scholarly journals Mining cross-frequency coupling microstates (CFCμstates) from EEG recordings during resting state and mental arithmetic tasks

2016 ◽  
Author(s):  
Stavros I. Dimitriadis ◽  
Yu Sun ◽  
Nitish Thakor ◽  
Anastasios Bezerianos
Keyword(s):  
Resting State ◽  
Mental Arithmetic ◽  
Frequency Coupling ◽  
Eeg Recordings ◽  
Cross Frequency Coupling

scholarly journals Altered cross-frequency coupling in resting-state MEG after mild traumatic brain injury

2016 ◽  
Vol 102 ◽  
pp. 1-11 ◽  
Author(s):  
Marios Antonakakis ◽  
Stavros I. Dimitriadis ◽  
Michalis Zervakis ◽  
Sifis Micheloyannis ◽  
Roozbeh Rezaie ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Mild Traumatic Brain Injury ◽  
Resting State ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

scholarly journals Dissociating harmonic and non-harmonic phase-amplitude coupling in the human brain

2020 ◽  
Author(s):  
Janet Giehl ◽  
Nima Noury ◽  
Markus Siegel
Keyword(s):  
Human Brain ◽  
Resting State ◽  
Higher Harmonics ◽  
Spectral Leakage ◽  
Harmonic Phase ◽  
Harmonic Signals ◽  
Cast Doubt ◽  
Frequency Coupling ◽  
Phase Amplitude ◽  
Cross Frequency Coupling

AbstractPhase-amplitude coupling (PAC) has been hypothesized to coordinate cross-frequency interactions of neuronal activity in the brain. However, little is known about the distribution of PAC across the human brain and the frequencies involved. Furthermore, it remains unclear to what extend PAC may reflect spurious cross-frequency coupling induced by physiological artifacts or rhythmic non-sinusoidal signals with higher harmonics. Here, we combined MEG, source-reconstruction and different measures of cross-frequency coupling to systematically characterize PAC across the resting human brain. We show that cross-frequency measures of phase-amplitude, phase-phase, and amplitude-amplitude coupling are all sensitive to signals with higher harmonics. In conjunction, these measures allow to distinguish harmonic and non-harmonic PAC. Based on these insights, we found no evidence for non-harmonic PAC in resting-state MEG. Instead, we found cortically and spectrally wide-spread PAC driven by harmonic signals. Furthermore, we show how physiological artifacts and spectral leakage cause spurious PAC across wide frequency ranges. Our result clarify how different measures of cross-frequency interactions can be combined to characterize PAC and cast doubt on the presence of prominent non-harmonic phase-amplitude coupling in human resting-state MEG.

scholarly journals Periodic Non-Sinusoidal Activity Can Produce Cross-Frequency Coupling in Cortical Signals in the Absence of Functional Interaction Between Neural Sources

2016 ◽  
Author(s):  
Edden M. Gerber ◽  
Boaz Sadeh ◽  
Andrew Ward ◽  
Robert T. Knight ◽  
Leon Y. Deouell
Keyword(s):  
Frequency Component ◽  
High Frequency Component ◽  
Functional Interaction ◽  
Scalp Eeg ◽  
Periodic Potentials ◽  
Frequency Coupling ◽  
Eeg Recordings ◽  
Low Amplitude ◽  
Cross Frequency Coupling ◽  
Intracranial Recordings

AbstractThe analysis of cross-frequency coupling (CFC) has become popular in studies involving intracranial and scalp EEG recordings in humans. It has been argued that some cases where CFC is mathematically present may not reflect an interaction of two distinct yet functionally coupled neural sources with different frequencies. Here we provide two empirical examples from intracranial recordings where CFC can be shown to be driven by the shape of a periodic waveform rather than by a functional interaction between distinct sources. Using simulations, we also present a generalized and realistic scenario where such coupling may arise. This scenario, which we term waveform-dependent CFC, arises when sharp waveforms (e.g., cortical potentials) occur in a periodic manner throughout parts of the data. Since the waveforms are repeated periodically, they constitute a slow wave that is inherently phase-aligned with the high-frequency component carried by the same waveforms. We submit that such behavior of the data, which seems to be present in various cortical signals, cannot be interpreted as reflecting functional modulation between distinct neural sources without additional evidence. In addition, we show that even low amplitude periodic potentials that cannot be readily observed or controlled for, are sufficient for significant CFC to occur.

scholarly journals From thoughtless awareness to effortful cognition: alpha - theta cross-frequency dynamics in experienced meditators during meditation, rest and arithmetic

2020 ◽  
Author(s):  
Julio Rodriguez-Larios ◽  
Pascal Faber ◽  
Peter Achermann ◽  
Shisei Tei ◽  
Kaat Alaerts
Keyword(s):  
Cognitive Processing ◽  
Information Integration ◽  
Recent Theory ◽  
Harmonic Frequency ◽  
Arithmetic Task ◽  
Continuous Eeg ◽  
Frequency Coupling ◽  
Eeg Recordings ◽  
Cross Frequency Coupling ◽  
The Brain

AbstractNeural activity is known to oscillate within discrete frequency bands and the synchronization between these rhythms is hypothesized to underlie information integration in the brain. Since strict synchronization is only possible for harmonic frequencies, a recent theory proposes that the interaction between different brain rhythms is facilitated by transient harmonic frequency arrangements. In this line, it has been recently shown that the transient occurrence of 2:1 harmonic cross-frequency relationships between alpha and theta rhythms (i.e. falpha≈12 Hz; ftheta≈6 Hz) is enhanced during effortful cognition. In this study, we tested whether achieving a state of ‘mental emptiness’ during meditation is accompanied by a relative decrease in the occurrence of 2:1 harmonic cross-frequency relationships between alpha and theta rhythms. Continuous EEG recordings (19 electrodes) were obtained from 43 highly experienced meditators during meditation practice, rest and an arithmetic task. We show that the occurrence of transient alpha:theta 2:1 harmonic relationships increased linearly from a meditative to an active cognitive processing state (i.e. meditation< rest< arithmetic task). It is argued that transient EEG cross-frequency arrangements that prevent alpha:theta cross-frequency coupling could facilitate the experience of ‘mental emptiness’ by avoiding the interaction between the memory and executive components of cognition.

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