Using Multilevel Modeling to Examine Blunted Neural Responses to Reward in Major Depression

Event-related potentials of social comparisons in depression and social anxiety

Social comparison is central in human life and can be especially challenging in depression and social anxiety. We assessed event-related potentials and emotions using a social comparison task in which participants received feedback on both their own and a co-player's performance, in participants with depression and/or social anxiety (n = 63) and healthy controls (n = 72). Participants reported more negative emotions for downward (being better than the co-player [participant correct, co-player wrong]) and upward (being worse than the co-player [participant wrong, co-player correct]) comparisons versus even outcomes, with these effects being stronger in depression and social anxiety. At the Medial Frontal Negativity, both controls and depressed participants showed a more negative amplitude for upward comparison versus both the participant and co-player performing wrong. Socially anxious subjects showed the opposite effect, possibly due to greater expectations about being worse than others. The P300 decreased for downward and upward comparisons compared to even outcomes, which may relate to the higher levels of conflict of social inequality. Depressed and socially anxious subjects showed a blunted P300 increase over time in response to the task outcomes, suggesting deficits in allocating resources for the attention of incoming social information. The LPP showed increased amplitude for downward and upward comparison versus the even outcomes and no group effect. Emotional findings suggest that social comparisons are more difficult for depressed and socially anxious individuals. Event-related potentials findings may shed light on the neural substrates of these difficulties.

Neural response to monetary and social rewards and familial risk for psychopathology in adolescent females

BACKGROUND

Adolescence is a key developmental period for the emergence of psychopathology. Reward-related brain activity increases across adolescence and has been identified as a potential neurobiological mechanism of risk for different forms of psychopathology. The reward positivity (RewP) is an event-related potential component that indexes reward system activation and has been associated with both concurrent and family history of psychopathology. However, it is unclear whether the RewP is also associated with higher-order psychopathology subfactors and whether this relationship is present across different types of reward.

METHODS

In a sample of 193 adolescent females and a biological parent, the present study examined the association between adolescent and parental psychopathology subfactors and adolescent RewP to monetary and social reward.

RESULTS

Results indicated that the adolescent and parental distress subfactors were negatively associated with the adolescent domain-general RewP. The adolescent and parental positive mood subfactors were negatively associated with the adolescent domain-general and domain-specific monetary RewP, respectively. Conversely, the adolescent and parental fear/obsessions subfactors were positively associated with the adolescent domain-general RewP. The associations between parental and adolescent psychopathology subfactors and the adolescent RewP were independent of each other.

CONCLUSIONS

The RewP in adolescent females is associated with both concurrent and parental psychopathology symptoms, suggesting that it indexes both severity and risk for higher-order subfactors.

Machine learning reveals differential effects of depression and anxiety on reward and punishment processing

Recent studies suggest that depression and anxiety are associated with unique aspects of EEG responses to reward and punishment, respectively; also, abnormal responses to punishment in depressed individuals are related to anxiety, the symptoms of which are comorbid with depression. In a non-clinical sample, we aimed to investigate the relationships between reward processing and anxiety, between punishment processing and anxiety, between reward processing and depression, and between punishment processing and depression. Towards this aim, we separated feedback-related brain activity into delta and theta bands to isolate activity that indexes functionally distinct processes. Based on the delta/theta frequency and feedback valence, we then used machine learning (ML) to classify individuals with high severity of depressive symptoms and individuals with high severity of anxiety symptoms versus controls. The significant difference between the depression and control groups was driven mainly by delta activity; there were no differences between reward- and punishment-theta activities. The high severity of anxiety symptoms was marginally more strongly associated with the punishment- than the reward-theta feedback processing. The findings provide new insights into the differences in the impacts of anxiety and depression on reward and punishment processing; our study shows the utility of ML in testing brain-behavior hypotheses and emphasizes the joint effect of theta-RewP/FRN and delta frequency on feedback-related brain activity.

The psychometric upgrade psychophysiology needs

Although biological measurements are constrained by the same fundamental psychometric principles as self-report measurements, these essential principles are often neglected in most fields of neuroscience, including psychophysiology. Potential reasons for this neglect could include a lack of understanding of appropriate measurement theory or a lack of accessible software for psychometric analysis. Generalizability theory is a flexible and multifaceted measurement theory that is well suited to handling the nuances of psychophysiological data, such as the often unbalanced number of trials and intraindividual variability of scores of event-related brain potential (ERP) data. The ERP Reliability Analysis Toolbox (ERA Toolbox) was designed for psychophysiologists and is tractable software that can support the routine evaluation of psychometrics using generalizability theory. Psychometrics can guide task refinement, data-processing decisions, and selection of candidate biomarkers for clinical trials. The present review provides an extensive treatment of additional psychometric characteristics relevant to studies of psychophysiology, including validity and validation, standardization, dimensionality, and measurement invariance. Although the review focuses on ERPs, the discussion applies broadly to psychophysiological measures and beyond. The tools needed to rigorously assess psychometric reliability and validate psychophysiological measures are now readily available. With the profound implications that psychophysiological research can have on understanding brain-behavior relationships and the identification of biomarkers, there is simply too much at stake to ignore the crucial processes of evaluating psychometric reliability and validity.

