An electrophysiological monetary incentive delay (e-MID) task: A way to decompose the different components of neural response to positive and negative monetary reinforcement

Cross-species translational paradigms for assessing positive valence system as defined by the RDoC matrix

Functions associated with processing reward-related information are fundamental drivers of motivation, learning, and goal-directed behavior. Such functions have been classified as the positive valence system under the Research Domain and Criteria (RDoC) criteria and are negatively impacted across a range of psychiatric disorders and mental illnesses. The positive valence system is composed of three comprehensive categories containing related but dissociable functions that are organized into either Reward Responsiveness, Reward Learning, or Reward Valuation. The presence of overlapping behavioral dysfunction across diagnostic mental disorders is in-part what motivated the RDoC initiative, which emphasized that the study of mental illness focus on investigating relevant behavior and cognitive functions and their underlying mechanisms, rather than separating efforts on diagnostic categories (i.e., transdiagnostic). Moreover, the RDoC approach is well-suited for preclinical neuroscience research, as the rise in genetic toolboxes and associated neurotechnologies enables researchers to probe specific cellular targets with high specificity. Thus, there is an opportunity to dissect whether behaviors and cognitive functions are supported by shared or distinct neural mechanisms. For preclinical research to effectively inform our understandings of human behavior however, the cognitive and behavioral paradigms should have predictive, neurobiological, and pharmacological predictive validity to the human test. Touchscreen-based testing systems provide a further advantage for this endeavor enabling tasks to be presented to animals using the same media and task design as in humans. Here, we outline the primary categories of the positive valence system and review the work that has been done cross-species to investigate the neurobiology and neurochemistry underlying reward-related functioning. Additionally, we provide clinical tasks outlined by RDoC, along with validity and/or need for further validation for analogous rodent paradigms with a focus on implementing the touchscreen-based cognitive testing systems.

Electrophysiological indices of reward anticipation as ADHD risk and prognostic biomarkers

The attention-deficit/hyperactivity disorder (ADHD) clinical phenotype has limitations for deciphering ADHD etiology and predicting prognosis. Although relative to the clinical phenotype, intermediate phenotypes may have better explanatory and prognostic power, the extent to which ADHD intermediate phenotypes are associated with ADHD risk and prognosis is unknown. The aim of this study was to evaluate evidence for event-related potential (ERP) measures of reward anticipation as ADHD risk and prognostic biomarkers. We examined, whether (1) in a sample of adolescents (N = 304; Mage = 15.78 years, SD = 1.08; 39.5% female), accounting for the effects of age, sex, ADHD severity and depression, ERPs are associated with ADHD polygenic risk scores (PRSs) (ADHD risk) and (2) in a sample of adolescents at-risk for ADHD (n = 99; Mage = 15.78 years, SD = 1.08; 39.5% female), accounting for the effects of age, sex, ADHD severity, depression, and baseline outcome values, ERPs are associated, prospectively, with alcohol misuse (ADHD prognosis). In adolescents, greater ADHD PRSs were associated with lower electrophysiological anticipatory attention to motivationally relevant feedback (b = -0.115, p = .046 95%CI [-0.228; -0.002]). The predictors accounted for 5% of the variance in the outcome. In adolescents at-risk for ADHD, at 18-month follow-up, lower electrophysiological anticipatory attention to motivationally relevant feedback was associated with greater alcohol consumption (b = -7.454, p = .007, 95%CI [-12.873; -2.034]). The predictors accounted for 31% of the variance in this outcome. These findings were replicated in sensitivity analyses with behavioral performance variables added as covariates. The current findings support the hypothesis that ERP amplitudes of reward anticipation may be ADHD risk and prognostic biomarkers and suggest that intermediate phenotypes may confer advantages over the ADHD clinical phenotype in delineating etiology and predicting prognosis.

Neurophysiological characteristics of reward processing in individuals at different levels of gaming

Altered reward processing has been repeatedly reported in Internet gaming disorder (IGD). However, it remains unclear whether these changes are linked to the severity of addictive symptoms or the extent of gaming experience. This study examined the neurophysiological responses regarding reward anticipation and consummation in individuals at different levels of gaming (including 22 casual gamers, 31 regular gamers, and 27 individuals with IGD) through a monetary incentive delay task. Three event-related potential components during reward anticipation-cue-related P300 (Cue-P3), contingent negative variation, and stimulus-preceding negativity (SPN)-and two during reward consummation-feedback-related negativity and feedback-related P300 (FB-P3)-were measured. We found that IGD individuals exhibited greater Cue-P3 but lower SPN amplitude compared to casual gamers, while regular gamers fell between the two without significant differences. Regressions indicated that more extensive gaming experience, rather than the severity of the symptoms, primarily contributed to the increased Cue-P3 in IGD. No group differences were found during reward consummation. Our results highlight disrupted reward anticipation processing in IGD, characterized by increased attention bias toward reward cues (Cue-P3) but diminished cognitive resources for reward anticipation (SPN) and emphasize the role of gaming experience in increased attention bias in IGD.

The ERP Components of Reward Processing Modulated by Status-Related Social Comparison

Background

Although social status is closely related to income distribution, few studies have focused on social comparisons caused by income distribution based on social status.

Purpose

The neural indices of status-related social comparisons were investigated by modifying the classical social comparison task with the incorporation of event-related potentials (ERPs).

Methods

The study employed a total of 29 subjects (15 females), the status scores of whom were initially obtained through the utilization of classical measurements of objective (7 items) and subjective (2 items) socioeconomic status. Subsequently, the subjects were required to complete a dot-estimation task. To induce status-related and response-related (upward, equal, and downward) social comparisons, subjects were informed that rewards were distributed based on whether their status score or their response was superior to that of a selected competitor.

Results

The behavioral results demonstrated that status-related social comparisons were perceived as more unfair than response-related social comparisons. The ERP results indicated that the cue-P3 amplitude was lower under status-related cues than response-related cues. Additionally, the amplitude of feedback-related negativity was larger under status-related equal comparisons than response-related equal comparisons. Furthermore, the P3 amplitude was larger under status-related upward comparisons relative to response-related upward comparisons.

Conclusion

The findings indicated that status-related comparisons may contribute to the development of unfair consideration (enhanced FRN) and a reduction in task motivations (lowered cue-P3). Additionally, the status-related upward comparison may serve as a significant factor in the onset of relative deprivation (enhanced P3). It would therefore be beneficial to gain further insight into the neural basis of social comparisons.

Neurophysiological Correlates of Near-Wins in Gambling: A Systematic Literature Review

Identification of specific patterns of brain activity related to problem gambling may provide a deeper understanding of its underlying mechanisms, highlighting the importance of neurophysiological studies to better understand development and persistence of gambling behavior. The patterns of cognitive functioning have been investigated through electroencephalography (EEG) studies based on the near-win/near-miss (NW) effect. The main goal of the present study was to evaluate the neurophysiological basis of NWs and their modulation by gambling problems through a systematic review of event-related potentials (ERP) studies elicited by feedback events. The review followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA). A total of 15 studies were included, 12 comprising non-problem gamblers (NPGs) and three comparing problem gamblers (PGs) with matched controls. For the P300 component, the win outcome elicited a larger amplitude than the other outcomes (NW and loss), followed by the NW outcome, which elicited a larger amplitude than loss in some studies. For feedback-related negativity (FRN), the loss outcome evoked a more negative amplitude in several studies, despite eliciting a similar amplitude to NW outcomes in others. For PGs, the NW outcome evoked a higher amplitude of P300 than loss, while NPGs showed a similar amplitude to both outcomes. The present review gathered information from different sources and provides a consistent view of the different studies. However, studies lack systematic and robust methodologies, leading to inconsistent results and making it difficult to reach any definitive conclusions.

