scholarly journals Decreased Global Network Efficiency in Young Male Smoker: An EEG Study during the Resting State

2017 ◽  
Vol 8 ◽  
Author(s):  
Shaoping Su ◽  
Dahua Yu ◽  
Jiadong Cheng ◽  
Yajing Chen ◽  
Xiaohua Zhang ◽  
...  
Keyword(s):  
Resting State ◽  
Young Male ◽  
Global Network ◽  
Network Efficiency ◽  
Male Smoker

scholarly journals Lower functional hippocampal redundancy in mild cognitive impairment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephanie Langella ◽  
◽  
Muhammad Usman Sadiq ◽  
Peter J. Mucha ◽  
Kelly S. Giovanello ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Cognitive Decline ◽  
Resting State ◽  
Memory Performance ◽  
Potential Mechanism ◽  
Network Efficiency ◽  
Cognitively Normal ◽  
Normal Individuals ◽  
The Relationship

AbstractWith an increasing prevalence of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) in response to an aging population, it is critical to identify and understand neuroprotective mechanisms against cognitive decline. One potential mechanism is redundancy: the existence of duplicate elements within a system that provide alternative functionality in case of failure. As the hippocampus is one of the earliest sites affected by AD pathology, we hypothesized that functional hippocampal redundancy is protective against cognitive decline. We compared hippocampal functional redundancy derived from resting-state functional MRI networks in cognitively normal older adults, with individuals with early and late MCI, as well as the relationship between redundancy and cognition. Posterior hippocampal redundancy was reduced between cognitively normal and MCI groups, plateauing across early and late MCI. Higher hippocampal redundancy was related to better memory performance only for cognitively normal individuals. Critically, functional hippocampal redundancy did not come at the expense of network efficiency. Our results provide support that hippocampal redundancy protects against cognitive decline in aging.

scholarly journals Identification and Quantification of Node Criticality through EWM–TOPSIS: A Study of Hong Kong’s MTR System

2021 ◽  
Author(s):  
Yifan Zhang ◽  
S. Thomas Ng
Keyword(s):  
Hong Kong ◽  
Public Transportation ◽  
Early Stage ◽  
Network Robustness ◽  
Global Network ◽  
Practical Significance ◽  
Topsis Method ◽  
Urban Resilience ◽  
Network Efficiency ◽  
Entropy Weight

AbstractPublic transport networks (PTNs) are critical in populated and rapidly densifying cities such as Hong Kong, Beijing, Shanghai, Mumbai, and Tokyo. Public transportation plays an indispensable role in urban resilience with an integrated, complex, and dynamically changeable network structure. Consequently, identifying and quantifying node criticality in complex PTNs is of great practical significance to improve network robustness from damage. Despite the proposition of various node criticality criteria to address this problem, few succeeded in more comprehensive aspects. Therefore, this paper presents an efficient and thorough ranking method, that is, entropy weight method (EWM)–technology for order preference by similarity to an ideal solution (TOPSIS), named EWM–TOPSIS, to evaluate node criticality by taking into account various node features in complex networks. Then we demonstrate it on the Mass Transit Railway (MTR) in Hong Kong by removing and recovering the top k critical nodes in descending order to compare the effectiveness of degree centrality (DC), betweenness centrality (BC), closeness centrality (CC), and the proposed EWM–TOPSIS method. Four evaluation indicators, that is, the frequency of nodes with the same ranking (F), the global network efficiency (E), the size of the largest connected component (LCC), and the average path length (APL), are computed to compare the performance of the four methods and measure network robustness under different designed attack and recovery strategies. The results demonstrate that the EWM–TOPSIS method has more obvious advantages than the others, especially in the early stage.

scholarly journals Distributed Global Functional Connectivity Networks Predict Responsiveness to L-DOPA and Subthalamic Deep Brain Stimulation

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Chengyuan Wu ◽  
Thomas Foltynie ◽  
Patricia Limousin ◽  
Ludvic Zrinzo ◽  
Harith Akram
Keyword(s):  
Deep Brain Stimulation ◽  
Functional Connectivity ◽  
Brain Stimulation ◽  
Resting State ◽  
Visuomotor Control ◽  
Global Network ◽  
Resting State Functional Connectivity ◽  
Graph Metrics ◽  
Stn Dbs ◽  
Deep Brain

