scholarly journals The Difference of Brain Functional Connectivity between Eyes-Closed and Eyes-Open Using Graph Theoretical Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Bo Tan ◽  
Xianxian Kong ◽  
Ping Yang ◽  
Zhenlan Jin ◽  
Ling Li
Keyword(s):  
Functional Connectivity ◽  
Alpha Band ◽  
Topological Parameters ◽  
Eyes Closed ◽  
Synchronization Likelihood ◽  
Functional Brain Networks ◽  
Eyes Open ◽  
The Difference ◽  
Path Lengths ◽  
Brain Functional Connectivity

To study the differences in functional brain networks between eyes-closed (EC) and eyes-open (EO) at resting state, electroencephalographic (EEG) activity was recorded in 21 normal adults during EC and EO states. The synchronization likelihood (SL) was applied to measure correlations between all pairwise EEG channels, and then the SL matrices were converted to graphs by thresholding. Graphs were measured by topological parameters in theta (4–7 Hz), alpha (8–13 Hz), and beta (14–30 Hz) bands. By changing from EC to EO states, mean cluster coefficients decreased in both theta and alpha bands, but mean shortest path lengths became shorter only in the alpha band. In addition, local efficiencies decreased in both theta and alpha bands, while global efficiencies in the alpha band increased inversely. Opening the eyes decreased both nodes and connections in frontal area in the theta band, and also decreased those in bilateral posterior areas in the alpha band. These results suggested that a combination of the SL and graph theory methods may be a useful tool for distinguishing states of EC and EO. The differences in functional connectivity between EC and EO states may reflect the difference of information communication in human brain.

Altered Functional Connectivity of Alpha Rhythm in Obsessive-Compulsive Disorder During Rest

2018 ◽  
Vol 50 (2) ◽  
pp. 88-99 ◽  
Author(s):  
Bo Tan ◽  
Qingxiao Liu ◽  
Chaoyang Wan ◽  
Zhenlan Jin ◽  
Yanchun Yang ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Obsessive Compulsive Disorder ◽  
Alpha Rhythm ◽  
Topological Analysis ◽  
Small World ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Eyes Closed ◽  
Synchronization Likelihood ◽  
Eyes Open

Obsessive-compulsive disorder (OCD) is a common inheritable psychiatric disorder characteristic of repetitive thinking, imagination (obsession), and stereotyped behaviors (compulsive). To explore whether there is an alteration of brain functional connectivity (BFC) in patients with OCD during rest, electroencephalogram (EEG) data of healthy controls (HCs) and patients with OCD were collected during rest in both eyes-closed and eyes-open states. Synchronization likelihood and graph theory were applied to construct and analyze brain functional networks of patients with OCD and HCs. Patients with OCD showed abnormal graph-theoretic parameters and impaired small world features in the alpha and beta bands. In addition, the topological analysis consistently showed that the long-range BFC of alpha rhythm was significantly reduced in the bilateral posterior areas in patients with OCD in comparison with HCs, while the BFC in the beta rhythm was significantly increased only in the eyes-open state. The findings suggest that the BFC of patients with OCD show abnormal small-world features and altered topological structure during rest, mainly in alpha and beta bands, which may provide a new insight for the diagnosis and treatment of OCD.

How reliable are the functional connectivity networks of MEG in resting states?

2011 ◽  
Vol 106 (6) ◽  
pp. 2888-2895 ◽  
Author(s):  
Seung-Hyun Jin ◽  
Jaeho Seol ◽  
June Sic Kim ◽  
Chun Kee Chung
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Alpha Band ◽  
Eyes Closed ◽  
Gamma Frequency ◽  
Centrality Metrics ◽  
Eyes Open ◽  
Network Metrics

