A distributional code for value in dopamine-based reinforcement learning.

Since its introduction, the reward prediction error theory of dopamine has explained a wealth of empirical phenomena, providing a unifying framework for understanding the representation of reward and value in the brain1-3. According to the now canonical theory, reward predictions are represented as a single scalar quantity, which supports learning about the expectation, or mean, of stochastic outcomes. Here we propose an account of dopamine-based reinforcement learning inspired by recent artificial intelligence research on distributional reinforcement learning4-6. We hypothesized that the brain represents possible future rewards not as a single mean, but instead as a probability distribution, effectively representing multiple future outcomes simultaneously and in parallel. This idea implies a set of empirical predictions, which we tested using single-unit recordings from mouse ventral tegmental area. Our findings provide strong evidence for a neural realization of distributional reinforcement learning.

Risk factors for internalizing symptoms: The influence of empathy, theory of mind, and negative thinking processes.

Internalizing symptoms such as elevated stress and sustained negative affect can be important warning signs for developing mental disorders. A recent theoretical framework suggests a complex interplay of empathy, theory of mind (ToM), and negative thinking processes as a crucial risk combination for internalizing symptoms. To disentangle these relationships, this study utilizes neural, behavioral, and self-report data to examine how the interplay between empathy, ToM, and negative thinking processes relates to stress and negative affect. We reanalyzed the baseline data of N = 302 healthy participants (57% female, Mage = 40.52, SDage = 9.30) who participated in a large-scale mental training study, the ReSource project. Empathy and ToM were assessed using a validated fMRI paradigm featuring naturalistic video stimuli and via self-report. Additional self-report scales were employed to measure internalizing symptoms (perceived stress, negative affect) and negative thinking processes (rumination and self-blame). Our results revealed linear associations of self-reported ToM and empathic distress with stress and negative affect. Also, both lower and higher, compared to average, activation in the anterior insula during empathic processing and in the middle temporal gyrus during ToM performance was significantly associated with internalizing symptoms. These associations were dependent on rumination and self-blame. Our findings indicate specific risk constellations for internalizing symptoms. Especially people with lower self-reported ToM and higher empathic distress may be at risk for more internalizing symptoms. Quadratic associations of empathy- and ToM-related brain activation with internalizing symptoms depended on negative thinking processes, suggesting differential effects of cognitive and affective functioning on internalizing symptoms. Using a multi-method approach, these findings advance current research by shedding light on which complex risk combinations of cognitive and affective functioning are relevant for internalizing symptoms.

Hair cortisol and dehydroepiandrosterone and their associations with optimism and pessimism in older people.

The cumulative negative effects of prolonged Hypothalamic-Pituitary-Adrenal axis (HPA axis) activation are associated with several age-related diseases. Some psychological traits such as optimism and pessimism have been shown to be related to both health and the stress response, although their relationship with the HPA axis is inconclusive. More stable HPA axis biomarkers, such as hair samples of cortisol (HC) and dehydroepiandrosterone (HDHEA), would help to clarify the association between these psychological traits and HPA axis functioning. The main aim of this study was to test the relationships between optimism and pessimism and chronic stress biomarkers measured in hair (HC and HDHEA). Additionally, a secondary objective was to explore sex differences in HC and HDHEA levels and their relationship with these psychological traits. We measured optimism, pessimism, and their combination (dispositional optimism) using the Life Orientation Test Revised (LOT-R) and chronic stress biomarkers (HC and HDHEA) in 119 healthy participants (46 men and 73 women) between 56 and 81 years old who belonged to a university program. Regression analyses controlling for perceived stress and BMI indicated that higher dispositional optimism was related to lower HC and HC:HDHEAratio (ß = -0.256, p = .008 and ß = -0.300, p = .002, respectively). More specifically, higher pessimism was related to higher HC (ß = 0.235; p = .012) and HC:HDHEAratio (ß = 0.240; p = .011), whereas higher optimism was associated with a lower HC:HDHEAratio(ß = -0.205; p = .031). Moderation analyses showed no sex differences. To date, this is the first study to investigate the link between these traits and HC and HDHEA in older people. Our results confirm that positive and negative expectations about the future (i.e. optimism and pessimism) may play an important role in health due to their relationship with the HPA axis. They also strengthen the idea that the negative effects of pessimism have a greater weight than the protective effects of optimism in their relationship with HPA axis regulation.

Are lateralized and bold fish optimistic or pessimistic?