Anticipatory and consummatory neural correlates of monetary and music rewarding stimuli

Most of the literature on the neural bases of human reward and punishment processing has used monetary gains and losses, but less is known about the neurophysiological mechanisms underlying the anticipation and consumption of other types of rewarding stimuli. In the present study, EEG was recorded from 19 participants who completed a modified version of the Monetary Incentive Delay (MID) task. During the task, cues providing information about potential future outcomes were presented to the participants. Then, they had to respond rapidly to a target stimulus to win money or listening to pleasant music, or to avoid losing money or listening to unpleasant music. Results revealed similar responses for monetary and music cues, with increased activity for cues indicating potential gains compared to losses. However, differences emerged in the outcome phase between money and music. Monetary outcomes showed an interaction between the type of the cue and the outcome in the Feedback Related Negativity and Fb-P3 ERPs and increased theta activity increased for negative feedbacks. In contrast, music outcomes showed significant interactions in the Fb-P3 and theta activities. These findings suggest similar neurophysiological mechanisms in processing cues for potential positive or negative outcomes in these two types of stimuli.

Electrophysiological Correlates of Reward Anticipation in Subjects with Schizophrenia: An ERP Microstate Study

The current study aimed to investigate alterations of event-related potentials (ERPs) microstate during reward anticipation in subjects with schizophrenia (SCZ), and their association with hedonic experience and negative symptoms. EEG data were recorded in thirty SCZ and twenty-three healthy controls (HC) during the monetary incentive delay task in which reward, loss and neutral cues were presented. Microstate analysis and standardized low-resolution electromagnetic tomography (sLORETA) were applied to EEG data. Furthermore, analyses correlating a topographic index (the ERPs score), calculated to quantify brain activation in relationship to the microstate maps, and scales assessing hedonic experience and negative symptoms were performed. Alterations in the first (125.0-187.5 ms) and second (261.7-414.1 ms) anticipatory cue-related microstate classes were observed. In SCZ, reward cues were associated to shorter duration and earlier offset of the first microstate class as compared to the neutral condition. In the second microstate class, the area under the curve was smaller for both reward and loss anticipation cues in SCZ as compared to HC. Furthermore, significant correlations between ERPs scores and the anticipation of pleasure scores were detected, while no significant association was found with negative symptoms. sLORETA analysis showed that hypo-activation of the cingulate cortex, insula, orbitofrontal and parietal cortex was detected in SCZ as compared to HC. Abnormalities in ERPs could be traced already during the early stages of reward processing and were associated with the anticipation of pleasure, suggesting that these dysfunctions might impair effective evaluation of incoming pleasant experiences. Negative symptoms and anhedonia are partially independent results.

Repetition suppression between monetary loss and social pain

The relationship between monetary loss and pain has been a recent research focus. Prior studies found similarities in the network representation patterns of monetary loss and pain, particularly social pain. However, the neural level evidence was lacking. To address this, we conducted an ERP experiment to investigate whether there is a repetitive suppression effect of monetary loss on the neural activity of social pain, aiming to understand if they engage overlapping neuronal populations. The results revealed that FRN amplitudes showed repetitive suppression effects of monetary loss on the neural activity of social pain. Our study suggests that monetary loss and social pain share common neural bases, indicating that they might involve shared neural modules related to cognitive conflict and affective appraisal.

Early and late contingent negative variation (CNV) reflect different aspects of deficits in schizophrenia

Abnormal reward processing and psychomotor slowing are well-known in schizophrenia (SZ). As a slow frontocentral potential, contingent negative variation (CNV) is associated with anticipatory attention, motivation and motor planning. The present study aims to evaluate the early and late amplitude and latencies of CNV in patients with SZ compared to healthy controls during a reward processing task and to show its association with clinical symptoms. We recruited 21 patients with SZ and 22 healthy controls to compare early and late CNV amplitude and latency values during a Monetary Incentive Delay (MID) Task between groups. Patients' symptom severity, levels of negative symptoms and depressive symptoms were assessed. Clinical features of the patients were further examined for their relation with CNV components. In conclusion, we found decreased early CNV amplitudes in SZ during the reward condition. They also displayed diminished and shortened late CNV responses for incentive cues, specifically at the central location. Furthermore, early CNV amplitudes exhibited a significant correlation with positive symptoms. Both CNV latencies were linked with medication dosage and the behavioural outcomes of the MID task. We revealed that early and late CNV exhibit different functions in neurophysiology and correspond to various facets of the deficits observed in patients. Our findings also emphasized that slow cortical potentials are indicative of deficient motivational processes as well as impaired reaction preparation in SZ. To gain a deeper understanding of the cognitive and motor impairments associated with psychosis, future studies must compare the effects of CNV in the early and late phases.

Pathways to adolescent social anxiety: Testing interactions between neural social reward function and perceived social threat in daily life

Recent theories suggest that for youth highly sensitive to incentives, perceiving more social threat may contribute to social anxiety (SA) symptoms. In 129 girls (ages 11-13) oversampled for shy/fearful temperament, we thus examined how interactions between neural responses to social reward (vs. neutral) cues (measured during anticipation of peer feedback) and perceived social threat in daily peer interactions (measured using ecological momentary assessment) predict SA symptoms two years later. No significant interactions emerged when neural reward function was modeled as a latent factor. Secondary analyses showed that higher perceived social threat was associated with more severe SA symptoms two years later only for girls with higher basolateral amygdala (BLA) activation to social reward cues at baseline. Interaction effects were specific to BLA activation to social reward (not threat) cues, though a main effect of BLA activation to social threat (vs. neutral) cues on SA emerged. Unexpectedly, interactions between social threat and BLA activation to social reward cues also predicted generalized anxiety and depression symptoms two years later, suggesting possible transdiagnostic risk pathways. Perceiving high social threat may be particularly detrimental for youth highly sensitive to reward incentives, potentially due to mediating reward learning processes, though this remains to be tested.

Tailoring transcranial alternating current stimulation based on endogenous event-related P3 to modulate premature responses: a feasibility study

Background

Transcranial alternating current stimulation (tACS) is a brain stimulation method for modulating ongoing endogenous oscillatory activity at specified frequency during sensory and cognitive processes. Given the overlap between event-related potentials (ERPs) and event-related oscillations (EROs), ERPs can be studied as putative biomarkers of the effects of tACS in the brain during cognitive/sensory task performance.

Objective

This preliminary study aimed to test the feasibility of individually tailored tACS based on individual P3 (latency and frequency) elicited during a cued premature response task. Thus, tACS frequency was individually tailored to match target-P3 ERO for each participant. Likewise, the target onset in the task was adjusted to match the tACS phase and target-P3 latency.

Methods

Twelve healthy volunteers underwent tACS in two separate sessions while performing a premature response task. Target-P3 latency and ERO were calculated in a baseline block during the first session to allow a posterior synchronization between the tACS and the endogenous oscillatory activity. The cue and target-P3 amplitudes, delta/theta ERO, and power spectral density (PSD) were evaluated pre and post-tACS blocks.