Feedback negativity and feedback-related P3 in individuals at risk for depression: Comparing surface potentials and current source densities

Blunted responses to reward feedback have been linked to major depressive disorder (MDD) and depression risk. Using a monetary incentive delay task (win, loss, break-even), we investigated the impact of family risk for depression and lifetime history of MDD and anxiety disorder with 72-channel electroencephalograms (EEG) recorded from 29 high-risk and 32 low-risk individuals (15-58 years, 30 male). Linked-mastoid surface potentials (ERPs) and their corresponding reference-free current source densities (CSDs) were quantified by temporal principal components analysis (PCA). Each PCA solution revealed a midfrontal feedback negativity (FN; peak around 310 ms) and a posterior feedback-P3 (fb-P3; 380 ms) as two distinct reward processing stages. Unbiased permutation tests and multilevel modeling of component scores revealed greater FN to loss than win and neutral for all stratification groups, confirming FN sensitivity to valence. Likewise, all groups had greater fb-P3 to win and loss than neutral, confirming that fb-P3 indexes motivational salience and allocation of attention. By contrast, group effects were subtle, dependent on data transformation (ERP, CSD), and did not confirm reduced FN or fb-P3 for at-risk individuals. Instead, CSD-based fb-P3 was overall reduced in individuals with than without MDD history, whereas ERP-based fb-P3 was greater for high-risk individuals than for low-risk individuals for monetary, but not neutral outcomes. While the present findings do not support blunted reward processing in depression and depression risk, our side-by-side comparison underscores how the EEG reference choice affects the characterization of subtle group differences, strongly advocating the use of reference-free techniques.

Normal congruency sequence effects in psychopathology: A behavioral and electrophysiological examination using a confound-minimized design

Clinical studies of adaptive control emphasize the role disruptions in control play in psychopathology. However, many studies used confound-laden designs and examined only one type of psychopathology. Recent studies of event-related potentials (ERPs) suggest that robust congruency sequence effects (CSEs)-a popular index of adaptive control-appear in confound-minimized designs. Thus, the present study sought to determine whether a confound-minimized CSE paradigm could identify adaptive control dysfunction in people with major depressive disorder (MDD), generalized anxiety disorder (GAD), and obsessive-compulsive disorder (OCD). We predicted that participants with MDD and GAD would show smaller ERP CSEs and that participants with OCD would show larger ERP CSEs than healthy controls. Data from 44 people with GAD, 51 people with MDD, 31 people with OCD, and 56 healthy comparison participants revealed normal CSEs as indexed by response times (RTs) and ERPs in the psychopathology groups. Moreover, psychiatric symptoms did not moderate these CSEs. Finally, we observed a strong mean-variance relationship in RT CSEs, such that participants with stronger post-recruitment of control in mean RT scores showed the most consistent post-conflict responses (i.e., the least intraindividual variability). These findings suggest that prior findings from confound-laden tasks indicating altered CSEs in psychopathology stem from processes that are unrelated to adaptive control. Future research should employ experimental designs that isolate these processes to advance our understanding of abnormal CSEs in psychopathology.

Neural Correlates of Anhedonia in Major Depressive Disorder: Insights from Concurrent Analysis of Feedback-Related Negativity and Stimulus-Preceding Negativity

Purpose

Anhedonia, a core symptom of major depressive disorder (MDD), is explored in this study, focusing on the neural underpinnings through the examination of two event-related potential (ERP) components: feedback-related negativity (FRN) and stimulus-preceding negativity (SPN).

Patients and Methods

This cross-sectional study was conducted in China from March 2022 to March 2023. It involved 35 MDD patients and 31 healthy controls (HC) participating in a modified 2-door task with simultaneous EEG recordings. Depression severity and anhedonia were assessed using the Hamilton Depression Scale (HAMD) and the Temporal Experience of Pleasure Scale (TEPS-CV), respectively. FRN and SPN metrics, along with correlations with each other and clinical assessments, were examined.

