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BACKGROUND: Current clinical studies have indicated that major depressive disorder (MDD) with adverse childhood experiences (ACEs) is associated with greater anhedonia. However, little is known about whether the change in reward sensitivity among young MDD individuals with ACEs are related to anhedonia. METHODS: We evaluated anhedonia and ACEs of each patient. Then, we performed Iowa gambling task during EEG to measure the reward positivity (RewP) and its difference (ΔRewP) in 86 MDD patients (31 with no or one ACE and 55 with two or more ACEs) and 44 healthy controls (HCs). Furthermore, we constructed a mediation model to assessed whether aberrant ΔRewP could mediate the relationship between ACEs and anhedonia. RESULTS: Compared with healthy controls and MDD patients with no or one ACE, MDD patients with two or more ACEs had the most severe symptoms of anhedonia and impaired decision-making, and showed significantly reduced reward sensitivity (most blunted ΔRewP). More importantly, ΔRewP mediated relationship between ACEs and anhedonia in MDD. CONCLUSIONS: We found that the ΔRewP partially mediates the association between ACEs and anhedonia in MDD patients, which provides evidence for the neurobiological basis of abnormal changes in the reward system in MDD individuals with early adverse experiences.

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BACKGROUND: A relatively understudied but growing body of research indicates that individuals with a history of childhood trauma exhibit altered reward processing in adulthood. Research to date has focused on adversity broadly, with studies typically finding evidence of blunted response to rewards in adults with a history of childhood trauma. OBJECTIVE: Given the role of reward processing in risk for psychopathology and the particularly pathogenic nature of sexual abuse (SA), the present study sought to assess whether adults with a history of severe childhood SA exhibit altered neurophysiological response to rewards. PARTICIPANTS AND SETTING: Female adults (N = 105) were included from two study sites that used the same measures of childhood trauma (Childhood Trauma Questionnaire, CTQ), reward processing (Doors Task), and psychopathology (SCID). METHODS: Based on participants' CTQ and SCID responses, three groups were created: Severe SA (n = 36), Clinical Match (with comparable lifetime psychopathology but no-to-minimal SA history; n = 35), and Healthy Controls (n = 34). Group differences in RewP amplitude were assessed. RESULTS: The Severe SA group exhibited larger reward positivity (RewP) amplitude to monetary rewards than the Clinical Match and Healthy Control groups (partial ƞ2 = 0.06, p = .047). This effect remained after covarying for severity of other forms of childhood trauma. CONCLUSIONS: Our study found that severe SA in childhood was related to a heightened response to reward in adulthood. Furthermore, this was not attributable to the severity of other forms of early trauma or comorbid psychopathology. Future studies are needed to identify how heightened reward processing following severe childhood SA may be implicated in the onset and course of psychopathology.

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BACKGROUND: The mechanisms that link neural and behavioral indices of reduced reward sensitivity in depression, particularly in children, remain unclear. Reward positivity (RewP), a neural index of reward processing, has been consistently associated with depression. Separately, recent studies using the drift-diffusion model on behavioral data have delineated computational indices of reward sensitivity. Therefore, in the current study, we examined whether RewP is a neural mediator of drift-diffusion model-based indices of reward processing in predicting pediatric depression across varying levels of symptom severity. METHODS: A community sample of 166 girls, ages 8 to 14 years, completed 2 tasks. The first was a reward guessing task from which RewP was computed using electroencephalography; the second was a probabilistic reward-based decision-making task. On this second task, drift-diffusion model analysis was applied to behavioral data to quantify the efficiency of accumulating reward-related evidence (drift rate) and potential baseline bias (starting point) toward the differently rewarded choices. Depression severity was measured using the self-report Children's Depression Inventory. RESULTS: RewP was correlated with drift rate, but not starting point bias, toward the more rewarded choice. Furthermore, RewP completely mediated the association between a slower drift rate toward the more rewarded option and higher depression symptom severity. CONCLUSIONS: Our findings suggest that reduced neural sensitivity to reward feedback may be a neural mechanism that underlies behavioral insensitivity to reward in children and adolescents with higher depression symptom severity, offering novel insights into the relationship between neural and computational indices of reward processing in this context.

