scholarly journals Harmoni: a Method for Eliminating Spurious Interactions due to the Harmonic Components in Neuronal Data

2021 ◽  
Author(s):  
Mina Jamshidi Idaji ◽  
Juanli Zhang ◽  
Tilman Stephani ◽  
Guido Nolte ◽  
Klaus-Robert Mueller ◽  
...  
Keyword(s):  
Phase Synchronization ◽  
Evaluation Criteria ◽  
Sinusoidal Signal ◽  
Frequency Synchronization ◽  
Neuronal Oscillations ◽  
Distributed Information ◽  
Research Fields ◽  
Electrophysiological Recordings ◽  
Neuronal Interactions ◽  
Harmonic Components

Cross-frequency synchronization (CFS) has been proposed as a mechanism for integrating spatially and spectrally distributed information in the brain. However, investigating CFS in Magneto- and Electroencephalography (MEG/EEG) is hampered by the presence of spurious neuronal interactions due to the non-sinusoidal waveshape of brain oscillations. Such waveshape gives rise to the presence of oscillatory harmonics mimicking genuine neuronal oscillations. Until recently, however, there has been no methodology for removing these harmonics from neuronal data. In order to address this long-standing challenge, we introduce a novel method (called HARMOnic miNImization - Harmoni) that removes the signal components which can be harmonics of a non-sinusoidal signal. Harmoni's working principle is based on the presence of CFS between harmonic components and the fundamental component of a non-sinusoidal signal. We extensively tested Harmoni in realistic EEG simulations. The simulated couplings between the source signals represented genuine and spurious CFS and within-frequency phase synchronization. Using diverse evaluation criteria, including ROC analyses, we showed that the within- and cross-frequency spurious interactions are suppressed significantly, while the genuine activities are not affected. Additionally, we applied Harmoni to real resting-state EEG data revealing intricate remote connectivity patterns which are usually masked by the spurious connections. Given the ubiquity of non-sinusoidal neuronal oscillations in electrophysiological recordings, Harmoni is expected to facilitate novel insights into genuine neuronal interactions in various research fields, and can also serve as a steppingstone towards the development of further signal processing methods aiming at refining within- and cross-frequency synchronization in electrophysiological recordings.

Remarks on the complete synchronization for the Kuramoto model with frustrations

2018 ◽  
Vol 16 (04) ◽  
pp. 525-563 ◽  
Author(s):  
Seung-Yeal Ha ◽  
Hwa Kil Kim ◽  
Jinyeong Park
Keyword(s):  
Phase Synchronization ◽  
Kuramoto Model ◽  
Prototype Model ◽  
Frequency Synchronization ◽  
Complete Synchronization ◽  
Synchronization Problem ◽  
Kuramoto Oscillators ◽  
Applicable Range ◽  
The Kuramoto Model ◽  
Complete Frequency

The synchronous dynamics of many limit-cycle oscillators can be described by phase models. The Kuramoto model serves as a prototype model for phase synchronization and has been extensively studied in the last 40 years. In this paper, we deal with the complete synchronization problem of the Kuramoto model with frustrations on a complete graph. We study the robustness of complete synchronization with respect to the network structure and the interaction frustrations, and provide sufficient frameworks leading to the complete synchronization, in which all frequency differences of oscillators tend to zero asymptotically. For a uniform frustration and unit capacity, we extend the applicable range of initial configurations for the complete synchronization to be distributed on larger arcs than a half circle by analyzing the detailed dynamics of the order parameters. This improves the earlier results [S.-Y. Ha, H. Kim and J. Park, Remarks on the complete frequency synchronization of Kuramoto oscillators, Nonlinearity 28 (2015) 1441–1462; Z. Li and S.-Y. Ha, Uniqueness and well-ordering of emergent phase-locked states for the Kuramoto model with frustration and inertia, Math. Models Methods Appl. Sci. 26 (2016) 357–382.] which can be applicable only for initial configurations confined in a half circle.