We investigated the reliability of nodal network metrics of functional connectivity (FC) networks of magnetoencephalography (MEG) covering the whole brain at the sensor level in the eyes-closed (EC) and eyes-open (EO) resting states. Mutual information (MI) was employed as a measure of FC between sensors in theta, alpha, beta, and gamma frequency bands of MEG signals. MI matrices were assessed with three nodal network metrics, i.e., nodal degree (Dnodal), nodal efficiency (Enodal), and betweenness centrality (normBC). Intraclass correlation (ICC) values were calculated as a measure of reliability. We observed that the test-retest reliabilities of the resting states ranged from a poor to good level depending on the bands and metrics used for defining the nodal centrality. The dominant alpha-band FC network changes were the salient features of the state-related FC changes. The FC networks in the EO resting state showed greater reliability when assessed by Dnodal (maximum mean ICC = 0.655) and Enodal (maximum mean ICC = 0.604) metrics. The gamma-band FC network was less reliable than the theta, alpha, and beta networks across the nodal network metrics. However, the sensor-wise ICC values for the nodal centrality metrics were not uniformly distributed, that is, some sensors had high reliability. This study provides a sense of how the nodal centralities of the human resting state MEG are distributed at the sensor level and how reliable they are. It also provides a fundamental scientific background for continued examination of the resting state of human MEG.

scholarly journals The effect of congenital blindness on resting-state functional connectivity revisited

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria J. S. Guerreiro ◽  
Madita Linke ◽  
Sunitha Lingareddy ◽  
Ramesh Kekunnaya ◽  
Brigitte Röder
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Visual Experience ◽  
Brain Regions ◽  
State Condition ◽  
Resting State Functional Connectivity ◽  
Congenital Blindness ◽  
Eyes Closed ◽  
Congenitally Blind ◽  
Eyes Open

AbstractLower resting-state functional connectivity (RSFC) between ‘visual’ and non-‘visual’ neural circuits has been reported as a hallmark of congenital blindness. In sighted individuals, RSFC between visual and non-visual brain regions has been shown to increase during rest with eyes closed relative to rest with eyes open. To determine the role of visual experience on the modulation of RSFC by resting state condition—as well as to evaluate the effect of resting state condition on group differences in RSFC—, we compared RSFC between visual and somatosensory/auditory regions in congenitally blind individuals (n = 9) and sighted participants (n = 9) during eyes open and eyes closed conditions. In the sighted group, we replicated the increase of RSFC between visual and non-visual areas during rest with eyes closed relative to rest with eyes open. This was not the case in the congenitally blind group, resulting in a lower RSFC between ‘visual’ and non-‘visual’ circuits relative to sighted controls only in the eyes closed condition. These results indicate that visual experience is necessary for the modulation of RSFC by resting state condition and highlight the importance of considering whether sighted controls should be tested with eyes open or closed in studies of functional brain reorganization as a consequence of blindness.

scholarly journals Radiofrequency signal affects alpha band in resting electroencephalogram

2015 ◽  
Vol 113 (7) ◽  
pp. 2753-2759 ◽  
Author(s):  
Rania Ghosn ◽  
Lydia Yahia-Cherif ◽  
Laurent Hugueville ◽  
Antoine Ducorps ◽  
Jean-Didier Lemaréchal ◽  
...  
Keyword(s):  
Salivary Cortisol ◽  
Spectral Power ◽  
Electrode Impedance ◽  
Alpha Band ◽  
Double Blind ◽  
Eyes Closed ◽  
Before And After ◽  
Sham Exposure ◽  
Eyes Open ◽  
Young Subjects

The aim of the present work was to investigate the effects of the radiofrequency (RF) electromagnetic fields (EMFs) on human resting EEG with a control of some parameters that are known to affect alpha band, such as electrode impedance, salivary cortisol, and caffeine. Eyes-open and eyes-closed resting EEG data were recorded in 26 healthy young subjects under two conditions: sham exposure and real exposure in double-blind, counterbalanced, crossover design. Spectral power of EEG rhythms was calculated for the alpha band (8–12 Hz). Saliva samples were collected before and after the study. Salivary cortisol and caffeine were assessed by ELISA and HPLC, respectively. The electrode impedance was recorded at the beginning of each run. Compared with the sham session, the exposure session showed a statistically significant ( P < 0.0001) decrease of the alpha band spectral power during closed-eyes condition. This effect persisted in the postexposure session ( P < 0.0001). No significant changes were detected in electrode impedance, salivary cortisol, and caffeine in the sham session compared with the exposure one. These results suggest that GSM-EMFs of a mobile phone affect the alpha band within spectral power of resting human EEG.

