keyword
MENU ▼
Read by QxMD icon Read
search

small-world

keyword
https://www.readbyqxmd.com/read/28344551/construction-and-analysis-of-weighted-brain-networks-from-sice-for-the-study-of-alzheimer-s-disease
#1
Jorge Munilla, Andrés Ortiz, Juan M Górriz, Javier Ramírez
Alzheimer's Disease (AD) is the most common neurodegenerative disease in elderly people, and current drugs, unfortunately, do not represent yet a cure but only slow down its progression. This is explained, at least in part, because the understanding of the neurodegenerative process is still incomplete, being sometimes mistaken, particularly at the first steps of the illness, with the natural aging process. A better identification of how the functional activity deteriorates is thus crucial to develop new and more effective treatments...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28336496/functional-eeg-network-analysis-in-schizophrenia-evidence-of-larger-segregation-and-deficit-of-modulation
#2
Javier Gomez-Pilar, Alba Lubeiro, Jesús Poza, Roberto Hornero, Marta Ayuso, César Valcárcel, Karim Haidar, José A Blanco, Vicente Molina
OBJECTIVE: Higher mental functions depend on global cerebral functional coordination. Our aim was to study fast modulation of functional networks in schizophrenia that has not been previously assessed. METHODS: Graph-theory was used to analyze the electroencephalographic (EEG) activity during an odd-ball task in 57 schizophrenia patients (18 first episode patients, FEPs) and 59 healthy controls. Clustering coefficient (CLC), characteristic path length (PL) and small-worldness (SW) were computed at baseline ([-300 0] ms prior to stimulus delivery) and response ([150 450] ms post-stimulus) windows...
March 20, 2017: Progress in Neuro-psychopharmacology & Biological Psychiatry
https://www.readbyqxmd.com/read/28326021/abnormalities-in-structural-covariance-of-cortical-gyrification-in-parkinson-s-disease
#3
Jinping Xu, Jiuquan Zhang, Jinlei Zhang, Yue Wang, Yanling Zhang, Jian Wang, Guanglin Li, Qingmao Hu, Yuanchao Zhang
Although abnormal cortical morphology and connectivity between brain regions (structural covariance) have been reported in Parkinson's disease (PD), the topological organizations of large-scale structural brain networks are still poorly understood. In this study, we investigated large-scale structural brain networks in a sample of 37 PD patients and 34 healthy controls (HC) by assessing the structural covariance of cortical gyrification with local gyrification index (lGI). We demonstrated prominent small-world properties of the structural brain networks for both groups...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/28324759/stability-and-instability-of-a-neuron-network-with-excitatory-and-inhibitory-small-world-connections
#4
Dongyuan Yu, Xu Xu, Jing Zhou, Eric Li
This study considers a delayed neural network with excitatory and inhibitory shortcuts. The global stability of the trivial equilibrium is investigated based on Lyapunov's direct method and the delay-dependent criteria are obtained. It is shown that both the excitatory and inhibitory shortcuts decrease the stability interval, but a time delay can be employed as a global stabilizer. In addition, we analyze the bounds of the eigenvalues of the adjacent matrix using matrix perturbation theory and then obtain the generalized sufficient conditions for local stability...
March 2, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28297942/modeling-structure-and-resilience-of-the-dark-network
#5
Manlio De Domenico, Alex Arenas
While the statistical and resilience properties of the Internet are no longer changing significantly across time, the Darknet, a network devoted to keep anonymous its traffic, still experiences rapid changes to improve the security of its users. Here we study the structure of the Darknet and find that its topology is rather peculiar, being characterized by a nonhomogeneous distribution of connections, typical of scale-free networks; very short path lengths and high clustering, typical of small-world networks; and lack of a core of highly connected nodes...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28295228/cognitive-network-reorganization-following-surgical-control-of-seizures-in-lennox-gastaut-syndrome
#6
Aaron E L Warren, A Simon Harvey, David F Abbott, Simon J Vogrin, Catherine Bailey, Andrew Davidson, Graeme D Jackson, John S Archer
We previously observed that adults with Lennox-Gastaut syndrome (LGS) show abnormal functional connectivity among cognitive networks, suggesting that this may contribute to impaired cognition. Herein we report network reorganization following seizure remission in a child with LGS who underwent functional magnetic resonance imaging (fMRI) before and after resection of a cortical dysplasia. Concurrent electroencephalography (EEG) was acquired during presurgical fMRI. Presurgical and postsurgical functional connectivity were compared using (1) graph theoretical analyses of small-world network organization and node-wise strength; and (2) seed-based analyses of connectivity within and between five functional networks...
