Furthermore, we can re-fit the source estimates to the EEG/MEG data while taking the fMRI-EEG/MEG co-registered source power estimates as time-variant prior spatial constraints. This additional estimation step can be implemented by means of an adaptive Wiener filter (AWF) [24]. It ensures that the spatiotemporal source reconstruction depends primarily upon EEG/MEG measurements, and thus provides robustness against inaccurate fMRI constraints. Relative to the fMRI-EEG/MEG co-registration, the AWF represents an integrative multimodal imaging superior to simply putting together the results separately obtained from fMRI and EEG.
