Event-Related Potentials (ERP) Indices of Motivation during the Effort Expenditure for Reward Task

Differential Insular Cortex Activation During Reward Anticipation in Major Depressive Disorder With and Without Anxiety

BACKGROUND

Anticipation involves preparatory resource allocation to optimize upcoming responses, linked to insular cortex function. Although individuals with major depressive disorder (MDD) show impairments in anticipatory processing and blunted insula activation, it is unclear whether this pattern holds across MDD with comorbid anxiety disorders (MDD+ANX) and MDD without comorbid anxiety disorders. The monetary incentive delay (MID) task, combined with magnetic resonance imaging (MRI)-guided electroencephalography (EEG) source localization, offers a robust approach to study anticipatory mechanisms in MDD subtypes.

METHODS

Participants with MDD (n = 53) or MDD+ANX (n = 108) and healthy control participants (CTLs; n = 38) completed the MID task during simultaneous EEG-MRI recording. Stimulus-preceding negativity event-related potentials were source localized to identify insular cortical activity differences across groups (MDD, MDD+ANX, CTL), sex (male, female), MID task conditions (gain, loss), hemisphere (left, right), and 6 insular subregions.

RESULTS

Behavioral performance revealed that the CTL group reacted faster than the MDD+ANX group in both gain and loss conditions (p = .03). Insular source analysis showed lower activity in the MDD+ANX (p < .001) and MDD (p = .06) groups than in the CTL group during gain anticipation and lower activity in the MDD+ANX group than in both CTL (p = .003) and MDD (p < .001) groups during loss anticipation.

CONCLUSIONS

Results highlight potential intervention targets for improving anticipatory deficits in MDD+ANX. The MDD+ANX group exhibited distinctive patterns of insular cortical activity, with lower activity during the anticipation of both gain and loss feedback than the CTL and MDD groups, suggesting significant neural alterations. Moreover, in the MDD+ANX group, higher anxiety severity was linked to increased insula activity during loss anticipation, indicating a specific neural correlate of anxiety in this comorbid condition.

Blunted stimulus-preceding negativity during reward anticipation in major depressive disorder

BACKGROUND

Reward processing dysfunction is a core characteristic of major depressive disorder (MDD), yet event-related potential (ERP) research in MDD has predominantly focused on reward receipt as opposed to anticipation. The stimulus-preceding negativity (SPN) ERP reflects anticipatory brain processing. This study examines whether individuals with MDD exhibit deficits during reward anticipation as evidenced by altered SPN amplitude.

METHODS

We assessed prefeedback-SPN amplitudes during a monetary incentive delay (MID) task in individuals with MDD (n = 142, 99 with comorbid anxiety disorders [MDD + ANX]) compared to Controls (n = 37). A mixed analysis of variance was performed on prefeedback-SPN amplitude and behavioral measures, with group (MDD, MDD + ANX, Control) as the between-subjects factor, and feedback (gain, loss) and electrode (F3, F4, Fz, C3, C4, Cz, P3, P4, Pz) as within-subjects factors.

RESULTS

A group main effect revealed faster reaction times for the Control group than MDD and MDD + ANX groups. A group x feedback interaction indicated that the MDD subgroup had smaller prefeedback-SPN amplitudes than MDD + ANX and Control groups when anticipating gain feedback. Additionally, individuals with current MDD, irrespective of past MDD and comorbid anxiety, exhibited smaller SPN amplitudes than Controls prior to gain feedback.

LIMITATIONS

The MID paradigm, designed for functional magnetic resonance imaging (fMRI) data acquisition, lacks optimization for ERP analysis. Moreover, the clinical groups included more females than the Control group.

CONCLUSIONS

Reduced resource allocation to reward anticipation may differentiate MDD from MDD + ANX and Control groups. Further investigation of the neural mechanisms of distinct MDD phenotypes is warranted.

The role of impulsivity and binge eating in outpatients with overweight or obesity: an EEG temporal discounting study

BACKGROUND

Binge eating (BE) is associated with a range of cognitive control deficits related to impulsivity, including lower response inhibition, preference for immediate gratification, and maladaptive decision-making. The aim was to investigate whether impulsivity and BE may interact with the decision process and underlying brain activity in outpatients with overweight or obesity who are starting a treatment to achieve weight loss.

METHODS

A sample of 26 treatment-seeking outpatients with overweight or obesity was evaluated for impulsivity, BE, and temporal discounting rates. Impulsivity was measured with the Barratt Impulsiveness Scale (BIS-11), according to which two groups were composed: high BIS and low BIS; BE was assessed with the eating disorders module of the Structured Clinical Interview for DSM5-Research Version, according to which two groups were composed: with (BE group) or without BE (NBE group). Changes in subjective value of rewards were measured with the Temporal Discounting Task (TDt) where participants had to choice between sooner but smaller vs. later but larger monetary rewards. These choices were made in two differently delayed conditions ("Now" and "Not-now"). Brain rhythms were recorded through high-density electroencephalogram (hd-EEG) during the TDt.

