EEG-fMRI (short for EEG-correlated fMRI or electroencephalography-correlated functional magnetic resonance imaging) is a multimodal neuroimaging technique whereby EEG and fMRI data are recorded synchronously for the study of electrical brain activity in correlation with haemodynamic changes in brain during the electrical activity, be it normal function or associated with disorders.
Scalp EEG reflects the brain‘s electrical activity, more specifically it represents post-synaptic potentials in the cerebral cortex. fMRI detects haemodynamic changes throughout the brain known as the BOLD effect (Blood Oxygen Level Dependent). EEG-fMRI therefore enables the direct correlation of these two important measures of brain activity.