Abstract INTRODUCTION Brain circuit dysfunction in Parkinson's disease (PD) involves an extensive global network. A distinctive basal ganglia resting-state functional connectivity (rsFC) pattern has been linked with the ranked response to L-DOPA. We therefore sought to investigate global rsFC patterns associated with response to L-DOPA and to subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with advanced PD. METHODS A total of 19 patients underwent 3-Tesla resting-state functional magnetic resonance imaging (rsfMRI) in the ON-medication state prior to STN DBS. Improvement in UPDRS-III hemibody scores were assessed following L-DOPA therapy and STN DBS. Global rsFC was measured between regions-of-interest (ROIs) defined by the Automated Anatomical Labeling (AAL) atlas and the Montreal Neurologic Institute (MNI) PD25 subcortical atlas. Seed- and network-level correlations were made with an FDR-P < .005. Graph theoretical analysis was performed with an analysis threshold of FDR-P < .005; and then looking at the top 15% of edges. RESULTS Response to L-DOPA and to DBS displayed cerebellar desynchronization with bilateral thalami and synchronization with bilateral ventromedial prefrontal cortices (vmPFC). L-DOPA response was additionally associated with desynchronization between the vmPFC and the fusiform gyrus. Meanwhile, DBS response was associated with more widespread areas, which have been implicated in visuomotor control and planning. Graph theory analysis revealed that DBS response was inversely related to global efficiency of the thalamus and putamen bilaterally. No significant graph metrics were found relative to L-DOPA response. CONCLUSION Response to DBS and to L-DOPA share similar characteristics, particularly in cerebello-thalamo-cortical circuits, including those that play a role in planning, learning, decision-making, and reward-based behavior. Preservation of distributed networks involved in visuomotor control and network integration of striatothalamocortical circuits appear to predict DBS response. These findings shed a light on the mechanism of action of DBS and L-DOPA and may help serve as useful treatment response biomarkers.

scholarly journals Brain Resting State Functional Networks in Infants with Prenatal Opioid Exposure

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicole Steinhardt ◽  
Ramana Vishnubhotla ◽  
Yi Zhao ◽  
David M. Haas ◽  
Gregory M. Sokol ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Functional Mri ◽  
Gestational Age ◽  
Resting State ◽  
Brain Regions ◽  
Brain Network ◽  
Anterior Cingulate ◽  
Global Network ◽  
Neurodevelopmental Outcomes ◽  
Distinct Component

Purpose: Infants of mothers with opioid and substance use can present with postnatal withdrawal symptoms and are at risk of poor neurodevelopmental outcomes in later childhood. Identifying methods to evaluate the consequences of substance exposure on the developing brain can help initiate proactive therapies to improve outcomes for opioid-exposed neonates. Additionally, early brain imaging in infancy has the potential to identify early brain developmental alterations that could prognosticate neurodevelopmental outcomes in these children. In this study, we aim to identify differences in global brain network connectivity in infants with prenatal opioid exposure compared to healthy control infants, using resting-state functional MRI performed at less than 2 months completed gestational age.   Materials and Methods: In this prospective, IRB-approved study, we recruited 20 infants with prenatal opioid exposure and 20 healthy, opioid naïve infants. Anatomic imaging and resting-state functional MRI were performed at less than 48 weeks corrected gestational age, and rs-fMRI images were co-registered to the UNC neonate brain template and 90 anatomic atlas-labelled regions. Covariate Assisted Principal (CAP) regression was performed to identify brain network functional connectivity that was significantly different among infants with prenatal opioid exposure compared to healthy neonates.   Results: Of the 5 significantly different CAP components identified, the most distinct component (CAP5, p= 3.86 x 10-6) spanned several brain regions, including the right inferior temporal gyrus, bilateral Hesch’s gyrus, left thalamus, left supramarginal gyrus, left inferior parietal lobule, left superior parietal gyrus, right anterior cingulate gyrus, right gyrus rectus, left supplementary motor area, and left pars triangularis. Functional connectivity in this network was lower in the infants with prenatal opioid exposure compared to non-opioid exposed infants.   Conclusion: This study demonstrates global network alterations in infants with prenatal opioid exposure compared to non-opioid exposed infants. Future studies should be aimed at identifying clinical significance of this altered connectivity.