Cognitive bias is defined as the influence of emotions on cognitive processes. The concept of the cognitive judgement bias has its origins in human psychology but has been applied to animals over the past 2 decades. In this study we were interested in determining if laterality and personality traits, which are known to influence learning style, might also be correlated with a cognitive bias in the three-spined sticklebacks (Gasterosteus aculeatus). We used the judgement bias test with the go/no-go procedure where fish were first trained to discriminate between a black and white card and, after reaching a minimum learning criterion, tested their response to an ambiguous card (grey). Optimistic subjects were expected to have a high expectation of reward associated with an ambiguous stimulus, whereas pessimistic subjects a high expectation of non-reward. We used an emergence and a mirror test to quantify boldness and laterality, respectively. We hypothesised that male, bolder and more strongly lateralized fish would be more optimistic than female, shy and less strongly lateralised fish. We found that males and more strongly lateralized fish were more optimistic than females and less strongly lateralized fish. In addition, bold males were more optimistic than shy males as we predicted, but females showed the opposite pattern. Finally, fish trained on the black colour card learned the training task faster than those trained on a white card. Our results indicate that both laterality and personality traits are linked to animals' internal states (pessimistic or optimistic outlooks) which likely has broad implications for understanding animal behaviour particularly in a welfare context.

Affect-congruent attention modulates generalized reward expectations.

Positive and negative affective states are respectively associated with optimistic and pessimistic expectations regarding future reward. One mechanism that might underlie these affect-related expectation biases is attention to positive- versus negative-valence features (e.g., attending to the positive reviews of a restaurant versus its expensive price). Here we tested the effects of experimentally induced positive and negative affect on feature-based attention in 120 participants completing a compound-generalization task with eye-tracking. We found that participants' reward expectations for novel compound stimuli were modulated in an affect-congruent way: positive affect induction increased reward expectations for compounds, whereas negative affect induction decreased reward expectations. Computational modelling and eye-tracking analyses each revealed that these effects were driven by affect-congruent changes in participants' allocation of attention to high- versus low-value features of compounds. These results provide mechanistic insight into a process by which affect produces biases in generalized reward expectations.

Hard to let it go: repetitive negative thinking and hoarding in later life in Japan.

Objectives: Hoarding in older adults can have a detrimental effect on daily life. Repetitive negative thinking (RNT) could result in a greater avoidance of discarding and increased saving behaviors; yet, the unique role of RNT on hoarding in older adults remains understudied. This study aimed to investigate whether the intensity of RNT contributes to hoarding in older adults. Methods: Two hundred and sixty-four older adults in Japan (ages 65-86 years, 132 males and 132 females) participated in an online survey. Hierarchical regression analyses were conducted to examine whether RNT could significantly explain the variance of hoarding after controlling for age, sex, years of education, self-reported cognitive impairment, and depression. Results: As we expected, RNT was significantly associated with greater hoarding behaviors, such as excessive acquisition (ß = .27, p = .005) and difficulty in discarding (ß = .27, p = .003). On the other hand, reflection, repetitive thinking without negative emotional valence, was significantly associated with higher scores on clutter (ß = .36 p < .001). Conclusion: Our findings highlight the importance of addressing RNT in the prevention and treatment of hoarding symptoms among older adults, potentially leading to more effective interventions and improved outcomes in managing hoarding behaviors in this population.

The relationship between perfectionism and interpersonal sensitivity with self-compassion in university students: the mediation of repetitive negative thinking.

Self-compassion is a construct of positive psychology related to personality and cognitive factors. Perfectionism and interpersonal sensitivity are prevalent personality traits among university students and are associated with low self-compassion. Further research is required to comprehend how these mechanisms work in creating self-compassion. Consequently, the current study investigated the direct and indirect relationship between perfectionism and interpersonal sensitivity with self-compassion via repetitive negative thinking. To this end, a sample of 450 students studying in Tehran during the 2022 academic year was selected as the study sample. The results indicated that perfectionism and interpersonal sensitivity demonstrate a negative direct relationship with self-compassion, while perfectionism and interpersonal sensitivity exhibit an indirect relationship with self-compassion via repetitive negative thinking. Based on the findings, it can be concluded that the relationship between perfectionism and interpersonal sensitivity with self-compassion is not straightforward and that repetitive negative thinking can mediate this relationship. The results can be used to improve methods for increasing self-compassion and paying attention to personality, and cognitive factors can be an important step toward more effective self-compassion interventions.

The effect of psychological treatment on repetitive negative thinking in youth depression and anxiety: a meta-analysis and meta-regression.

