Subjective preferences differentially modulate the processing of rewards gained by own vs. observed choices

Electrophysiological correlates of (mis)judging social information

Social information can be used to optimize decision-making. However, the simultaneous presentation of multiple sources of advice can lead to a distinction bias in judging the validity of the information. While the involvement of event-related potential (ERP) components in social information processing has been studied, how they are modulated by (mis)judging an advisor's information validity remains unknown. In two experiments participants performed a decision-making task with highly accurate or inaccurate cues. Each experiment consisted of an initial, learning, and test phase. During the learning phase, three advice cues were simultaneously presented and the validity of them had to be assessed. The effect of different cue constellations on ERPs was investigated. In the subsequent test phase, the willingness to follow or oppose an advice cue was tested. Results demonstrated the distinction bias with participants over or underestimating the accuracy of the most uncertain cues. The P2 amplitude was significantly increased during cue presentation when advisors were in disagreement as compared to when all were in agreement, regardless of cue validity. Further, a larger P3 amplitude during outcome presentation was found when advisors were in disagreement and increased with more informative cues. As such, the most uncertain cues were related to the smallest P3 amplitude. The findings hint at the possible role of P3 in judging and learning the predictability of social cues. This study provides novel insights into the role of P2 and P3 components during the judgment of social information validity.

All the Pringle ladies: Neural and behavioral responses to high-calorie food rewards in young adult women

Reward processing is vital for learning and survival, and can be indexed using the Reward Positivity (RewP), an event-related potential (ERP) component that is larger for rewards than losses. Prior work suggests that heightened motivation to obtain reward, as well as greater reward value, is associated with an enhanced RewP. However, the extent to which internal and external factors modulate neural responses to rewards, and whether such neural responses motivate reward-seeking behavior, remains unclear. The present study investigated whether the degree to which a reward is salient to an individual's current motivational state modulates the RewP, and whether the RewP predicts motivated behaviors, in a sample of 133 women. To elicit the RewP, participants completed a forced-choice food reward guessing task. Data were also collected on food-related behaviors (i.e., type of food chosen, consumption of the food reward) and motivational salience factors (i.e., self-reported hunger, time since last meal, and subjective "liking" of food reward). Results showed that hungrier participants displayed an enhanced RewP compared to less hungry individuals. Further, self-reported snack liking interacted with RewP magnitude to predict behavior, such that when participants reported low levels of snack liking, those with a smaller RewP were more likely to consume their snacks than those with a larger RewP. Our data suggest that food-related motivational state may increase neural sensitivity to food reward in young women, and that neural markers of reward sensitivity might interact with subjective reward liking to predict real-world eating behavior.

Reduced positive affect alters reward learning via reduced information encoding in the Reward Positivity

Reward Positivity (RewP) is a feedback-locked event-related potential component that is specifically elicited by rewarding feedback and scales with positive reward prediction error, a hallmark of reinforcement learning models. The RewP is also diminished in depression, suggesting that it may be a novel marker of anhedonia. Here, we examined if a sad mood induction offered an opportunity to causally induce a mood-related alteration of the RewP and reward-related learning. In Experiment 1 (N = 50 total), participants were randomly assigned to previously established sad or neutral mood induction procedures before a probabilistic selection task. This manipulation failed to induce changes in affect, suggesting that standard methods are inadequate. In Experiment 2 (N = 50 total), participants were randomly assigned to newly developed happy versus sad mood manipulations, which successfully induced large changes in affect. While the RewP was unaffected by mood induction, positive mood moderated the relationship between prediction error encoding in the RewP and reward learning, such that low positive mood and low prediction error encoding resulted in poorer reward learning. These findings provide a mechanistic example of how reduced positive affect moderates reward learning via poorer information encoding in the RewP.

