The earliest efforts in the fMRI-constrained EEG/MEG source imaging utilize fMRI statistical parametric maps to obtain a priori information on where EEG/MEG sources are likely located. Depending on different source models, the spatial information from fMRI is typically used to constrain the locations of multiple current dipoles, namely the fMRI-constrained dipole fitting [131–133], or to constrain the distributed source distribution, namely the fMRI-constrained current density imaging [20–22, 24, 134–139].
