitarian logistics context on future research and collaboration opportunities in South African humanitarian logistics is also discussed. Finally, two recent case studies in the South African humanitarian logistics environment are discussed.

scholarly journals Correlations between triaxial shapes and formation history of dark matter haloes

2020 ◽  
Vol 500 (1) ◽  
pp. 1029-1037
Author(s):  
Erwin T Lau ◽  
Andrew P Hearin ◽  
Daisuke Nagai ◽  
Nico Cappelluti
Keyword(s):  
Dark Matter ◽  
Large Scale ◽  
Mass Density ◽  
Critical Role ◽  
Peak Height ◽  
Density Peak ◽  
Surface Mass ◽  
Formation History ◽  
History Of ◽  
The Impact

ABSTRACT The shape of dark matter (DM) haloes plays a critical role in constraining cosmology with upcoming large-scale structure surveys. In this paper, we study the correlations between the triaxial shapes and formation histories in DM haloes in the MultiDark Planck 2 N-body cosmological simulation. We find that halo ellipticity is strongly correlated with halo properties that serve as proxies of halo formation history, such as halo concentration and the normalized peak-centroid offset. These correlations are nearly independent of the halo density peak height. We present a simple model for the correlation between halo ellipticity and concentration using conditional abundance matching, and provide fitting formulae for the multidimensional distributions of triaxial halo shape as a function of halo peak height. We apply our halo shape model to gauge the effects of halo ellipticity and orientation bias on the excess surface mass density profiles in cluster-sized haloes. Our model should be useful for exploring the impact of triaxial halo shape on cosmological constraints in upcoming weak lensing surveys of galaxy clusters.

scholarly journals No Alteration Between Intrinsic Connectivity Networks by a Pilot Study on Localized Exposure to the Fourth-Generation Wireless Communication Signals

2022 ◽  
Vol 9 ◽  
Author(s):  
Lei Yang ◽  
Qingmeng Liu ◽  
Yu Zhou ◽  
Xing Wang ◽  
Tongning Wu ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Network Connectivity ◽  
Fourth Generation ◽  
Imaging Data ◽  
Communication Signals ◽  
Exposure Effect ◽  
Brain Functions ◽  
Intrinsic Connectivity ◽  
Intrinsic Connectivity Networks ◽  
The Impact

Neurophysiological effect of human exposure to radiofrequency signals has attracted considerable attention, which was claimed to have an association with a series of clinical symptoms. A few investigations have been conducted on alteration of brain functions, yet no known research focused on intrinsic connectivity networks, an attribute that may relate to some behavioral functions. To investigate the exposure effect on functional connectivity between intrinsic connectivity networks, we conducted experiments with seventeen participants experiencing localized head exposure to real and sham time-division long-term evolution signal for 30 min. The resting-state functional magnetic resonance imaging data were collected before and after exposure, respectively. Group-level independent component analysis was used to decompose networks of interest. Three states were clustered, which can reflect different cognitive conditions. Dynamic connectivity as well as conventional connectivity between networks per state were computed and followed by paired sample t-tests. Results showed that there was no statistical difference in static or dynamic functional network connectivity in both real and sham exposure conditions, and pointed out that the impact of short-term electromagnetic exposure was undetected at the ICNs level. The specific brain parcellations and metrics used in the study may lead to different results on brain modulation.

scholarly journals Large-Scale Functional Networks, Cognition and Brain Structures Supporting Social Cognition and Theory of Mind Performance in Prodromal to Mild Alzheimer’s Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Jose Manuel Valera-Bermejo ◽  
Matteo De Marco ◽  
Micaela Mitolo ◽  
Chiara Cerami ◽  
Alessandra Dodich ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Social Cognition ◽  
Theory Of Mind ◽  
Large Scale ◽  
Grey Matter ◽  
Network Connectivity ◽  
Functional Networks ◽  
Default Mode ◽  
The Right

