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https://www.readbyqxmd.com/read/28544891/emergence-of-ultrafast-sparsely-synchronized-rhythms-and-their-responses-to-external-stimuli-in-an-inhomogeneous-small-world-complex-neuronal-network
#1
Sang-Yoon Kim, Woochang Lim
We consider an inhomogeneous small-world network (SWN) composed of inhibitory short-range (SR) and long-range (LR) interneurons, and investigate the effect of network architecture on emergence of synchronized brain rhythms by varying the fraction of LR interneurons plong. The betweenness centralities of the LR and SR interneurons (characterizing the potentiality in controlling communication between other interneurons) are distinctly different. Hence, in view of the betweenness, SWNs we consider are inhomogeneous, unlike the "canonical" Watts-Strogatz SWN with nearly the same betweenness centralities...
April 28, 2017: Neural Networks: the Official Journal of the International Neural Network Society
https://www.readbyqxmd.com/read/28531764/disrupted-resting-brain-graph-measures-in-individuals-at-high-risk-for-alcoholism
#2
Bharath Holla, Rajanikant Panda, Ganesan Venkatasubramanian, Bharat Biswal, Rose Dawn Bharath, Vivek Benegal
Familial susceptibility to alcoholism is likely to be linked to the externalizing diathesis seen in high-risk offspring from high-density alcohol use disorder (AUD) families. The present study aimed at comparing resting brain functional connectivity and their association with externalizing symptoms and alcoholism familial density in 40 substance-naive high-risk (HR) male offspring from high-density AUD families and 30 matched healthy low-risk (LR) males without a family history of substance dependence using graph theory-based network analysis...
May 14, 2017: Psychiatry Research
https://www.readbyqxmd.com/read/28520668/structural-connectivity-related-to-persistent-symptoms-after-mild-tbi-in-adolescents-and-response-to-aerobic-training-preliminary-investigation
#3
Weihong Yuan, Shari L Wade, Catherine Quatman-Yates, Jason A Hugentobler, Paul J Gubanich, Brad G Kurowski
OBJECTIVE: To quantify structural connectivity abnormalities in adolescents with mild traumatic brain injury (mTBI) and to investigate connectivity changes following aerobic training using graph theory and diffusion tensor imaging tractography. SETTING: Outpatient research setting. PARTICIPANTS: Twenty-two children (age: 15.83 ± 1.77 years, 10 females) with 4 to 16 weeks of persistent symptoms after mTBI and a matched healthy comparison group...
May 17, 2017: Journal of Head Trauma Rehabilitation
https://www.readbyqxmd.com/read/28515708/disrupted-structural-and-functional-networks-and-their-correlation-with-alertness-in-right-temporal-lobe-epilepsy-a-graph-theory-study
#4
Wenyu Jiang, Jianping Li, Xuemei Chen, Wei Ye, Jinou Zheng
Previous studies have shown that temporal lobe epilepsy (TLE) involves abnormal structural or functional connectivity in specific brain areas. However, limited comprehensive studies have been conducted on TLE associated changes in the topological organization of structural and functional networks. Additionally, epilepsy is associated with impairment in alertness, a fundamental component of attention. In this study, structural networks were constructed using diffusion tensor imaging tractography, and functional networks were obtained from resting-state functional MRI temporal series correlations in 20 right temporal lobe epilepsy (rTLE) patients and 19 healthy controls...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28510210/brain-connectivity-during-encoding-and-retrieval-of-spatial-information-individual-differences-in-navigation-skills
#5
Greeshma Sharma, Klaus Gramann, Sushil Chandra, Vijander Singh, Alok Prakash Mittal
Emerging evidence suggests that the variations in the ability to navigate through any real or virtual environment are accompanied by distinct underlying cortical activations in multiple regions of the brain. These activations may appear due to the use of different frame of reference (FOR) for representing an environment. The present study investigated the brain dynamics in the good and bad navigators using Graph Theoretical analysis applied to low-density electroencephalography (EEG) data. Individual navigation skills were rated according to the performance in a virtual reality (VR)-based navigation task and the effect of navigator's proclivity towards a particular FOR on the navigation performance was explored...