Results

Target-P3 amplitude significantly increased after activetACS, when compared to sham. Evoked-delta during cue-P3 was decreased after tACS. No effects were found for delta ERO during target-P3 nor for the PSD and behavioral outcomes.

Conclusion

The present findings highlight the possible effect of phase synchronization between individualized tACS parameters and endogenous oscillatory activity, which may result in an enhancement of the underlying process (i.e., an increase of target-P3). However, an unsuccessful synchronization between tACS and EEG activity might also result in a decrease in the evoked-delta activity during cue-P3. Further studies are needed to optimize the parameters of endogenous activity and tACS synchronization. The implications of the current results for future studies, including clinical studies, are further discussed since transcranial alternating current stimulation can be individually tailored based on endogenous event-related P3 to modulate responses.

Competition influences outcome processing involving social comparison: An ERP study

In a complicated social context, outcome evaluation involves not only oneself but also others in relation to the self (i.e., social comparison). Previous event-related potential (ERP) studies have investigated the processing of social comparison-related outcomes when one's interests are independent of the interests of others (i.e., noncompetition circumstances). However, it is unclear how social comparison-related outcomes are processed in the brain when there are conflicts of interest between oneself and others (i.e., competition circumstances). To address this issue, participants in the current study were asked to perform an attentional task with several peers and were subsequently presented with self-related outcomes (i.e., the performance difference between the current trial and several preceding trials) and social comparison-related outcomes (i.e., the performance difference between oneself and their peer). Importantly, rewards and punishments were based on social comparison-related outcomes in the competition condition and on self-related outcomes in the noncompetition condition. ERP results revealed that in the competition condition, positive outcomes involving social comparison elicited a greater P300 response than negative outcomes, whereas this effect was not observed in the noncompetition condition. Additionally, there was generally a larger late positive potential (LPP) response to negative outcomes involving social comparison than to positive outcomes only when one obtained a self-related positive outcome in the competition condition. These findings suggest that competition might strengthen outcome processing involving social comparison at late time ranges relying on self-related outcomes to some extent.

Distinct neural dynamics of the observed ostracism effect in decision-making under risk and ambiguity

Observational ostracism, as a form of social exclusion, can significantly affect human behavior. However, the effects of observed ostracism on risky and ambiguous decision-making and the underlying neural mechanisms remain unclear. This event-related potential study investigated these issues by involving participants in a wheel-of- fortune task, considering observed ostracism and inclusion contexts. The results showed that the cue-P3 component was more enhanced during the choice phase for risky decisions than for ambiguous decisions in the observed inclusion contexts but not in the observed ostracism contexts. During the outcome evaluation phase, feedback-related negativity amplitudes following both risky and ambiguous decisions were higher in the no-gain condition than in the gain condition in the observed inclusion context. In contrast, this effect was only observed following risky decisions in the observed ostracism context. The feedback-P3 component did not exhibit an observed ostracism effect in risky and ambiguous decision-making tasks. Risk levels further modulated the cue-P3 and feedback-related negativity components, while ambiguity levels further modulated the feedback-P3 components. These findings demonstrate a neural dissociation between risk and ambiguity decision-making during observed ostracism that unfolds from the choice phase to the outcome evaluation phase.

Specific mechanisms underlying executive and emotional apathy: A phenotyping study

Apathy is a behavioral symptom prevalent both in neuropsychiatric pathologies and in the healthy population. However, the knowledge of the cognitive and neural mechanisms underlying apathy is still very limited, even if clinical and fMRI data support the existence of three forms of apathy (executive, emotional, initiative). These forms could be explained by the alteration of specific mechanisms. This present study's aim is to specify the cognitive and neuronal mechanisms of executive and emotional apathy. We used an EEG study conducted on 68 subjects comprising two groups of young people with specific executive or emotional phenotypes of apathy and one group with no apathy. Despite having symptom of apathy, participants were free of any neurological, metabolic, or psychiatric diagnoses and with high education. Two tasks were used: the DPX for cognitive control and the MID for motivation. Our results showed that distinct mechanisms underlie these two forms of apathy, and, for the first time, we specified these mechanisms. A deficit of the proactive control mode, reflected by a reduced probe-N2 amplitude in AY trials, underlies the executive form of apathy (p < .03), whereas liking motivational blunting, highlighted by a reduced LPP amplitude for financial loss, characterizes the emotional form (p < .04). The main limit of the results is that generalizability to the general population may be reduced since the apathetic samples were chosen for having a specific form of apathy. To conclude, better knowledge of these mechanisms informs new, more targeted treatments, both pharmacological and non-pharmacological, necessary for reducing the debilitating consequences of apathy.

Enhanced Punishment Responses in Patients With Schizophrenia: An Event-Related Potential Study

It is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia. Reduced reward anticipation has been suggested as a core symptom of schizophrenia. The Monetary Incentive Delay Task (MID) is frequently used to detect reward anticipation. The present study aims to evaluate the amplitude and latency of event-related potential (ERP) P300 in patients with schizophrenia (SCH) compared to healthy controls during the MID task. Twenty patients with SCH and 21 demographically matched healthy controls (HC) were included in the study. ERP P300 amplitude and latency values were compared between groups using an MID task in which reward and loss cues were presented. Relations between P300 and clinical facets were investigated in the patient group. SCH group had enhanced mean P300 amplitudes and delayed peak latency in the punishment condition compared with HC. These higher responses were also associated with negative symptoms. SCH group showed altered reward processing as being more sensitive to loss of reward conditions as firstly evidenced by electrophysiological methods, possibly due to abnormality in various systems including social withdrawal, social defeat, and behavioral inhibition system.

The effect of hair type and texture on electroencephalography and event-related potential data quality

Research utilizing event-related potential (ERP) methods is generally biased with regard to sample representativeness. Among the myriad of factors that contribute to sample bias are researchers' assumptions about the extent to which racial differences in hair texture, volume, and style impact electrode placement, and subsequently, study eligibility. The current study examines these impacts using data collected from n = 213 individuals ages 17-19 years, and offers guidance on collection of ERP data across the full spectrum of hair types. Individual differences were quantified for hair texture using a visual scale, and for hair volume by measuring the amount of gel used in cap preparation. Electroencephalography data quality was assessed with multiple metrics at the preprocessing, post-processing, and variable generation stages. Results indicate that hair volume is associated with small, but systematic differences in signal quality and signal amplitude. Such differences are highly problematic as they could be misattributed to cognitive differences among groups. However, inclusion of gel volume as a covariate to account for individual differences in hair volume significantly reduced, and in most cases eliminated, group differences. We discuss strategies for overcoming real and perceived technical barriers for researchers seeking to achieve greater inclusivity and representativeness in ERP research.

Transcranial Direct Current Stimulation Decreases P3 Amplitude and Inherent Delta Activity during a Waiting Impulsivity Paradigm: Crossover Study

The inability to wait for a target before initiating an action (i.e., waiting impulsivity) is one of the main features of addictive behaviors. Current interventions for addiction, such as transcranial Direct Current Stimulation (tDCS), have been suggested to improve this inability. Nonetheless, the effects of tDCS on waiting impulsivity and underlying electrophysiological (EEG) markers are still not clear. Therefore, this study aimed to evaluate the effects of neuromodulation over the right inferior frontal gyrus (rIFG) on the behavior and EEG markers of reward anticipation (i.e., cue and target-P3 and underlying delta/theta power) during a premature responding task. For that, forty healthy subjects participated in two experimental sessions, where they received active and sham tDCS over the rIFG combined with EEG recording during the task. To evaluate transfer effects, participants also performed two control tasks to assess delay discounting and motor inhibition. The active tDCS decreased the cue-P3 and target-P3 amplitudes, as well as delta power during target-P3. While no tDCS effects were found for motor inhibition, active tDCS increased the discounting of future rewards when compared to sham. These findings suggest a tDCS-induced modulation of the P3 component and underlying oscillatory activity during waiting impulsivity and the discounting of future rewards.