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The effect of stress on risk-taking or risk-averse behavior in decision-making has been inconclusive in previous research, with few studies revealing the underlying neural mechanisms. This study employed event-related potentials technique and combined a social cold pressor assessment test with a mental arithmetic task to induce stress responses, aiming to investigate the influence of exogenous stress on the risk decision-making process. Stress induction results indicated that, in addition to raising heart rate and blood pressure, stress responses were accompanied by enhanced negative emotions, diminished positive emotions, and alterations in neural activity. The outcomes of risk decision-making showed that stress did not significantly affect risk preference or time of choice but did reduce the feedback-related negativity/reward positivity, with a particularly significant effect observed for large outcomes. Stress also altered the amplitude of the P3 component, with stress decreasing the P3 value for winning outcomes relative to losing outcomes. The study suggests that understanding how stress affects risk preference should consider the emotional valence induced by stress. Contrary to the reward sensitivity hypothesis, stress weakened reward sensitivity. Stress led to changes in the allocation of cognitive resources for outcome evaluation: compared to negative outcomes, stress reduced cognitive resources for positive outcomes, which might be related to the enhanced negative emotions induced by stress. The study highlights the importance of focusing on the subjective emotional experience induced by stress in future research on stress and risk decision-making.

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The neural circuits of reward processing and interval timing (including the perception and production of temporal intervals) are functionally intertwined, suggesting that it might be possible for momentary reward processing to influence subsequent timing behavior. Previous animal and human studies have mainly focused on the effect of reward on interval perception, whereas its impact on interval production is less clear. In this study, we examined whether feedback, as an example of performance-contingent reward, biases interval production. We recorded EEG from 20 participants while they engaged in a continuous drumming task with different realistic tempos (1728 trials per participant). Participants received color-coded feedback after each beat about whether they were correct (on time) or incorrect (early or late). Regression-based EEG analysis was used to unmix the rapid occurrence of a feedback response called the reward positivity (RewP), which is traditionally observed in more slow-paced tasks. Using linear mixed modeling, we found that RewP amplitude predicted timing behavior for the upcoming beat. This performance-biasing effect of the RewP was interpreted as reflecting the impact of fluctuations in reward-related anterior cingulate cortex activity on timing, and the necessity of continuous paradigms to make such observations was highlighted.

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Learning often involves trial-and-error, i.e. repeating behaviours that lead to desired outcomes, and adjusting behaviour when outcomes do not meet our expectations and thus lead to prediction errors (PEs). PEs have been shown to be reflected in the reward positivity (RewP), an event-related potential (ERP) component between 200 and 350 ms after performance feedback which is linked to striatal processing and assessed via electroencephalography (EEG). Here we show that this is also true for delayed feedback processing, for which a critical role of the hippocampus has been suggested. We found a general reduction of the RewP for delayed feedback, but the PE was similarly reflected in the RewP and the later P300 for immediate and delayed positive feedback, while no effect was found for negative feedback. Our results suggest that, despite processing differences between immediate and delayed feedback, positive PEs drive feedback processing and learning irrespective of delay.

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The influence of effort expenditure on the subjective value in feedback involving material reward has been the focus of previous research. However, little is known about the impact of effort expenditure on subjective value evaluations when feedback involves reward that is produced in the context of social interaction (e.g. self-other agreement). Moreover, how effort expenditure influences confidence (second-order subjective value) in feedback evaluations remains unclear. Using electroencephalography, this study aimed to address these questions. Event-related potentials showed that, after exerting high effort, participants exhibited increased reward positivity difference in response to self-other (dis)agreement feedback. After exerting low effort, participants reported high confidence, and the self-other disagreement feedback evoked a larger P3a. Time-frequency analysis showed that the high-effort task evoked increased frontal midline theta power. In the low (vs. high)-effort task, the frontal midline delta power for self-other disagreement feedback was enhanced. These findings suggest that, at the early feedback evaluation stage, after exerting high effort, individuals exhibit an increased sensitivity of subjective value evaluation in response to self-other agreement feedback. At the later feedback evaluation stage, after completing the low-effort task, the self-other disagreement feedback violates the individuals'high confidence and leads to a metacognitive mismatch.

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The present research tested the effect of manipulated perceived control (over obtaining the outcomes) and effort on reward valuation using the event-related potential known as the Reward Positivity (RewP). This test was conducted in an attempt to integrate two research literatures with opposite findings: Effort justification occurs when high effort leads to high reward valuation, whereas effort discounting occurs when high effort leads to low reward valuation. Based on an examination of past methods used in these literatures, we predicted that perceived control and effort would interactively influence RewP. Consistent with the effort justification literature (cognitive dissonance theory), when individuals have high perceived control, high effort should lead to more reward valuation than low effort should. Consistent with the effort discounting literature, when individuals have low perceived control, low effort should lead to more reward valuation than high effort should. Results supported these interactive and integrative predictions.

