Shifts in attentional scope modulate event-related potentials evoked by reward

Outcome valence and stimulus frequency affect neural responses to rewards and punishments

The Reward-Positivity (RewP) is a frontocentral event-related potential elicited following reward and punishment feedback. Reinforcement learning theories propose the RewP reflects a reward prediction error that increases following more favorable (vs. unfavorable) outcomes. An alternative perspective, however, proposes this component indexes a salience-prediction error that increases following more salient outcomes. Evidence from prior studies that included both reward and punishment conditions is mixed, supporting both accounts. However, these studies often varied how feedback stimuli were repeated across reward and punishment conditions. Differences in the frequency of feedback stimuli may drive inconsistencies by introducing salience effects for infrequent stimuli regardless of whether they are associated with rewards or punishments. To test this hypothesis, the current study examined the effect of outcome valence and stimulus frequency on the RewP and neighboring P2 and P3 components in reward, punishment, and neutral contexts across two separate experiments that varied how often feedback stimuli were repeated between conditions. Experiment 1 revealed infrequent feedback stimuli generated overlapping positivity across all three components. However, controlling for stimulus frequency, experiment 2 revealed favorable outcomes that increased RewP and P3 positivity. Together, these results suggest the RewP reflects some combination of reward- and salience-prediction error encoding. Results also indicate infrequent feedback stimuli elicited strong salience effects across all three components that may inflate, eliminate, or reverse outcome valence effects for the RewP and P3. These results resolve several inconsistencies in the literature and have important implications for electrocortical investigations of reward and punishment feedback processing.

Investigating anticipatory processes during sequentially changing reward prospect: An ERP study

Performance-contingent reward prospect modulates the stability-flexibility balance in voluntary task switching. High reward prospect typically increases stability, indicated by a low voluntary switch rate (VSR). But this effect depends on the immediate reward history: Only when a high reward repeats (reward remains high), stability is increased. In contrast, when reward increases (high reward following low reward) cognitive flexibility is promoted, indicated by a relatively high VSR. To investigate the underlying mechanisms of changing reward expectations during voluntary task choice, we conducted two experiments and measured reward cue-locked event-related potentials (P2, P3b, CNV). The experiments yielded consistent findings: The P2 was stronger in response to high vs. low reward reflecting an early attentional boost by high reward anticipation. The P3b was highest in increase, intermediate in remain-high, and lowest in low reward trials suggesting responsiveness to working memory updating and motivational arousal. Finally, the CNV increased over time and was sensitive to both reward magnitude and sequence with the lowest amplitude in reward remain-low trials suggesting that preparatory control only increases when worth the effort. Taken together, early attentional processes (P2) were boosted by mere reward magnitude, while later processes (P3b, CNV) were sensitive to both reward magnitude and its sequence.

Therapeutic efficacy of connectivity-directed transcranial magnetic stimulation on anticipatory anhedonia

BACKGROUND

There are currently no effective treatments specifically targeting anticipatory anhedonia, a major symptom of severe depression which is associated with poor outcomes. The present study investigated the efficacy of individualized repetitive transcranial magnetic stimulation (rTMS) targeting the left dorsolateral prefrontal cortex (lDLPFC)-nucleus accumbens (NAcc) network on anticipatory anhedonia in depression.

METHODS

This randomized, double-blind, sham-controlled clinical trial (NCT03991572) enrolled 56 depression patients with anhedonia symptoms. Each participant received 15 once-daily sessions of rTMS at 10 Hz and 100% motor threshold. Stimulation was localized to the site of strongest IDLPFC-NAcc connectivity by functional magnetic resonance imaging. The Hamilton depression rating scale (HAMD) was used to measure depression severity, the temporal experience pleasure scale (TEPS) to measure anticipatory and consummatory anhedonia to specifically measure anticipatory/motivational anhedonia. Event-related potentials during the monetary incentive delay (MID) task were recorded to evaluate the electrophysiological correlates of reward anticipation and response.

RESULTS

Patients in the Real group showed significant improvements in anticipatory anhedonia and general depression symptoms posttreatment compared to the Sham group. The Real group also demonstrated more positive going cue-N2 and cue-P3 amplitude during MID reward trials after treatment. The change in cue-P3 posttreatment was positive correlated with improved TEPS-anti score.

CONCLUSION

Individualized rTMS of the lDLPFC-NAcc network can effectively alleviate anticipatory anhedonia and improved the reward seeking as evidenced by enhanced MID behavioral performance and more positive going cue-N2 and cue-P3. The lDLPFC-NAcc network plays a critical role in anticipatory reward and motivation processing.

Representing strangers in personal space triggers coding of defensive hand movement

Our brain codes manipulable tools as possibilities for action, particularly for those surrounding the body. Recent studies showed people would adjust their motor program when observing others around their own bodies (i.e. in the personal space). However, it remained unclear whether representing a personal space invader can automatically trigger motor coding. To address this, we devised an interaction task to measure the activation of pushing movements in facing a stranger approaching into personal space. The LRP (lateralized readiness potential) analyses revealed that observing a stranger in personal space caused an initial LRP bias associated with pushing movements, and an LRP deflection before responding of pull, suggesting representing personal space invaders activated the motor coding of push. The behavioral results showed the personal space intrusion prolonged the reaction time of participants' subsequent instructed pulling responses. The results of experiment 2 confirmed the behavioral observation of experiment 1 and further revealed the relationship between the response bias of push and social anxiety. Together, the present study demonstrates representing a stranger in personal space activated coding of defensive hand movements and biased subsequent motor responses.

Losses tune differently than gains: how gains and losses shape attentional scope and influence goal pursuit

Research on the asymmetric effect of negative versus positive affective states (induced by gains or losses) on scope of attention, both at a perceptual and a conceptual level, is abundant. However, little is known about the moderating effect of anticipating gains or losses versus actually experiencing them and about any downstream consequences of these effects on goal-directed behaviour. In two studies, we show that gains versus losses induce qualitatively different processes. In Experiment 1, we demonstrate that the anticipation of monetary gains results in a narrowing of attentional scope, while experiencing gains broadens the scope of attention. We find the reverse pattern concerning monetary losses - while anticipation of monetary losses results in broadening of attentional scope, the actual experience of losses results in narrowing of attentional scope. Additionally, Experiment 2 replicates these findings and shows how differential attentional tuning as a function of the anticipation versus experience of gains versus losses modulates priming-induced goal-directed behaviour.