scholarly journals Static Balance in Patients with Vestibular Impairments: A Preliminary Study

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Hossein Talebi ◽  
Mohammad Taghi Karimi ◽  
Seyed Hamid Reza Abtahi ◽  
Niloofar Fereshtenejad
Keyword(s):  
Path Length ◽  
Center Of Pressure ◽  
Balance Control ◽  
Force Plate ◽  
Static Balance ◽  
Eyes Closed ◽  
Significant Difference ◽  
Eyes Open ◽  
Age Limits ◽  
The Difference

Aims. Vestibular system is indicated as one of the most important sensors responsible for static and dynamic postural control. In this study, we evaluated static balance in patients with unilateral vestibular impairments.Materials and Methods. We compared static balance control using Kistler force plate platform between 10 patients with unilateral vestibular impairments and 20 normal counterparts in the same sex ratio and age limits (50±7). We evaluated excursion and velocity of center of pressure (COP) and path length in anteroposterior (AP) and mediolateral (ML) planes with eyes open and with eyes closed.Results. There was no significant difference between COP excursions in ML and AP planes between both groups with eyes open and eyes closed (pvalue > 0.05). In contrast, the difference between velocity and path length of COP in the mentioned planes was significant between both groups with eyes open and eyes closed (pvalue < 0.05).Conclusions. The present study showed the static instability and balance of patients with vestibular impairments indicated by the abnormal characteristics of body balance.

scholarly journals Reorganization of Brain Functional Connectivity Network and Vision Restoration Following Combined tACS-tDCS Treatment After Occipital Stroke

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiahua Xu ◽  
Zheng Wu ◽  
Andreas Nürnberger ◽  
Bernhard A. Sabel
Keyword(s):  
Visual Field ◽  
Functional Connectivity ◽  
Temporal Lobe ◽  
Brain Stimulation ◽  
Occipital Lobe ◽  
Clustering Coefficient ◽  
Alpha Band ◽  
Delta Band ◽  
Brain Functional Connectivity

Objective: Non-invasive brain stimulation (NIBS) is already known to improve visual field functions in patients with optic nerve damage and partially restores the organization of brain functional connectivity networks (FCNs). However, because little is known if NIBS is effective also following brain damage, we now studied the correlation between visual field recovery and FCN reorganization in patients with stroke of the central visual pathway.Method: In a controlled, exploratory trial, 24 patients with hemianopia were randomly assigned to one of three brain stimulation groups: transcranial direct current stimulation (tDCS)/transcranial alternating current stimulation (tACS) (ACDC); sham tDCS/tACS (AC); sham tDCS/sham tACS (Sham), which were compared to age-matched controls (n = 24). Resting-state electroencephalogram (EEG) was collected at baseline, after 10 days stimulation and at 2 months follow-up. EEG recordings were analyzed for FCN measures using graph theory parameters, and FCN small worldness of the network and long pairwise coherence parameter alterations were then correlated with visual field performance.Result: ACDC enhanced alpha-band FCN strength in the superior occipital lobe of the lesioned hemisphere at follow-up. A negative correlation (r = −0.80) was found between the intact visual field size and characteristic path length (CPL) after ACDC with a trend of decreased alpha-band centrality of the intact middle occipital cortex. ACDC also significantly decreased delta band coherence between the lesion and the intact occipital lobe, and coherence was enhanced between occipital and temporal lobe of the intact hemisphere in the low beta band. Responders showed significantly higher strength in the low alpha band at follow-up in the intact lingual and calcarine cortex and in the superior occipital region of the lesioned hemisphere.Conclusion: While ACDC decreases delta band coherence between intact and damaged occipital brain areas indicating inhibition of low-frequency neural oscillations, ACDC increases FCN connectivity between the occipital and temporal lobe in the intact hemisphere. When taken together with the lower global clustering coefficient in responders, these findings suggest that FCN reorganization (here induced by NIBS) is adaptive in stroke. It leads to greater efficiency of neural processing, where the FCN requires fewer connections for visual processing.

