Multimodal fMRI-EEG/MEG integrated neuroimaging approaches hold the potential to greatly enhance our ability to reveal the brain functional connectivity, due to the combined high spatial and temporal resolution. The more precise is our ability to image the brain functional anatomy, the better we would be able to pinpoint neural connectivity among specific brain regions. The higher temporal resolution we can achieve, the better chance we would be able to view a wide range of dynamics in functional interactions within a local or large scale. Efforts have been made in integrating fMRI with electromagnetic source imaging [22] using the directed transfer function (DTF) approach. Other existing methods, such as structural equation modeling (SEM) [207], and Partial Directed Coherence (PDC) [208], are also applicable to fMRI-EEG/MEG imaging data [209].
