However, the integration of fMRI and EEG/MEG also faces great challenges, which arguably compromise its intuitive promise and benefits to neuroimaging and neuroscience fields. To list a few most critical ones, what is the physiological and physical relationship between hemodynamic and electrophysiological responses? How can EEG be reliably recorded during concurrent fMRI scans without affecting the signal quality for both modalities? How should we fuse the recorded fMRI-EEG/MEG data in a principled way for integrative imaging with enhance spatiotemporal resolution?
