Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes
AbstractIntroduction: EEG-fMRI detects BOLD changes associated with epileptic interictal discharges (IED) and can identify epileptogenic networks in epilepsy patients. Besides positive BOLD changes, negative BOLD changes have sometimes been observed in the default-mode network, particularly using gr...
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Frontiers Media S.A.
2014-11-01
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| Series: | Frontiers in Neuroscience |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fnins.2014.00335/full |
| _version_ | 1811258720642924544 |
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| author | Julia eJacobs Antonia eMenzel Georgia eRamantani Katharina eKoerbl Jakob eAsslaender Andreas eSchulze-Bonhage Jürgen eHennig Pierre eLeVan |
| author_facet | Julia eJacobs Antonia eMenzel Georgia eRamantani Katharina eKoerbl Jakob eAsslaender Andreas eSchulze-Bonhage Jürgen eHennig Pierre eLeVan |
| author_sort | Julia eJacobs |
| collection | DOAJ |
| description | AbstractIntroduction: EEG-fMRI detects BOLD changes associated with epileptic interictal discharges (IED) and can identify epileptogenic networks in epilepsy patients. Besides positive BOLD changes, negative BOLD changes have sometimes been observed in the default-mode network, particularly using group analysis. A new fast fMRI sequence called MREG (Magnetic Resonance Encephalography) shows increased sensitivity to detect IED-related BOLD changes compared to the conventional EPI sequence, including frequent occurrence of negative BOLD responses in the DMN. The present study quantifies the concordance between the DMN and negative BOLD related to IEDs of temporal and extra-temporal origin.Methods: Focal epilepsy patients underwent simultaneous EEG-MREG. Areas of overlap were calculated between DMN regions, defined as precuneus, posterior cingulate, bilateral inferior parietal and mesial prefrontal cortices according to a standardized atlas, and significant negative BOLD changes revealed by an event-related analysis based on the timings of IED seen on EEG. Correlation between IED number/lobe of origin and the overlap were calculated. Results: 15 patients were analyzed, some showing IED over more than one location resulting in 30 different IED types. The average overlap between negative BOLD and DMN was significantly larger in temporal (23.7 ± 19.6cm³) than extra-temporal IEDs (7.4 ± 5.1 cm³, p=0.008). There was no significant correlation between the number of IEDs and the overlap between DMN structures and negative BOLD areas.Discussion: MREG results in an increased sensitivity to detect negative BOLD responses related to focal IED in single patients, with responses often occurring in DMN regions. In patients with high overlap with the DMN, this suggests that epileptic IEDs may be associated with a brief decrease in attention and cognitive ability. Interestingly this observation was not dependent on the frequency of IED but more common in IED of temporal origin. |
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| institution | Directory Open Access Journal |
| issn | 1662-453X |
| language | English |
| last_indexed | 2024-04-12T18:17:42Z |
| publishDate | 2014-11-01 |
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| spelling | doaj.art-5e801728ea334b6cb42872e508b4decb2022-12-22T03:21:32ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2014-11-01810.3389/fnins.2014.00335107731Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikesJulia eJacobs0Antonia eMenzel1Georgia eRamantani2Katharina eKoerbl3Jakob eAsslaender4Andreas eSchulze-Bonhage5Jürgen eHennig6Pierre eLeVan7University Medical Center FreiburgUniversity Medical Center FreiburgUniversity Medical Center FreiburgUniversity Medical Center FreiburgUniversity Medical Center FreiburgUniversity Medical Center FreiburgUniversity Medical Center FreiburgUniversity Medical Center FreiburgAbstractIntroduction: EEG-fMRI detects BOLD changes associated with epileptic interictal discharges (IED) and can identify epileptogenic networks in epilepsy patients. Besides positive BOLD changes, negative BOLD changes have sometimes been observed in the default-mode network, particularly using group analysis. A new fast fMRI sequence called MREG (Magnetic Resonance Encephalography) shows increased sensitivity to detect IED-related BOLD changes compared to the conventional EPI sequence, including frequent occurrence of negative BOLD responses in the DMN. The present study quantifies the concordance between the DMN and negative BOLD related to IEDs of temporal and extra-temporal origin.Methods: Focal epilepsy patients underwent simultaneous EEG-MREG. Areas of overlap were calculated between DMN regions, defined as precuneus, posterior cingulate, bilateral inferior parietal and mesial prefrontal cortices according to a standardized atlas, and significant negative BOLD changes revealed by an event-related analysis based on the timings of IED seen on EEG. Correlation between IED number/lobe of origin and the overlap were calculated. Results: 15 patients were analyzed, some showing IED over more than one location resulting in 30 different IED types. The average overlap between negative BOLD and DMN was significantly larger in temporal (23.7 ± 19.6cm³) than extra-temporal IEDs (7.4 ± 5.1 cm³, p=0.008). There was no significant correlation between the number of IEDs and the overlap between DMN structures and negative BOLD areas.Discussion: MREG results in an increased sensitivity to detect negative BOLD responses related to focal IED in single patients, with responses often occurring in DMN regions. In patients with high overlap with the DMN, this suggests that epileptic IEDs may be associated with a brief decrease in attention and cognitive ability. Interestingly this observation was not dependent on the frequency of IED but more common in IED of temporal origin.http://journal.frontiersin.org/Journal/10.3389/fnins.2014.00335/fullDefault modeEEG-fMRIrefractory epilepsyepileptic spikesfast fMRI |
| spellingShingle | Julia eJacobs Antonia eMenzel Georgia eRamantani Katharina eKoerbl Jakob eAsslaender Andreas eSchulze-Bonhage Jürgen eHennig Pierre eLeVan Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes Frontiers in Neuroscience Default mode EEG-fMRI refractory epilepsy epileptic spikes fast fMRI |
| title | Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes |
| title_full | Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes |
| title_fullStr | Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes |
| title_full_unstemmed | Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes |
| title_short | Negative BOLD in default-mode structures measured with EEG-MREG is larger in temporal than extra-temporal epileptic spikes |
| title_sort | negative bold in default mode structures measured with eeg mreg is larger in temporal than extra temporal epileptic spikes |
| topic | Default mode EEG-fMRI refractory epilepsy epileptic spikes fast fMRI |
| url | http://journal.frontiersin.org/Journal/10.3389/fnins.2014.00335/full |
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