Neural responses to reward and pleasant pictures prospectively predict remission from depression

Electrocortical Reactivity during Self-Referential Processing Predicts the Development of Depression across Adolescence

BACKGROUND

Negative attentional biases and self-schemas have been implicated in the development of depression. Research has indicated that a larger late positive potential (LPP) to negative self-referential words is associated with depression-as well as a maternal history of depression, an indicator of risk. However, it is unclear whether the LPP to self-referential words predicts the actual development of depression. The present study examined whether electrocortical reactivity during self-referential processing predicts the development of depression across adolescence.

METHODS

The sample consisted of 165 8 to 14-year-old girls with no lifetime history of a depressive disorder who completed the self-referential encoding task (SRET) while electroencephalography was recorded at a baseline assessment. Participants and their parent completed the Kiddie Schedule for Affective Disorders and Schizophrenia for School Aged Children at the baseline, 2-year, 4-year, and 6-year follow-up assessments.

RESULTS

Results indicated that a larger LPP to negative self-referential words at baseline predicted an increased likelihood of developing chronic-intermittent depression (i.e., persistent and/or recurrent), but not non-chronic, single episode depression, across adolescence. In contrast, neither SRET recall biases nor the LPP to positive self-referential words predicted the development of either type of depression.

CONCLUSIONS

The present study suggests that electrocortical reactivity associated with a negative self-schema in late childhood predicts the development of a more pernicious subtype of depression across adolescence. Moreover, the present study highlights the importance of considering clinical course in the examination of biomarkers of risk for depression.

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.

Distinct profiles of anhedonia and reward processing and their prospective associations with quality of life among individuals with mood disorders

Leading professional health bodies have called for the wider adoption of Patient Reported Outcome Measures, such as quality of life, in research and clinical practice as a means for understanding why the global burden of depression continues to climb despite increased rates of treatment use. Here, we examined whether anhedonia-an often recalcitrant and impairing symptom of depression-along with its neural correlates, was associated with longitudinal changes in patient-reported quality of life among individuals seeking treatment for mood disorders. We recruited 112 participants, including n = 80 individuals with mood disorders (58 unipolar, 22 bipolar) and n = 32 healthy controls (63.4% female). We assessed anhedonia severity along with two electroencephalographic markers of neural reward responsiveness (scalp-level 'Reward Positivity' amplitude and source-localized reward-related activation in the dorsal anterior cingulate cortex), and assessed quality of life at baseline, 3- and 6-month follow-up. Anhedonia emerged as a robust correlate of quality of life cross-sectionally and longitudinally among individuals with mood disorders. Furthermore, increased neural reward responsiveness at baseline was associated with greater improvements in quality of life over time, and this improvement was mediated by longitudinal improvements in anhedonia severity. Finally, differences in quality of life observed between individuals with unipolar and bipolar mood disorders were mediated by differences in anhedonia severity. Our findings indicate that anhedonia and its reward-related neural correlates are linked to variability in quality of life over time in individuals with mood disorders. Treatments capable of improving anhedonia and normalizing brain reward function may be necessary for improving broader health outcomes for individuals seeking treatment for depression.ClinicalTrials.gov identifier: NCT01976975.

Working memory training for reward processing in university students with subsyndromal depression: The influence of baseline severity of depression

Previous studies have tentatively suggested that working memory training (WMT) has the potential to improve reward processing, but it is not known how long this improvement lasts, whether there is a lag effect, or whether it is reflected in neurophysiological indicators. In this study, 40 university students with subsyndromal depression were randomly assigned to a training group or a control group and completed a 20-day working memory training task and a simple memory task, respectively. All participants completed the Temporal Experience of Pleasure Scale (TEPS) and a doors task with electroencephalogram (EEG) signals recorded simultaneously on a pre- and post-test and a 3-month follow-up. The reward-related positivity (RewP) amplitude, theta power, and their differences between conditions (i.e., ΔRewP and Δtheta power, respectively) in the doors task were the primary outcomes, and the score on TEPS was the secondary outcome. The results indicated no group-related effects were demonstrated in primary and secondary outcomes at post-test and 3-month follow-up. Furthermore, the differences in the pre- and post-test in Δtheta power were moderated by the baseline severity of depression. This was primarily driven by the fact that the change values in the control group increased with the severity of depression, while the change values in the training group had high homogeneity. Our findings did not provide support for the effect of WMT on reward processing across the whole sample, but without intervention, there would be high heterogeneity in the change in the cognitive control ability to loss feedback, which is detrimental to individuals with high depression severity.

