Neural Processing of Immediate versus Delayed Feedback in Action–Feedback and Stimulus–Feedback Associations

The feedback-related negativity (FRN) or reward positivity (RewP), reflecting striatal reward system activity, is reduced with delayed feedback, whereas the N170, associated with medial temporal lobe (MTL) activity, is increased. The type of the learned association could also affect which system is involved: We expected the striatal reward system to be adept at learning action-feedback associations and the MTL to be primarily involved in learning stimulus-feedback associations, which should be reflected in stronger prediction error (PE) representations in the FRN/RewP and N170, respectively. The relative contributions of the striatum and MTL to feedback learning and processing, however, also seem to be determined by the feedback's timing (immediate vs. delayed). We recorded EEG while 40 participants learned in an action-feedback condition or a stimulus-feedback condition with immediate and delayed feedback. Replicating previous studies, the FRN/RewP was most negative for unexpected negative feedback and most positive for unexpected positive feedback. Surprisingly, this PE × Feedback Valence interaction was more pronounced for the stimulus-feedback condition than the action-feedback condition. Interestingly, we found a PE × Feedback Valence interaction also in the N170, but with most negative amplitudes for unexpected positive and expected negative feedback. This interaction appeared across feedback timings for the stimulus-feedback condition, but only for immediate feedback for the action-feedback condition. The results suggest that striatal and MTL systems cooperate across feedback timings for stimulus-feedback associations, but not for action-feedback associations learned with delayed feedback.