March 11, 2017: Epilepsia
https://www.readbyqxmd.com/read/28293468/a-method-for-independent-component-graph-analysis-of-resting-state-fmri
#7
Demetrius Ribeiro de Paula, Erik Ziegler, Pubuditha M Abeyasinghe, Tushar K Das, Carlo Cavaliere, Marco Aiello, Lizette Heine, Carol di Perri, Athena Demertzi, Quentin Noirhomme, Vanessa Charland-Verville, Audrey Vanhaudenhuyse, Johan Stender, Francisco Gomez, Jean-Flory L Tshibanda, Steven Laureys, Adrian M Owen, Andrea Soddu
INTRODUCTION: Independent component analysis (ICA) has been extensively used for reducing task-free BOLD fMRI recordings into spatial maps and their associated time-courses. The spatially identified independent components can be considered as intrinsic connectivity networks (ICNs) of non-contiguous regions. To date, the spatial patterns of the networks have been analyzed with techniques developed for volumetric data. OBJECTIVE: Here, we detail a graph building technique that allows these ICNs to be analyzed with graph theory...
March 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28290133/the-effects-of-acute-gaba-treatment-on-the-functional-connectivity-and-network-topology-of-cortical-cultures
#8
Yao Han, Hong Li, Yiran Lang, Yuwei Zhao, Hongji Sun, Peng Zhang, Xuan Ma, Jiuqi Han, Qiyu Wang, Jin Zhou, Changyong Wang
γ-Aminobutyric acid (GABA) is an inhibitory transmitter, acting on receptor channels to reduce neuronal excitability in matured neural systems. However, electrophysiological responses of whole neuronal ensembles to the exposure to GABA are still unclear. We used micro-electrode arrays (MEAs) to study the effects of the increasing amount of GABA on functional network of cortical neural cultures. Then the recorded data were analyzed by the cross-covariance analysis and graph theory. Results showed that after the GABA treatment, the activity parameters of firing rate, bursting rate, bursting duration and network burst frequency in neural cultures decreased as expected...
March 13, 2017: Neurochemical Research
https://www.readbyqxmd.com/read/28290074/abnormal-brain-white-matter-network-in-young-smokers-a-graph-theory-analysis-study
#9
Yajuan Zhang, Min Li, Ruonan Wang, Yanzhi Bi, Yangding Li, Zhang Yi, Jixin Liu, Dahua Yu, Kai Yuan
Previous diffusion tensor imaging (DTI) studies had investigated the white matter (WM) integrity abnormalities in some specific fiber bundles in smokers. However, little is known about the changes in topological organization of WM structural network in young smokers. In current study, we acquired DTI datasets from 58 male young smokers and 51 matched nonsmokers and constructed the WM networks by the deterministic fiber tracking approach. Graph theoretical analysis was used to compare the topological parameters of WM network (global and nodal) and the inter-regional fractional anisotropy (FA) weighted WM connections between groups...