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Grounded in self-determination theory (SDT), the purpose of this research is to investigate the influence of providing choices following competence frustration on one's intrinsic motivation in a follow-up task. Study 1 conducted a between-group EEG experiment with 50 participants and used a component of event-related potentials (ERPs) to represent intrinsic motivation. Study 2 was a behavioural experiment with 149 participants, adopting the self-report method to measure intrinsic motivation. The stimuli and procedure in Study 1 are identical to Study 2. All participants were asked to complete a high-difficult time-estimation (TE) task during sessions 1-2, and a moderate-difficult stopwatch (SW) task during session 3 (no choices in the control group vs. providing choices in the experimental group). In Study 1, we observed a smaller reward positivity (RewP) difference wave in the experimental (vs. control) group during session 3. In Study 2, participants' intrinsic motivation in the experimental (vs. control) group is significantly lower. The results suggest that providing choices impairs the competence-frustrated participants' intrinsic motivation in the follow-up task and hinders competence restoration. Thus, the current research contributes original neuroscientific and subjective evidences for the adverse influence of providing choices on the competence-frustrated individual's intrinsic motivation, and suggests important practical implications.

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The reinforcement learning (RL) theory of the reward positivity (RewP), an event-related potential (ERP) component that measures reward responsivity, suggests that the RewP should be largest when positive outcomes are unexpected and has been supported by work using appetitive outcomes (e.g., money). However, the RewP can also be elicited by the absence of aversive outcomes (e.g., shock). The limited work to-date that has manipulated expectancy while using aversive outcomes has not supported the predictions of RL theory. Nonetheless, this work has been difficult to reconcile with the appetitive literature because the RewP was not observed as a reward signal in these studies, which used passive tasks that did not involve participant choice. Here, we tested the predictions of the RL theory by manipulating expectancy in an active/choice-based threat-of-shock doors task that was previously found to elicit the RewP as a reward signal. Moreover, we used principal components analysis to isolate the RewP from overlapping ERP components. Eighty participants viewed pairs of doors surrounded by a red or green border; shock delivery was expected (80%) following red-bordered doors and unexpected (20%) following green-bordered doors. The RewP was observed as a reward signal (i.e., no shock > shock) that was not potentiated for unexpected feedback. In addition, the RewP was larger overall for unexpected (vs expected) feedback. Therefore, the RewP appears to reflect the additive (not interactive) effects of reward and expectancy, challenging the RL theory of the RewP, at least when reward is defined as the absence of an aversive outcome.

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Altered reward processing has been implicated in the onset and maintenance of binge-eating disorder (BED). However, it is unclear which precise neurocognitive reward processes may contribute to BED. In the present study, 40 individuals with BED and 40 age-, sex-, and BMI-matched controls completed a reward (incentive delay) task while their neural activity was recorded using electroencephalography (EEG). Individuals with BED also completed a 10-day ecological momentary assessment (EMA) protocol assessing binge-eating behavior in the natural environment. Event-related potential (ERP) analysis of the EEG indicated that individuals with BED had stronger anticipatory (CNV) and outcome-related (RewP) neural reward activity to food and monetary rewards, compared to controls. However, within the BED group, greater frequency of binge eating during the EMA protocol was associated with stronger anticipatory (CNV) but weaker outcome-related (RewP) neural reward activity. These associations within the BED group were unique to food, and not monetary, rewards. Although preliminary, these results suggest that both anticipatory ("wanting") and outcome ("liking") reward processes may be generally amplified in BED. However, they also suggest that among individuals with BED, disorder severity may be associated with increased anticipatory reward processes ("wanting"), but relatively decreased reward-outcome processing ("liking"), of food rewards specifically.

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Maladaptive responses to peer acceptance and rejection arise in numerous psychiatric disorders in adolescence; yet, homogeneity and heterogeneity across disorders suggest common and unique mechanisms of impaired social function. We tested the hypothesis that social feedback is processed similarly to other forms of feedback (e.g., monetary) by examining the correspondence between the brain's response to social acceptance and rejection and behavioral performance on a separate reward and loss task. We also examined the relationship between these brain responses and depression and social anxiety severity. The sample consisted of one hundred and thirteen 16-21-year olds who received virtual peer acceptance/rejection feedback in an event-related potential (ERP) task. We used temporospatial principal component analysis and identified a component consistent with the reward positivity (RewP) or feedback negativity (FN). RewP to social acceptance was not significantly related to reward bias or the FN to social rejection related to loss avoidance. The relationship between RewP and depression severity, while nonsignificant, was of a similar magnitude to prior studies. Exploratory analyses yielded a significant relationship between lower socioeconomic status (SES) and blunted RewP and between lower SES and heightened loss avoidance and blunted reward bias. These findings build on prior work to improve our understanding of the function of the brain's response to social feedback, while also suggesting a pathway for further study, whereby poverty leads to depression via social and reward learning mechanisms.

