scholarly journals Activation-Inhibition dynamics of the oscillatory bursts of the human EEG during resting state. The macroscopic macroscopic temporal range of few seconds

2021 ◽  
Author(s):  
Carlos M. Gómez ◽  
Brenda Y. Angulo-Ruíz ◽  
Vanesa Muñoz ◽  
Elena I. Rodriguez-Martínez
Keyword(s):  
Resting State ◽  
Present Report ◽  
Time Derivative ◽  
Peak Amplitude ◽  
Statistical Characteristics ◽  
Oscillatory Activity ◽  
Amplitude Envelope ◽  
Frequency Content ◽  
Frequency Range ◽  
Human Eeg

AbstractThe ubiquitous brain oscillations occur in bursts of oscillatory activity. The present report tries to define the statistical characteristics of electroencephalographical (EEG) bursts of oscillatory activity during resting state in humans to define (i) the statistical properties of amplitude and duration of oscillatory bursts, (ii) its possible correlation, (iii) its frequency content, and (iv) the presence or not of a fixed threshold to trigger an oscillatory burst. The open eyes EEG recordings of five subjects with no artifacts were selected from a sample of 40 subjects. The recordings were filtered in frequency ranges of 2 Hz wide from 1 to 99 Hz. The analytic Hilbert transform was computed to obtain the amplitude envelopes of oscillatory bursts. The criteria of thresholding and a minimum of three cycles to define an oscillatory burst were imposed. Amplitude and duration parameters were extracted and they showed durations between hundreds of milliseconds and a few seconds, and peak amplitudes showed a unimodal distribution. Both parameters were positively correlated and the oscillatory burst durations were explained by a linear model with the terms peak amplitude and peak amplitude of amplitude envelope time derivative. The frequency content of the amplitude envelope was contained in the 0–2 Hz range. The results suggest the presence of amplitude modulated continuous oscillations in the human EEG during the resting conditions in a broad frequency range, with durations in the range of few seconds and modulated positively by amplitude and negatively by the time derivative of the amplitude envelope suggesting activation-inhibition dynamics. This macroscopic oscillatory network behavior is less pronounced in the low-frequency range (1–3 Hz).

scholarly journals Resting state alpha oscillatory activity is a valid and reliable marker of schizotypy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jelena Trajkovic ◽  
Francesco Di Gregorio ◽  
Francesca Ferri ◽  
Chiara Marzi ◽  
Stefano Diciotti ◽  
...  
Keyword(s):  
At Risk ◽  
Resting State ◽  
Right Hemisphere ◽  
Normal Population ◽  
Alpha Activity ◽  
Oscillatory Activity ◽  
Loop Current ◽  
Clinical Tool ◽  
Reliable Marker ◽  
The Right

AbstractSchizophrenia is among the most debilitating neuropsychiatric disorders. However, clear neurophysiological markers that would identify at-risk individuals represent still an unknown. The aim of this study was to investigate possible alterations in the resting alpha oscillatory activity in normal population high on schizotypy trait, a physiological condition known to be severely altered in patients with schizophrenia. Direct comparison of resting-state EEG oscillatory activity between Low and High Schizotypy Group (LSG and HSG) has revealed a clear right hemisphere alteration in alpha activity of the HSG. Specifically, HSG shows a significant slowing down of right hemisphere posterior alpha frequency and an altered distribution of its amplitude, with a tendency towards a reduction in the right hemisphere in comparison to LSG. Furthermore, altered and reduced connectivity in the right fronto-parietal network within the alpha range was found in the HSG. Crucially, a trained pattern classifier based on these indices of alpha activity was able to successfully differentiate HSG from LSG on tested participants further confirming the specific importance of right hemispheric alpha activity and intrahemispheric functional connectivity. By combining alpha activity and connectivity measures with a machine learning predictive model optimized in a nested stratified cross-validation loop, current research offers a promising clinical tool able to identify individuals at-risk of developing psychosis (i.e., high schizotypy individuals).

scholarly journals Publisher Correction: Resting state alpha oscillatory activity is a valid and reliable marker of schizotypy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jelena Trajkovic ◽  
Francesco Di Gregorio ◽  
Francesca Ferri ◽  
Chiara Marzi ◽  
Stefano Diciotti ◽  
...  
Keyword(s):  
Resting State ◽  
Oscillatory Activity ◽  
Reliable Marker