Effort discounts reward-based control allocation: A neurodynamic perspective

The amount of cognitive and neural resources allocated to a task is largely determined by the reward we can expect. However, it remains under-appreciated how this reward-expectation-based control allocation is modulated by effort expenditure. The present event-related potential study investigated this issue through the lens of neural dynamics. Thirty-four participants completed an effort-based monetary incentive delay task while their EEG was recorded. Effort demand was manipulated by adding no (low effort) or much (high effort) noise to the target. Behaviorally, participants exhibited reward-related speeding regardless of effort expenditure, as revealed by faster RTs for reward than neutral trials. Our ERP results demonstrated a widespread facilitatory influence of reward expectation on neural dynamics extending from cue evaluation as indexed by the cue-P3, to control preparation as indexed by the contingent negative variation (CNV), and finally to control engagement as indexed by the target-P3. Critically, the neural facilitation was discounted by effort expenditure during both the control-preparation and control-engagement stages instead of the cue-evaluation stage. Overall, this study provides neurodynamic evidence that control allocation is determined by reward and effort via a cost-benefit analysis.

Lack of effect of methamphetamine on reward-related brain activity in healthy adults

INTRODUCTION

Stimulant drugs are thought to alter processing of rewarding stimuli. However, the mechanisms by which they do this are not fully understood.

METHOD

In this study we used EEG to assess effects of single doses of methamphetamine (MA) on neural responses during anticipation and receipt of reward in healthy volunteers. Healthy young men and women (N = 28) completed three sessions in which they received placebo, a low MA dose (10 mg) or a higher MA dose (20 mg) under double blind conditions. Subjective and cardiovascular measures were obtained, and EEG was used to assess brain activity during an electrophysiological version of the Monetary Incentive Delay (eMID) task.

RESULTS

EEG measures showed expected patterns during anticipation and receipt of reward, and MA produced its expected effects on mood and cardiovascular function. However, MA did not affect EEG responses during either anticipation or receipt of rewards.

CONCLUSIONS

These findings suggest that the effects of MA on EEG signals of reward processing are subtle, and not related to the drug's effects on subjective feelings of well-being. The findings contribute to our understanding of the neural effects of MA during behaviors related to reward.

Reduced Reward Processing in Schizophrenia: A Comprehensive EEG Event-Related Oscillation Study

It is well known that abnormal reward processing is a characteristic feature of various psychopathologies including schizophrenia (SZ). Reduced reward anticipation has been suggested as a core symptom of SZ. The present study aims to evaluate the event-related oscillations (EROs) delta, theta, alpha, beta, and gamma in patients with SZ during the Monetary Incentive Delay (MID) task, which elicits the neural activity of reward processing. Twenty-one patients with SZ and twenty-two demographically matched healthy controls were included in the study. EROs were compared between groups and correlation analyses were conducted to determine a possible relationship between clinical scores and ERO values. Compared with healthy controls, the SZ group had reduced (1) delta and theta amplitudes in the reward condition (2) total beta and non-incentive cue-related beta amplitudes, and (3) incentive cue-related frontal gamma amplitudes. These reductions can be interpreted as impaired dopaminergic neurotransmission and disrupted cognitive functioning in the reward processing of SZ. In contrast, SZ patients showed higher incentive cue-related theta and occipital gamma amplitudes compared to controls. These increments may reflect negative symptoms in SZ. Moreover, theta amplitudes showed a negative correlation with Calgary Depression Scale for Schizophrenia scores and a positive correlation with attentional impulsivity. This is the first study showing the impairments of SZ patients in EROs from delta to gamma frequency bands compared with healthy controls during reward anticipation. Being the first comprehensive study, our results can be interpreted as providing evidence for disrupted brain dynamics in the reward processing of SZ studied by EROs. It may become possible to help patients' wellness by improving our understanding of reward processing in schizophrenia and developing innovative rehabilitation treatments based on these findings.

Comparing monetary gain and loss in the monetary incentive delay task: EEG evidence

What is more effective to guide behavior: The desire to gain or the fear to lose? Electroencephalography (EEG) studies have yielded inconsistent answers. In a systematic exploration of the valence and magnitude parameters in monetary gain and loss processing, we used time-domain and time-frequency-domain analyses to uncover the underlying neural processes. A group of 24 participants performed a monetary incentive delay (MID) task in which cue-induced anticipation of a high or low magnitude of gain or loss was manipulated trial-wise. Behaviorally, the anticipation of both gain and loss expedited responses, with gain anticipation producing greater facilitation than loss anticipation. Analyses of cue-locked P2 and P3 components revealed the significant valence main effect and valence × magnitude interaction: amplitude differences between high and low incentive magnitudes were larger with gain vs. loss cues. However, the contingent negative variation component was sensitive to incentive magnitude but did not vary with incentive valence. In the feedback phase, the RewP component exhibited reversed patterns for gain and loss trials. Time-frequency analyses revealed a large increase in delta/theta-ERS oscillatory activity in high- vs. low-magnitude conditions and a large decrease of alpha-ERD oscillatory activity in gain vs. loss conditions in the anticipation stage. In the consumption stage, delta/theta-ERS turned out stronger for negative than positive feedback, especially in the gain condition. Overall, our study provides new evidence for the neural oscillatory features of monetary gain and loss processing in the MID task, suggesting that participants invested more attention under gain and high-magnitude conditions vs. loss and low-magnitude conditions.

Mothers exhibit higher neural activity in gaining rewards for their children than for themselves

Are people willing to exert greater effort to obtain rewards for their children than they are for themselves? Although previous studies have demonstrated that social distance influences neural responses to altruistic reward processing, the distinction between winning rewards for oneself and winning them for one's child is unclear. In the present study, a group of 31 mothers performed a monetary incentive delay task in which cue-induced reward anticipations of winning a reward for themselves, their children and donation to a charity program were manipulated trial-wise, followed by performance-contingent feedback. Behaviorally, the anticipation of winning a reward for their children accelerated participants' responses. Importantly, the electroencephalogram results revealed that across the reward anticipation and consumption phases, the child condition elicited comparable or higher brain responses of participants than the self condition did. The source localization results showed that participants' reward anticipations for their children were associated with more activation in the social brain regions, compared to winning a reward for themselves or a charity donation. Overall, these findings advance our understanding of the neural mechanisms of altruistic reward processing and suggest that the priority of winning a reward for one's child may transcend the limits of the self-advantage effect in reward processing.