Stimulus-Dependent Synchronization of Neuronal Assemblies

1993 ◽  
Vol 5 (4) ◽  
pp. 550-569 ◽  
Author(s):  
E. R. Grannan ◽  
D. Kleinfeld ◽  
H. Sompolinsky
Keyword(s):  
Receptive Fields ◽  
Spatial Variations ◽  
Neuronal Oscillations ◽  
Neuronal Assemblies ◽  
Neuronal Interactions ◽  
Cooperative Dynamics ◽  
Neuronal Oscillators ◽  
External Stimuli ◽  
Activity Dependent

We study theoretically how an interaction between assemblies of neuronal oscillators can be modulated by the pattern of external stimuli. It is shown that spatial variations in the stimuli can control the magnitude and phase of the synchronization between the output of neurons with different receptive fields. This modulation emerges from cooperative dynamics in the network, without the need for specialized, activity-dependent synapses. Our results further suggest that the modulation of neuronal interactions by extended features of a stimulus may give rise to complex spatiotemporal fluctuations in the phases of neuronal oscillations.

A fast and accurate frequency estimation algorithm for sinusoidal signal with harmonic components

2016 ◽  
Vol 87 (10) ◽  
pp. 105002 ◽  
Author(s):  
Jinghua Hu ◽  
Mengchun Pan ◽  
Zhidun Zeng ◽  
Jiafei Hu ◽  
Dixiang Chen ◽  
...  
Keyword(s):  
Frequency Estimation ◽  
Estimation Algorithm ◽  
Sinusoidal Signal ◽  
Harmonic Components

scholarly journals Cross-frequency synchronization connects networks of fast and slow oscillations during visual working memory maintenance

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Felix Siebenhühner ◽  
Sheng H Wang ◽  
J Matias Palva ◽  
Satu Palva
Keyword(s):  
Working Memory ◽  
Visual Working Memory ◽  
Attentional Control ◽  
Phase Synchronization ◽  
Sensory Information ◽  
Gamma Oscillations ◽  
Frequency Synchronization ◽  
Neuronal Processing ◽  
Gamma Frequencies ◽  
Frequency Phase

Neuronal activity in sensory and fronto-parietal (FP) areas underlies the representation and attentional control, respectively, of sensory information maintained in visual working memory (VWM). Within these regions, beta/gamma phase-synchronization supports the integration of sensory functions, while synchronization in theta/alpha bands supports the regulation of attentional functions. A key challenge is to understand which mechanisms integrate neuronal processing across these distinct frequencies and thereby the sensory and attentional functions. We investigated whether such integration could be achieved by cross-frequency phase synchrony (CFS). Using concurrent magneto- and electroencephalography, we found that CFS was load-dependently enhanced between theta and alpha–gamma and between alpha and beta-gamma oscillations during VWM maintenance among visual, FP, and dorsal attention (DA) systems. CFS also connected the hubs of within-frequency-synchronized networks and its strength predicted individual VWM capacity. We propose that CFS integrates processing among synchronized neuronal networks from theta to gamma frequencies to link sensory and attentional functions.

Phase Synchronization Impact on Throughput Performance in LTE Network

2017 ◽  
Vol 9 (4) ◽  
pp. 18-25
Author(s):  
Rajesh P. ◽  
Madhusudana C.K. ◽  
Prakash Nagarajan ◽  
Rakesh Hanumantha
Keyword(s):  
Phase Synchronization ◽  
Frequency Synchronization ◽  
Core Network ◽  
Testing Environment ◽  
Synchronization Mode ◽  
Traffic Conditions ◽  
Lte Network ◽  
Term Evolution ◽  
Real Traffic

This paper presents a study of phase synchronization impact on throughput in Long Term Evolution (LTE) network with different transport protocols. Phase synchronization is needed for advanced features in LTE and other precise technologies with minimal clock error of Nano seconds. An End to End LTE testing environment is built by using real User Equipment (UE) and LTE core network for studying the throughput impact due to Phase Synchronization in different transport modes. This experimentation is carried out for comparing the throughput of the system with Frequency Synchronization Mode (FM) and Frequency & Phase synchronization Mode (FPM). A novel study has been conducted on throughput for TCP and UDP traffic in different LTE bandwidths, based on real traffic conditions. The study shows that system performance in Uplink (UL) and Downlink (DL) throughput has improved by using Frequency along with Phase synchronization in LTE network using GPS as a clock source.

