%0 Journal Article
%T Causality within the Epileptic Network: An EEG-fMRI Study Validated by Intracranial EEG
%A Anna Elisabetta Vaudano
%A Laura Tassi
%A Andrea Ruggieri
%A Gaetano Cantalupo
%A Francesca Benuzzi
%A Paolo Nichelli
%A Louis Lemieux
%A Stefano Meletti
%J Frontiers in Neurology
%D 2013
%I Frontiers Media
%R 10.3389/fneur.2013.00185
%X Accurate localization of the Seizure Onset Zone (SOZ) is crucial in patients with drug-resistance focal epilepsy. EEG with fMRI recording (EEG-fMRI) has been proposed as a complementary non-invasive tool, which can give useful additional information in the pre-surgical work-up. However, fMRI maps related to interictal epileptiform activities (IED) often show multiple regions of signal change, or ˇ°networks,ˇ± rather than highly focal ones. Effective connectivity approaches like Dynamic Causal Modeling (DCM) applied to fMRI data potentially offers a framework to address which brain regions drives the generation of seizures and IED within an epileptic network. Here, we present a first attempt to validate DCM on EEG-fMRI data in one patient affected by frontal lobe epilepsy. Pre-surgical EEG-fMRI demonstrated two distinct clusters of blood oxygenation level dependent (BOLD) signal increases linked to IED, one located in the left frontal pole and the other in the ipsilateral dorso-lateral frontal cortex. DCM of the IED-related BOLD signal favored a model corresponding to the left dorso-lateral frontal cortex as driver of changes in the fronto-polar region. The validity of DCM was supported by: (a) the results of two different non-invasive analysis obtained on the same dataset: EEG source imaging (ESI), and ˇ°psycho-physiological interactionˇ± analysis; (b) the failure of a first surgical intervention limited to the fronto-polar region; (c) the results of the intracranial EEG monitoring performed after the first surgical intervention confirming a SOZ located over the dorso-lateral frontal cortex. These results add evidence that EEG-fMRI together with advanced methods of BOLD signal analysis is a promising tool that can give relevant information within the epilepsy surgery diagnostic work-up.
%K functional neuroimaging
%K epilepsy surgery
%K seizure onset zone
%K intracerebral recordings
%K effective connectivity
%K EEG
%K fMRI
%K dynamic causal modeling
%U http://www.frontiersin.org/Journal/10.3389/fneur.2013.00185/abstract