scholarly journals Homotopic contralesional excitation suppresses spontaneous circuit repair and global network reconnections following ischemic stroke

2021 ◽  
Author(s):  
Annie R Bice ◽  
Qingli Xiao ◽  
Justin Kong ◽  
Ping Yan ◽  
Zachary Pollack Rosenthal ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Resting State ◽  
Stroke Recovery ◽  
Global Network ◽  
Resting State Functional Connectivity ◽  
Targeted Interventions ◽  
Global Circuit ◽  
Excitatory Activity ◽  
Transcriptional Changes ◽  
Evoked Activity

Understanding circuit-level changes that affect the brain's capacity for plasticity will inform the design of targeted interventions for treating stroke recovery. We combine optogenetic photostimulation with optical neuroimaging to examine how contralesional excitatory activity affects cortical remodeling after stroke in mice. Following photothrombosis of left primary somatosensory forepaw (S1FP) cortex, mice received chronic excitation of right S1FP, a maneuver mimicking the use of the unaffected limb during recovery. Contralesional excitation suppressed perilesional S1FP remapping and was associated with abnormal patterns of evoked activity in the unaffected limb. Contralesional stimulation prevented the restoration of resting-state functional connectivity (RSFC) within the S1FP network, RSFC in several networks functionally-distinct from somatomotor regions, and resulted in persistent limb-use asymmetry. In stimulated mice, perilesional tissue exhibited suppressed transcriptional changes in several genes important for recovery. These results suggest that contralesional excitation impedes local and global circuit reconnection through suppression of several neuroplasticity-related genes after stroke.

Vulnerability Analysis of Link-Weighted Shanghai Metrorail Transit Network

2018 ◽  
Author(s):  
Yanjie Zhang ◽  
Yalda Saadat ◽  
Dongming Zhang ◽  
Bilal M. Ayyub ◽  
Hongwei Huang
Keyword(s):  
Network Topology ◽  
Structural Features ◽  
Network Size ◽  
Global Network ◽  
Interval Length ◽  
Network Efficiency ◽  
Multiple Characteristic ◽  
Shanghai Metro ◽  
Metro System ◽  
Metro Network

With the degradation of metrorail facilities and the increase in network size, it is urgently needed to perform vulnerability assessment to ensure the safe operation of the metro system. In this paper, a link-weighted network model is proposed by considering the physical interval length between neighboring metro stations as link weight factor. Firstly, the metro network was essentially mapped into a bipartite topological diagram that consists of nodes denoting metro stations and links representing metro routes including any tunnels or bridges. After analyzing the network for its complexity level, it was revealed that the metro network topology can be appropriately constructed by using the Space L method. On this basis, multiple characteristic indexes of the network were calculated to characterize network topology structural features. We then tested the state of Shanghai metro network under different failure scenarios by removing a fraction of nodes from the network. Quantitative vulnerability analyses were conducted according to the change in the topological structure of Shanghai metro network and the change in the corresponding global network efficiency due to disruptions. Finally, both the network efficiency of link-weighted and unweighted Shanghai metro network topology were calculated and compared. This study has identified the vulnerable metro stations, which could provide support for the reasonable resource allocation of maintenance work and the decision-making in emergency treatment after failure. In order to increase the adaptability to emergencies and improve the operational efficiency, it was proposed that during the planning, construction, and operation of the metro system, the management and protection of the vulnerable stations should be given increased attention.

Schizophrenia symptoms and brain network efficiency: A resting-state fMRI study

2015 ◽  
Vol 234 (2) ◽  
pp. 208-218 ◽  
Author(s):  
Tsung-Wei Su ◽  
Tun-Wei Hsu ◽  
Yi-Ching Lin ◽  
Ching-Po Lin
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Brain Network ◽  
Network Efficiency ◽  
Fmri Study

scholarly journals Neural decoding of visual stimuli varies with fluctuations in global network efficiency

2017 ◽  
Vol 38 (6) ◽  
pp. 3069-3080 ◽  
Author(s):  
Luca Cocchi ◽  
Zhengyi Yang ◽  
Andrew Zalesky ◽  
Johannes Stelzer ◽  
Luke J. Hearne ◽  
...  
Keyword(s):  
Visual Stimuli ◽  
Global Network ◽  
Neural Decoding ◽  
Network Efficiency

scholarly journals Progressive reconfiguration of resting-state brain networks as psychosis develops: Preliminary results from the North American Prodrome Longitudinal Study (NAPLS) consortium