March 13, 2017: Brain Imaging and Behavior
https://www.readbyqxmd.com/read/28268278/resting-state-eeg-network-change-in-alpha-and-beta-bands-after-upper-limb-amputation
#10
Yuanyuan Lyu, Xiaoli Guo, Zhuo Wang, Shanbao Tong
To investigate the reorganization of functional brain network following amputation, twenty-two right-hand amputees and twenty-four age- and education-matched controls participated in a resting-state EEG study. EEG networks in alpha and beta bands were constructed using phase synchronization. Both global and local network parameters were compared between amputees and healthy controls. In the aspect of global connectivity, amputees showed increased clustering coefficient (C), decreased characteristic path length (L) and increased small worldness (S) in alpha band, and an increase of L in beta band...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28257928/the-effects-of-a-mid-task-break-on-the-brain-connectome-in-healthy-participants-a-resting-state-functional-mri-study
#11
Yu Sun, Julian Lim, Zhongxiang Dai, KianFoong Wong, Fumihiko Taya, Yu Chen, Junhua Li, Nitish Thakor, Anastasios Bezerianos
Although rest breaks are commonly administered as a countermeasure to reduce mental fatigue and boost cognitive performance, the effects of taking a break on behavior are not consistent. Moreover, our understanding of the underlying neural mechanisms of rest breaks and how they modulate mental fatigue is still rudimentary. In this study, we investigated the effects of receiving a rest break on the topological properties of brain connectivity networks via a two-session experimental paradigm, in which one session comprised four successive blocks of a mentally demanding visual selective attention task (No-rest session), whereas the other contained a rest break between the second and third task blocks (Rest session)...
February 28, 2017: NeuroImage
https://www.readbyqxmd.com/read/28256774/identifying-topological-motif-patterns-of-human-brain-functional-networks
#12
Yongbin Wei, Xuhong Liao, Chaogan Yan, Yong He, Mingrui Xia
Recent imaging connectome studies demonstrated that the human functional brain network follows an efficient small-world topology with cohesive functional modules and highly connected hubs. However, the functional motif patterns that represent the underlying information flow remain largely unknown. Here, we investigated motif patterns within directed human functional brain networks, which were derived from resting-state functional magnetic resonance imaging data with controlled confounding hemodynamic latencies...
March 3, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28249008/characterization-of-the-resting-state-brain-network-topology-in-the-6-hydroxydopamine-rat-model-of-parkinson-s-disease
#13
Robert Westphal, Camilla Simmons, Michel B Mesquita, Tobias C Wood, Steve C R Williams, Anthony C Vernon, Diana Cash
Resting-state functional MRI (rsfMRI) is an imaging technology that has recently gained attention for its ability to detect disruptions in functional brain networks in humans, including in patients with Parkinson's disease (PD), revealing early and widespread brain network abnormalities. This methodology is now readily applicable to experimental animals offering new possibilities for cross-species translational imaging. In this context, we herein describe the application of rsfMRI to the unilaterally-lesioned 6-hydroxydopamine (6-OHDA) rat, a robust experimental model of the dopamine depletion implicated in PD...
2017: PloS One
https://www.readbyqxmd.com/read/28226435/resting-state-eeg-network-change-in-alpha-and-beta-bands-after-upper-limb-amputation
#14
Yuanyuan Lyu, Xiaoli Guo, Zhuo Wang, Shanbao Tong, Yuanyuan Lyu, Xiaoli Guo, Zhuo Wang, Shanbao Tong, Yuanyuan Lyu, Xiaoli Guo, Zhuo Wang, Shanbao Tong
To investigate the reorganization of functional brain network following amputation, twenty-two right-hand amputees and twenty-four age- and education-matched controls participated in a resting-state EEG study. EEG networks in alpha and beta bands were constructed using phase synchronization. Both global and local network parameters were compared between amputees and healthy controls. In the aspect of global connectivity, amputees showed increased clustering coefficient (C), decreased characteristic path length (L) and increased small worldness (S) in alpha band, and an increase of L in beta band...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28213111/childhood-maltreatment-is-associated-with-alteration-in-global-network-fiber-tract-architecture-independent-of-history-of-depression-and-anxiety
#15
Kyoko Ohashi, Carl M Anderson, Elizabeth A Bolger, Alaptagin Khan, Cynthia E McGreenery, Martin H Teicher
Childhood maltreatment is a major risk factor for psychopathology. It is also associated with alterations in the network architecture of the brain, which we hypothesized may play a significant role in the development of psychopathology. In this study, we analyzed the global network architecture of physically healthy unmedicated 18-25 year old subjects (n=262) using diffusion tensor imaging (DTI) MRI and tractography. Anatomical networks were constructed from fiber streams interconnecting 90 cortical or subcortical regions for subjects with no-to-low (n=122) versus moderate-to-high (n=140) exposure to maltreatment...
