EEG source localization constrained by time varying fMRI.

A novel approach for Electroencephalogram (EEG) and functional Magnetic Resonance Imaging (fMRI) integration analysis was developed, specifically designed to explore the spatial and temporal details of the "sequential multi-event-related potential" type of neural activities. The approach utilizes the high temporal resolution nature of EEG to compute a current density mapping of the cortical activity, informed by the high spatial resolution fMRI in a time-variant, spatially selective manner. This method was implemented in the analysis of an EEG/fMRI study on motor activation in responses to a visual stimulus that evoked an emotional response. The processed windowed EEG signals were analyzed to select the temporally relevant partial fMRI mapping, which in turn was used to inform EEG source localization calculation. The results were compared against traditional fMRI-informed EEG approaches to demonstrate the spatiotemporal variant fMRI constraints feature as well as the performance of the developed method.