RESULTS

Patients with BE reported more impulsive tendencies and perceived sooner rewards as more gratifying when both options were delayed (Not-now condition, p = 0.02). The reward choice in the TDt was accompanied by a general EEG alpha band desynchronization in parietal areas observed without differences between experimental conditions and patients groups. No effects were observed within the Now condition or in the other EEG bands.

CONCLUSIONS

The tendency to favor immediate rewards may constitute an obstacle to adhering to treatment plans and achieving weight loss goals for outpatients with overweight or obesity. Clinicians are therefore encouraged to include psychological factors, such as impulsivity and dysfunctional eating behaviors, when designing weight loss programs. By addressing these psychological aspects, clinicians can better support patients in overcoming barriers to adherence and achieving sustainable weight loss.

TRIAL REGISTRATION

This study was approved by the Ethics Committee of the Department of Psychological, Health, and Territorial Sciences of the University G. d'Annunzio of Chieti-Pescara (Prot. n. 254 of 03/14/2017).

Disentangling effort from probability of success: Temporal dynamics of frontal midline theta in effort-based reward processing

The ability to weigh a reward against the effort required to acquire it is critical for decision-making. However, extant experimental paradigms oftentimes confound increased effort demand with decreased reward probability, thereby obscuring neural correlates underlying these cognitive processes. To resolve this issue, we designed novel tasks that disentangled probability of success - and therefore reward probability - from effort demand. In Experiment 1, reward magnitude and effort demand were varied while reward probability was kept constant. In Experiment 2, effort demand and reward probability were varied while reward magnitude remained fixed. Electroencephalogram (EEG) data was recorded to explore how frontal midline theta (FMT; an electrophysiological index of mPFC function) and component P3 (an index of incentive salience) respond to effort demand, and reward magnitude and probability. We found no evidence that FMT tracked effort demands or net value during cue evaluation. At feedback, however, FMT power was enhanced for high compared to low effort trials, but not modulated by reward magnitude or probability. Conversely, P3 was sensitive to reward magnitude and probability at both cue and feedback phases and only integrated expended effort costs at feedback, such that P3 amplitudes continued to scale with reward magnitude and probability but were also increased for high compared to low effort reward feedback. These findings suggest that, when likelihood of success is equal, FMT power does not track net value of prospective effort-based rewards. Instead, expended cognitive effort potentiates FMT power and enhances the saliency of rewards at feedback. SIGNIFICANCE STATEMENT: The way the brain weighs rewards against the effort required to achieve them is critical for understanding motivational disorders. Current paradigms confound increased effort demand with decreased reward probability, making it difficult to disentangle neural activity associated with effort costs from those associated with reward likelihood. Here, we explored the temporal dynamics of effort-based reward (via frontal midline theta (FMT) and component P3) while participants underwent a novel paradigm that kept probability of reward constant between mental effort demand conditions. Our findings suggest that the FMT does not track net value and that expended effort enhances, instead of attenuates, the saliency of rewards.

The effects of stress on reward responsiveness: a systematic review and preliminary meta-analysis of the event-related potential literature

Exposure to stressful events is associated with a range of negative physical and mental health outcomes, including depression. It is critical to understand the mechanisms through which stress impacts mental health to identify promising targets for prevention and intervention efforts. Low-reward responsiveness is thought to be a mechanism of effects of stress on negative health outcomes and can be reliably measured at the neurophysiological level by using event-related potentials (ERPs), such as the reward positivity (RewP) component. The goal of this systematic review and preliminary meta-analysis was to examine evidence of associations between stress and alterations in reward responsiveness measured using ERPs. Through a systematic review of the literature, 23 studies examining the effects of laboratory-induced stressors and naturalistic stressors or perceived stress on reward responsiveness met study criteria, 13 of which were included in the meta-analysis. Most studies were conducted in undergraduate and community samples, with three selected for specific conditions, and primarily in adults. The systematic review supported evidence of associations between laboratory-induced stressors and blunted reward responsiveness as measured by the RewP but there were more mixed results when considering direct associations between naturalistic stressors/perceived stress and reward-related ERPs. Given that all studies examined the RewP, the meta-analysis focused on this component and indicated that there was a weak, nonsignificant negative association between stress and RewP. Results emphasize the complex nature of relations between stress and reward-related ERPs and the need to consider alternative models in future research. We also provide reporting recommendations for ERP researchers to facilitate future meta-analyses.

