Multiple networks for interhemispheric integration in the visual brain: fMRI BOLD response increases with EEG synchronization.
Fornari E, Knyazeva M, Meuli R, Maeder P
Centre Hospitalier Universitaire Vaudois (CHUV)
Natural images contain a wide spectrum of spatial information, ranging from low to high spatial frequencies (SF). Our study, combining fMRI and EEG techniques, was aimed at mapping neural assemblies involved in the Gestalt-based interhemispheric integration of bilateral stimuli systematically varying in spatial frequencies. Visual stimuli of various spatial frequencies induce SF-specific pattern of activation and of interhemispheric EEG synchronization in the beta-gamma band. fMRI and EEG data suggest involvement of occipital and parietal neuronal networks in the processing of different spatial frequencies. Linear relation between BOLD and EEG coherence suggests that local activation can be boosted by synchronization.