scholarly journals The differences in postural stability between cross-country and Alpine skiers with intellectual disabilities

2020 ◽  
Vol 22 (4) ◽  
Author(s):  
Marta Gimunová ◽  
Alena Skotáková ◽  
Vojtěch Grün ◽  
Kateřina Jenčíková_ ◽  
Leoš Daněk ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Everyday Life ◽  
Postural Stability ◽  
Sports Training ◽  
Eyes Closed ◽  
Eyes Open ◽  
Cross Country ◽  
The Difference ◽  
Alpine Skiers ◽  
One Way Anova

Purpose: The purpose of this study was to analyse differences in postural stability between athletes with ID competing in Alpine and Cross country (XC) skiing to assess the effect of special sports training on postural stability in persons with ID. Methods: Athletes with ID were divided into four groups by their discipline: Alpine skiers (n = 9), XC skiers 2.5 to 10 km (n = 10), XC skiers 500 to 1000 m (n = 18) and XC skiers 50 and 100 m (n = 10). All participants were asked to stand barefooted on the Zebris FDM platform (Medical GmbH, Germany) with their eyes open and closed. To compare differences between groups one-way ANOVA with Tukey HSD test was used. To compare the difference between the eyes open and closed, t-test was used. Results: Statistical analysis showed no significant differences between Alpine and XC skiers in analysed variables. The analysis of COP velocity showed superior postural stability in XC skiers 2.5 to 10 km compared to XC skiers 500 and 1000 m. In XC skiers 500 and 1000 m, XC skiers 2.5 to 10 km and Alpine skiers a significant increase in COP velocity was observed when having the eyes closed. In XC skiers 50 and 100 m, no statistically significant differences between the eyes open and closed conditions were observed. Conclusions: Despite different sports training, no difference between Alpine and XC skiers in postural stability was observed. When comparing XC skiers, better postural stability was observed in skiers running longer distances, suggesting that this sports training enhances balance skills needed in everyday life.

scholarly journals Serotonin modulates learning content-specific neuroplasticity of functional brain networks

2021 ◽  
Author(s):  
Manfred Klöbl ◽  
René Seiger ◽  
Thomas Vanicek ◽  
Patricia Handschuh ◽  
Murray Bruce Reed ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Underlying Mechanism ◽  
Learning Effects ◽  
Semantic Learning ◽  
Learning Content ◽  
Daily Dose ◽  
Functional Brain Networks ◽  
Brain Functional Connectivity ◽  
Serotonergic Modulation

AbstractLearning-induced neuroplastic changes, further modulated by content and setting, are mirrored in brain functional connectivity. Animal models emphasized the crucial role of serotonin in neuroplasticity particularly for emotional relearning, but comparable studies in humans are scarce. Assessing the translation of learning effects from animals to humans, 99 healthy subjects underwent six weeks of emotional or semantic learning and subsequent relearning and three resting-state acquisitions for functional connectivity estimation. During relearning, subjects received either a daily dose of the selective serotonin reuptake inhibitor escitalopram or placebo. The influence of escitalopram on functional connectivity was connection- and learning content-dependent, with potentiation of decreases during emotional and increases during semantic learning. The directedness of these effects indicates serotonergic modulation of emotional feedback routes. These results demonstrate that escitalopram intake during relearning facilitates content-dependent network adaptations and support the conclusion that enhanced neuroplasticity might be the major underlying mechanism in psychiatric therapies.

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