Mission impossible: combining event-related EEG and fMRI on a single-trial level
Little is yet known about the relation between the scalp-recorded event-related EEG and the fMRI BOLD response. This holds true in particular for brain activation related to higher order cognitive processing. Whereas previous research focused on the event-related potential (ERP), an alternative approach will be presented integrating EEG and fMRI on a trial-by-trial basis. The basic idea is to apply independent component analysis (ICA) to disentangle otherwise overlapping EEG activations. An example will be presented showing that ICA-filtered single-trial EEG amplitudes not only predicted the subjects’ reaction times, but also systematically correlated with the fMRI BOLD response. The potential of simultaneous EEG/fMRI studies will be discussed with regard to an event-related brain dynamics view of cognitive processes.