AbstractAn amendment to this paper has been published and can be accessed via a link at the top of the paper.

scholarly journals The Time-Robustness Analysis of Individual Identification Based on Resting-State EEG

2021 ◽  
Vol 15 ◽  
Author(s):  
Yang Di ◽  
Xingwei An ◽  
Wenxiao Zhong ◽  
Shuang Liu ◽  
Dong Ming
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Resting State ◽  
Individual Identification ◽  
Frequency Range ◽  
Cross Spectrum ◽  
Power Spectral ◽  
Phase Lags ◽  
Individual Features

An ongoing interest towards identification based on biosignals, such as electroencephalogram (EEG), magnetic resonance imaging (MRI), is growing in the past decades. Previous studies indicated that the inherent information about brain activity may be used to identify individual during resting-state of eyes open (REO) and eyes closed (REC). Electroencephalographic (EEG) records the data from the scalp, and it is believed that the noisy EEG signals can influence the accuracies of one experiment causing unreliable results. Therefore, the stability and time-robustness of inter-individual features can be investigated for the purpose of individual identification. In this work, we conducted three experiments with the time interval of at least 2 weeks, and used different types of measures (Power Spectral Density, Cross Spectrum, Channel Coherence and Phase Lags) to extract the individual features. The Pearson Correlation Coefficient (PCC) is calculated to measure the level of linear correlation for intra-individual, and Support Vector Machine (SVM) is used to obtain the related classification accuracy. Results show that the classification accuracies of four features were 85–100% for intra-experiment dataset, and were 80–100% for fusion experiments dataset. For inter-experiments classification of REO features, the optimized frequency range is 13–40 Hz for three features, Power Spectral Density, Channel Coherence and Cross Spectrum. For inter-experiments classification of REC, the optimized frequency range is 8–40 Hz for three features, Power Spectral Density, Channel Coherence and Cross Spectrum. The classification results of Phase Lags are much lower than the other three features. These results show the time-robustness of EEG, which can further use for individual identification system.

scholarly journals Constraints on ultra-low-frequency gravitational waves with statistics of pulsar spin-down rates

2019 ◽  
Vol 489 (3) ◽  
pp. 3547-3552
Author(s):  
Hiroki Kumamoto ◽  
Yuya Imasato ◽  
Naoyuki Yonemaru ◽  
Sachiko Kuroyanagi ◽  
Keitaro Takahashi
Keyword(s):  
Black Hole ◽  
Gravitational Waves ◽  
Time Derivative ◽  
Low Frequency ◽  
Upper Bounds ◽  
Galactic Centre ◽  
Frequency Range ◽  
Rate Distribution ◽  
Black Hole Binaries ◽  
Supermassive Black Hole

Abstract We probe ultra-low-frequency gravitational waves (GWs) with statistics of spin-down rates of millisecond pulsars (thereafter MSPs) by a method proposed in our previous work. The considered frequency range is 10−12 Hz ≲ fGW ≲ 10−10  Hz . The effect of such low-frequency GWs appears as a bias to spin-down rates that has a quadrupole pattern in the sky. We use the skewness of the spin-down rate distribution and the number of MSPs with negative spin-down rates to search for the bias induced by GWs. Applying this method to 149 MSPs selected from the ATNF pulsar catalogue, we derive upper bounds on the time derivative of the GW amplitudes of $\dot{h} \lt 6.2 \times 10^{-18}~{\rm s}^{-1}$ and $\dot{h} \lt 8.1 \times 10^{-18}~{\rm s}^{-1}$ in the directions of the Galactic Centre and M87, respectively. Approximating the GW amplitude as $\dot{h} \sim 2 \pi f_{\rm GW} h$, the bounds translate into h < 3 × 10−8 and h < 4 × 10−8, respectively, for fGW = 1/(1000 yr). Finally, we give the implications to possible supermassive black hole binaries at these sites.

scholarly journals Amplitude of fNIRS Resting-State Global Signal Is Related to EEG Vigilance Measures: A Simultaneous fNIRS and EEG Study