The different role of trait empathy and state social exclusion empathy on subsequent feelings about gambling outcome：Evidence from event-related potentials and time-frequency decompositions

Empathy plays an essential role in determining how we understand and respond to others' emotional experiences. Previous studies have mainly focused on the influencing factors of physical pain and monetary loss empathy, as well as on their effects on subsequent feelings. However, little is known about social pain empathy and its influence on subsequent feelings, and the role of personal trait empathy. In this study, we performed Cyberball Games and gambling tasks to explore the effect of social exclusion empathy on subsequent feelings for gambling outcomes (others' losses and gains) by analyzing the brain activity of excluded and non-excluded players at the gambling outcome feedback stage. It was found that both feedback-related negativity (FRN) and theta-band oscillatory are more negative for loss outcome than gain for the excluded players, while these effects cannot be found for the non-excluded players. Furthermore, we only observed a larger P300 amplitude in the gain outcome than that of loss, regardless of the players' role. More interestingly, we found state social pain empathy is negatively correlated with the d-FRN amplitude under non-excluded conditions, while trait empathy is positively correlated with P300 amplitude regardless of the players' role. These results provide insight into the different roles of state social pain empathy and trait empathy on subsequent gambling outcomes. Furthermore, different from previous studies, the current results show that d-FRN could reflect the state empathy discrepancy rather than the biomarker of state empathy.

Developmental differences in processing the valence and magnitude of incentive cues: Mid-adolescents are more sensitive to potential gains than early- or late-adolescents

Recent research has focused on the interaction between motivation and cognitive control and shown that both are important for goal-directed behavior. There also is evidence for developmental differences in the sensitivity and behavioral effectiveness of incentives, showing that mid-adolescents might be especially susceptible to rewards. Further pursuing this line of research, the present study examined developmental differences in incentive processing and whether these potential differences also would correspond to changes in cognitive control. We compared the processing of high and low potential gains and losses in early-, mid-, and late adolescents by means of event-related potentials (ERPs) and examined whether these incentives also led to specific performance differences in task-switching. We expected that potential gains compared to potential losses and high compared to low incentives would lead to more preparatory updating as reflected in the P3b and consequently to better task performance and smaller global and local switch costs as indicators of cognitive control in all age groups. Furthermore, we expected that mid-adolescents should be especially sensitive to high gains and thus show the most pronounced enhancements in task performance and global and local switch costs in trials with high gains, respectively. Our results corroborate the idea of a special sensitivity to high rewards during mid-adolescence. The analysis of ERPs showed age-related differences in the processing of incentive cues that also varied with cognitive control demands. However, the different incentives did not impact age-related differences in indices of cognitive control, but had a general effect on response speed.

Neural dynamics of effort-modulated reward processing

Previous studies have established that effort can either decrease reward value as a cost or increase reward value as an augmenter, which is referred to as the effort paradox. The present event-related potential study investigated the neural dynamics underlying the modulation of reward processing by effort expenditure. Thirty-two participants completed a modified monetary incentive delay task in a high-effort context and a low-effort context to earn monetary rewards while their EEG was recorded during effort anticipation, effort execution, and effort completion, respectively. Results revealed the multiphase nature of the effort-reward relationship, which unfolds over time. During effort anticipation, effort discounts reward value as reflected by a reduced contingent negative variation for high- versus low-effort trials. During effort exertion, the target-P3 reward effect was accrued by effort expenditure. Finally, effort also provides its own value following effort completion, as revealed by an enhanced stimulus-preceding negativity for high-effort relative to low-effort trials. These findings provide new insights into the relationship between effort expenditure and reward processing and are helpful to mitigate the effort paradox.

Towards a Functional Neuromarker of Impulsivity: Feedback-Related Brain Potential during Risky Decision-Making Associated with Self-Reported Impulsivity in a Non-Clinical Sample

Risk-taking is part of the multidimensional nature of impulsivity, consisting of an active engagement in behaviors or choices with potentially undesirable results, with probability as the cost for an expected reward. In order to understand the neurophysiological activity during risky behavior and its relationship with other dimensions of impulsivity, we have acquired event-related-potential (ERP) data and self-reported impulsivity scores from 17 non-clinical volunteers. They underwent high-resolution electroencephalography (HR-EEG) combined with an adapted version of the Balloon Analogue Risk Task (BART), and completed the Barratt Impulsiveness Scale (BIS-10) and the Urgency, Premeditation, Perseverance, Sensation Seeking, Impulsive Behavior Scale (UPPS). The ERP components were sensitive to valence (FRN, P300) and risk/reward magnitude (SPN, RewP). Our main finding evidenced a positive correlation between the amplitude of the P300 component following positive feedback and both the global UPPS score and the (lack of) perseverance UPPS subscale, significant for several adjacent electrodes. This finding might suggest an adaptive form of impulsive behavior, which could be associated to the reduction on the difference of the P300 amplitude following negative and positive feedback. However, further investigation with both larger clinical and non-clinical samples is required.