Results

In comparison to the HC group, the MDD group exhibited significantly lower scores in TEPS-CV (t = 2.854, p = 0.006) and its subscales (t = -3.596, p = 0.001 and t = 2.434, p = 0.018, respectively), along with consistently reduced amplitudes of FRN (F 1.64= 4.726, p = 0.033) and SPN (F 1.64= 4.195, p = 0.045) across all conditions. Limited correlations were observed between ERP metrics and clinical indicators, except for positive correlations between FRN amplitudes (loss minus win) and HAMD scores (r = 0.392, p = 0.020), and SPN amplitudes after losing (SPN-L) and TEPS-CV consumption subscale scores (r = 0.357, p = 0.035). Notably, while the HC group displayed no significant FRN-SPN correlations, the MDD group exhibited positive FRN-SPN correlations under distinct conditions (r = 0.376, p = 0.026 and r = 0.355, p = 0.037, respectively).

Conclusion

Our data reveal subjective and objective anhedonia in both consumption and anticipation, suggesting a shared impairment in reward feedback processing and anticipatory neural mechanisms in individuals with MDD. These findings deepen our understanding of anhedonia's neural foundations and may guide targeted interventions for this core symptom.

Learning new words via feedback-Association between feedback-locked ERPs and recall performance-An exploratory study

Feedback learning is thought to involve the dopamine system and its projection sites in the basal ganglia and anterior cingulate cortex (ACC), regions associated with procedural learning. Under certain conditions, such as when feedback is delayed, feedback-locked activation is pronounced in the medial temporal lobe (MTL), which is associated with declarative learning. In event-related potential research, the feedback-related negativity (FRN) has been linked to immediate feedback processing, while the N170, possibly reflecting MTL activity, has been related to delayed feedback processing. In the current study, we performed an exploratory investigation on the relation between N170 and FRN amplitude and memory performance in a test for declarative memory (free recall), also exploring the role of feedback delay. To this end, we adapted a paradigm in which participants learned associations between non-objects and non-words with either immediate or delayed feedback, and added a subsequent free recall test. We indeed found that N170, but not FRN amplitudes, depended on later free recall performance, with smaller amplitudes for later remembered non-words. In an additional analysis with memory performance as dependent variable, the N170, but not the FRN amplitude predicted free recall, modulated by feedback timing and valence. This finding shows that the N170 reflects an important process during feedback processing, possibly related to expectations and their violation, but is distinct from the process reflected by the FRN.

Deficits in doors P300 amplitude during adolescence associated with preschool-onset depression

The psychophysiological underpinnings of preschool-onset depression (PO-MDD) remain underexplored. Moreover, there is currently a limited understanding of the potential impact that PO-MDD might have on neurobiological functions later in development such as general cognitive domains and reward processing. Thus, the current study sought to examine potential neurophysiological differences, measured via electroencephalography (EEG), in adolescents with and without a history of PO-MDD. Participants and their caregivers (N = 138) from a large longitudinal study completed semi-structured clinical interviews at a baseline visit (ages 3-7) to determine PO-MDD status. At a follow-up visit approximately 11 years later, adolescents (ages 13-19) completed the doors gambling task while EEG was recorded to measure event-related potentials (ERPs) elicited by both the doors and feedback stimuli, to index cognitive and reward processing functions (i.e., doors-P300, gain/loss feedback-P300, and RewP). Adolescents with a history of PO-MDD exhibited significantly smaller doors-P300 compared with adolescents with no history of PO-MDD, whereas there were no group differences in gain/loss feedback-P300 or RewP. Additionally, reduced doors-P300 was independently associated with lower baseline income-to-needs ratio, older age, and female gender. The current study suggests that reduced doors-P300 amplitude during adolescence might reflect impaired neurophysiological development related to PO-MDD. Thus, the P300 derived from the doors stimuli might be a valuable neural measure to further our understanding of potential neurophysiological differences associated with early-onset childhood depression.

Transdiagnostic considerations of the relationship between reward sensitivity and psychopathological symptoms - a cross-lagged panel analysis

BACKGROUND

Reward sensitivity constitutes a potential key mechanism regarding the etiology and maintenance of mental disorders, especially depression. However, due to a lack of longitudinal studies, the temporal dynamics are not clear yet. Although some evidence indicates that reward processing could be a transdiagnostic mechanism of disorders, these observations could be also a product of comorbidity with depression. This study aimed at investigating the temporal dynamics of reward sensitivity and the course of psychopathological symptoms in a longitudinal investigation, while taking a possible mediating role of depression into account.

METHODS

We conducted a three-wave longitudinal online survey with a 4-week interval. A total of N = 453 participants filled out all three questionnaires. Reward sensitivity was assessed with the Positive Valence System Scale-21 (PVSS-21), depression with the Patient Health Questionnaire (PHQ-9), eating disorder symptoms with the Eating Disorder Examination-Questionnaire-8 (EDE-Q-8), social anxiety with the Mini-social phobia inventory (Mini-SPIN) and alcohol consumption with the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C). Cross-lagged panels and mediation analyses were calculated using path analyses.