Neural abnormalities of reward processing in adolescents with bipolar disorders: An ERP study

Adolescent onset is common in bipolar disorders (BDs) and is associated with a worse illness course in adulthood. A model of BDs suggests that a dysregulated behavioral approach system (BAS), a neural system that mobilizes reward-seeking behavior, is at the root of BDs. Normative adolescence is often accompanied by dynamic changes to neural structures underlying the BAS and related cognitive processes. It is possible that adolescent-onset BDs is associated with abnormal BAS neurodevelopment. Consistently, the present study is the first to compare specific BAS-relevant anticipatory and consummatory reward processes as indexed by event-related potentials (ERPs) in adolescents with BDs and typically developing peers. Using a sample of 43 adolescents with BDs and 56 without psychopathology, we analyzed N1 and P3 responses to anticipatory cues and feedback-related negativity (FRN) and P3 responses to feedback stimuli during a monetary incentive delay (MID) task. Hierarchical linear models examined relationships between ERP amplitudes and diagnostic group, MID condition, sex, and age. During anticipation phase, adolescent boys with BDs exhibited significantly larger N1 amplitudes in loss than even or gain trials. During feedback phase, compared to their healthy peers, adolescents with BDs had smaller FRN amplitudes across all conditions. Additional effects involving age, sex and trial type were observed. The findings indicate subtle, non-ubiquitous BAS-relevant neural abnormalities involving early attentional processes during reward anticipation and reward learning following feedback in adolescents with BDs. Adolescents with BDs did not show overall hypersensitive neural responses to monetary reward anticipation or feedback observed in adults with BDs.

Aberrant reward dynamics in depression with anticipatory anhedonia

OBJECTIVE

Previous studies have shown that anticipatory anhedonia is linked to abnormal reward processing. The present study aimed to explore the underlying neural mechanism of the influence of anticipatory anhedonia symptoms on reward processing.

METHODS

Electrophysiological activities in the anticipatory and consummatory phase were recorded during the Monetary Incentive Delay (MID) task in 24 depressed high anticipatory anhedonia (HAA) patients, 25 depressed low anticipatory anhedonia (LAA) patients, and 29 healthy controls (HC).

RESULTS

We suggested a significant condition × group interaction effect on feedback-related negativity (FRN) amplitudes during the consummatory phase, a smaller FRN in reward cue trails compared with neutral cue trail was revealed in the HC and LAA group, but such reward-related effect was not found in the HAA group. In addition, we found significant correlations between FRN, fb-P3 and cue-N1, cue-N2 in the HC group, besides, significant correlations between FRN, fb-P3 and cue-P2 was also revealed in the HC and LAA group. However, no significant correlation was found in HAA patients.

CONCLUSIONS

Our results suggest that the link between the anticipatory and consummatory phase was interrupted in depressed HAA patients, which may be driven by the aberrant consummatory reward processing.

SIGNIFICANCE

The current study is the first one to demonstrate the influence of anticipatory anhedonia symptom on the association between anticipatory and consummatory phase of reward process.

Be Careful When Using Peer-Influence on Nudging Solicitation: Evidence of Potential Negative Effect from a Sample of Chinese University Students

PURPOSE

Peer information is now commonly used in solicitation. However, scholars have long focused on testing its effectiveness on increasing the donation amount without paying attention to its potential negative effects on donors. Thus, the current study employs high vs low peer donation amount (HPDA vs LPDA) information to explore its effect on "how-much-to-donate" decisions and the corresponding neural and psychological reactions at the same time.

PARTICIPANTS AND METHODS

Student samples from a Chinese university and behavioral experiments with the event-related potential (ERP) method were used in this study.

RESULTS

The behavioral results are consistent with previous research in which HPDA was positively associated with higher donation levels. ERP results show the mechanisms behind decision-making can be summarized into a cognitive approach represented by cost-benefit analysis and an affective approach represented by reward perception. More surprisingly, in contrast to the behavioral results, LPDA elicits higher level of reward perception than HPDA.

CONCLUSION

The results indicate that although HPDA leads to higher levels of donation, donors do not show higher levels of reward anticipation at the neurological level, indicating the increment of donation may come at the cost of donors. Theoretical and practical implications are also discussed.

The domain-variant indirect association between electrophysiological response to reward and ADHD presentations is moderated by dopaminergic polymorphisms

BACKGROUND

Understanding the etiopathogenesis of attention-deficit/hyperactivity disorder (ADHD) may necessitate decomposition of the heterogeneous clinical phenotype into more homogeneous intermediate phenotypes. Reinforcement sensitivity is a promising candidate, but the exact nature of the ADHD-reward relation - including how, for whom, and to which ADHD dimensions atypicalities in reward processing are relevant - is equivocal.

METHODS

Aims were to examine, in a carefully phenotyped sample of adolescents (N = 305; Mage = 15.30 years, SD = 1.07; 39.7% girls), whether functional dopaminergic polymorphisms implicated in both reward processing and ADHD (1) are differentially associated with event-related potentials (ERPs) of reward anticipation at distinct levels of ADHD risk (nno risk = 174, nat-risk = 131, ndiagnosed = 83); and (2) moderate the indirect effect of dispositional affectivity on the association between ERPs and ADHD domains.

RESULTS

In adolescents at-risk for or with ADHD, carrying a hypodopaminergic allele was associated with enhanced ERPs of attention allocation to cue and attenuated ERPs of anticipatory attention to feedback. No associations were observed in adolescents not at-risk for or without ADHD. Controlling for age and sex, both the negative indirect effect of positive affectivity (PA) on the association between ERPs and inattention and the positive indirect effect of PA on the association between ERPs and hyperactivity/impulsivity were supported only for those with high activity dopamine transporter (DAT) alleles.

CONCLUSIONS

Reward and affective processing are promising intermediate phenotypes relevant to disentangling ADHD developmental pathways. Consistent with developmental multifinality, through the successive effects of reward anticipation and positive affectivity, functional dopaminergic variants may confer protection against inattention or risk for hyperactivity/impulsivity.

Reward network dysfunction is associated with cognitive impairment after stroke

Stroke survivors not only suffer from severe motor, speech and neurocognitive deficits, but in many cases also from a "lack of pleasure" and a reduced motivational level. Especially apathy and anhedonic symptoms can be linked to a dysfunction of the reward system. Rewards are considered as important co-factor for learning, so the question arises as to why and how this affects the rehabilitation of stroke patients. We investigated reward behaviour, learning ability and brain network connectivity in acute (3-7d) mild to moderate stroke patients (n = 28) and age-matched healthy controls (n = 26). Reward system activity was assessed using the Monetary Incentive Delay task (MID) during magnetoencephalography (MEG). Coherence analyses were used to demonstrate reward effects on brain functional network connectivity. The MID-task showed that stroke survivors had lower reward sensitivity and required greater monetary incentives to improve performance and showed deficits in learning improvement. MEG-analyses showed a reduced network connectivity in frontal and temporoparietal regions. All three effects (reduced reward sensitivity, reduced learning ability and altered cerebral connectivity) were found to be closely related and differed strongly from the healthy group. Our results reinforce the notion that acute stroke induces reward network dysfunction, leading to functional impairment of behavioural systems. These findings are representative of a general pattern in mild strokes and are independent of the specific lesion localisation. For stroke rehabilitation, these results represent an important point to identify the reduced learning capacity after stroke and to implement individualised recovery exercises accordingly.