It's About Time: The Circadian Network as Time-Keeper for Cognitive Functioning, Locomotor Activity and Mental Health

A variety of organisms including mammals have evolved a 24h, self-sustained timekeeping machinery known as the circadian clock (biological clock), which enables to anticipate, respond, and adapt to environmental influences such as the daily light and dark cycles. Proper functioning of the clock plays a pivotal role in the temporal regulation of a wide range of cellular, physiological, and behavioural processes. The disruption of circadian rhythms was found to be associated with the onset and progression of several pathologies including sleep and mental disorders, cancer, and neurodegeneration. Thus, the role of the circadian clock in health and disease, and its clinical applications, have gained increasing attention, but the exact mechanisms underlying temporal regulation require further work and the integration of evidence from different research fields. In this review, we address the current knowledge regarding the functioning of molecular circuits as generators of circadian rhythms and the essential role of circadian synchrony in a healthy organism. In particular, we discuss the role of circadian regulation in the context of behaviour and cognitive functioning, delineating how the loss of this tight interplay is linked to pathological development with a focus on mental disorders and neurodegeneration. We further describe emerging new aspects on the link between the circadian clock and physical exercise-induced cognitive functioning, and its current usage as circadian activator with a positive impact in delaying the progression of certain pathologies including neurodegeneration and brain-related disorders. Finally, we discuss recent epidemiological evidence pointing to an important role of the circadian clock in mental health.

Social exclusion modulates neural dynamics of monetary and social reward processing in young adult females

Evidence suggests that social exclusion increases one's sensitivity to monetary and social rewards. However, whether and how social exclusion modulates the neural dynamics of reward processing remains unknown. The current study aimed to address this gap by systematically investigating the differential influences of social exclusion on various stages of monetary and social reward processing. Forty-five female participants were recruited, and the Cyberball game was used to manipulate social exclusion. To disentangle the anticipatory and consummatory stages of monetary and social reward processing, we recorded event-related potentials during two incentive delay tasks, one with a monetary reward and one with a social reward. The results showed that during the anticipatory stage, a larger contingent negative variation was observed for the exclusion group than for the inclusion group, regardless of reward type. During the consummatory stage, although the reward-related positivity was larger in the exclusion group than in the inclusion group, this difference was only observed for the social, and not monetary, reward feedback. These findings advance our understanding of the relationship between social exclusion and reward processing and suggest that while social exclusion might exert comparable enhancement effect for monetary and social reward processing during the anticipatory stage, it exerts a specific enhancement effect for social reward processing during the consummatory stage.

The reward positivity is sensitive to affective liking

The EEG feature known as the Reward Positivity (RewP) is elicited by reward receipt and appears to reflect sensitively and specifically positive prediction errors during reinforcement learning. Yet, the RewP also is modulated by state and trait affect, suggesting that it has a more complex computational role than simple reinforcement surprise. We conducted a series of experiments aimed to investigate underlying affect processing reflected in the RewP during a reinforcement learning task. In the first experiment (N = 25), we manipulated the type of rewards a person could win (simple points or hedonically-appraised pictures). Although there were no differences in the amplitudes of the RewP for different types of rewards, there was a significant correlation between the individual rating of liking for the images and RewP amplitude. In a second experiment (N = 25), we manipulated reinforcement rates (easy vs. hard) and affective picture content (liked vs. ambivalent) to examine the potential interaction of prediction error and liking on RewP amplitude. We again found a significant relationship between liking and RewP amplitude, however, only in the hard condition. These findings suggest that the RewP reflects cortical computations of reward surprise as well as hedonic liking, identifying it as a possible nexus where multidimensional value is computed.

Amphetamine alters an EEG marker of reward processing in humans and mice

The bench-to-bedside development of pro-cognitive therapeutics for psychiatric disorders has been mired by translational failures. This is, in part, due to the absence of pharmacologically sensitive cognitive biomarkers common to humans and rodents. Here, we describe a cross-species translational marker of reward processing that is sensitive to the aminergic agonist, d-amphetamine. Motivated by human electroencephalographic (EEG) findings, we recently reported that frontal midline delta-band power is an electrophysiological biomarker of reward surprise in humans and in mice. In the current series of experiments, we determined the impact of parametric doses of d-amphetamine on this reward-related EEG response from humans (n = 23) and mice (n = 28) performing a probabilistic learning task. In humans, d-amphetamine (placebo, 10 mg, 20 mg) boosted the Reward Positivity event-related potential (ERP) component as well as the spectral delta-band representations of this signal. In mice, d-amphetamine (placebo, 0.1 mg/kg, 0.3 mg/kg, 1.0 mg/kg) boosted both reward and punishment ERP features, yet there was no modulation of spectral activities. In sum, the present results confirm the role of dopamine in the generation of the Reward Positivity in humans, and pave the way toward a pharmacologically valid biomarker of reward sensitivity across species.

