Assessment of aging by cortical functional connectivity estimated through synchronization electroencephalographic measurements

This work was aimed to study the physiological cerebral aging from the analysis of functional electroencephalographic (EEG) connectivity between different cortical areas in two groups of healthy subjects between 50-65 years and between 66-80 years. With this purpose, digital monopolar EEG recordings were carried out at rest and closed eyes, taking as sampling rate, 256 Hz and as reference, the average of the 16 channels recorded (6-frontals, 4-temporals, 2-centrals, 2-parietal, 2-occipital). The functional cortical connectivity was estimated from the interdependence between channels using the coherence function in the frequency bands delta/theta/alpha/beta, and an index (L) of nonlinear generalized synchronization. The pairwise connectivity between all possible channels and a global connectivity between each channel and all others was computed. The results show that certain local interdependencies measured by the index L and by the delta band coherence, decreased with age; these were especially significant for the temporal-occipital-central connections. Moreover, a significant linear decrease with age of the interdependence indices aforementioned for the pair and local averages was observed. Also global interdependencies, especially those of nonlinear type, for certain central-lateral and posterior areas, decline with age. It is concludes that individual and global measures of EEG functional connectivity between certain brain areas can help to objectively evaluate the neurophysiological aging.

Download Full-text

Changes in the temporal variability of the EEG functional connectivity during aging

European Journal of Investigation in Health, Psychology and Education ◽

10.3390/ejihpe7010001 ◽

2015 ◽

Vol 7 (1) ◽

pp. 5-15

Author(s):

Almudena González ◽

Guzmán Alba ◽

Julián González

Keyword(s):

Functional Connectivity ◽

Cognitive Performance ◽

Temporal Variability ◽

Healthy Subjects ◽

Generalized Synchronization ◽

Performance Deficits ◽

Cortical Areas ◽

Eyes Closed ◽

Eeg Recordings ◽

Eeg Functional Connectivity

This work is aimed at investigating changes in the temporal variability of EEG functional connectivity (FC) during agin. The variability in the FC has been linked to cognitive performance. The study was carried out in two groups of healthy subjects: one of 10 adults between 50-65 years old and another of 15 subjects ranging 66-85 years. EEG recordings were made at rest using 16 monopolar channels: under eyes closed (EC) and under hyperventilation (HV). The cortical FC between all EEG channel pairs was estimated from an index (L) of nonlinear generalized synchronization. For each subject and condition, the global connectivity (GC) of each area/channel with the rest of them was calculated, then the GC average and the GC temporal variability (TVC) of such connectivities was computed from the GC mean and standard deviation of successive EEG recordings respectively. The changes with age and condition of GC and TVC of each cortical area were estimated via a MANOVA. We found that the GC does not change with age during OC or HV, but the TVC of all cortical areas is significantly higher (p<0.01) for subjects under 65 and mainly for the central, temporal and parietal areas (p<0.01). It is concluded that TVC decreasing with aging may be related to cognitive performance deficits.

Download Full-text

Changes in the temporal variability of the EEG functional connectivity during aging

European Journal of Investigation in Health, Psychology and Education ◽

10.1989/ejihpe.v7i1.189 ◽

2015 ◽

Vol 7 (1) ◽

pp. 5-15

Author(s):

Almudena González ◽

Guzmán Alba ◽

Julián González

Keyword(s):

Functional Connectivity ◽

Cognitive Performance ◽

Temporal Variability ◽

Healthy Subjects ◽

Generalized Synchronization ◽

Performance Deficits ◽

Cortical Areas ◽

Eyes Closed ◽

Eeg Recordings ◽

Eeg Functional Connectivity

This work is aimed at investigating changes in the temporal variability of EEG functional connectivity (FC) during agin. The variability in the FC has been linked to cognitive performance. The study was carried out in two groups of healthy subjects: one of 10 adults between 50-65 years old and another of 15 subjects ranging 66-85 years. EEG recordings were made at rest using 16 monopolar channels: under eyes closed (EC) and under hyperventilation (HV). The cortical FC between all EEG channel pairs was estimated from an index (L) of nonlinear generalized synchronization. For each subject and condition, the global connectivity (GC) of each area/channel with the rest of them was calculated, then the GC average and the GC temporal variability (TVC) of such connectivities was computed from the GC mean and standard deviation of successive EEG recordings respectively. The changes with age and condition of GC and TVC of each cortical area were estimated via a MANOVA. We found that the GC does not change with age during OC or HV, but the TVC of all cortical areas is significantly higher (p<0.01) for subjects under 65 and mainly for the central, temporal and parietal areas (p<0.01). It is concluded that TVC decreasing with aging may be related to cognitive performance deficits.

Download Full-text

Reorganization of Resting-State EEG Functional Connectivity Patterns in Children with Cerebral Palsy Following a Motor Imagery Virtual-Reality Intervention

Applied Sciences ◽

10.3390/app11052372 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2372

Author(s):

Carlos Alberto Stefano Filho ◽

José Ignacio Serrano ◽

Romis Attux ◽

Gabriela Castellano ◽

Eduardo Rocon ◽

...