The peculiarities of emotional state of children with speech disorders

2020 ◽  
Vol 7 (1) ◽  
pp. 64-68
Author(s):  
Olena Belova
Keyword(s):  
Emotional State ◽  
Evaluation Criteria ◽  
Speech Disorders ◽  
Speech Development ◽  
Behavioral Type ◽  
Research Fields ◽  
Foreign Countries ◽  
Different Types ◽  
Disordered Speech ◽  
Pedagogical Literature

The state of the aggression problem in the junior schoolchildren with typical psychophysical development and disordered speech in the scientific psychological-pedagogical literature of our and foreign countries is analyzed in this paper. The topicality of this problem in remedial pedagogy and special psychology is found out. The evaluation criteria by types and subtypes of aggression are determined (the self-regulated type includes controlled and competitive subtypes; the latent type of aggression is divided into protective and depressive; the behavioral type includes demonstrative and physical subtypes of aggression). The peculiarities of manifestation (by types and subtypes) of the aggression state, modelling in minds of different types of behavior, the awareness of the internal and external mechanisms of aggression and manifestation of aggression in actions are considered. The aggression manifestation in the junior schoolchildren with typical psychophysical development and disordered speech are studied (henceforth we use the abbreviation: a disorder of speech development – DSD) in the different research fields, specifically, “I am an individual”, “I am in a family”, “I am in the society”. The comparison of the aggression levels among junior pupils with normal physical and psychological development and also in kids with phonetic underdeveloped speech (henceforth we use the abbreviation: phonetic underdeveloped speech – PhUS), phonetic-phonemic underdeveloped speech (henceforth we use the abbreviation: phonetic-phonemic underdeveloped speech – Ph-PhUS) and slovenly manifested general speech underdevelopment (henceforth we use the abbreviation: slovenly manifested general speech underdevelopment – UGSU) is considered.

Implement Synchronization Algorithms in OFDM System

2014 ◽  
Vol 926-930 ◽  
pp. 2490-2493
Author(s):  
Meng Ke Lu ◽  
Jian Xin Yuan
Keyword(s):  
Performance Analysis ◽  
Communication System ◽  
Phase Synchronization ◽  
Cyclic Prefix ◽  
Frequency Synchronization ◽  
Ofdm System ◽  
Awgn Channel ◽  
Training Symbol ◽  
And Performance ◽  
Theoretical Performance

With the advent of 4G, OFDM has an increasingly important role in the life of the system. This paper discusses the design simulation of the OFDM communication system, including coding, modulation, IFFT, synchronization, demodulation and decoding modules studied and discussed and cyclic prefix based on training symbol for OFDM system in time and frequency synchronization and phase synchronization algorithm and its performance, then introduced the SCME channel attributes. And those who have the OFDM system in AWGN channel and SCME channel emulation, and performance analysis, consistent with the theoretical performance.

scholarly journals Condensation of Synchronous Orbits on Complex Networks

2021 ◽  
Author(s):  
Ruiwu Niu ◽  
Xiaoqun Wu ◽  
Jianwen Feng ◽  
Gui-jun Pan ◽  
Jun-an Lu ◽  
...  
Keyword(s):  
Statistical Mechanics ◽  
Complex Networks ◽  
Numerical Simulations ◽  
Phase Synchronization ◽  
Single Layer ◽  
The Other ◽  
Frequency Synchronization ◽  
Synchronization Process ◽  
Mechanics Analysis ◽  
Kuramoto Oscillators

