Genetic absence epilepsy: Effective connectivity from piriform cortex to mediodorsal thalamus

Young, James C; Paolini, Antonio G.; Pedersen, Mangor; Jackson, Graeme D.

doi:10.1016/j.yebeh.2019.05.042

Cited by 5 publications

(11 citation statements)

References 62 publications

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“…We chose to use PTE because (1) (2) it has been shown to perform well in the presence of noise and non-Gaussian distributed measurements, which are typical of EEG 11 ; and (3) we have previously used this method to detect frequency-specific connectivity between cortical and thalamic EEG recordings of discharges in a rodent epilepsy model. 10 PTE analysis was performed for seven of eight patients who had intraoperative GPFA recorded in both CM and scalp/ cortex; one subject (Patient 2 in Table 1), in whom only two GPFA discharges were observed, was excluded from the PTE analysis. 10 Frequency bands of interest were delta (0.5-3 Hz), theta (4-7 Hz), alpha (8)(9)(10)(11)(12), and beta (13-30 Hz).…”

Section: Effective Connectivity Measured Using Ptementioning

confidence: 99%

“…10 PTE analysis was performed for seven of eight patients who had intraoperative GPFA recorded in both CM and scalp/ cortex; one subject (Patient 2 in Table 1), in whom only two GPFA discharges were observed, was excluded from the PTE analysis. 10 Frequency bands of interest were delta (0.5-3 Hz), theta (4-7 Hz), alpha (8)(9)(10)(11)(12), and beta (13-30 Hz). PTE analysis was not performed on SSW data due to large heterogeneity in EEG morphology and lag times for this discharge type, and due to the comparatively small number of SSW discharges in both scalp and thalamus that were captured per patient.…”

Section: Effective Connectivity Measured Using Ptementioning

confidence: 99%

“…8 In neuroscience, effective connectivity is defined as the influence that one neural system exerts over another 9 and can be used to evaluate the predisposition of neural pathways to propagate seizure activity. 10 Phase transfer entropy (PTE) is a recently introduced phase-based measure of effective connectivity that can estimate the frequency band-specific strength of information flow between pairs of brain regions. 11 It is based on the principle of Granger causality, 9 although it is capable of handling non-Gaussian distributed variables, making it well suited to biological measurements such as EEG.…”

Section: Introductionmentioning

confidence: 99%

“…Using PTE analysis, we recently found frequency-specific effective connectivity from piriform cortex to mediodorsal thalamus during absence seizures in a rodent epilepsy model. 10 In this study, we aimed to assess the relative roles of the cortex and thalamus (CM) in initiating epileptic activity characteristic of LGS. Intraoperative EEG recordings were acquired from both the thalamus and scalp during DBS surgery.…”

Section: Introductionmentioning

confidence: 99%

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Cortex leads the thalamic centromedian nucleus in generalized epileptic discharges in Lennox‐Gastaut syndrome

