Resting-state EEG power predicts conflict-related brain activity in internally guided but not in externally guided decision-making

Most experimental studies of decision-making have specifically examined situations in which a single correct answer exists (externally guided decision-making). Along with such externally guided decision-making, there are instances of decision-making in which no correct answer based on external circumstances is available for the subject (internally guided decision-making, e.g. preference judgment). We compared these two different types of decision-making in terms of conflict-monitoring and their relation with resting-state brain activity. Current electroencephalography (EEG) data demonstrated that conflict-related N2 amplitudes (i.e., difference between large-conflict and small-conflict conditions) in externally guided decision-making were modulated by the type of external stimulus (i.e., large-conflict stimulus pair or small-conflict stimulus pair) but were not found to be correlated with resting-state brain activity (i.e. resting-state EEG power). In contrast, conflict-related N2 amplitudes in internally guided decision-making were found to be correlated with resting-state brain activity, but were not found to be modulated by the type of stimulus itself: the degree to which the type of external stimulus modulates the conflict during stimulus encoding varies according to individual differences in intrinsic brain activity. Considering those results comprehensively, we demonstrate for the first time resting-state and stimulus-related differences between externally and internally guided decision-making.