Do food images as action outcomes evoke a reward positivity?

Favourable compared to unfavourable action outcomes typically evoke a positive-going amplitude shift at frontomedial electrodes in the scalp-recorded electroencephalogram. Since prior studies on this Reward Positivity (RewP) have heavily relied on monetary outcomes, it is still debated whether the RewP is also elicited by other kinds of reward. We addressed this issue by focussing on food as another major category of daily reward. Twenty-eight healthy participants completed a decision task, in which they received images of personally liked, neutral or disliked food as outcome stimuli. Importantly, single trial outcomes were of relevance for a prolonged task goal (i.e., obtaining the liked foods and avoiding the disliked foods). The observed amplitude pattern did not correspond to the typical RewP effect observed for monetary outcomes. In particular, disliked foods evoked a similar positive-going amplitude shift as liked foods when compared to neutral foods. Exploratory analyses indicated that this pattern may result from a spatiotemporal overlap between a potential RewP response and other, emotion-related ERP components (i.e., the Early Posterior Negativity and the Late Positive Potential). We discuss our findings with regard to theoretical and methodological implications for the usage of the RewP in the study of reward processing.

Neural correlates of acceptance and rejection in online speed dating: An electroencephalography study

Pursuing dating relationships is important for many people's well-being, because it helps them fulfill the need for stable social relationships. However, the neural underpinnings of decision-making processes during the pursuit of dating interactions are unclear. In the present study, we used a novel online speed dating paradigm where participants (undergraduate students, N = 25, aged 18-25 years, 52% female) received direct information about acceptance or rejection of their various speed dates. We recorded EEG measurements during speed dating feedback anticipation and feedback processing stages to examine the stimulus preceding negativity (SPN) and feedback-related brain activity (Reward Positivity, RewP, and theta oscillatory power). The results indicated that the SPN was larger when participants anticipated interest versus disinterest from their speed dates. A larger RewP was observed when participants received interest from their speed dates. Theta power was increased when participants received rejection from their speed dates. This theta response could be source-localized to brain areas that overlap with the physical pain matrix (anterior cingulate cortex, dorsolateral prefrontal cortex, and the supplementary motor area). This study demonstrates that decision-making processes-as evident in a speed date experiment-are characterized by distinct neurophysiological responses during anticipating an evaluation and processing thereof. Our results corroborate the involvement of the SPN in reward anticipation, RewP in reward processing and mid-frontal theta power in processing of negative social-evaluative feedback. These findings contribute to a better understanding of the neurocognitive mechanisms implicated in decision-making processes when pursuing dating relationships.

Selective Devaluation Affects the Processing of Preferred Rewards

The present study investigated whether the representation of subjective preferences in the event-related potential is manipulable through selective devaluation, i.e., the consumption of a specific food item until satiety. Thirty-four participants completed a gambling task in which they chose between virtual doors to find one of three snack items, representing a high, medium, or low preference outcome as defined by individual desire-to-eat ratings. In one of two test sessions, they underwent selective devaluation of the high preference outcome. In the other, they completed the task on an empty stomach. Consistent with previous findings, averaged across sessions, amplitudes were increased for more preferred rewards in the time windows of P2, late FRN, and P300. As hypothesised, we also found a selective devaluation effect for the high preference outcome in the P300 time window, reflected in a decrease in amplitude. The present results provide evidence for modulations of reward processing not only by individual factors, such as subjective preferences, but also by the current motivational state. Importantly, the present data suggest that selective devaluation effects in the P300 may be a promising tool to further characterise altered valuation of food rewards in the context of eating disorders and obesity.