2017 ◽  
Author(s):  
Hengyi Cao ◽  
Yoonho Chung ◽  
Sarah C. McEwen ◽  
Carrie E. Bearden ◽  
Jean Addington ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
North American ◽  
Resting State ◽  
Network Architecture ◽  
Brain Networks ◽  
Brain Network ◽  
Network Efficiency ◽  
The North ◽  
Network Diversity ◽  
Global Efficiency

AbstractMounting evidence has shown disrupted brain network architecture across the psychosis spectrum. However, whether these changes relate to the development of psychosis is unclear. Here, we used graph theoretical analysis to investigate longitudinal changes in resting-state brain networks in samples of 72 subjects at clinical high risk (including 8 cases who converted to full psychosis) and 48 healthy controls drawn from the North American Prodrome Longitudinal Study (NAPLS) consortium. We observed progressive reduction in global efficiency (P = 0.006) and increase in network diversity (P = 0.001) in converters compared with non-converters and controls. More refined analysis separating nodes into nine key brain networks demonstrated that these alterations were primarily driven by progressively diminished local efficiency in the default-mode network (P = 0.004) and progressively enhanced node diversity across all networks (P < 0.05). The change rates of network efficiency and network diversity were significantly correlated (P = 0.003), suggesting these changes may reflect shared underlying neural mechanisms. In addition, change rates of global efficiency and node diversity were significantly correlated with change rate of cortical thinning in the prefrontal cortex in converters (P < 0.03) and could be predicted by visuospatial memory scores at baseline (P < 0.04). These results provide preliminary evidence for longitudinal reconfiguration of resting-state brain networks during psychosis development and suggest that decreased network efficiency, reflecting an increase in path length between nodes, and increased network diversity, reflecting a decrease in the consistency of functional network organization, are implicated in the progression to full psychosis.

scholarly journals Altered Brain Functional Network in Subtypes of Parkinson's Disease: A Dynamic Perspective

2021 ◽  
Vol 13 ◽  
Author(s):  
Junlan Zhu ◽  
Qiaoling Zeng ◽  
Qiao Shi ◽  
Jiao Li ◽  
Shuwen Dong ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Functional Connectivity ◽  
Dynamic Properties ◽  
Network Connectivity ◽  
Functional Network ◽  
Global Network ◽  
Network Efficiency ◽  
Dominant Phenotype ◽  
Window Approach

Background: Parkinson's disease (PD) is a highly heterogeneous disease, especially in the clinical characteristics and prognosis. The PD is divided into two subgroups: tremor-dominant phenotype and non-tremor-dominant phenotype. Previous studies reported abnormal changes between the two PD phenotypes by using the static functional connectivity analysis. However, the dynamic properties of brain networks between the two PD phenotypes are not yet clear. Therefore, we aimed to uncover the dynamic functional network connectivity (dFNC) between the two PD phenotypes at the subnetwork level, focusing on the temporal properties of dFNC and the variability of network efficiency.Methods: We investigated the resting-state functional MRI (fMRI) data from 29 tremor-dominant PD patients (PDTD), 25 non-tremor-dominant PD patients (PDNTD), and 20 healthy controls (HCs). Sliding window approach, k-means clustering, independent component analysis (ICA), and graph theory analysis were applied to analyze the dFNC. Furthermore, the relationship between alterations in the dynamic properties and clinical features was assessed.Results: The dFNC analyses identified four reoccurring states, one of them showing sparse connections (state I). PDTD patients stayed longer time in state I and showed increased FNC between BG and vSMN in state IV. Both PD phenotypes exhibited higher FNC between dSMN and FPN in state II and state III compared with the controls. PDNTD patients showed decreased FNC between BG and FPN but increased FNC in the bilateral FPN compared with both PDTD patients and controls. In addition, PDNTD patients exhibited greater variability in global network efficiency. Tremor scores were positively correlated with dwell time in state I along with increased FNC between BG and vSMN in state IV.Conclusions: This study explores the dFNC between the PDTD and PDNTD patients, which offers new evidence on the abnormal time-varying brain functional connectivity and their network destruction of the two PD phenotypes, and may help better understand the neural substrates underlying different types of PD.

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