Mood congruent tuning of reward expectation in positive mood: evidence from FRN and theta modulations.

Positive mood broadens attention and builds additional mental resources. However, its effect on performance monitoring and reward prediction errors remain unclear. To examine this issue, we used a standard mood induction procedure (based on guided imagery) and asked 45 participants to complete a gambling task suited to study reward prediction errors by means of the feedback-related negativity (FRN) and mid-frontal theta band power. Results showed a larger FRN for negative feedback as well as a lack of reward expectation modulation for positive feedback at the theta level with positive mood, relative to a neutral mood condition. A control analysis showed that this latter result could not be explained by the mere superposition of the event-related brain potential component on the theta oscillations. Moreover, these neurophysiological effects were evidenced in the absence of impairments at the behavioral level or increase in autonomic arousal with positive mood, suggesting that this mood state reliably altered brain mechanisms of reward prediction errors during performance monitoring. We interpret these new results as reflecting a genuine mood congruency effect, whereby reward is anticipated as the default outcome with positive mood and therefore processed as unsurprising (even when it is unlikely), while negative feedback is perceived as unexpected.

Paul K ，Pourtois G 《-》

Dissociable effects of reward magnitude on fronto-medial theta and FRN during performance monitoring.

Reward processing is influenced by reward magnitude, as previous EEG studies showed changes in amplitude of the feedback-related negativity (FRN) and reward positivity (RewP), or power of fronto-medial theta (FMθ). However, it remains unclear whether these changes are driven by increased reward sensitivity, altered reward predictions, enhanced cognitive control, or a combination of these effects. To address this question, we asked 36 participants to perform a simple gambling task where feedback valence (reward vs. no-reward), its magnitude (small vs. large reward), and expectancy (expected vs. unexpected) were manipulated in a factorial design, while 64-channel EEG was recorded concurrently. We performed standard ERP analyses (FRN and RewP) as well as time-frequency decompositions (FMθ) of feedback-locked EEG data. Subjective reports showed that large rewards were more liked and expected than small ones. At the EEG level, increasing magnitude led to a larger RewP irrespective of expectancy, whereas the FRN was not influenced by this manipulation. In comparison, FMθ power was overall increased when reward magnitude was large, except if it was unexpected. These results show dissociable effects of reward magnitude on the RewP and FMθ power. Further, they suggest, that although large reward magnitude boosts reward processing (RewP), it can nonetheless undermine the need for enhanced cognitive control (FMθ) in case reward is unexpected. We discuss these new results in terms of optimistic bias or positive mood resulting from an increased reward magnitude.

Paul K ，Vassena E ，Severo MC ，Pourtois G ... -  《-》

Modulatory effects of positive mood and approach motivation on reward processing: Two sides of the same coin?

Paul K ，Pourtois G ，Harmon-Jones E 《-》

When the outcome is different than expected: Subjective expectancy shapes reward prediction error at the FRN level.

Converging evidence in human electrophysiology suggests that evaluative feedback provided during performance monitoring (PM) elicits two distinctive and successive ERP components: the feedback-related negativity (FRN) and the P3b. Whereas the FRN has previously been linked to reward prediction error (RPE), the P3b has been conceived as reflecting motivational or attentional processes following the early processing of the RPE, including action value updating. However, it remains unclear whether these two consecutive neurophysiological effects depend on the direction of the unexpectedness (better- or worse-than-expected outcomes; signed RPE) or instead only on the degree of unexpectedness irrespective of direction (i.e., unsigned RPE). To address this question, we devised an experiment in which we manipulated the objective reward probability and the subjective reward expectancy (via instructions) in a factorial within-subject design and explored amplitude changes of the FRN and the P3b. A 64-channel EEG was recorded while 32 participants performed a speeded go/no-go task in which evaluative feedback based on the reward probability either violated expectancy (thereby creating a RPE) or did not. This violation corresponded either to better- or worse-than-expected events. Results showed that the FRN was larger when RPE occurred than when it did not, but irrespective of the direction of this violation. Interestingly, in these two conditions, action value was updated for the positive feedback selectively, as shown by the P3b amplitude. These results obey a two-stage model of PM assuming that unsigned RPE is first rapidly detected (FRN level) before the positive feedback's value is updated selectively (P3b effect).

Walentowska W ，Severo MC ，Moors A ，Pourtois G ... -  《-》

Correlation of cue-locked FRN and feedback-locked FRN in the auditory monetary incentive delay task.

Krugliakova E ，Klucharev V ，Fedele T ，Gorin A ，Kuznetsova A ，Shestakova A ... -  《-》