May 16, 2017: Brain Informatics
https://www.readbyqxmd.com/read/28505729/optimization-of-synchronizability-in-multiplex-networks-by-rewiring-one-layer
#6
Sanjiv K Dwivedi, Murilo S Baptista, Sarika Jalan
The mathematical framework of multiplex networks has been increasingly realized as a more suitable framework for modeling real-world complex systems. In this work, we investigate the optimization of synchronizability in multiplex networks by evolving only one layer while keeping other layers fixed. Our main finding is to show the conditions under which the efficiency of convergence to the most optimal structure is almost as good as the case where both layers are rewired during an optimization process. In particular, interlayer coupling strength responsible for the integration between the layers turns out to be a crucial factor governing the efficiency of optimization even for the cases when the layer going through the evolution has nodes interacting much more weakly than those in the fixed layer...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28491028/resting-state-functional-connectivity-and-network-analysis-of-cerebellum-with-respect-to-crystallized-iq-and-gender
#7
Vasileios C Pezoulas, Michalis Zervakis, Sifis Michelogiannis, Manousos A Klados
During the last years, it has been established that the prefrontal and posterior parietal brain lobes, which are mostly related to intelligence, have many connections to cerebellum. However, there is a limited research investigating cerebellum's relationship with cognitive processes. In this study, the network of cerebellum was analyzed in order to investigate its overall organization in individuals with low and high crystallized Intelligence Quotient (IQ). Functional magnetic resonance imaging (fMRI) data were selected from 136 subjects in resting-state from the Human Connectome Project (HCP) database and were further separated into two IQ groups composed of 69 low-IQ and 67 high-IQ subjects...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28487638/construction-of-individual-morphological-brain-networks-with-multiple-morphometric-features
#8
Wan Li, Chunlan Yang, Feng Shi, Shuicai Wu, Qun Wang, Yingnan Nie, Xin Zhang
In recent years, researchers have increased attentions to the morphological brain network, which is generally constructed by measuring the mathematical correlation across regions using a certain morphometric feature, such as regional cortical thickness and voxel intensity. However, cerebral structure can be characterized by various factors, such as regional volume, surface area, and curvature. Moreover, most of the morphological brain networks are population-based, which has limitations in the investigations of individual difference and clinical applications...
2017: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/28474385/disrupted-topological-organization-of-structural-networks-revealed-by-probabilistic-diffusion-tractography-in-tourette-syndrome-children
#9
Hongwei Wen, Yue Liu, Islem Rekik, Shengpei Wang, Jishui Zhang, Yue Zhang, Yun Peng, Huiguang He
Tourette syndrome (TS) is a childhood-onset neurobehavioral disorder. Although previous TS studies revealed structural abnormalities in distinct corticobasal ganglia circuits, the topological alterations of the whole-brain white matter (WM) structural networks remain poorly understood. Here, we used diffusion MRI probabilistic tractography and graph theoretical analysis to investigate the topological organization of WM networks in 44 drug-naive TS children and 41 age- and gender-matched healthy children. The WM networks were constructed by estimating inter-regional connectivity probability and the topological properties were characterized using graph theory...
May 5, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28474183/do-all-roads-lead-to-rome-a-comparison-of-brain-networks-derived-from-inter-subject-volumetric-and-metabolic-covariance-and-moment-to-moment-hemodynamic-correlations-in-old-individuals
#10
Xin Di, Suril Gohel, Andre Thielcke, Hans F Wehrl, Bharat B Biswal
Relationships between spatially remote brain regions in human have typically been estimated by moment-to-moment correlations of blood-oxygen-level dependent signals in resting-state using functional MRI (fMRI). Recently, studies using subject-to-subject covariance of anatomical volumes, cortical thickness, and metabolic activity are becoming increasingly popular. However, question remains on whether these measures reflect the same inter-region connectivity and brain network organizations. In the current study, we systematically analyzed inter-subject volumetric covariance from anatomical MRI images, metabolic covariance from fluorodeoxyglucose positron emission tomography images from 193 healthy subjects, and resting-state moment-to-moment correlations from fMRI images of a subset of 44 subjects...
May 4, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28469552/disrupted-topology-of-frontostriatal-circuits-is-linked-to-the-severity-of-insomnia
#11
Feng-Mei Lu, Chun-Hong Liu, Shun-Li Lu, Li-Rong Tang, Chang-Le Tie, Juan Zhang, Zhen Yuan
Insomnia is one of the most common health complaints, with a high prevalence of 30~50% in the general population. In particular, neuroimaging research has revealed that widespread dysfunctions in brain regions involved in hyperarousal are strongly correlated with insomnia. However, whether the topology of the intrinsic connectivity is aberrant in insomnia remains largely unknown. In this study, resting-state functional magnetic resonance imaging (rsfMRI) in conjunction with graph theoretical analysis, was used to construct functional connectivity matrices and to extract the attribute features of the small-world networks in insomnia...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28462585/pramipexole-modulates-interregional-connectivity-within-the-sensorimotor-network
#12
Zheng Ye, Anke Hammer, Thomas F Münte
Pramipexole is widely prescribed to treat Parkinson's disease but has been reported to cause impulse control disorders such as pathological gambling. Recent neurocomputational models suggested that D2 agonists may distort functional connections between the striatum and the motor cortex, resulting in impaired reinforcement learning and pathological gambling. To examine how D2 agonists modulate the striatal-motor connectivity, we carried out a pharmacological resting-state functional magnetic resonance imaging study with a double-blind randomized within-subject crossover design...
May 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28453119/-dynamics-and-interactions-between-the-university-community-and-public-health-2-0
#13
Rodolfo Rodríguez-Gómez
Objectives: To explore the experiences of a group of participants in a university community with the web in general and with digital contents on public health, to describe their motivations and to understand how social networks influence their interaction with content on public health. Methodology: Qualitative research. Deep semi-structured interviews were conducted to understand the phenomenon. Results: Five categories emerged after the study: socialization and internalization of the cyberculture, social marketing linked to the web and public health, culture of fear and distrust, the concept of health, and the health system and public health...