RESULTS

Depressive and eating disorder symptoms predicted reward insensitivity at later points in time. Effects were larger from T2 to T3. A bidirectional relationship concerning social anxiety was found. Higher alcohol consumption predicted higher reward sensitivity. Depression at T2 fully mediated the association between psychopathological symptoms at T1 and reward sensitivity at T3 for social anxiety and eating disorder symptoms.

CONCLUSIONS

Our findings imply that reduced reward sensitivity seems to be a consequence rather than an antecedent of psychopathological symptoms. Comorbid depression plays a crucial role in other mental disorders regarding observed hyposensitivity towards rewards. Therefore, our results do not support a transdiagnostic notion of reward sensitivity, but they indicate a potential role of reward sensitivity for symptom persistence.

TRIAL REGISTRATION

The study was preregistered at the Open Science Framework (OSF) ( https://archive.org/details/osf-registrations-6n3s8-v1 ; registration DOI https://doi.org/10.17605/OSF.IO/6N3S8 ).

Positive valence system function and anhedonia in middle-aged and older adults at high suicide risk

Positive valence systems are disrupted in late-life depression and in individuals at risk for suicide. The reward positivity (RewP) is an event-related potential measure of positive valence system function that relates to depression and anhedonia in children and young adults. However, it is unclear whether a reliable RewP signal can be elicited in middle-aged and older adults at high risk for suicide and, if so, whether this signal is similarly associated with clinical symptoms. In the current study, a RewP was elicited with a standard gambling task in middle-aged and older adults (N = 31) at discharge from a hospitalization for suicidal thought or behaviors. The resulting electrocortical response differed significantly for monetary wins compared to losses. Internal reliability of the RewP and the feedback negativity (FN) to monetary loss was good to excellent. Internal reliability of difference measures was lower but still largely acceptable, with residualized differences scores demonstrating stronger reliability than subtraction-based scores. A smaller residualized RewP, after accounting for the influence of the FN, was associated with greater severity of lassitude, an index of appetitive anhedonia. These findings set the groundwork for future studies of positive valence system function and depression in middle-aged and older adults at high risk for suicide.

Event-related potentials during the ultimatum game in people with symptoms of depression and/or social anxiety

Depression and social anxiety are common disorders that have a profound impact on social functioning. The need for studying the neural substrates of social interactions in mental disorders using interactive tasks has been emphasized. The field of neuroeconomics, which combines neuroscience techniques and behavioral economics multiplayer tasks such as the Ultimatum Game (UG), can contribute in this direction. We assessed emotions, behavior, and Event-Related Potentials in participants with depression and/or social anxiety symptoms (MD/SA, n = 63, 57 females) and healthy controls (n = 72, 67 females), while they played the UG. In this task, participants received fair, mid-value, and unfair offers from other players. Mixed linear models were implemented to assess trial level changes in neural activity. The MD/SA group reported higher levels of sadness in response to mid-value and unfair offers compared to controls. In controls, the Medial Frontal Negativity associated with fair offers increased over time, while this dynamic was not observed in the MD/SA group. The MD/SA group showed a decreased P3/LPP in all offers, compared to controls. These results indicate an enhanced negative emotional response to unfairness in the MD/SA group. Neural results reveal a blunted response over time to positive social stimuli in the MD/SA group. Moreover, between-group differences in P3/LPP may relate to a reduced saliency of offers and/or to a reduced availability of resources for processing incoming stimuli in the MD/SA group. Findings may shed light into the neural substrates of social difficulties in these disorders.

Towards thoughtful planning of ERP studies: How participants, trials, and effect magnitude interact to influence statistical power across seven ERP components

In the field of EEG, researchers generally rely on rules of thumb, rather than a priori statistical calculations, when planning the number of trials to include in an ERP study. To aid in this practice, studies have tried to establish minimum numbers of trials required to reliably isolate ERPs. However, these guidelines do not necessarily apply across different study designs, as the reliability of an ERP waveform is not the same as the statistical power of a given experiment. Experiment parameters such as number of participants, trials, and effect magnitude interact to affect power in complex ways. Both under- and over-powered ERP studies represent a waste of time and resources that impedes the progress of the field. The current study fills this gap by subsampling real ERP data to estimate the relationship between experiment design parameters and statistical power. The simulations include seven commonly studied ERP components: the ERN, LRP, N170, MMN, P3, N2pc, and N400. In the first set of experiments, we determined the probability of obtaining a statistically significant ERP effect for each component. In the second and third set of experiments, we determined the probability of obtaining a statistically significant difference in ERP amplitude within and between groups for each component. Results indicate that the rules of thumb for ERP experiment design in the literature often lead to underpowered studies. Going forward, these results provide researchers with experiment design guidelines that are specific to the component under study, allowing for the design of sufficiently powered ERP studies.

