Objective: The project aimed to determine the alterations in the effective connectivity (EC) neural network in patients with insular epilepsy based on interictal high-frequency oscillations (HFOs) from magnetoencephalography (MEG) data.
Methods: We studied MEG data from 22 insular epilepsy patients and 20 normal subjects. Alterations in spatial pattern and connection properties of the patients with insular epilepsy were investigated in the entire brain network and insula-based network.
Results: Analyses of the parameters of graph theory revealed the over-connectivity and small-world configuration of the global connectivity patterns observed in the patients. In the insula-based network, the insular cortex ipsilateral to the seizure onset displayed increased efferent and afferentEC. Left insular epilepsy featured strong connectivity with the bilateral hemispheres, whereas right insular epilepsy featured increased connectivity with only the ipsilateral hemisphere.
Conclusions: Patients with insular epilepsy display alterations in the EC network in terms of both whole-brain connectivity and the insula-based network during interictal HFOs.
Significance: Alterations of interictal HFO-based networks provide evidence that epilepsy networks, instead of epileptic foci, play a key role in the complex pathophysiological mechanisms of insular epilepsy. The dysfunction of HFO networks may prove to be a novel promising biomarker and the cause of interictal brain dysfunctions in insular epilepsy.
Keywords: Effective connectivity; Graph theory; Insular epilepsy; Magnetoencephalography; Ripples.
Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.
Detection and localization of interictal ripples with magnetoencephalography in the presurgical evaluation of drug-resistant insular epilepsy.Brain Res. 2019 Mar 1;1706:147-156. doi: 10.1016/j.brainres.2018.11.006. Epub 2018 Nov 5. Brain Res. 2019. PMID: 30408475
What graph theory actually tells us about resting state interictal MEG epileptic activity.Neuroimage Clin. 2015 May 23;8:503-15. doi: 10.1016/j.nicl.2015.05.008. eCollection 2015. Neuroimage Clin. 2015. PMID: 26106575 Free PMC article.
A Magnetoencephalography Study of Pediatric Interictal Neuromagnetic Activity Changes and Brain Network Alterations Caused by Epilepsy in the High Frequency (80-1000 Hz).IEEE Trans Neural Syst Rehabil Eng. 2019 Mar;27(3):389-399. doi: 10.1109/TNSRE.2019.2898683. Epub 2019 Feb 12. IEEE Trans Neural Syst Rehabil Eng. 2019. PMID: 30762563 Free PMC article.
Multimodal investigation of epileptic networks: The case of insular cortex epilepsy.Prog Brain Res. 2016;226:1-33. doi: 10.1016/bs.pbr.2016.04.004. Epub 2016 May 6. Prog Brain Res. 2016. PMID: 27323937 Review.
Non-invasive brain mapping in epilepsy: Applications from magnetoencephalography.J Neurosci Methods. 2016 Feb 15;260:283-91. doi: 10.1016/j.jneumeth.2015.11.012. Epub 2015 Nov 28. J Neurosci Methods. 2016. PMID: 26642968 Review.