Impairment of social cognition (SC) skills such as recognition and attribution of intentions and affective states of others (Theory of Mind, ToM) has been evidenced in Alzheimer’s Disease (AD). This study investigated the neuropsychological, neuroanatomical and brain-functional underpinnings of SC processing to obtain an understanding of the social neurophenotype in early probable AD. Forty-six patients with mild cognitive impairment and mild probable AD underwent SC assessment including emotion recognition (Ekman-60-faces task) and cognitive and affective ToM (Reading-the-Mind-in-the-Eyes test and Story-based Empathy task). Linear models tested the association between SC scores and neuropsychological measures, grey matter maps and large-scale functional networks activity. The executive domain had the most predominant association with SC scores in the cognitive profile. Grey matter volume of the anterior cingulate, orbitofrontal, temporoparietal junction (TPJ), superior temporal, and cerebellar cortices were associated with ToM. Social cognition scores were associated with lower connectivity of the default-mode network with the prefrontal cortex. The right fronto-parietal network displayed higher inter-network connectivity in the right TPJ and insula while the salience network showed lower inter-network connectivity with the left TPJ and insula. Connectivity coupling alterations of executive-attentional networks may support default mode social-cognitive-associated decline through the recruitment of frontal executive mechanisms.

scholarly journals Rewiring Strategy Based on Directed Betweenness to Mitigate Disruptions of Large-Scale Supply Chain Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hui Xia
Keyword(s):  
Supply Chain ◽  
Empirical Data ◽  
Large Scale ◽  
Network Connectivity ◽  
The Other ◽  
Network Robustness ◽  
Data Driven ◽  
Supply Chain Network ◽  
Supply Chain Networks ◽  
The Impact

In current large-scale supply chain networks, unexpected disruptions degrade the supply availability and network connectivity for modern enterprises. How to improve the robustness of supply chain networks is very important for modern enterprises. In this paper, we explore how to improve the robustness of supply chain networks from a topological perspective. Firstly, through the empirical data-driven study, we show that the directed betweenness metric is more suitable than the other topological metrics in evaluating the robustness of supply chain networks. Then, we propose a rewiring algorithm based on directed betweenness to improve network robustness under the impact of disruptions. The experimental results in the large-scale supply chain network show that the rewiring algorithm based on directed betweenness effectively improves the network robustness.

scholarly journals Altered functional connectivity of cortical networks in semantic variant Primary Progressive Aphasia

2020 ◽  
Author(s):  
Haroon Popal ◽  
Megan Quimby ◽  
Daisy Hochberg ◽  
Bradford C. Dickerson ◽  
Jessica A. Collins
Keyword(s):  
Functional Connectivity ◽  
Default Mode Network ◽  
Large Scale ◽  
Network Connectivity ◽  
Primary Progressive Aphasia ◽  
Cognitive Networks ◽  
Default Mode ◽  
Progressive Aphasia ◽  
Primary Progressive ◽  
Semantic Variant

AbstractAs their illness progresses, patients with the semantic variant of Primary Progressive Aphasia (svPPA) frequently exhibit peculiar behaviors indicative of altered visual attention or an increased interest in artistic endeavors. In the present study, we examined changes within and between large-scale functional brain networks that may explain this altered visual behavior. We first examined the connectivity of the visual association network, the dorsal attention network, and the default mode network in healthy young adults (n=89) to understand the typical architecture of these networks in the healthy brain. We then compared the large-scale functional connectivity of these networks in a group of svPPA patients (n=12) to a group of age-matched cognitively normal controls (n=30). Our results showed that the between-network connectivity of the dorsal attention and visual association networks was elevated in svPPA patients relative to controls. We further showed that this heightened between-network connectivity was associated with a decrease in the within-network connectivity of the default mode network, possibly due to progressive degeneration of the anterior temporal lobes in svPPA. These results suggest that focal neurodegeneration can lead to the reorganization of large-scale cognitive networks beyond the primarily affected network(s), possibly contributing to cognitive or behavioral changes that are commonly present as part of the clinical phenotype of svPPA.

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