September 2016: Revista de Salud Pública
https://www.readbyqxmd.com/read/28446651/how-small-can-the-epileptogenic-region-be-a-case-in-point
#14
Graeme D Jackson, Mangor Pedersen, A Simon Harvey
OBJECTIVE: To present a case that demonstrates that seizures and interictal disturbances can be driven by a small area of functionally abnormal cortex. METHODS: Two novel functional MRI network analysis methods were used to supplement conventional seizure and lesion localization methods: (1) regional homogeneity to quantify local connectivity, or synchrony, with a resolution of less than 1 cm(3) of cortex; and (2) small-worldness to combine information about whole brain network segregation and integration...
April 26, 2017: Neurology
https://www.readbyqxmd.com/read/28433624/temporal-slice-registration-and-robust-diffusion-tensor-reconstruction-for-improved-fetal-brain-structural-connectivity-analysis
#15
Bahram Marami, Seyed Sadegh Mohseni Salehi, Onur Afacan, Benoit Scherrer, Caitlin K Rollins, Edward Yang, Judy A Estroff, Simon K Warfield, Ali Gholipour
Diffusion weighted magnetic resonance imaging, or DWI, is one of the most promising tools for the analysis of neural microstructure and the structural connectome of the human brain. The application of DWI to map early development of the human connectome in-utero, however, is challenged by intermittent fetal and maternal motion that disrupts the spatial correspondence of data acquired in the relatively long DWI acquisitions. Fetuses move continuously during DWI scans. Reliable and accurate analysis of the fetal brain structural connectome requires careful compensation of motion effects and robust reconstruction to avoid introducing bias based on the degree of fetal motion...
April 19, 2017: NeuroImage
https://www.readbyqxmd.com/read/28426955/the-small-world-of-a-fear-memory
#16
Nicholas I Woods, Mazen A Kheirbek
How are fear memories organized? In this issue of Neuron, Vetere et al. (2017) take a network-based approach to demonstrate the importance of highly interconnected hub regions in the consolidation of a fear memory. By doing so, they provide an elegant framework for predicting behavior from functional network properties.
April 19, 2017: Neuron
https://www.readbyqxmd.com/read/28422138/abnormal-resting-state-functional-connectivity-in-the-orbitofrontal-cortex-of-heroin-users-and-its-relationship-with-anxiety-a-pilot-fnirs-study
#17
Hada Fong-Ha Ieong, Zhen Yuan
Drug addiction is widely linked to the orbitofrontal cortex (OFC), which is essential for regulating reward-related behaviors, emotional responses, and anxiety. Over the past two decades, neuroimaging has provided significant contributions revealing functional and structural alternations in the brains of drug addicts. However, the underlying neural mechanism in the OFC and its correlates with drug addiction and anxiety still require further elucidation. We first presented a pilot investigation to examine local networks in OFC regions through resting-state functional connectivity (rsFC) using functional near-infrared spectroscopy (fNIRS) from eight abstinent addicts in a heroin-dependent group (HD) and seven subjects in a control group (CG)...
April 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28415342/griffiths-phase-on-hierarchical-modular-networks-with-small-world-edges
#18
Shanshan Li
The Griffiths phase has been proposed to induce a stretched critical regime that facilitates self-organizing of brain networks for optimal function. This phase stems from the intrinsic structural heterogeneity of brain networks, i.e., the hierarchical modular structure. In this work, the Griffiths phase is studied in modified hierarchical networks with small-world connections based on the 3-regular Hanoi network. Through extensive simulations, the hierarchical level-dependent inter-module wiring probabilities are identified to determine the emergence of the Griffiths phase...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28415292/current-redistribution-in-resistor-networks-fat-tail-statistics-in-regular-and-small-world-networks
#19
Jörg Lehmann, Jakob Bernasconi
The redistribution of electrical currents in resistor networks after single-bond failures is analyzed in terms of current-redistribution factors that are shown to depend only on the topology of the network and on the values of the bond resistances. We investigate the properties of these current-redistribution factors for regular network topologies (e.g., d-dimensional hypercubic lattices) as well as for small-world networks. In particular, we find that the statistics of the current redistribution factors exhibits a fat-tail behavior, which reflects the long-range nature of the current redistribution as determined by Kirchhoff's circuit laws...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28414133/complexity-of-weighted-graph-a-new-technique-to-investigate-structural-complexity-of-brain-activities-with-applications-to-aging-and-autism
#20
Mehran Ahmadlou, Hojjat Adeli
In recent years complexity of the brain structure in healthy and disordered subjects has been studied increasingly. But to the best of the authors' knowledge, researchers so far have investigated the structural complexity only in the context of two restricted networks known as Small-World and Scale-free networks; whereas other aspects of the structural complexity of brain activities may be affected by aging and neurodegenerative disorders such as the Alzheimer's disease and autism spectrum disorder. In this study, two general complexity metrics of graphs, Graph Index Complexity and Offdiagonal Complexity are proposed as general measures of complexity, not restricted to SWN only...
April 13, 2017: Neuroscience Letters
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