2020 ◽  
Vol 14 ◽  
Author(s):  
Yuxuan Chen ◽  
Julia Tang ◽  
Yafen Chen ◽  
Jesse Farrand ◽  
Melissa A. Craft ◽  
...  
Keyword(s):  
Human Brain ◽  
Resting State ◽  
Near Infrared ◽  
Low Frequency ◽  
Temporal Correlation ◽  
Frequency Range ◽  
Functional Near Infrared Spectroscopy ◽  
Physical Constraints ◽  
Global Signal ◽  
Eeg Data

Recently, functional near-infrared spectroscopy (fNIRS) has been utilized to image the hemodynamic activities and connectivity in the human brain. With the advantage of economic efficiency, portability, and fewer physical constraints, fNIRS enables studying of the human brain at versatile environment and various body positions, including at bed side and during exercise, which complements the use of functional magnetic resonance imaging (fMRI). However, like fMRI, fNIRS imaging can be influenced by the presence of a strong global component. Yet, the nature of the global signal in fNIRS has not been established. In this study, we investigated the relationship between fNIRS global signal and electroencephalogram (EEG) vigilance using simultaneous recordings in resting healthy subjects in high-density and whole-head montage. In Experiment 1, data were acquired at supine, sitting, and standing positions. Results found that the factor of body positions significantly affected the amplitude of the resting-state fNIRS global signal, prominently in the frequency range of 0.05–0.1 Hz but not in the very low frequency range of less than 0.05 Hz. As a control, the task-induced fNIRS or EEG responses to auditory stimuli did not differ across body positions. However, EEG vigilance plays a modulatory role in the fNIRS signals in the frequency range of less than 0.05 Hz: resting-state sessions of low EEG vigilance measures are associated with high amplitudes of fNIRS global signals. Moreover, in Experiment 2, we further examined the epoch-to-epoch fluctuations in concurrent fNIRS and EEG data acquired from a separate group of subjects and found a negative temporal correlation between EEG vigilance measures and fNIRS global signal amplitudes. Our study for the first time revealed that vigilance as a neurophysiological factor modulates the resting-state dynamics of fNIRS, which have important implications for understanding and processing the noises in fNIRS signals.

scholarly journals Changes in the Resting-State Cortical Oscillatory Activity 6 Months After Modified Tinnitus Retraining Therapy

2019 ◽  
Vol 13 ◽  
Author(s):  
Sang-Yeon Lee ◽  
Jihye Rhee ◽  
Ye Ji Shim ◽  
Yoonjoong Kim ◽  
Ja-Won Koo ◽  
...  
Keyword(s):  
Resting State ◽  
Oscillatory Activity ◽  
Tinnitus Retraining Therapy ◽  
Retraining Therapy

scholarly journals High-definition tDCS to the right temporoparietal junction modulates slow-wave resting state power and coherence in healthy adults

2019 ◽  
Vol 122 (4) ◽  
pp. 1735-1744 ◽  
Author(s):  
Peter H. Donaldson ◽  
Melissa Kirkovski ◽  
Joel S. Yang ◽  
Soukayna Bekkali ◽  
Peter G. Enticott
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Resting State ◽  
Oscillatory Activity ◽  
High Definition ◽  
Temporoparietal Junction ◽  
Eyes Open ◽  
Right Temporoparietal Junction ◽  
The Right ◽  
Cathodal Stimulation

The right temporoparietal junction (rTPJ) is a multisensory integration hub that is increasingly utilized as a target of stimulation studies exploring its rich functional network roles and potential clinical applications. While transcranial direct current stimulation (tDCS) is frequently employed in such studies, there is still relatively little known regarding its local and network neurophysiological effects, particularly at important nonmotor sites such as the rTPJ. The current study applied either anodal, cathodal, or sham high-definition tDCS to the rTPJ of 53 healthy participants and used offline EEG to assess the impacts of stimulation on resting state (eyes open and eyes closed) band power and coherence. Temporoparietal and central region delta power was increased after anodal stimulation (the latter trend only), whereas cathodal stimulation increased frontal region delta and theta power. Increased coherence between right and left temporoparietal regions was also observed after anodal stimulation. All significant effects occurred in the eyes open condition. These findings are discussed with reference to domain general and mechanistic theories of rTPJ function. Low-frequency oscillatory activity may exert long-range inhibitory network influences that enable switching between and integration of endogenous/exogenous processing streams. NEW & NOTEWORTHY Through the novel use of high-definition transcranial direct current stimulation (tDCS) and EEG, we provide evidence that both anodal and cathodal stimulation of the right temporoparietal junction selectively modulate slow-wave power and coherence in distributed network regions of known relevance to proposed temporoparietal junction functionality. These results also provide direct evidence of the ability of tDCS to modulate oscillatory activity at a long-range network level, which may have explanatory power in terms of both neurophysiological and behavioral effects.