Reward responsiveness in autism and autistic traits - Evidence from neuronal, autonomic, and behavioural levels

Autism has been linked to atypicalities in reward processing, especially in the social domain. However, results are heterogeneous, and their interpretation is hindered by the use of personally non-relevant social rewards. In this study we investigated behavioural (reaction times), neuronal (event-related potentials), and autonomic (pupil sizes) responses to personally relevant social rewards, money, and neutral outcomes in 26 autistic and 53 non-autistic subjects varying in levels of autistic traits. As hypothesised and preregistered, autism and autistic traits did not differently influence responses to social, monetary, or neutral outcomes on either response level. While groups did not differ in behaviour (reaction times), autism was linked to generally enhanced brain responses in early anticipation and larger pupil constrictions in reward reception. Together, these results suggest that when using personally relevant stimuli, autism is linked to generally preserved, although less neuronally efficient processing of rewards. Considering the role of social relevance in reward processing, we propose an interpretation of contradictory evidence from clinical practice and empirical research.

Effects of medial prefrontal transcranial alternating current stimulation on neural activity and connectivity in people with Huntington's disease and neurotypical controls

We investigated the effects of transcranial alternating current stimulation (tACS) targeted to the medial prefrontal cortex (mPFC) on resting electroencephalographic (EEG) indices of oscillatory power, aperiodic exponent and offset, and functional connectivity in 22 late premanifest and early manifest stage individuals with HD and 20 neurotypical controls. Participants underwent three 20-minute sessions of tACS at least 72 hours apart; one session at alpha frequency (either each participant's Individualised Alpha Frequency (IAF), or 10Hz when an IAF was not detected); one session at delta frequency (2Hz); and a session of sham tACS. Session order was randomised and counterbalanced across participants. EEG recordings revealed a reduction of the spectral exponent ('flattening' of the 1/f slope) of the eyes-open aperiodic signal in participants with HD following alpha-tACS, suggestive of an enhancement in excitatory tone. Contrary to expectation, there were no changes in oscillatory power or functional connectivity in response to any of the tACS conditions in the participants with HD. By contrast, alpha-tACS increased delta power in neurotypical controls, who further demonstrated significant increases in theta power and theta functional connectivity in response to delta-tACS. This study contributes to the rapidly growing literature on the potential experimental and therapeutic applications of tACS by examining neurophysiological outcome measures in people with HD as well as neurotypical controls.

Medial prefrontal transcranial alternating current stimulation for apathy in Huntington's disease

We investigated the effects of transcranial alternating current stimulation (tACS) targeted to the bilateral medial prefrontal cortex (mPFC) and administered at either delta or alpha frequencies, on brain activity and apathy in people with Huntington's disease (HD) (n = 17). Given the novelty of the protocol, neurotypical controls (n = 20) were also recruited. All participants underwent three 20-min sessions of tACS; one session at alpha frequency (Individualised Alpha Frequency (IAF), or 10 Hz when an IAF was not detected); one session at delta frequency (2 Hz); and a session of sham tACS. Participants completed the Monetary Incentive Delay (MID) task with simultaneous recording of EEG immediately before and after each tACS condition. The MID task presents participants with cues signalling potential monetary gains or losses that increase activity in key regions of the cortico-basal ganglia-thalamocortical networks, with dysfunction of the latter network being implicated in the pathophysiology of apathy. We used the P300 and Contingent Negative Variation (CNV) event-related potentials elicited during the MID task as markers of mPFC engagement. HD participants' CNV amplitude significantly increased in response to alpha-tACS, but not delta-tACS or sham. Neurotypical controls' P300 and CNV were not modulated by any of the tACS conditions, but they did demonstrate a significant decrease in post-target response times following alpha-tACS. We present this as preliminary evidence of the ability of alpha-tACS to modulate brain activity associated with apathy in HD.

Adolescent ADHD and electrophysiological reward responsiveness: A machine learning approach to evaluate classification accuracy and prognosis

We evaluated event-related potential (ERP) indices of reinforcement sensitivity as ADHD biomarkers by examining, in N=306 adolescents (M_age=15.78, SD=1.08), the extent to which ERP amplitude and latency variables measuring reward anticipation and response (1) differentiate, in age- and sex-matched subsamples, (i) youth with vs. without ADHD, (ii) youth at-risk for vs. not at-risk for ADHD, and, in the with ADHD subsample, (iii) youth with the inattentive vs. the hyperactive/impulsive (H/I) and combined presentations. We further examined the extent to which ERP variables (2) predict, in the ADHD subsample, substance use (i) concurrently and (ii) prospectively at 18-month follow-up. Linear support vector machine analyses indicated ERPs weakly differentiate youth with/without (65%) - and at-risk for/not at-risk for (63%) - ADHD but better differentiate ADHD presentations (78%). Regression analyses showed in adolescents with ADHD, ERPs explain a considerable proportion of variance (50%) in concurrent alcohol use and, controlling for concurrent marijuana and tobacco use, explain a considerable proportion of variance (87 and 87%) in, and predict later marijuana and tobacco use. Findings are consistent with the dual-pathway model of ADHD. Results also highlight limitations of a dichotomous, syndromic classification and indicate differences in neural reinforcement sensitivity are a promising ADHD prognostic biomarker.

Distinct neural dynamics underlying risk and ambiguity during valued-based decision making

Uncertainty can be fractioned into risk and ambiguity psychologically and neurobiologically. However, whether and how risk and ambiguity are dissociated in terms of neural dynamics during value-based decision making remain elusive. The present event-related potential (ERP) study addressed these issues by asking participants to perform a wheel-of-fortune task either during a risky context (Experiment 1; N = 30) where outcome probability was known or during an ambiguous context (Experiment 2; N = 30) where outcome probability was unknown. Results revealed that the cue-P3 was more enhanced for risk versus ambiguity during the anticipatory phase, whereas the RewP was more increased for ambiguity than risk during the consummatory phase. Moreover, the SPN and the fb-P3 components were further modulated by the levels of risk and ambiguity, respectively. These findings demonstrate a neural dissociation between risk and ambiguity, which unfolds from the anticipatory phase to the consummatory phase.

Valence precedes value in neural encoding of prediction error

Event-related potentials that follow feedback in reinforcement learning tasks have been proposed to reflect neural encoding of prediction errors. Prior research has shown that in the interval of 240-340 ms multiple different prediction error encodings appear to co-occur, including a value signal carrying signed quantitative prediction error and a valence signal merely carrying sign. The effects used to identify these two encoders, respectively a sign main effect and a sign × size interaction, do not reliably discriminate them. A full discrimination is made possible by comparing tasks in which the reinforcer available on a given trial is set to be either appetitive or aversive against tasks where a trial allows the possibility of either. This study presents a meta-analysis of reinforcement learning experiments, the majority of which presented the possibility of winning or losing money. Value and valence encodings were identified by conventional difference wave methodology but additionally by an analysis of their predicted behavior using a Bayesian analysis that incorporated nulls into the evidence for each encoder. The results suggest that a valence encoding, sensitive only to the available outcomes on the trial at hand precedes a later value encoding sensitive to the outcomes available in the wider experimental context. The implications of this for modeling computational processes of reinforcement learning in humans are discussed.

Neural deficits in anticipatory and consummatory reward processing are uniquely associated with current depressive symptoms during adolescence

Deficits within the consummatory phase of reward processing are associated with increased depression symptoms and risk; however, few studies have also examined other aspects of reward processing in relation to depression. In the current study, a community sample of 121 adolescents (M_age  = 13.1, Min = 11.14; Max = 15.12; 54% male) completed self-report questionnaires to assess depressive symptoms and the monetary incentive delay (MID) task while EEG was recorded. Results indicated that a reduced cue-P300 as well as a reduced reward positivity (RewP) and feedback negativity (FN) to gain and loss feedback, respectively, were associated with increased depressive symptoms; on the other hand, SPN and feedback P300 were unrelated to depressive symptoms. An exploratory multiple regression analysis revealed that a reduced money cue-P300, a reduced RewP, and a reduced (i.e., less negative) FN, all explained unique variance in depressive symptoms. The current study demonstrates that reduced cue-P300, RewP, and FN amplitudes may reflect distinct deficits in reward processing among adolescents with increased depressive symptoms. Notably, this study is one of the first to leverage the MID task in adolescents in relation to depressive symptoms, allowing for a more in-depth view of the individual differences in reward processing among adolescents with increased depressive symptomatology.