Pathways to depression: Dynamic associations between neural responses to appetitive cues in the environment, stress, and the development of illness

This review focuses on research my colleagues and I have conducted on etiological pathways to depression. Much of this work has focused on the measurement of neural responses to appetitive cues, using two event-related brain potential (ERP) components, the Late Positive Potential (LPP) and the Reward Positivity (RewP). Reductions in each of these components have been associated with current symptoms of depression, and in some cases have been shown to differentiate anxious from depressive phenotypes. In this review, I will describe three broad and related approaches we have taken in our research to address a series of interdependent issuess. The first attempts to understand different sources of variation in the LPP and RewP, and how these sources interact with one another. The second tries to identify whether variation in the processes measured by these ERP components might reflect a latent vulnerability to depression and its symptoms, that is evident prior to illness onset. And the third examines the possibility that the processes reflected in the LPP and RewP might play a mechanistic role in the development of depression.

The thrill of victory: Savoring positive affect, psychophysiological reward processing, and symptoms of depression

Depression is characterized by a pattern of maladaptive emotion regulation. Recently, researchers have begun to focus on associations between depression and two positive affect regulation strategies: savoring and dampening. Savoring, or upregulation of positive affect, is positively associated with well-being and negatively associated with depression, whereas dampening, or downregulation of positive affect, is positively associated with depression, anhedonia, and negative affect. To date, no research has examined whether savoring or dampening can affect neurophysiological reactivity to reward, which previous research has shown is associated with symptoms of depression. Here, we examined associations between psychophysiological reward processing-primarily captured by the Reward Positivity (RewP), an event-related potential (ERP) deflection elicited by feedback indicating reward (vs. nonreward)-positive affect regulation strategies, and symptoms of depression. One hundred undergraduates completed questionnaires assessing affect, emotion regulation, and depressive symptoms and completed a computerized guessing task, once before and again after being randomly assigned to emotion-regulation strategy conditions. Results indicate that (a) the relationship between RewP amplitude and depressive symptoms may, in part, depend upon positive affect regulation strategies and (b) the RewP elicited by reward appears sensitive to a savoring intervention. These findings suggest that mitigating depressive symptoms in emerging adults may depend on both top-down (i.e., savoring) and bottom-up (i.e., RewP) forms of positive affect regulation and have important implications for clinical prevention and intervention efforts for depressive symptoms and disorder. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Reliability of reward ERPs in middle-late adolescents using a custom and a standardized preprocessing pipeline

Despite advantage of neuroimaging measures in translational research frameworks, less is known about the psychometric properties thereof, especially in middle-late adolescents. Earlier, we examined evidence of convergent and incremental validity of reward anticipation and response event-related potentials (ERPs) and here we examined, in the same sample of 43 adolescents (M_age  = 15.67 years; SD = 1.01; range: 14-18; 32.6% boys), data quality (signal-to-noise ratio [SNR]), stability (mean amplitude across trials), and internal consistency (Cronbach's α and split-half reliability) of the same ERPs. Further, because observed time course and peak amplitude of ERP grand averages and thus findings on SNR, stability, and internal consistency may depend on preprocessing method, we employed a custom and a standardized preprocessing pipeline and compared findings across those. Using our custom pipeline, reward anticipation components were stable by the 40th trial, achieved acceptable internal consistency by the 19th, and all (but the stimulus-preceding negativity [SPN]) achieved acceptable SNR by the 41st trial. Initial response to reward components were stable by the 20th trial and achieved acceptable internal consistency by the 11th and acceptable SNR by the 45th trial. Difference scores had worse psychometric properties than parent measures. Time course and peak amplitudes of ERPs and thus results on SNR, stability, and internal consistency were comparable across preprocessing pipelines. In case of reward anticipation ERPs examined here, 41 trials (+4 artifacted and removed) and, in case of reward response ERPs, 45 trials (+5 artifacted) yielded stable and internally consistent estimates with acceptable SNR. Results are robust across preprocessing methods.

Neural Responses to Reward and Punishment Stimuli in Depressed Status Individuals and Their Effects on Cognitive Activities