EEG Event-Related Desynchronization and Event-Related Synchronization

2017 ◽  
Author(s):  
Gert Pfurtscheller ◽  
Fernando Lopes da Silva
Keyword(s):  
Resting State ◽  
Rhythmic Activity ◽  
Oscillatory Activity ◽  
Motor Tasks ◽  
Stroke Patients ◽  
Phase Coupling ◽  
Pressure Oscillations ◽  
Frequency Bands ◽  
Event Related Desynchronization ◽  
Evoked Response Potentials

Event-related desynchronization (ERD) reflects a decrease of oscillatory activity related to internally or externally paced events. The increase of rhythmic activity is called event-related synchronization (ERS). They represent dynamical states of thalamocortical networks associated with cortical information-processing changes. This chapter discusses differences between ERD/ERS and evoked response potentials and methodologies for quantifying ERD/ERS and selecting frequency bands. It covers the interpretation of ERD/ERS in the alpha and beta bands and theta ERS and alpha ERD in behavioral tasks. ERD/ERS in scalp and subdural recordings, in various frequency bands, is discussed. Also presented is the modulation of alpha and beta rhythms by 0.1-Hz oscillations in the resting state and phase-coupling of the latter with slow changes of prefrontal hemodynamic signals (HbO2), blood pressure oscillations, and heart rate interval variations in the resting state and in relation to behavioral motor tasks. Potential uses of ERD-based strategies in stroke patients are discussed.

scholarly journals Investigating the Efficacy of an Individualized Alpha/Delta Neurofeedback Protocol in the Treatment of Chronic Tinnitus

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Dominik Güntensperger ◽  
Christian Thüring ◽  
Tobias Kleinjung ◽  
Patrick Neff ◽  
Martin Meyer
Keyword(s):  
Resting State ◽  
Peak Frequency ◽  
Chronic Tinnitus ◽  
Frequency Range ◽  
Tinnitus Questionnaire ◽  
Eeg Activity ◽  
Individual Level ◽  
Link Type ◽  
Delta Band

First attempts have demonstrated that the application of alpha/delta neurofeedback in the treatment of chronic tinnitus leads to a reduction of symptoms at the group level. However, recent research also suggests that chronic tinnitus is a decidedly heterogeneous phenomenon, one that requires treatment of distinct subgroups or even on an individual level. Thus, the purpose of this study was to evaluate an individually adjusted alpha/delta neurofeedback protocol. Following previous studies, the delta band fixed between 3 and 4 Hz was chosen as the frequency for inhibition. However, unlike the previous studies, the frequency range for the rewarded alpha band was not fixed between 8 and 12 Hz but rather individually determined according to each patient’s specific alpha peak frequency (IAF). Twenty-six chronic tinnitus patients participated in 15 weekly neurofeedback training sessions and extensive pre- and post-tests, as well as follow-up testing 3 and 6 months after training. The main outcome measures were tinnitus-related distress measured with the Tinnitus Handicap Inventory (THI) and Tinnitus Questionnaire (TQ), tinnitus loudness, and pre- and post-training resting-state EEG activity in trained frequency bands. In Results, the neurofeedback protocol led to a significant reduction of tinnitus-related distress and tinnitus loudness. While distress remained on a low level even 6 months after the completion of training, loudness returned to baseline levels in the follow-up period. In addition, resting-state EEG activity showed an increase in the trained alpha/delta ratio over the course of the training. This ratio increase was related to training-induced changes of tinnitus-related distress as measured with TQ, mainly due to increases in the alpha frequency range. In sum, this study confirms the alpha/delta neurofeedback as a suitable option for the treatment of chronic tinnitus and represents a first step towards the development of individual neurofeedback protocols. This clinical trial was registered online at ClinicalTrials.gov (NCT02383147) and kofam.ch (SNCTP000001313).

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