title: Relationship between task-related gamma oscillations and BOLD signal: new insights from combined fMRI and intracranial EEG.
abstract: Cognitive neuroscience relies on two sets of techniques to map the neural networks underlying cognition in humans: recordings of either regional metabolic changes (fMRI or PET) or fluctuations in the neural electromagnetic fields (EEG and MEG). Despite major advances in the last few years, an explicit linkage between the two is still missing and the neuroimaging community faces two complementary but unrelated sets of functional descriptions of the human brain. Such an explicit framework, linking the two approaches in potentially complex cognitive tasks and in a variety of brain regions would permit to combine them into fine spatio-temporally-grained human brain mapping procedures. We combined fMRI and intra-cranial EEG recordings of the same epileptic patients during a semantic decision task and found a close spatial correspondence between regions of fMRI activations and recording sites showing EEG energy modulations in the gamma range (>40 Hz). Our findings further support previous findings that gamma band modulations co-localize with BOLD variations and also indicate that fMRI may be used as a constraint to improve source reconstruction of gamma band EEG responses.
authors.affiliation: INSERM U821-Brain Dynamics and Cognition, Lyon, France. lachaux@lyon.inserm.fr
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Lachaux
authors.forename: Pierre
authors.initials: P
authors.lastname: Fonlupt
authors.forename: Philippe
authors.initials: P
authors.lastname: Kahane
authors.forename: Lorella
authors.initials: L
authors.lastname: Minotti
authors.forename: Dominique
authors.initials: D
authors.lastname: Hoffmann
authors.forename: Olivier
authors.initials: O
authors.lastname: Bertrand
authors.forename: Monica
authors.initials: M
authors.lastname: Baciu
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology; D016000:Cluster Analysis; D003071:Cognition / Q000502:physiology; D003627:Data Interpretation, Statistical; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D010100:Oxygen / Q000097:blood*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011932:Reading; D014796:Visual Perception / Q000502:physiology
chemical_list: D010100:Oxygen