Individuals in depressed status respond abnormally to reward stimuli, but the neural processes involved remain unclear. Whether this neural response affects subsequent cognitive processing activities remains to be explored. In the current study, participants, screened as depressed status individuals and healthy individuals by Beck Depression Inventory and Hospital Anxiety Depression Scale, performed both a door task and a cognitive task. Specifically, in each trial, they selected one from two identical doors based on the expectations of rewards and punishments and received the rewarded or punished feedback, and then they performed a cognitive task in which they judged the correctness of a math equation. The neural responses of their choice in the door task were recorded. The results showed that when the two groups received punished feedback, their accuracy was significantly higher than they received rewarded feedback. Compared with the healthy group, the depressed status group spent more time completing cognitive tasks. Analysis of electroencephalography (EEG) data showed that the amplitude of RewP induced by rewarded feedback was larger than that induced by punished feedback, and the amplitude of RewP and fb-P3 induced by the depressed status group was smaller than that of the healthy group. The results of an order analysis showed that the main effects of group variable in fb-P3 and RewP appeared in the second half of the data, and the main effect of feedback type in RewP appeared in the first half of the data. The results showed that the neural response of individuals in depressed status to reward and punishment stimuli was weakened compared with healthy individuals and affected the subsequent cognitive processing to some extent. The effect of feedback appeared in the early stage and gradually decreased. The neural response of individuals in depressed status had a cumulative effect, and the differences appeared in the later stage. The results of this study support the emotional situation insensitive hypothesis, that is, individuals in depressed status are less sensitive to reward and punishment than healthy individuals.

Safety on demand: Post-hypnotic suggestions of safety reduce neural signals of reward sensitivity with long-term beneficial effects

Increased reward sensitivity has been proposed as an important transdiagnostic feature for a series of disorders, including addictive behaviors. Earlier studies suggest that a positive affective state characterized by the feeling of safety could reduce an individual's reward sensitivity. A promising technique to establish a feeling of safety on demand is to utilize post-hypnotic suggestions. We hypothesized that the feeling of safety elicited by post-hypnotic suggestions reduces neural signals of reward sensitivity. To test our predictions, we hypnotized 24 highly suggestible participants, suggested them to feel safe and coupled this feeling of safety to a post-hypnotic trigger that reactivates the feeling of safety outside the hypnotic state. Participants then played a risk game both in a safety condition using the post-hypnotic safety trigger and in a control condition using a neutral trigger. Simultaneously, we recorded their EEG. Participants reported significantly higher ratings of safety in the safety condition compared to the control condition. Even several weeks after the main experimental session, the post-hypnotic safety trigger still elicited a significantly stronger feeling of safety compared to the control condition. Moreover, the Reward Positivity (RewP) was significantly reduced in the safety condition. As the RewP amplitude has been proposed as a psychophysiological marker for reward sensitivity, we conclude that the suggestion of safety by post-hypnotic suggestions turns participants into a quiescence motivational state that makes them less reward sensitive. Therefore, we discuss implications of the post-hypnotic safety trigger for the treatment of disorders associated with increased reward sensitivity such as addictive behaviors.

Win, lose, or draw: Examining salience, reward memory, and depression with the reward positivity

The reward positivity (RewP) is a putative biomarker of depression. Careful control of stimulus properties and manipulation of both stimulus valence and salience could facilitate interpretation of the RewP. RewP interpretation could further be improved by investigating functional outcomes of a blunted RewP in depression, such as reduced memory for rewarding outcomes. This study sought to advance RewP interpretation first by advancing task design through use of neutral (i.e., draw) control trials and counterbalanced feedback stimuli. Second, we examined the RewP's association with memory and the impact of depression. Undergraduates completed self-report measures of depression and anhedonia prior to a modified doors task in which words were displayed in colored fonts that indicated win, loss, or draw feedback. Memory of the feedback associated with each word (i.e., source memory) was tested. Results showed that RewP response to wins was more positive than to losses, which was more positive than to draws. The RewP was not associated with depression or anhedonia. The low depression group showed a source memory advantage for win words, but the high depression group did not. Source memory showed small relations to the RewP, but these did not survive Bonferroni correction. Results suggest the RewP is sensitive to salience and highlight challenges in detecting an association between the RewP and depression in modified doors tasks. Findings indicate that depression is related to dysfunctional source memory for reward but not loss and that future research should probe the possible associations between the RewP and memory in depression.

The neural habituation to hedonic and eudaimonic rewards: Evidence from reward positivity

Rewards play an important role in people's well-being. However, the mechanisms underlying neural habituation to hedonic rewards (attainment of pleasure) and eudaimonic rewards (attainment of meaning and self-realization) and their implications for longitudinal changes in well-being remain unknown. By operationalizing hedonic rewards as "winning money for oneself" and eudaimonic rewards as "winning money for a charity", 78 participants (41 women, aged from 17 to 24 years) completed a revised monetary gambling task during event-related potential (ERP) recording. Subsequently, the participants' well-being was measured after one year. The results showed that the reward positivity (RewP) effect readily decreased as the hedonic rewards were repeated, whereas the RewP effect in response to eudaimonic rewards was relatively sustained over time. Moreover, the declining RewP effect for repeated eudaimonic rewards was marginally positively associated with longitudinal decreases in well-being. These findings demonstrate at the neural level that sensitivity to repeated hedonic rewards is more prone to decrease than sensitivity to repeated eudaimonic rewards, and sustained eudaimonic reward sensitivity in the short term has greater implications for changes in well-being in the long term.