Low doses of lysergic acid diethylamide (LSD) increase reward-related brain activity

Renewed interest in classic psychedelics as treatments for psychiatric disorders warrants a deeper understanding of their neural mechanisms. Single, high doses of psychedelic drugs have shown promise in treating depressive disorders, perhaps by reversing deficits in reward processing in the brain. In addition, there are anecdotal reports that repeated ingestion of low doses of LSD, or "microdosing", improve mood, cognition, and feelings of wellbeing. However, the effects of low doses of classic psychedelics on reward processing have not been studied. The current study examined the effects of two single, low doses of LSD compared to placebo on measures of reward processing. Eighteen healthy adults completed three sessions in which they received placebo (LSD-0), 13 μg LSD (LSD-13) and 26 μg LSD (LSD-26) in a within-subject, double-blind design. Neural activity was recorded while participants completed the electrophysiological monetary incentive delay task. Event-related potentials were measured during feedback processing (Reward-Positivity: RewP, Feedback-P3: FB-P3, and Late-Positive Potential: LPP). Compared to placebo, LSD-13 increased RewP and LPP amplitudes for reward (vs. neutral) feedback, and LSD-13 and LSD-26 increased FB-P3 amplitudes for positive (vs. negative) feedback. These effects were unassociated with most subjective measures of drug effects. Thus, single, low doses of LSD (vs. placebo) increased three reward-related ERP components reflecting increased hedonic (RewP), motivational (FB-P3), and affective processing of feedback (LPP). These results constitute the first evidence that low doses of LSD increase reward-related brain activity in humans. These findings may have important implications for the treatment of depressive disorders.

The modulation of attentional deployment on emotional sensitivity to missed opportunity in depressive individuals: An event-related potential study

BACKGROUND

Depression affects individuals' physical and mental health seriously. It's important to explore the pathological mechanisms underlying depression. However, the emotional sensitivity to missed opportunity in depressive individuals and whether attentional deployment influences it remain unclear. The exploration of these questions could help to find novel approaches for the treatment of depression.

METHODS

Experiment 1 investigated the emotional sensitivity to missed opportunity in depressive participants during a sequential risk-taking task relative to healthy participants. Experiment 2 added attentional deployment manipulation to the task, i.e., inducing participants to focus on the positive or negative part of decision outcome, and investigated the modulation of attentional deployment on depressive participants' emotional sensitivity to missed opportunity and the neural mechanisms underlying this process by using EEG.

RESULTS

Depressive participants showed stronger emotional sensitivity to missed opportunity and LPP was a biomarker of this sensitivity. Moreover, focusing on the positive part of outcome reduced depressive participants' emotional sensitivity to missed opportunity effectively, and alpha power in the parietal area played a key role in this process.

CONCLUSIONS

The current study primarily revealed that depressive individuals were more sensitive to missed opportunity and attentional deployment was an effective way to modulate this sensitivity.

The potential application of event-related potentials to enhance research on reward processes in eating disorders

OBJECTIVE

Reward-related processes have been posited as key mechanisms underlying the onset and persistence of eating disorders, prompting a growing body of research in this area. Existing studies have primarily utilized self-report, behavioral, and functional magnetic resonance imaging measures to interrogate reward among individuals with eating disorders. However, limitations inherent in each of these methods (e.g., poor temporal resolution) may obscure distinct neurocognitive reward processes, potentially contributing to underdeveloped models of reward dysfunction within eating disorders. The temporal precision of event-related potentials (ERPs), derived from electroencephalography, may thus offer a powerful complementary tool for elucidating the neurocognitive underpinnings of reward. Indeed, a considerable amount of research in other domains of psychopathology (e.g., depression, substance use disorders), as well as studies investigating food reward among non-clinical samples, highlights the utility of ERPs for probing reward processes. However, no study to date has utilized ERPs to directly examine reward functioning in eating disorders.

METHODS

In this paper, we review evidence underscoring the clinical utility of ERP measures of reward, as well as a variety of reward-related tasks that can be used to elicit specific ERP components with demonstrated relevance to reward processing. We then consider the ways in which these tasks/components may be used to help answer a variety of open questions within the eating disorders literature on reward.

RESULTS/DISCUSSION

Given the promise of ERP measures of reward to the field of eating disorders, we ultimately hope to spur and guide research in this currently neglected area.

PUBLIC SIGNIFICANCE

Abnormalities in reward functioning appear to contribute to eating disorders. Event-related potentials (ERPs) offer temporally precise measures of neurocognitive reward processing and thus may be important tools for understanding the relationship between reward and disordered eating. However, research in this area is currently lacking. This paper attempts to facilitate the use of ERPs to study reward among individuals with eating disorders by reviewing the relevant theories and methods.

Δ9-THC reduces reward-related brain activity in healthy adults

RATIONALE

Greater availability of cannabis in the USA has raised concerns about adverse effects of the drug, including possible amotivational states. Lack of motivation may be assessed by examining acute effects of cannabinoids on reward processing.

OBJECTIVES

This study examined single doses of delta-9-tetrahydrocannabinol (∆9-THC; 7.5, 15 mg oral) in healthy adults using a version of the monetary incentive delay (MID) task adapted for electroencephalography (EEG; e-MID) in a within-subjects, double blind design.

METHODS

Two phases of reward processing were examined: anticipation, which occurs with presentation of cues that indicate upcoming reward, punishment, or neutral conditions, and outcome, which occurs with feedback indicating hits or misses. During anticipation, we measured two event-related potential (ERP) components: the P300, which measures attention and motivation, and the LPP, which measures affective processing. During outcome processing, we measured P300 and LPP, as well as the RewP, which measures outcome evaluation.

RESULTS

We found that ∆9-THC modulated outcome processing, but not reward anticipation. Specifically, both doses of ∆9-THC (7.5 and 15 mg) reduced RewP amplitudes after outcome feedback (hits and misses) relative to placebo. ∆9-THC (15 mg) also reduced P300 and LPP amplitudes following hits compared to misses, relative to both placebo and 7.5 mg ∆9-THC.

CONCLUSIONS

These findings suggest that ∆9-THC dampens responses to both reward and loss feedback, which may reflect an "amotivational" state. Future studies are needed to determine generalizability of this effect, such as its pharmacological specificity and its specificity to monetary vs other types of reward.