Abstract In this paper we study frequency synchronization of Kuramoto oscillators. We find a typical phenomenon of condensed synchronous orbits on single-layer or duplex networks through statistical mechanics analysis and numerical simulations, where the distribution of synchronous orbits is in a bell-shaped form. Further, we investigate phase synchronization on single-layer and duplex networks with different distributions of inherent frequencies. We find that normally distributed inherent frequencies with low variances are more beneficial for phase synchronization, and separately distributed inherent frequencies can slow down the synchronization process. In the end, we investigate the influence of one layer's inherent frequencies on the other layer's phase synchronization through inter-layer couplings. Interestingly, we find that one layer's inherent frequencies with a highly condensed distribution can greatly improve phase synchronization on the other layer. The results shed new lights to our understanding of the nature of synchronization on single-layer as well as multilayer complex networks of coupled Kuramoto oscillators.

scholarly journals Enhancing oscillations in intracranial electrophysiological recordings with data-driven spatial filters

2021 ◽  
Author(s):  
Natalie Schaworonkow ◽  
Bradley Voytek
Keyword(s):  
Temporal Dynamics ◽  
Noise Removal ◽  
Data Driven ◽  
Fast Method ◽  
Multiple Use ◽  
Spatial Filters ◽  
Neuronal Oscillations ◽  
Spatial Spread ◽  
Electrophysiological Recordings ◽  
Improve Measurement

In invasive electrophysiological recordings, a variety of neuronal oscillations can be detected across the cortex, with overlap in space and time. This overlap complicates measurement of neuronal oscillations using standard referencing schemes, like common average or bipolar referencing. Here, we illustrate the effects of spatial mixing on measuring neuronal oscillations in invasive electrophysiological recordings and demonstrate the benefits of using data-driven referencing schemes in order to improve measurement of neuronal oscillations. We discuss referencing as the application of a spatial filter. Spatio-spectral decomposition is used to estimate data-driven spatial filters, a computationally fast method which specifically enhances signal-to-noise ratio for oscillations in a frequency band of interest. We show that application of these data-driven spatial filters has benefits for data exploration, investigation of temporal dynamics and assessment of peak frequencies of neuronal oscillations. We demonstrate multiple use cases, exploring between-participant variability in presence of oscillations, spatial spread and waveform shape of different rhythms as well as narrowband noise removal with the aid of spatial filters. We find high between-participant variability in the presence of neural oscillations, a large variation in spatial spread of individual rhythms and many non-sinusoidal rhythms across the cortex. Improved measurement of oscillatory rhythms will yield better conditions for establishing links between cortical activity and behavior, as well as bridging scales between the invasive intracranial measurements and noninvasive macroscale scalp measurements.

scholarly journals Theta phase synchronization between the human hippocampus and the prefrontal cortex supports learning of unexpected information

2017 ◽  
Author(s):  
Matthias J. Gruber ◽  
Liang-Tien Hsieh ◽  
Bernhard P. Staresina ◽  
Christian E. Elger ◽  
Juergen Fell ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Phase Synchronization ◽  
Theta Oscillations ◽  
Presurgical Evaluation ◽  
Human Hippocampus ◽  
Electrophysiological Recordings ◽  
Rhinal Cortex ◽  
Theta Phase ◽  
Oscillatory Mechanisms ◽  
Rare Opportunity

AbstractEvents that violate predictions are thought to not only modulate activity within the hippocampus and prefrontal cortex, but also to enhance communication between the two regions. Several studies in rodents have shown that synchronized theta oscillations facilitate communication between the prefrontal cortex and hippocampus during salient events, but it remains unclear whether similar oscillatory mechanisms support interactions between the two regions in humans. Here, we had the rare opportunity to conduct simultaneous electrophysiological recordings from the human hippocampus and prefrontal cortex from two patients undergoing presurgical evaluation for pharmaco-resistant epilepsy. Recordings were conducted during a task that involved encoding of contextually expected and unexpected visual stimuli. Across both patients, hippocampal-prefrontal theta phase synchronization was significantly higher during encoding of unexpected study items, compared to contextually expected study items. In contrast, we did not find increased theta synchronization between the prefrontal cortex and rhinal cortex. Our findings are consistent with the idea that theta oscillations orchestrate communication between the hippocampus and prefrontal cortex during the processing of contextually salient information.

Sign in / Sign up

Export Citation Format

Share Document