Acute stress reduces reward-related neural activity: Evidence from the reward positivity

Stress and blunted reward processing are risk factors for Major Depressive Disorder (MDD). The experience of acute stress reduces fMRI correlates of reward-related neural activity; however, few studies have examined how acute stress impacts measures of reward derived from event-related potentials (ERPs). The current study examined the impact of an acute stressor on the Reward Positivity (RewP), an ERP that indexes reward sensitivity, in twenty-six college students. Participants completed a monetary reward task while they placed their left hand in cold water set at 13 °C (i.e. acute stress condition) and again while their hand was placed in room temperature water (i.e. control condition). These conditions were separated by one week and performed in a counter-balanced order across participants. The results revealed that the RewP amplitude was blunted in the acute stress condition compared to the control condition. Moreover, there was a trend toward this effect interacting with self-reported depressive symptoms: the RewP was reduced only among individuals who reported low depressive symptoms. The current study suggests that an acute stressor reduces the RewP, and that this effect might be moderated by current depressive symptoms. Future studies might examine the temporal association between reward processing and stress, and how they interact to predict depressive symptoms.LAY SUMMARYThe current study examined the impact of acute stress on the brain's reward system. The results indicated that acute stress reduced activity within the brain's reward system, particularly among individuals with low depressive symptoms.

A Functional Coupling of Brain and Behavior During Social Categorization of Faces

Considerable research has focused on how people derive information about others' social category memberships from their faces. Theoretical models posit that early extraction of task-relevant information from a face should determine the efficiency with which that face is categorized, but evidence supporting this idea has been elusive. Here, we used a novel trial-level data analytic approach to examine the relationship between two event-related potential components-the P2, indexing early attention to category-relevant information, and the P3, indexing stimulus evaluation-and the speed of overt categorization judgments. As predicted, a larger face-elicited P2 on a particular trial was associated with faster overt race or gender categorization of that face. Moreover, this association was mediated by P3 latency, indicating that extraction of more category-relevant information early in processing facilitated stimulus evaluation. These findings support continuous flow models of information processing and the long-theorized functional significance of face-elicited neurophysiological responses for social categorization.

Using multilevel models for the analysis of event-related potentials

Multilevel modeling (MLM) is becoming increasingly accessible and popular in the analysis of event-related potentials (ERPs). In this article, we review the benefits of MLM for analyzing psychophysiological data, which often contains repeated observations within participants, and introduce some of the decision-making points in the analytic process, including how to set up the data set, specify the model, conduct hypothesis tests, and visualize the model estimates. We highlight how the use of MLM can extend the types of theoretical questions that can be answered using ERPs, including investigations of how ERPs vary meaningfully across trials within a testing session. We also address reporting practices and provide tools to calculate effect sizes and simulate power curves. Ultimately, we hope this review contributes to emerging best practices for the use of MLM with psychophysiological data.

Revenge is sweet: Investigation of the effects of Approach-Motivated anger on the RewP in the motivated anger delay (MAD) paradigm

Past research has found that neural activity associated with feedback processing is enhanced by positive approach-motivated states. However, no past work has examined how reward processing changes in the context of revenge. Using a novel aggression paradigm, we sought to explore the influence of approach-motivated anger on neural responses to feedback indicating the opportunity to seek revenge against an offending opponent by examining the reward positivity (RewP), an event-related potential indexing performance feedback. In Experiment 1, after receiving insulting feedback from an opponent, participants played a reaction time game with three trial types: revenge trials, aggravation trials, and no-consequence trials. Results revealed that RewP amplitudes were larger to revenge trial win feedback than no-consequence trial win feedback or revenge trial loss feedback. RewP amplitudes were larger to both aggravation trial win and loss feedback than on no-consequence trials. Experiment 2 examined the influence of approach-motivated anger during the acquisition of rewards on the RewP without the possibility of retribution from the offending individual. Participants played a reaction time game similar to Experiment 1, except instead of giving or receiving noise blasts, participants could win money from the insulter (revenge trials) or a neutral-party (e.g., bank). Results indicated that revenge wins elicited larger RewP amplitudes than bank wins. These results suggest that anger enhances revenge-related RewP amplitudes to obtaining revenge opportunities and further aggravation wins or losses. Anger appears to enhance the pleasurable feelings of revenge.