et al. 2020

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We aimed to assess the roles of the cortex and thalamus (centromedian nucleus [CM]) during epileptic activity in Lennox-Gastaut syndrome (LGS) patients undergoing deep brain stimulation (DBS) surgery as part of the ESTEL (Electrical Stimulation of the Thalamus for Epilepsy of Lennox-Gastaut Phenotype) trial. Methods: Twelve LGS patients (mean age = 26.8 years) underwent bilateral CM-DBS implantation. Intraoperatively, simultaneous electroencephalogram (EEG) was recorded (range = 10-34 minutes) from scalp electrodes and bilateral thalamic DBS electrodes. Temporal onsets of epileptic discharges (generalized paroxysmal fast activity [GPFA] and slow spike-and-wave [SSW]) were manually marked on recordings from scalp (ie, "cortex") and thalamus (ie, CM-DBS electrodes). Phase transfer entropy (PTE) analysis quantified the degree of information transfer from cortex to thalamus within different frequency bands around GPFA events. Results: GPFA was captured in eight of 12 patients (total event number across patients = 168, cumulative duration = 358 seconds). Eighty-six percent of GPFA events were seen in both scalp and thalamic recordings. In most events (83%), onset occurred first at scalp, with thalamic onset lagging by a median of 98 milliseconds (interquartile range = 78.5 milliseconds). Results for SSW were more variable and seen in 11 of 12 patients; 25.4% of discharges were noted in both scalp and thalamus. Of these, 74.5% occurred first at scalp, with a median lag of 75 milliseconds (interquartile range = 228 milliseconds). One to 0.5 seconds and 0.5-0 seconds before GPFA onset, PTE analysis showed significant energy transfer from scalp to thalamus in the delta (1-3 Hz) frequency band. For alpha (8-12 Hz) and beta (13-30 Hz) frequencies, PTE was greatest 1-0.5 seconds before GPFA onset. Significance: Epileptic activity is detectable in CM of thalamus, confirming that this nucleus participates in the epileptic network of LGS. Temporal onset of GPFA mostly occurs earlier at the scalp than in the thalamus. This supports our prior EEGfunctional magnetic resonance imaging results and provides further evidence for a cortically driven process underlying GPFA in LGS.

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Section: Effective Connectivity Measured Using Ptementioning

confidence: 99%

Section: Effective Connectivity Measured Using Ptementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cortex leads the thalamic centromedian nucleus in generalized epileptic discharges in Lennox‐Gastaut syndrome

et al. 2020

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“…Thus, this region is susceptible to the onset of epileptic seizures. However, these seizures commonly present no motor phenotype, and their clinical condition is restricted to cognitive, motivational, and social aspects [28][29][30] . The c-Fos expression found in the ACAd of the NPS group may be the result of increased activity in other limbic areas with efferent projections to this region.…”

Section: C-fos Expression In Seizure-related Areas Of Nps Ratsmentioning

confidence: 99%

C-Fos expression in epileptogenic areas of nephropathic rats undergoing star fruit poisoning

et al. 2020

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Estimating Directed Connectivity with OPM-MEG: A Feasibility Study

Pedersen,

Vashista,

Henare

et al. 2024

Preprint

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We investigated the feasibility of using directed connectivity analysis for magnetoencephalography data recorded via Optically Pumped Magnetometers (OPM-MEG). Ten healthy adult participants were scanned twice in an OPM-MEG system, and Beamformer source localisation was employed to obtain source time series within 62 cortical brain regions. Multivariate transfer entropy (mTE) was used to quantify directed connectivity, with lags ranging from 1 to 10 time points. Our findings showed that out-degree connectivity (node to network) in somatomotor and attention networks was higher than in other networks. In contrast, in-degree connectivity (network to node) was not different between networks. Longer time lags were associated with shorter physical distances between nodes. Transfer entropy networks demonstrated a small-world network topology, reinforcing the biological plausibility of our findings. Brain connections with higher transfer entropy values exhibited a stronger Phase Lag Index and Pearson’s correlation coefficient than non-significant transfer entropy connections, suggesting a relationship between directed and non-directed connectivity measures. All results were consistent across the two scans. OPM-MEG research is likely to expand significantly, and based on our preliminary findings, we propose that directed connectivity measures may provide valuable insights into the underlying mechanisms of brain communication.

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Genetic absence epilepsy: Effective connectivity from piriform cortex to mediodorsal thalamus

Cited by 5 publications

References 62 publications

Cortex leads the thalamic centromedian nucleus in generalized epileptic discharges in Lennox‐Gastaut syndrome

Cortex leads the thalamic centromedian nucleus in generalized epileptic discharges in Lennox‐Gastaut syndrome

C-Fos expression in epileptogenic areas of nephropathic rats undergoing star fruit poisoning

Estimating Directed Connectivity with OPM-MEG: A Feasibility Study

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