title: Cortex-based inter-subject analysis of iEEG and fMRI data sets: application to sustained task-related BOLD and gamma responses.
abstract: Linking regional metabolic changes with fluctuations in the local electromagnetic fields directly on the surface of the human cerebral cortex is of tremendous importance for a better understanding of detailed brain processes. Functional magnetic resonance imaging (fMRI) and intra-cranial electro-encephalography (iEEG) measure two technically unrelated but spatially and temporally complementary sets of functional descriptions of human brain activity. In order to allow fine-grained spatio-temporal human brain mapping at the population-level, an effective comparative framework for the cortex-based inter-subject analysis of iEEG and fMRI data sets is needed. We combined fMRI and iEEG recordings of the same patients with epilepsy during alternated intervals of passive movie viewing and music listening to explore the degree of local spatial correspondence and temporal coupling between blood oxygen level dependent (BOLD) fMRI changes and iEEG spectral power modulations across the cortical surface after cortex-based inter-subject alignment. To this purpose, we applied a simple model of the iEEG activity spread around each electrode location and the cortex-based inter-subject alignment procedure to transform discrete iEEG measurements into cortically distributed group patterns by establishing a fine anatomic correspondence of many iEEG cortical sites across multiple subjects. Our results demonstrate the feasibility of a multi-modal inter-subject cortex-based distributed analysis for combining iEEG and fMRI data sets acquired from multiple subjects with the same experimental paradigm but with different iEEG electrode coverage. The proposed iEEG-fMRI framework allows for improved group statistics in a common anatomical space and preserves the dynamic link between the temporal features of the two modalities.
authors.affiliation: Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands. Electronic address: fabrizio.esposito@maastrichtuniversity.nl.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Esposito
authors.affiliation: Psychology Department, Tel Aviv University, Tel Aviv, Israel; Functional Brain Center, Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Neomi
authors.initials: N
authors.lastname: Singer
authors.affiliation: Functional Brain Center, Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
authors.forename: Ilana
authors.initials: I
authors.lastname: Podlipsky
authors.affiliation: Functional Neurosurgery Unit, Tel Aviv Medical Center, Tel Aviv, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Division of Neurosurgery, David Geffen School of Medicine and Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, USA.
authors.forename: Itzhak
authors.initials: I
authors.lastname: Fried
authors.affiliation: Psychology Department, Tel Aviv University, Tel Aviv, Israel; Functional Brain Center, Wohl Institute for Advanced Imaging, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Talma
authors.initials: T
authors.lastname: Hendler
authors.affiliation: Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands; Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands.
authors.forename: Rainer
authors.initials: R
authors.lastname: Goebel
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D064847:Multimodal Imaging / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: BOLD; Combined intra-cranial EEG-fMRI; Distributed source modeling; Gamma; Intra-cranial EEG; Multi-modal imaging; fMRI