Dissociated cortical phase- and amplitude-coupling patterns in the human brain

Siems, Marcus; Siegel, Markus

doi:10.1101/485599

Cited by 6 publications

(3 citation statements)

References 78 publications

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“…orthogonal amplitude envelope correlations and imaginary coherence) show changes, whereas phase-based and broadband measures tend to remain more stable. This result is consistent with work showing that these two dimensions of statistical association between timeseries are not biologically redundant [52]. Across bands, we see that effects tend to be similarly sized within low and high frequency groups individually, but not across them.…”

Section: Discussionsupporting

confidence: 92%

Fluctuations in functional connectivity associated with interictal epileptiform discharges (IEDs) in intracranial EEG

Stiso

Caciagli

Hadar

et al. 2021

Preprint

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All epilepsies are defined by a propensity for recurrent seizures, characterized by hypersynchronous electrographic activity. Understanding this overarching property would be advanced by a thorough quantification of how the global synchrony of the epileptic brain responds to small perturbations that do not trigger seizures. Here, we leverage analysis of transient focal bursts of epileptiform activity, termed interictal epileptiform discharges (IEDs), to characterize this response. Specifically, we use a group of 145 participants implanted with intracranial EEG (iEEG) electrodes to quantify changes in 5 functional connectivity measures associated with three properties of IEDs: their presence, spread, and number. We perform this analysis in 5 frequency bands in order to contextualize our findings in relation to ongoing neural processes at different spatial and temporal scales. We find that, across frequency bands, both the presence and spread of IEDs tend to lead to independent increases of functional connectivity, but only in functional connectivity measures influenced by the amplitude, rather than the phase, of a signal. We find that these increases are not explained by simple subgroups of connections, such as the weakest connections in the brain, or only connections within the seizure onset zone. Evaluating patterns of similarity across different bands and measure combinations, we find that the presence of IEDs impacts high frequencies (gamma and high gamma)and low frequencies (theta, alpha, and beta) differently, although responses within each group are similar. Using grouped LASSO regression, we identify which individual-level features explain differences in functional connectivity changes associated with IEDs. While no single feature robustly explains observed differences, the most consistently included predictor across bands and measures is the anatomical locus of IEDs. Overall, this work provides compelling evidence for increases in global synchrony associated with IEDs, and delivers a thorough exploration of different functional connectivity measures, frequency bands, and IED properties. These observations show a disruption of several types of ongoing neural dynamics associated with IEDs. Additionally, we provide a starting point for future models of how small perturbations affect neural systems and how those systems support the hypersynchrony seen in epilepsy.

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Section: Discussionsupporting

confidence: 92%

Fluctuations in functional connectivity associated with interictal epileptiform discharges (IEDs) in intracranial EEG

Stiso

Caciagli

Hadar

et al. 2021

Preprint

View full text Add to dashboard Cite

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“…5H, red dots) (21); however, ∼40% of the trials demonstrated poor correlation or uncoupled cross-frequency calcium dynamics (Fig. 5H, black dots), similar to the dissociation of phase and amplitude coupling observed in previous EEG studies (52,53). The 1d-pupil-fMRI correlation maps acquired from both groups independently showed a negative correlation through most of the brain (Fig.…”

Section: State the Map Insupporting

confidence: 78%

Indexing brain state-dependent pupil dynamics with simultaneous fMRI and optical fiber calcium recording

Pais‐Roldán

Takahashi

Sobczak

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Pupillometry, a noninvasive measure of arousal, complements human functional MRI (fMRI) to detect periods of variable cognitive processing and identify networks that relate to particular attentional states. Even under anesthesia, pupil dynamics correlate with brain-state fluctuations, and extended dilations mark the transition to more arousable states. However, cross-scale neuronal activation patterns are seldom linked to brain state-dependent pupil dynamics. Here, we complemented resting-state fMRI in rats with cortical calcium recording (GCaMP-mediated) and pupillometry to tackle the linkage between brain-state changes and neural dynamics across different scales. This multimodal platform allowed us to identify a global brain network that covaried with pupil size, which served to generate an index indicative of the brain-state fluctuation during anesthesia. Besides, a specific correlation pattern was detected in the brainstem, at a location consistent with noradrenergic cell group 5 (A5), which appeared to be dependent on the coupling between different frequencies of cortical activity, possibly further indicating particular brain-state dynamics. The multimodal fMRI combining concurrent calcium recordings and pupillometry enables tracking brain state-dependent pupil dynamics and identifying unique cross-scale neuronal dynamic patterns under anesthesia.

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“…To assess potential limitations due to scalplevel analysis [3,4], the analysis was further replicated using a source level approach. In order to control the possible effects derived from the use of different FC methods, which may result from distinct neural mechanisms [5], we performed the analysis using four different techniques to estimate patterns of phase-and amplitude-based correlation: the Phase locking value (PLV) [6], the Phase lag index (PLI) [7], the Amplitude Envelope Correlation (AEC) [8] and a corrected version performing a time-domain orthogonalization procedure (AECC) [8]. Our analysis was focused on the alpha band since it has been previously shown to provide the largest signal to noise ratio and the more reliable estimate of FC networks [9].…”

Section: Introductionmentioning

confidence: 99%

A comparison between power spectral density and network metrics: An EEG study

Demuru

Cava

Pani

et al. 2020

Biomedical Signal Processing and Control

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Power spectral density (PSD) and network analysis performed on functional correlation (FC) patterns represent two common approaches used to characterize Electroencephalographic (EEG) data. Despite the two approaches are widely used, their possible association may need more attention. To investigate this question, we performed a comparison between PSD and some widely used nodal network metrics (namely strength, clustering coefficient and betweenness centrality), using two different publicly available resting-state EEG datasets, both at scalp and source levels, employing four different FC methods (PLV, PLI, AEC and AECC). Here we show that the two approaches may provide similar information and that their correlation depends on the method used to estimate FC. In particular, our results show a strong correlation between PSD and nodal network metrics derived from FC methods (PLV and AEC) that do not limit the effects of volume conduction/signal leakage. The correlations are less relevant for more conservative FC methods (AECC). These findings suggest that the results derived from the two different approaches may be not independent and should not be treated as distinct analyses. We conclude that it may represent good practice to report the findings from the two approaches in conjunction to have a more comprehensive view of the results.

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Dissociated cortical phase- and amplitude-coupling patterns in the human brain

Cited by 6 publications

References 78 publications

Fluctuations in functional connectivity associated with interictal epileptiform discharges (IEDs) in intracranial EEG

Fluctuations in functional connectivity associated with interictal epileptiform discharges (IEDs) in intracranial EEG

Indexing brain state-dependent pupil dynamics with simultaneous fMRI and optical fiber calcium recording

A comparison between power spectral density and network metrics: An EEG study

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