Expectations of immediate and delayed reward differentially affect cognitive task performance

The current study used a modified Monetary Incentive Delay task to examine the neural mechanisms underlying anticipating and receiving an immediate or delayed reward and examined the influence of pursuing these rewards on cognitive task performance. A pre-cue indicating the potential of gaining a monetary reward (immediate-, delayed-, vs. no-reward) was followed by a target stimulus requiring a fast and accurate response. Then, response-contingent feedback was presented indicating whether or not the participant would receive the corresponding reward. Linear mixed-effect models revealed the fastest behavioural responses and the strongest neural activity, as reflected in event-related-potentials and event-related-spectral-perturbation responses, for immediate reward, followed by delayed reward, with the slowest behavioural responses and the weakest neural activities observed in the no-reward condition. Expectations related to the cue-P3 component and the cue-delta activities predicted behavioural performance, especially in the immediate reward condition. Moreover, exploratory analyses revealed that depression moderated the relationship between target-locked neural activity and behavioural performance in the delayed reward condition, with lower neural activity being related to worse behavioural performance amongst participants scoring high on depression. These results indicate that differential value representations formed through delay discounting directly affect neural responses in reward processing and directly influence the effort invested in the current task, which is reflected by behavioural responses and is in agreement with the expected value of control theory.

The Neural and Psychological Processes of Peer-Influenced Online Donation Decision: An Event-Related Potential Study

With the rapid development of information and communication technology (ICT), social media-based donation platforms emerged.¹ These platforms innovatively demonstrate peer information (e.g., number of donated peers) on the donation page, which inevitably brings the peer influence into donors’ donation decision process. However, how the peer influence will affect the psychological process of donation decisions are remained unknown. This study used the number of donated peers to examine the effects of peer influence on donors’ donation decisions and extracted event-related potential (ERP) from electroencephalographic data to explore the underlying psychological process. The behavioral results indicated that the number of donated peers positively influenced donors’ willingness to donate. The ERP results suggested that a larger number of donated peers might indicate a higher level of conformity and greater perceived emotional rewards, as a larger P2 amplitude was observed. Following the early processing of emotional stimuli, cognitive detection of decisional risk took place, and the donors reckoned a smaller number of donated peers as a high potential risk, which was reflected by a larger N2 amplitude. In the later stage, the larger number of donated peers, which represented a higher magnitude of prospective emotional rewards, led to a higher incentive to donate, and reflected in a larger amplitude of P3. Additionally, implications and future directions were discussed.

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.

The influence of reward anticipation on conflict control in children and adolescents: Evidences from hierarchical drift-diffusion model and event-related potentials

Reward is deemed a performance reinforcer. The current study investigated how social and monetary reward anticipation affected cognitive control in 39 children, 40 adolescents, and 40 adults. We found that cognitive control performance improved with age in a Simon task, and the reaction time (RT) was modulated by the reward magnitude. The conflict monitoring process (target N2 amplitudes) of adolescents and the attentional control processes (target P3 amplitudes) of adolescents and adults could be adjusted by reward magnitude, suggesting that adolescents were more sensitive to rewards compared to children. Reward magnitudes influenced the neural process of attentional control with larger P3 in congruent trails than that in incongruent trials only in low reward condition. The result of hierarchical drift-diffusion model indicated that children had slower drift rates, higher decision threshold, and longer non-decision time than adolescents and adults. Adolescents had faster drift rates in monetary task than in social task under the high reward condition, and they had faster drift rates under high reward condition than no reward condition only in the monetary task. The correlation analysis further showed that adults' non-decision time and decision threshold correlated with conflict monitoring process (N2 responses) and attentional control process on conflicts (P3 responses). Adolescents' drift rates associated with neural process of attentional control. The current study reveals that reward magnitude and reward type can modulate cognitive control process, especially in adolescents.

At-risk alcohol users have disrupted valence discrimination during reward anticipation

Alcohol use disorder is characterised by disrupted reward learning, underpinned by dysfunctional cortico-striatal reward pathways, although relatively little is known about the biology of reward processing in populations who engage in risky alcohol use. Cues that trigger reward anticipation can be categorized according to their learnt valence (i.e., positive vs. negative outcomes) and motivational salience (i.e., incentive vs. neutral cues). Separating EEG signals associated with these dimensions is challenging because of their inherent collinearity, but the recent application of machine learning methods to single EEG trials affords a solution. Here, the Alcohol Use Disorders Identification Test (AUDIT) was used to quantify risky alcohol use, with participants split into high alcohol (HA) (n = 22, mean AUDIT score: 13.82) and low alcohol (LA) (n = 22, mean AUDIT score: 5.77) groups. We applied machine learning multivariate single-trial classification to the electroencephalography (EEG) data collected during reward anticipation. The LA group demonstrated significant valence discrimination in the early stages of reward anticipation within the cue-P3 time window (400-550 ms), whereas the HA group was insensitive to valence within this time window. Notably, the LA, but not the HA group demonstrated a relationship between single-trial variability in the early valence component and reaction times for gain and loss trials. This study evidences disrupted hypoactive valence sensitivity in the HA group, revealing potential neurophysiological markers for risky drinking behaviours which place individuals at-risk of adverse health events.

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.

Effects of retrieval-extinction training on internet gaming disorder

BACKGROUND AND AIMS

Internet gaming disorder (IGD) leads to serious impairments in cognitive functions, and lacks of effective treatments. Cue-induced craving is a hallmark feature of this disease and is associated with addictive memory elements. Memory retrieval-extinction manipulations could interfere with addictive memories and attenuate addictive syndromes, which might be a promising intervention for IGD. The aims of this study were to explore the effect of a memory retrieval-extinction manipulation on gaming cue-induced craving and reward processing in individuals with IGD.

METHODS

A total of 49 individuals (mean age: 20.52 ± 1.58) with IGD underwent a memory retrieval-extinction training (RET) with a 10-min interval (R-10min-E, n = 24) or a RET with a 6-h interval (R-6h-E, n = 25) for two consecutive days. We assessed cue-induced craving pre- and post-RET, and at the 1- and 3-month follow-ups. The neural activities during reward processing were also assessed pre- and post-RET.

RESULTS

Compared with the R-6h-E group, gaming cravings in individuals with IGD were significantly reduced after R-10min-E training at the 3-month follow-up (P < 0.05). Moreover, neural activities in the individuals with IGD were also altered after R-10min-E training, which was corroborated by enhanced reward processing, such as faster responses (P < 0.05) and stronger frontoparietal functional connectivity to monetary reward cues, while the R-6h-E training had no effects.

DISCUSSION AND CONCLUSIONS

The two-day R-10min-E training reduced addicts' craving for Internet games, restored monetary reward processing in IGD individuals, and maintained long-term efficacy.

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 the Relationships of P3b with Negative Symptoms and Neurocognition in Subjects with Chronic Schizophrenia

Neurocognitive deficits and negative symptoms (NS) have a pivotal role in subjects with schizophrenia (SCZ) due to their impact on patients' functioning in everyday life and their influence on goal-directed behavior and decision-making. P3b is considered an optimal electrophysiological candidate biomarker of neurocognitive impairment for its association with the allocation of attentional resources to task-relevant stimuli, an important factor for efficient decision-making, as well as for motivation-related processes. Furthermore, associations between P3b deficits and NS have been reported. The current research aims to fill the lack of studies investigating, in the same subjects, the associations of P3b with multiple cognitive domains and the expressive and motivation-related domains of NS, evaluated with state-of-the-art instruments. One hundred and fourteen SCZ and 63 healthy controls (HCs) were included in the study. P3b amplitude was significantly reduced and P3b latency prolonged in SCZ as compared to HCs. In SCZ, a positive correlation was found between P3b latency and age and between P3b amplitude and the Attention-vigilance domain, while no significant correlations were found between P3b and the two NS domains. Our results indicate that the effortful allocation of attention to task-relevant stimuli, an important component of decision-making, is compromised in SCZ, independently of motivation deficits or other NS.