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A recent study by Tsypes and colleagues (2019) found that children with recent suicidal ideation had blunted neural reward processing, as measured by the reward positivity (RewP), compared to matched controls, and that this difference was driven by reduced neural responses to monetary loss, rather than to reward. Here, we aimed to conceptually replicate and extend these findings in two samples (n = 264, 27 with suicidal ideation; and n = 314, 49 with suicidal ideation at baseline) of children and adolescents (11 to 15 years and 8 to 15 years, respectively). Results from both samples showed no evidence that children and adolescents with suicidal ideation have abnormal reward or loss processing, nor that reward processing predicts suicidal ideation two years later. The results highlight the need for greater statistical power, as well as continued research examining the neural underpinnings of suicidal thoughts and behaviors.

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Stress-induced dysfunction of reward processing is documented to be a critical factor associated with mental illness. Although many studies have attempted to clarify the relationship between stress and reward, few studies have investigated the effect of acute stress on the temporal dynamics of reward processing. The present study applied event-related potentials (ERP) to examine how acute stress differently influences reward anticipation and consumption. In this study, seventy-eight undergraduates completed a two-door reward task following a Trier Social Stress Task (TSST) or a placebo task. The TSST group showed higher cortisol levels, perceived stress, anxiety, and negative affect than the control group. For the control group, a higher magnitude of reward elicited a reduced cue-N2 but increased stimulus-preceding negativity (SPN), suggesting that controls were sensitive to reward magnitude. In contrast, these effects were absent in the stress group, suggesting that acute stress reduces sensitivity to reward magnitude during the anticipatory phase. However, the reward positivity (RewP) and P3 of both groups showed similar patterns, which suggests that acute stress has no impact on reward responsiveness during the consummatory phase. These findings suggest that acute stress selectively blunts sensitivity to reward magnitude during the anticipatory rather than the consummatory phase.

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BACKGROUND: Life stress and blunted reward processing each have been associated with the onset and maintenance of major depressive disorder. However, much of this work has been cross-sectional, conducted in separate lines of inquiry, and focused on recent life stressor exposure, despite the fact that theories of depression posit that stressors can have cumulative effects over the lifespan. To address these limitations, we investigated whether acute and chronic stressors occurring over the lifespan interacted with blunted reward processing to predict increases in depression over time in healthy youth. METHOD: Participants were 245 adolescent girls aged 8-14 years old (Mage = 12.4, s.d. = 1.8) who were evaluated at baseline and two years later. The reward positivity (RewP), an event-related potential measure of reward responsiveness, was assessed at baseline using the doors task. Cumulative lifetime exposure to acute and chronic stressors was assessed two years later using the Stress and Adversity Inventory for Adolescents (Adolescent STRAIN). Finally, depressive symptoms were assessed at both baseline and follow-up using the Children's Depression Inventory. RESULTS: As hypothesized, greater lifetime acute stressor exposure predicted increases in depressive symptoms over two years, but only for youth exhibiting a blunted RewP. This interaction, however, was not found for chronic stressors. CONCLUSIONS: Lifetime acute stressor exposure may be particularly depressogenic for youth exhibiting a blunted RewP. Conversely, a robust RewP may be protective in the presence of greater acute lifetime stressor exposure.

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Stress and neural responses to reward can interact to predict psychopathology, but the mechanisms of this interaction are unclear. One possibility is that the strength of neural responses to reward can affect the ability to maintain positive affect during stress. In this study, 105 participants completed a monetary reward task to elicit the reward positivity (RewP), an event-related potential sensitive to rewards. Subsequently, during a stressful period, participants reported on their affect nine times a day and on daily positive and negative events for 10 days. Even during heightened stress, experiencing more positive events was associated with increased positive affect. The RewP significantly moderated this association: Individuals with a larger RewP reported greater increases in positive affect when they experienced more positive events, relative to individuals with a smaller RewP. A blunted RewP might contribute to stress susceptibility by affecting how much individuals engage in positive emotion regulation during stress.