Parsing patterns of reward responsiveness: Initial evidence from latent profile analysis

Variation in reward responsiveness has been linked to psychopathology. Reward responsiveness is a complex phenomenon that encompasses different temporal dimensions (i.e., reward anticipation or consumption) that can be measured using multiple appetitive stimuli. Furthermore, distinct measures, such as neural and self-report measures, reflect related but distinct aspects of reward responsiveness. To understand reward responsiveness more comprehensively and better identify deficits in reward responsiveness implicated in psychopathology, we examined ways multiple measures of reward responsiveness jointly contribute to distinct psychological problems by using latent profile analysis. Specifically, we identified three profiles of reward responsiveness among 139 female participants based on their neural responses to money, food, social acceptance, and erotic images and self-reported responsiveness to reward anticipation and consumption. Profile 1 (n = 30) exhibited blunted neural responses to social rewards and erotic images, low self-reported reward responsiveness, but average neural responses to monetary and food rewards. Profile 2 (n = 71) showed elevated neural response to monetary rewards, average neural responses to other stimuli, and average self-reported reward responsiveness. Profile 3 (n = 38) showed more variable neural responses to reward (e.g., hypersensitivity to erotic images, hyposensitivity to monetary rewards), and high self-reported reward responsiveness. These profiles were differentially associated with variables generally linked to aberrations in reward responsiveness. For example, Profile 1 was most strongly associated with anhedonic depression and social dysfunction, whereas Profile 3 was associated with risk-taking behaviors. These preliminary findings may help to elucidate ways different measures of reward responsiveness manifest within and across individuals and identify specific vulnerabilities for distinct psychological problems.

Effort and Appetitive Responding in Depression: Examining Deficits in Motivational and Consummatory Stages of Reward Processing Using the Effort-Doors Task

Background

Reward sensitivity is a dimensional construct central to understanding the nature of depression. Psychophysiological research on this construct has primarily focused on the reward positivity, an event-related potential (ERP) that indexes consummatory reward sensitivity. This study extended prior research by focusing on ERPs that index the motivational component of reward.

Methods

A novel effort-for-reward task was used to elicit motivational and consummatory ERPs. Groups consisting of 34 participants with depression and 32 participants without depression were compared across a range of reward-related ERPs.

Results

Participants with depression exhibited reduced responsivity to effort completion cues following high effort expenditure, reduced anticipation of rewards after low effort expenditure (i.e., the stimulus preceding negativity), and reduced reward positivity following high effort expenditure. ERPs occurring prior to reward receipt accounted for unique variance in depression status and differentiated between subgroups of depressed individuals.

Conclusions

Findings support the utility of leveraging multiple ERPs that index separate reward processing deficits to better characterize depression and depressive subtypes.

Rethinking the risk for depression using the RDoC: A psychophysiological perspective

Considering that the classical categorical approach to mental disorders does not allow a clear identification of at-risk conditions, the dimensional approach provided by the Research Domain Criteria (RDoC) is useful in the exploration of vulnerability to psychopathology. In the RDoC era, psychophysiological models have an important role in the reconceptualization of mental disorders. Indeed, progress in the study of depression vulnerability has increasingly been informed by psychophysiological models. By adopting an RDoC lens, this narrative review focuses on how psychophysiological models can be used to advance our knowledge of the pathophysiological mechanisms underlying depression vulnerability. Findings from psychophysiological research that explored multiple RDoC domains in populations at-risk for depression are reviewed and discussed. Future directions for the application of psychophysiological research in reaching a more complete understanding of depression vulnerability and, ultimately, improving clinical utility, are presented.

