Cross-frequency coupling during isoflurane anaesthesia as revealed by electroencephalographic harmonic wavelet bicoherence

Li, D; Li, X; Hagihira, Satoshi; Sleigh, James W.

doi:10.1093/bja/aes397

Cited by 32 publications

(19 citation statements)

References 39 publications

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“…Phase-phase coupling, such as the SynchFastSlow component of bispectral analysis, has also been explored during general anesthesia (Nunes et al, 2012; Li et al, 2013). However, phase-phase coupling has been shown to be vulnerable to power spectral changes and spurious coupling (Miller et al, 2004; Scheffer-Teixeira and Tort, 2016) whereas changes in PAC were shown to be dissociated from power spectral changes (Mukamel et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Propofol, Sevoflurane, and Ketamine Induce a Reversible Increase in Delta-Gamma and Theta-Gamma Phase-Amplitude Coupling in Frontal Cortex of Rat

Pal

2017

Front. Syst. Neurosci.

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Studies from human and non-human species have demonstrated a breakdown of functional corticocortical connectivity during general anesthesia induced by anesthetics with diverse molecular, neurophysiological, and pharmacological profiles. Recent studies have demonstrated that changes in long-range neural communication, and by corollary, functional connectivity, might be influenced by cross-frequency coupling (CFC) between the phase of slow oscillations and the amplitude of local fast oscillations. Phase-amplitude coupling (PAC) between slow oscillations and alpha rhythm during general anesthesia reveal distinct patterns depending on the anesthetic. In this study, we analyzed the effect of three clinically used anesthetics (propofol: n = 6, sevoflurane: n = 10, and ketamine: n = 8) with distinct molecular mechanisms on changes in PAC in the frontal cortex of rat. The loss of righting reflex was used as a surrogate for unconsciousness. PAC was calculated using the modulation index (MI) algorithm between delta (1–4 Hz), theta (4–10 Hz), low gamma (25–55 Hz), and high gamma (65–125 Hz) bands. A linear mixed model with fixed effects was used for statistical comparisons between waking, anesthetized, and post-anesthesia recovery epochs. All three anesthetics increased the coupling between delta and low gamma (p < 0.0001) as well as between theta and low gamma (p < 0.0001) oscillations, which returned to baseline waking levels during the post-anesthetic recovery period. In addition, a reversible reduction in high gamma power (p < 0.0001) was a consistent change during anesthesia induced by all three agents. The changes in delta-high gamma and theta-high gamma PAC as well as power spectral changes in delta, theta, and low gamma bandwidths did not show a uniform response across the three anesthetics. These results encourage the study of alternative PAC patterns as drug-invariant markers of general anesthesia in humans.

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Section: Discussionmentioning

confidence: 99%

Propofol, Sevoflurane, and Ketamine Induce a Reversible Increase in Delta-Gamma and Theta-Gamma Phase-Amplitude Coupling in Frontal Cortex of Rat

Pal

2017

Front. Syst. Neurosci.

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“…These findings complement prior work showing that propofol impairs long-range cortical connectivity 18,49,50 with feedforward and feedback connections being affected in different frequency bands 40,45,48,51 . While anesthetics are thought to affect cross-frequency coupling within region 52,53 and phase-amplitude coupling within frontal and parietal electrodes 18,27,50,52,54 , our results suggest that cross-frequency power coupling between levels of the cortical hierarchy is affected by anesthesia. Theoretically this would affect integration of information across the cortical hierarchy.…”

Section: Implications For the Understanding Of The Impairment Of Consmentioning

confidence: 54%

Propofol-Induced Unresponsiveness is Associated with Impaired Feedforward Connectivity in the Cortical Hierarchy

Sanders

Banks

Darracq

et al. 2017

Preprint

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“…Finally, the input signal is reconstructed by inverse WT according to the new coefficients. The mother wavelet “db4” function with Level 4 was used to remove the artifacts using wavelet denoising techniques (this will be explained in detail in the next section) [27,28]. The fourth sub-stage used the Savitzky–Golay smoothing filter to smooth out a noisy signal whose frequency span is large.…”

Section: Methodsmentioning

confidence: 99%

Reduction of the Dimensionality of the EEG Channels during Scoliosis Correction Surgeries Using a Wavelet Decomposition Technique

Al-Kadi

Reaz

Ali

et al. 2014

Sensors

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This paper presents a comparison between the electroencephalogram (EEG) channels during scoliosis correction surgeries. Surgeons use many hand tools and electronic devices that directly affect the EEG channels. These noises do not affect the EEG channels uniformly. This research provides a complete system to find the least affected channel by the noise. The presented system consists of five stages: filtering, wavelet decomposing (Level 4), processing the signal bands using four different criteria (mean, energy, entropy and standard deviation), finding the useful channel according to the criteria's value and, finally, generating a combinational signal from Channels 1 and 2. Experimentally, two channels of EEG data were recorded from six patients who underwent scoliosis correction surgeries in the Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM) (the Medical center of National University of Malaysia). The combinational signal was tested by power spectral density, cross-correlation function and wavelet coherence. The experimental results show that the system-outputted EEG signals are neatly switched without any substantial changes in the consistency of EEG components. This paper provides an efficient procedure for analyzing EEG signals in order to avoid averaging the channels that lead to redistribution of the noise on both channels, reducing the dimensionality of the EEG features and preparing the best EEG stream for the classification and monitoring stage.

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Cross-frequency coupling during isoflurane anaesthesia as revealed by electroencephalographic harmonic wavelet bicoherence

Cited by 32 publications

References 39 publications

Propofol, Sevoflurane, and Ketamine Induce a Reversible Increase in Delta-Gamma and Theta-Gamma Phase-Amplitude Coupling in Frontal Cortex of Rat

Propofol, Sevoflurane, and Ketamine Induce a Reversible Increase in Delta-Gamma and Theta-Gamma Phase-Amplitude Coupling in Frontal Cortex of Rat

Propofol-Induced Unresponsiveness is Associated with Impaired Feedforward Connectivity in the Cortical Hierarchy

Reduction of the Dimensionality of the EEG Channels during Scoliosis Correction Surgeries Using a Wavelet Decomposition Technique

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