Keyword(s):

Virtual Reality ◽

Cerebral Palsy ◽

Functional Connectivity ◽

Motor Imagery ◽

Resting State ◽

Post Intervention ◽

Children With Cerebral Palsy ◽

Eeg Recordings ◽

Eeg Functional Connectivity ◽

Careful Exploration

Motor imagery (MI) has been suggested to provide additional benefits when included in traditional approaches of physical therapy for children with cerebral palsy (CP). Regardless, little is understood about the underlying neurological substrates that might justify its supposed benefits. In this work, we studied resting-state (RS) electroencephalography (EEG) recordings of five children with CP that underwent a MI virtual-reality (VR) intervention. Our aim was to explore functional connectivity (FC) patterns alterations following this intervention through the formalism of graph theory, performing both group and subject-specific analyses. We found that FC patterns were more consistent across subjects prior to the MI-VR intervention, shifting along the anterior-posterior axis, post-intervention, for the β and γ bands. Additionally, group FC patterns were not found for the α range. Furthermore, intra-subject analyses reinforced the existence of large inter-subject variability and the need for a careful exploration of individual pattern alterations. Such patterns also hinted at a dependency between short-term functional plasticity mechanisms and the EEG frequency bands. Although our sample size is small, we provide a longitudinal analysis framework that can be replicated in future studies, especially at the group level, and whose foundation can be easily extended to verify the validity of our hypotheses.

Download Full-text

EEG functional connectivity metrics wPLI and wSMI account for d distinct types of brain functional interactions

10.1101/450270 ◽

2018 ◽

Author(s):

Laura Sophie Imperatori ◽

Monica Betta ◽

Luca Cecchetti ◽

André Canales Johnson ◽

Emiliano Ricciardi ◽

...

Keyword(s):

Functional Connectivity ◽

Brain Connectivity ◽

Relative Increase ◽

Estimation Methods ◽

Phase Lag ◽

Neural Interactions ◽

Linear And Nonlinear ◽

Eeg Recordings ◽

Eeg Functional Connectivity ◽

Nonlinear Components

AbstractFunctional connectivity (FC) estimation methods are extensively used in neuroimaging to measure brain inter-regional interactions. The weighted Phase Lag Index (wPLI) and the weighted Symbolic Mutual Information (wSMI) represent relatively robust exemplars of spectral (wPLI) and information-theoretic (wSMI) connectivity measures that recently gained increased popularity due to their relative immunity to volume conduction. wPLI and wSMI are posited to have different sensitivity to linear and nonlinear relationships between neural sources, but their performance has never been directly compared. Here, using simulated high-density (hd-)EEG data, we evaluated the accuracy of these two metrics for detecting distinct types of regional interdependencies characterised by different combinations of linear and nonlinear components. Our results demonstrate that while wPLI performs generally better at detecting functional couplings presenting a mixture of linear and nonlinear interdependencies, only wSMI is able to detect exclusively nonlinear interaction dynamics. To evaluate the potential impact of these differences on real experimental data, we computed wPLI and wSMI connectivity in hd-EEG recordings of 12 healthy adults obtained in wakefulness and deep (N3-)sleep. While both wPLI and wSMI revealed a relative decrease in alpha-connectivity during sleep relative to wakefulness, only wSMI identified a relative increase in theta-connectivity, while wPLI detected an increase in delta-connectivity, likely reflecting the occurrence of traveling slow waves. Overall, our findings indicate that wPLI and wSMI provide distinct but complementary information about functional brain connectivity, and that their combined use could advance our knowledge of neural interactions underlying different behavioural states.

Download Full-text

Functional connectivity reveals altered activation of distinct brain areas in pruritus of cholestasis

Zeitschrift für Gastroenterologie ◽

10.1055/s-0037-1612698 ◽

2018 ◽

Vol 56 (01) ◽

pp. E2-E89

Author(s):

A Kremer ◽

T Buchwald ◽

M Vetter ◽

A Dörfler ◽

C Forster

Keyword(s):

Functional Connectivity ◽

Brain Areas

Download Full-text

Engaging regularly with fiction influences connectivity in cortical areas for language and mentalizing

10.31234/osf.io/e7bqj ◽

2017 ◽

Author(s):

Roel M. Willems ◽

Franziska Hartung

Keyword(s):

Functional Connectivity ◽

Time Course ◽

Language Skills ◽

Brain Regions ◽

Brain Areas ◽

Daily Lives ◽

Cortical Areas ◽

Social Abilities ◽

Behavioral Evidence ◽

Amount Of Reading

Behavioral evidence suggests that engaging with fiction is positively correlated with social abilities. The rationale behind this link is that engaging with fictional narratives offers a ‘training modus’ for mentalizing and empathizing. We investigated the influence of the amount of reading that participants report doing in their daily lives, on connections between brain areas while they listened to literary narratives. Participants (N=57) listened to two literary narratives while brain activation was measured with fMRI. We computed time-course correlations between brain regions, and compared the correlation values from listening to narratives to listening to reversed speech. The between-region correlations were then related to the amount of fiction that participants read in their daily lives. Our results show that amount of fiction reading is related to functional connectivity in areas known to be involved in language and mentalizing. This suggests that reading fiction influences social cognition as well as language skills.

Download Full-text