The P300 and late positive potential in pregnancy prospectively predict increases in depressive and anxious symptoms in the early postpartum period

Postnatal depression and anxiety disorders pose a major burden on maternal mental health. While psychosocial risk factors for perinatal depression and anxiety are well-researched, there is a dearth of research examining neural biomarkers of risk for postnatal increases in depression and anxiety. Previous studies suggest two different event-related potentials, the P300 and the late positive potential (LPP), may predict the course of depressive and anxious symptoms in non-perinatal populations. In a sample of 221 perinatal women, the present study utilized an emotional interrupt task administered in pregnancy to examine whether antenatal P300 and LPP amplitudes may predict change in depressive and anxious symptoms from pregnancy to the early postpartum period. Zero-order correlations and linear regressions revealed that a reduced antenatal P300 to target stimuli and an enhanced LPP to positive infant images were uniquely associated with postnatal depressive and anxiety symptoms, respectively, and that these ERPs were independent predictors beyond antenatal self-report measures of psychological symptoms. Furthermore, individuals with increased depressive symptoms in pregnancy exhibited a stronger negative association between antenatal P300 amplitude and postnatal depressive symptoms. The present findings underscore the possibility that the measurement of ERPs during pregnancy could serve as a screening tool for risk for perinatal depression and anxiety, and thereby assist with identifying at-risk individuals who might benefit from prevention efforts.

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.

Manipulating Reward Sensitivity Using Reward Circuit-Targeted Transcranial Magnetic Stimulation

BACKGROUND

The reward circuit is important for motivation and learning, and dysregulations of the reward circuit are prominent in anhedonic depression. Noninvasive interventions that can selectively target the reward circuit may hold promise for the treatment of anhedonia.

METHODS

We tested a novel transcranial magnetic stimulation intervention for modulating the reward circuit. A total of 35 healthy individuals participated in a crossover controlled study targeting the reward circuit or a control site with intermittent theta burst stimulation (iTBS), an excitatory form of transcranial magnetic stimulation. Individual reward circuit targets were defined based upon functional magnetic resonance imaging functional connectivity with the ventral striatum, yielding targets in the rostromedial prefrontal cortex (rmPFC). Reward circuit function was assessed at baseline using functional magnetic resonance imaging, and reward circuit modulation was assessed using an event-related potential referred to as the reward positivity, which has been shown to reliably track reward sensitivity, as well as individual differences in depression and risk for depression.

RESULTS

Relative to control iTBS, rmPFC iTBS enhanced the reward positivity. This effect was moderated by reward function, suggesting greater enhancements in individuals with lower reward function. This effect was also moderated by rmPFC-ventral striatum connectivity insofar as iTBS reached the rmPFC, suggesting that efficacy relies jointly on the strength of the rmPFC-ventral striatum pathway and ability of transcranial magnetic stimulation to target the rmPFC.

CONCLUSIONS

These data suggest that the reward circuit can be modulated by rmPFC iTBS, and amenability to such modulations is related to measures of reward circuit function. This provides the first step toward a novel noninvasive treatment of disorders of the reward circuit.

Neural correlates of emotional reactivity predict response to cognitive-behavioral therapy in obsessive-compulsive disorder

BACKGROUND

Examining predictive biomarkers to identify individuals who will likely benefit from a specific treatment is important for the development of targeted interventions. The late positive potential (LPP) is a neural marker of attention and elaborated stimulus processing, and increased LPP responses to negative stimuli are characteristic of pathological anxiety. The present study investigated whether LPP reactivity would prospectively predict response to cognitive-behavioral therapy (CBT), the first-line treatment for obsessive-compulsive disorder (OCD).

METHODS

To this end, the LPP in response to negative as compared to neutral pictures was examined in 45 patients with OCD, who underwent CBT in a naturalistic outpatient setting. LPP amplitudes were used as predictors of symptom reduction after CBT.

RESULTS

We found that higher LPP amplitudes to negative relative to neutral stimuli were predictive of lower self-reported OCD symptoms after completion of CBT, controlling for pre-treatment symptoms. Further, LPP reactivity was negatively correlated with self-reported habitual use of suppression in everyday life.

LIMITATIONS

Some participants had already begun treatment at the time of study participation. Overall, results need further replication in larger samples and standardized therapy settings.

CONCLUSIONS

The current findings suggest that patients with increased emotional reactivity benefit more from CBT, possibly through less avoidance of anxiety-provoking stimuli during exposure with response prevention, a crucial component in CBT for OCD. Although its clinical utility still needs to be evaluated further, the LPP constitutes a promising candidate as a prognostic marker for CBT response in OCD.