Transfer function between EEG and BOLD signals of epileptic activity
Simultaneous EEG-fMRI recordings have seen growing application in the evaluation of epilepsy, namely in the characterization of brain networks related to epileptic activity. In EEG-correlated fMRI studies, epileptic events are usually described as boxcar signals based on the timing information retri...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2013-01-01
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| Series: | Frontiers in Neurology |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fneur.2013.00001/full |
| _version_ | 1811254962661883904 |
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| author | Marco eLeite Marco eLeite Alberto eLeal Alberto eLeal Patricia eFigueiredo Patricia eFigueiredo |
| author_facet | Marco eLeite Marco eLeite Alberto eLeal Alberto eLeal Patricia eFigueiredo Patricia eFigueiredo |
| author_sort | Marco eLeite |
| collection | DOAJ |
| description | Simultaneous EEG-fMRI recordings have seen growing application in the evaluation of epilepsy, namely in the characterization of brain networks related to epileptic activity. In EEG-correlated fMRI studies, epileptic events are usually described as boxcar signals based on the timing information retrieved from the EEG, and subsequently convolved with a heamodynamic response function to model the associated BOLD changes. Although more flexible approaches may allow a higher degree of complexity for the haemodynamics, the issue of how to model these dynamics based on the EEG remains an open question. In this work, a new methodology for the integration of simultaneous EEG-fMRI data in epilepsy is proposed, which incorporates a transfer function from the EEG to the BOLD signal. Independent component analysis (ICA) of the EEG is performed, and a number of metrics expressing different models of the EEG-BOLD transfer function are extracted from the resulting time courses. These metrics are then used to predict the fMRI data and to identify brain areas associated with the EEG epileptic activity. The methodology was tested on both ictal and interictal EEG-fMRI recordings from one patient with a hypothalamic hamartoma. When compared to the conventional analysis approach, plausible, consistent and more significant activations were obtained. Importantly, frequency-weighted EEG metrics yielded superior results than those weighted solely on the EEG power, which comes in agreement with previous literature. Reproducibility, specificity and sensitivity should be addressed in an extended group of patients in order to further validate the proposed methodology and generalize the presented proof of concept. |
| first_indexed | 2024-04-12T17:16:33Z |
| format | Article |
| id | doaj.art-1cf06e0a91464b2ab163eb99464afb32 |
| institution | Directory Open Access Journal |
| issn | 1664-2295 |
| language | English |
| last_indexed | 2024-04-12T17:16:33Z |
| publishDate | 2013-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neurology |
| spelling | doaj.art-1cf06e0a91464b2ab163eb99464afb322022-12-22T03:23:38ZengFrontiers Media S.A.Frontiers in Neurology1664-22952013-01-01410.3389/fneur.2013.0000138518Transfer function between EEG and BOLD signals of epileptic activityMarco eLeite0Marco eLeite1Alberto eLeal2Alberto eLeal3Patricia eFigueiredo4Patricia eFigueiredo5Instituto Superior Técnico, Technical University of LisbonInstitute for Systems and RoboticsCentro Hospitalar Psiquiátrico de LisboaCentro de Investigação e Intervenção Social (CIS-IUL)Instituto Superior Técnico, Technical University of LisbonInstitute for Systems and RoboticsSimultaneous EEG-fMRI recordings have seen growing application in the evaluation of epilepsy, namely in the characterization of brain networks related to epileptic activity. In EEG-correlated fMRI studies, epileptic events are usually described as boxcar signals based on the timing information retrieved from the EEG, and subsequently convolved with a heamodynamic response function to model the associated BOLD changes. Although more flexible approaches may allow a higher degree of complexity for the haemodynamics, the issue of how to model these dynamics based on the EEG remains an open question. In this work, a new methodology for the integration of simultaneous EEG-fMRI data in epilepsy is proposed, which incorporates a transfer function from the EEG to the BOLD signal. Independent component analysis (ICA) of the EEG is performed, and a number of metrics expressing different models of the EEG-BOLD transfer function are extracted from the resulting time courses. These metrics are then used to predict the fMRI data and to identify brain areas associated with the EEG epileptic activity. The methodology was tested on both ictal and interictal EEG-fMRI recordings from one patient with a hypothalamic hamartoma. When compared to the conventional analysis approach, plausible, consistent and more significant activations were obtained. Importantly, frequency-weighted EEG metrics yielded superior results than those weighted solely on the EEG power, which comes in agreement with previous literature. Reproducibility, specificity and sensitivity should be addressed in an extended group of patients in order to further validate the proposed methodology and generalize the presented proof of concept.http://journal.frontiersin.org/Journal/10.3389/fneur.2013.00001/fullEpilepsyICABOLDEEG-fMRIHeuristic |
| spellingShingle | Marco eLeite Marco eLeite Alberto eLeal Alberto eLeal Patricia eFigueiredo Patricia eFigueiredo Transfer function between EEG and BOLD signals of epileptic activity Frontiers in Neurology Epilepsy ICA BOLD EEG-fMRI Heuristic |
| title | Transfer function between EEG and BOLD signals of epileptic activity |
| title_full | Transfer function between EEG and BOLD signals of epileptic activity |
| title_fullStr | Transfer function between EEG and BOLD signals of epileptic activity |
| title_full_unstemmed | Transfer function between EEG and BOLD signals of epileptic activity |
| title_short | Transfer function between EEG and BOLD signals of epileptic activity |
| title_sort | transfer function between eeg and bold signals of epileptic activity |
| topic | Epilepsy ICA BOLD EEG-fMRI Heuristic |
| url | http://journal.frontiersin.org/Journal/10.3389/fneur.2013.00001/full |
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