February 16, 2017: NeuroImage
https://www.readbyqxmd.com/read/28167818/emergent-hyperbolic-network-geometry
#16
Ginestra Bianconi, Christoph Rahmede
A large variety of interacting complex systems are characterized by interactions occurring between more than two nodes. These systems are described by simplicial complexes. Simplicial complexes are formed by simplices (nodes, links, triangles, tetrahedra etc.) that have a natural geometric interpretation. As such simplicial complexes are widely used in quantum gravity approaches that involve a discretization of spacetime. Here, by extending our knowledge of growing complex networks to growing simplicial complexes we investigate the nature of the emergent geometry of complex networks and explore whether this geometry is hyperbolic...
February 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28129401/impact-of-bounded-noise-and-rewiring-on-the-formation-and-instability-of-spiral-waves-in-a-small-world-network-of-hodgkin-huxley-neurons
#17
Yuangen Yao, Haiyou Deng, Chengzhang Ma, Ming Yi, Jun Ma
Spiral waves are observed in the chemical, physical and biological systems, and the emergence of spiral waves in cardiac tissue is linked to some diseases such as heart ventricular fibrillation and epilepsy; thus it has importance in theoretical studies and potential medical applications. Noise is inevitable in neuronal systems and can change the electrical activities of neuron in different ways. Many previous theoretical studies about the impacts of noise on spiral waves focus an unbounded Gaussian noise and even colored noise...
2017: PloS One
https://www.readbyqxmd.com/read/28129055/task-linked-diurnal-brain-network-reorganization-in-older-adults-a-graph-theoretical-approach
#18
John A E Anderson, Saman Sarraf, Tarek Amer, Buddhika Bellana, Vincent Man, Karen L Campbell, Lynn Hasher, Cheryl L Grady
Testing older adults in the morning generally improves behavioral performance relative to afternoon testing. Morning testing is also associated with brain activity similar to that of young adults. Here, we used graph theory to explore how time of day (TOD) affects the organization of brain networks in older adults across rest and task states. We used nodes from the automated anatomical labeling atlas to construct participant-specific correlation matrices of fMRI data obtained during 1-back tasks with interference and rest...
October 19, 2016: Journal of Cognitive Neuroscience
https://www.readbyqxmd.com/read/28125912/olfactory-network-differences-in-master-sommeliers-connectivity-analysis-using-granger-causality-and-graph-theoretical-approach
#19
Karthik Sreenivasan, Xiaowei Zhuang, Sarah J Banks, Virendra Mishra, Zhengshi Yang, Gopikrishna Deshpande, Dietmar Cordes
Previous studies investigating the differences in olfactory processing and judgments between trained sommeliers and controls have shown increased activations in brain regions involving higher level cognitive processes in sommeliers. However, there is little information about the influence of expertise on causal connectivity and topological properties of the connectivity networks between these regions. Therefore, the current study focuses on addressing these questions in a functional magnetic resonance imaging (fMRI) study of olfactory perception in Master Sommeliers...
March 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28113670/dynamic-functional-segregation-and-integration-in-human-brain-network-during-complex-tasks
#20
Shen Ren, Junhua Li, Fumihiko Taya, Joshua deSouza, Nitish Thakor, Anastasios Bezerianos
The analysis of the topology and organisation of brain networks is known to greatly benefit from network measures in graph theory. However, to evaluate dynamic changes of brain functional connectivity, more sophisticated quantitative metrics characterising temporal evolution of brain topological features are required. To simplify conversion of time-varying brain connectivity to a static graph representation is straightforward but the procedure loses temporal information that could be critical in understanding the brain functions...
September 9, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
keyword
keyword
53943
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"