Expectancy affects the feedback-related negativity (FRN) for delayed feedback in probabilistic learning

Learning from feedback is a prerequisite for adapting to the environment. Prediction error signals coded by midbrain dopamine (DA) neurons are projected to the basal ganglia and anterior cingulate cortex (ACC). It has been suggested that neuronal activity shifts away from the DA system when feedback is delayed. The feedback-related negativity (FRN), an ERP that is generated in the ACC and has been shown to be sensitive to feedback valence and prediction error magnitude, was found to be reduced for delayed feedback. It has, however, not yet been investigated if the FRN for delayed feedback reflects a reward prediction error. In this study, effects of feedback delay (1 s vs. 7 s) on the processing of expected and unexpected positive and negative feedback were investigated in a between-subjects design in healthy human participants conducting a probabilistic feedback learning task. FRN and P300 amplitudes were decreased for subjects learning from delayed compared to immediate feedback. Importantly, the FRN, extracted from the negative-positive feedback difference wave, was significantly smaller for expected compared to unexpected feedback for both the immediate and delayed feedback conditions. Expectancy effects for the P300 were also seen, but did not interact with feedback valence. These results demonstrate an influence of feedback expectancy, and thus the prediction error, on early feedback processing even for delayed feedback, suggesting that neuronal structures underlying feedback processing are comparable for immediate and delayed feedback, at least to some extent. Modulations of the P300 by feedback delay may be linked to feedback salience.