Electrophysiological responses to images ranging in motivational salience: Attentional abnormalities associated with schizophrenia-spectrum disorder risk

Individuals at risk for schizophrenia-spectrum disorders display abnormalities related to motivational salience, or the ability of stimuli to elicit attention due to associations with rewards or punishments. However, the nature of these abnormalities is unclear because most focus on responses to stimuli from broad “pleasant” and “unpleasant” categories and ignore the variation of motivational salience within these categories. In two groups at risk for schizophrenia-spectrum disorders—a Social Anhedonia group and a Psychotic-like Experiences group—and a control group, the current study examined event-related potential components sensitive to motivational salience—the Early Posterior Negativity (EPN), reflecting earlier selective attention, and the Late Positive Potential (LPP), reflecting sustained attention. Compared to controls, the Social Anhedonia group showed smaller increases in the EPN in response to erotica and smaller increases in the LPP as the motivational salience of pleasant images increased (exciting<affiliative<erotica). In contrast, the Psychotic-like Experiences group had larger increases in LPP amplitudes as the motivational salience of pleasant images increased. Also, both at-risk groups showed larger increases in the LPP to threatening images but smaller increases to mutilation images. These findings suggest that examining abnormalities beyond those associated with broad categories may be a way to identify mechanisms of dysfunction.

Neural Sensitivity to Social and Monetary Reward in Depression: Clarifying General and Domain-Specific Deficits

Reward dysfunction is thought to be play a critical role in the pathogenesis of depression. Multiple studies have linked depression to abnormal neural sensitivity to monetary rewards, but it remains unclear whether this reward dysfunction is generalizable to other rewards types. The current study begins to address this gap by assessing abnormal sensitivity to both monetary and social rewards in relation to depressive symptoms. We recorded event-related potentials (ERPs) during two incentive delay tasks, one with monetary reward and one with social reward. Both tasks were administered within the same sample, enabling a direct comparison of reward types. ERPs elicited by social and nonsocial rewards were morphologically similar across several stages of processing: cue salience, outcome anticipation, early outcome evaluation, outcome salience. Moderation analyses showed depression was linked with a pattern of general deficits across social and monetary rewards, specifically for the stages of outcome anticipation (stimulus-preceding negativity) and outcome salience (feedback-P3); self-reported reward sensitivity was generally associated with early outcome evaluation (reward positivity). Regression analyses modeling task-specific variance, however, showed a unique association between depression and outcome salience for social rewards, controlling for monetary rewards. The findings from this study underscore the importance of assessing neural sensitivity to multiple reward types in depression, particularly social reward. Characterizing the profile of reward functioning in depression across reward types may help to link laboratory-based deficits to relatively global vs. focal difficulties in real-world functioning.

Neural Response to Rewards, Stress and Sleep Interact to Prospectively Predict Depressive Symptoms in Adolescent Girls

Blunted reward processing both characterizes major depressive disorder and predicts increases in depressive symptoms. However, little is known about the interaction between blunted reward processing and other risk factors in relation to increases in depressive symptoms. Stressful life events and sleep problems are prominent risk factors that contribute to the etiopathogenesis of depression and have been linked to reward dysfunction; these factors may interact with reward dysfunction to predict increased depressive symptoms. In a large sample of 8- to 14-year-old adolescent girls, the current study examined how blunted reward processing, stressful life events, and sleep problems at baseline interacted to predict increases in depressive symptoms 1 year later. Reward processing was indexed by the reward positivity (RewP), an event-related potential elicited during a simple monetary reward paradigm (i.e., Doors task). Two-way interactions confirmed that a blunted RewP predicted increased depressive symptoms at (a) high levels of stress but not average or low levels of stress, and (b) high and average levels of sleep problems but not low levels of sleep problems. Finally, a 3-way interaction confirmed that a blunted RewP predicted increased depressive symptoms at high levels of stress and sleep problems but not average or low levels of stress and sleep problems. Thus, adolescents characterized by low reward response (i.e., blunted RewP) were at an increased risk of developing depressive symptoms if they experienced increased stressful life events or sleep problems; moreover, risk was greatest among adolescents characterized by all 3.

Relation of depression symptoms to sustained reward and loss sensitivity

Depression is characterized by altered sensitivity to rewards, with recent evidence suggesting that the ability to sustain responses to rewards across long experimental tasks is diminished. Most work on sustained reward responsiveness has taken a categorical approach and focused on major depressive disorder. However, impairments in reward sensitivity are also found at lower levels of symptom severity and may be relevant for understanding basic mechanisms linking reward processing abnormalities to depression. The current study took a dimensional approach to examine the relation between depression symptoms and sustained reward responsiveness by examining how early neural responses to rewards and losses change over a short time course (i.e., during the experiment). In a sample of 45 unselected undergraduates, changes in the amplitude of the reward positivity (RewP) and feedback negativity (FN) were examined over the course of a simple gambling task using multilevel modeling. Amplitude of the RewP was sustained and amplitude of the FN increased during the task. Unlike prior work focused on clinical populations, depression symptoms in this unselected sample were associated with enhanced RewP and FN responding over the course of the task. Results echo prior work that underscores the importance of examining changes in response to reward across trials and further suggests that sustained responses to both rewards and losses vary in relation to symptom level.