Multimodal integration of fNIRS, fMRI and EEG neuroimaging


Investigating human brain function can be improved byemploying a multimodal neuroimaging approach. The integrationof different non-invasive electrophysiological (e.g., electroenceph-alography-EEG and magnetoencephalography) and haemodynamic(e.g., functional magnetic resonance imaging-fMRI and functionalnear-infrared spectroscopy-fNIRS) neuroimaging modalities simul-taneously measuring functional brain activation during motor andcognitive tasks compliments each other’s limitations (Shibasaki,2008). Both EEG and MEG measure functional brain activity di-rectly by detecting the variations in electrical and magnetic fields,respectively, produced by neuronal activity across the scalp. BothfMRI and fNIRS measure functional brain activity indirectly viachanges in the blood oxygenation level-dependent (fMRI-BOLD in-crease) contrast signal and concentration changes in oxygenated(fNIRS-O2Hb increase) and deoxygenated (fNIRS-HHb decrease)haemoglobin, respectively, which are related to an increase in re-gional cerebral blood flow subsequent to increased neuronal activ-ity (i.e., neurovascular coupling). Since each neuroimagingmodality has its own characteristic features especially in termsof spatial and temporal resolution, previous studies have simulta-neously measured combinations of two out of the modalities dur-ing motor and cognitive tasks, and found good relationshipsbetween the techniques (Cui et al., 2011; Shibasaki, 2008;Steinbrink et al., 2006).

Clinical Neurophysiology