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A candidate pathophysiological process in major depressive disorder is diminished neural reactivity to reward delivery, which is theorized to give rise to anhedonia. Reduced amplitude in the reward positivity (RewP), which captures initial reward evaluation, has been linked to current symptoms of depression among child, adolescent, and young adult samples. However, the developmental trajectory of this association is incomplete, with relatively few studies in middle and older adulthood. Further, emerging evidence in the literature also suggests that this association may be linked to female sex-specific processes, but no studies to date have directly contrasted the effect of sex on the depression-RewP association. The current study sought to address these gaps by testing how sex and age may moderate the depression-RewP association within a mature adult community sample. Symptoms of depression were evaluated using a survey and a clinical interview, and the RewP was elicited using a simple guessing task. There was a three-way interaction between depression symptom severity, age, and sex in predicting RewP amplitude. This was driven by younger (late 30's to early 40's) female-sexed people such that for this group, elevated symptoms of depression were associated with blunting of the RewP. This association tapered around age 50. This effect was specific to clinician-rated rather than self-reported depressive symptom severity. This pattern of effects suggests that among female-sexed people, developmental processes continue to shape the association between reward responsiveness and depression throughout middle adulthood.

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Initiation of alcohol use at younger ages is prognostic of later drinking problems. Reward system dysfunction is theorized to contribute to early initiation and escalation of drinking, but existing evidence supports both hyposensitivity and hypersensitivity as risk-markers; research employing effective indices of reward processing is needed for clarification. The reward positivity (RewP) is a well-established neurophysiological index of hedonic "liking," an important aspect of reward processing. Adult research has yielded conflicting findings, with different studies reporting reduced, enhanced, or null associations of RewP with engagement in or risk for harmful alcohol use. No study has examined relations between RewP and multiple indices of drinking in youth. Here, we examined how RewP measured in a gain/loss feedback task related to self-reported drinking initiation and past-month drinking, when accounting for age along with depression and externalizing symptoms, in 250 mid-adolescent females. Analyses showed that (1) compared to not-yet drinkers, adolescents endorsing drinking initiation responded less strongly to monetary gain (RewP) but not loss feedback (FN), and (2) past-month drinking was unrelated to both RewP and FN magnitude. These findings provide evidence for reduced hedonic "liking" as a concomitant of early drinking initiation in adolescent females and warrant further research with mixed-sex adolescent samples exhibiting greater drinking variability.

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Contextual valence is an important dimension during value-based decision-making. Previous research has revealed behavioral and neural asymmetries between the gain context and the loss context. The present event-related potential study investigated the effects of contextual valence on neural dynamics underlying magnitude and time, two important reward dimensions, during feedback evaluation. Forty-two participants performed a simple guessing task in which they experienced both a gain context wherein high or low rewards were delivered immediately or six months later, and a loss context wherein high or low losses were delivered in the same way. Results showed that in the gain context, time and magnitude information were processed in a parallel way during the time windows of the reward positivity (RewP) and the P3. In the loss context, however, time and magnitude information were processed in a serial way such that time information was encoded during the RewP and P3 periods, whereas magnitude information was not tracked until the time window of the late positive potential. Our findings suggest that the neural dynamics underlying time and magnitude information are distinct between the gain and loss contexts, thus providing a novel perspective for the well-known gain-loss asymmetry.

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Vickrey auctions (VA) and Becker-DeGroot-Marschak auctions (BDM) are strategically equivalent demand-revealing mechanisms, differentiated only by a human opponent in the VA, and a random-number-generator opponent in the BDM. Game parameters are such that players are incentivized to reveal their private subjective values (SV) and behavior should be identical in both tasks. However, this has been repeatedly shown not to be the case. In this study, the neural correlates of outcome feedback processing during VA and BDM were directly compared using electroencephalography. Twenty-eight healthy participants bid for household products which were then divided into high- and low-SV categories. The VA included a human opponent deception to induce a social environment, while in reality a random-number-generator was used in both tasks. A P3 component peaking at 336 ms over midline parietal sites showed more positive amplitudes for high bid values, and for win outcomes in the VA but not the BDM. Both auctions also elicited a Reward Positivity potential, maximal at 275 ms along the central midline electrodes, that was not modulated by auction task or SV. Further, an exploratory N170 potential in the right occipitotemporal electrodes and a vertex positive potential component were stronger in the VA relative to the BDM. Results point to an enhanced cortical response to bid outcomes during VA task in a potential component associated with emotional control, and to the occurrence of face-sensitive potentials in VA but not in BDM auction. These findings suggest modulation of bid outcome processing by the social-competitive aspect of auction tasks. Directly comparing two prominent auction paradigms affords the opportunity to isolate the impact of social environment on competitive, risky decision-making. Findings suggest that feedback processing as early as 176 ms is facilitated by the presence of a human competitor, and later processing is modulated by social context and subjective value.

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