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Author(s): Afnan J; Cai Z; Lina JM; Abdallah C; Pellegrino G; Arcara G; Khajehpour H; Frauscher B; Gotman J; Grova C;...
Magnetoencephalography (MEG) is widely used for studying resting-state brain connectivity. However, MEG source imaging is ill posed and has limited spatial resolution. This introduces source-leakag...
Article GUID: 40161991
Author(s): Van Hulst A; Zheng S; Argiropoulos N; Ybarra M; Ball GDC; Kakinami L;
The World Health Organization recommends using + 2 SD of body mass index z-score (zBMI) to define overweight/obesity (OWO) in children ages 2 to 5 years whereas + 1 SD is used as cut-point from 5 years onwards. Empirical evidence for using different cut-poi...
Article GUID: 40140102
Author(s): Avigdor T; Ren G; Abdallah C; Dubeau F; Grova C; Frauscher B;
Morning awakening is part of everyday life. Surprisingly, information remains scarce on its underlying neurophysiological correlates. Here simultaneous polysomnography and stereo-electroencephalography recordings from 18 patients are used to assess the spec...
Article GUID: 40126936
Author(s): Potvin-Jutras Z; Intzandt B; Mohammadi H; Liu P; Chen JJ; Gauthier CJ;
Cerebrovascular reactivity (CVR) and cerebral pulsatility (CP) are important indicators of cerebrovascular health, which are associated with physical activity (PA). While sex differences influence the impact of PA on cerebrovascular health, sex-specific eff...
Article GUID: 40079560
Author(s): Rosenstein B; Rye M; Roussac A; Naghdi N; Macedo LG; Elliott J; DeMont R; Weber MH; Pepin V; Dover G; Fortin M;...
Study DesignProspective Randomized Controlled Trial.ObjectivesTo investigate the effect of combined motor control and isolated lumbar strengthening exercise (MC + ILEX) vs general exercise (GE) on ...
Article GUID: 40066720
Author(s): Tam BT; Wan K; Santosa S; Cai Z;
With over 420 million children (aged 0-19 years) worldwide living with overweight or obesity, the "obesity epidemic" or "globesity" is a defining public health challenge of this generation. While significant efforts have been made to address...
Article GUID: 39991475
Author(s): Alizadeh M; Collins DL; Kersten-Oertel M; Xiao Y;
Purpose: As a portable and cost-effective imaging modality with better accessibility than Magnetic Resonance Imaging (MRI), transcranial sonography (TCS) has demonstrated its flexibility and potential utility in various clinical diagnostic applications, inc...
Article GUID: 39920905
Author(s): Costa DN; Santosa S; Jensen MD;
Adult males and females have markedly different body composition, energy expenditure, and have different degrees of risk for metabolic diseases. A major aspect of metabolic regulation involves the appropriate storage and disposal of glucose and fatty acids....
Article GUID: 39869194
Author(s): Ali OBK; Vidal A; Grova C; Benali H;
Astrocytes critically shape whole-brain structure and function by forming extensive gap junctional networks that intimately and actively interact with neurons. Despite their importance, existing computational models of whole-brain activity ignore the roles ...
Article GUID: 39804928
Title: | EEG/MEG source imaging of deep brain activity within the maximum entropy on the mean framework: Simulations and validation in epilepsy |
Authors: | Afnan J, Cai Z, Lina JM, Abdallah C, Delaire E, Avigdor T, Ros V, Hedrich T, von Ellenrieder N, Kobayashi E, Frauscher B, Gotman J, Grova C, |
Link: | https://pubmed.ncbi.nlm.nih.gov/38994740/ |
DOI: | 10.1002/hbm.26720 |
Category: | |
PMID: | 38994740 |
Dept Affiliation: | SOH
1 Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montréal, Québec, Canada. 2 Integrated Program in Neuroscience, McGill University, Montréal, Québec, Canada. 3 Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada. 4 Physnum Team, Centre De Recherches Mathématiques, Montréal, Québec, Canada. 5 Electrical Engineering Department, École De Technologie Supérieure, Montréal, Québec, Canada. 6 Center for Advanced Research in Sleep Medicine, Sacré-Coeur Hospital, Montréal, Québec, Canada. 7 Analytical Neurophysiology Lab, Department of Neurology, Duke University School of Medicine, Durham, North Carolina, USA. 8 Multimodal Functional Imaging Lab, Department of Physics and Concordia School of Health, Concordia University, Montréal, Québec, Canada. |
Description: |
Electro/Magneto-EncephaloGraphy (EEG/MEG) source imaging (EMSI) of epileptic activity from deep generators is often challenging due to the higher sensitivity of EEG/MEG to superficial regions and to the spatial configuration of subcortical structures. We previously demonstrated the ability of the coherent Maximum Entropy on the Mean (cMEM) method to accurately localize the superficial cortical generators and their spatial extent. Here, we propose a depth-weighted adaptation of cMEM to localize deep generators more accurately. These methods were evaluated using realistic MEG/high-density EEG (HD-EEG) simulations of epileptic activity and actual MEG/HD-EEG recordings from patients with focal epilepsy. We incorporated depth-weighting within the MEM framework to compensate for its preference for superficial generators. We also included a mesh of both hippocampi, as an additional deep structure in the source model. We generated 5400 realistic simulations of interictal epileptic discharges for MEG and HD-EEG involving a wide range of spatial extents and signal-to-noise ratio (SNR) levels, before investigating EMSI on clinical HD-EEG in 16 patients and MEG in 14 patients. Clinical interictal epileptic discharges were marked by visual inspection. We applied three EMSI methods: cMEM, depth-weighted cMEM and depth-weighted minimum norm estimate (MNE). The ground truth was defined as the true simulated generator or as a drawn region based on clinical information available for patients. For deep sources, depth-weighted cMEM improved the localization when compared to cMEM and depth-weighted MNE, whereas depth-weighted cMEM did not deteriorate localization accuracy for superficial regions. For patients' data, we observed improvement in localization for deep sources, especially for the patients with mesial temporal epilepsy, for which cMEM failed to reconstruct the initial generator in the hippocampus. Depth weighting was more crucial for MEG (gradiometers) than for HD-EEG. Similar findings were found when considering depth weighting for the wavelet extension of MEM. In conclusion, depth-weighted cMEM improved the localization of deep sources without or with minimal deterioration of the localization of the superficial sources. This was demonstrated using extensive simulations with MEG and HD-EEG and clinical MEG and HD-EEG for epilepsy patients. |