BACKGROUND: Depression and anxiety are prevalent in youth populations and typically emerge during adolescence. Repetitive negative thinking (RNT) is a putative transdiagnostic mechanism with consistent associations with depression and anxiety. Targeting transdiagnostic processes like RNT for youth depression and anxiety may offer more targeted, personalised and effective treatment. METHODS: A meta-analysis was conducted to examine the effect of psychological treatments on RNT, depression and anxiety symptoms in young people with depression or anxiety, and a meta-regression to examine relationships between outcomes. RESULTS: Twenty-eight randomised controlled trials examining 17 different psychological interventions were included. Effect sizes were small to moderate across all outcomes (Hedge's g depression = -0.47, CI -0.77 to -0.17; anxiety = -0.42, CI -0.65 to -0.20; RNT = -0.45, CI -0.67 to -0.23). RNT-focused and non-RNT focused approaches had comparable effects; however, those focusing on modifying the process of RNT had significantly larger effects on RNT than those focusing on modifying negative thought content. Meta-regression revealed a significant relationship between RNT and depression outcomes only across all intervention types and with both depression and anxiety for RNT focused interventions only. CONCLUSION: Consistent with findings in adults, this review provides evidence that reducing RNT with psychological treatment is associated with improvements in depression and anxiety in youth. Targeting RNT specifically may not lead to better outcomes compared to general approaches; however, focusing on modifying the process of RNT may be more effective than targeting content. Further research is needed to determine causal pathways.

Intensity of repetitive negative thinking in depression is associated with greater functional connectivity between semantic processing and emotion regulation areas.

BACKGROUND: Repetitive negative thinking (RNT), a cognitive process that encompasses past (rumination) and future (worry) directed thoughts focusing on negative experiences and the self, is a transdiagnostic construct that is especially relevant for major depressive disorder (MDD). Severe RNT often occurs in individuals with severe levels of MDD, which makes it challenging to disambiguate the neural circuitry underlying RNT from depression severity. METHODS: We used a propensity score, i.e., a conditional probability of having high RNT given observed covariates to match high and low RNT individuals who are similar in the severity of depression, anxiety, and demographic characteristics. Of 148 MDD individuals, we matched high and low RNT groups (n = 50/group) and used a data-driven whole-brain voxel-to-voxel connectivity pattern analysis to investigate the resting-state functional connectivity differences between the groups. RESULTS: There was an association between RNT and connectivity in the bilateral superior temporal sulcus (STS), an important region for speech processing including inner speech. High relative to low RNT individuals showed greater connectivity between right STS and bilateral anterior insular cortex (AI), and between bilateral STS and left dorsolateral prefrontal cortex (DLPFC). Greater connectivity in those regions was specifically related to RNT but not to depression severity. CONCLUSIONS: RNT intensity is directly related to connectivity between STS and AI/DLPFC. This might be a mechanism underlying the role of RNT in perceptive, cognitive, speech, and emotional processing. Future investigations will need to determine whether modifying these connectivities could be a treatment target to reduce RNT.

The effect of emotional regulation difficulties on sexual and psychological distress using repetitive negative thinking as a mediator.

BACKGROUND: Sexual distress, a determinant factor in diagnosing sexual dysfunction, plays a significant role in individuals' sexual well-being, yet it has been overlooked in research. AIM: This exploratory study adopted a transdiagnostic approach to sexual distress and sought to examine the association between emotional regulation difficulties and sexual and psychological distress, with repetitive negative thinking as a potential mediator. METHODS: We used a quantitative cross-sectional design with a sample of 509 partnered individuals. OUTCOMES: The survey included a sociodemographic questionnaire, the Difficulties in Emotion Regulation Scale-Short Form, the Kessler Psychological Distress Scale, the Persistent and Intrusive Negative Thoughts Scale, and the Female Sexual Distress Scale-Revised. RESULTS: Correlational analysis revealed significant associations among emotional regulation difficulties, repetitive negative thinking, psychological distress, and sexual distress. Furthermore, a mediation model demonstrated that repetitive negative thinking significantly mediated emotion dysregulation and psychological and sexual distress. CLINICAL IMPLICATIONS: These findings underscore the importance of considering emotion regulation difficulties and repetitive negative thinking as a maladaptive coping strategy when evaluating sexual distress and suggest that therapeutic interventions targeting such difficulties and thoughts may yield beneficial outcomes. STRENGTHS AND LIMITATIONS: These findings reinforce the importance of considering the role of emotional regulation difficulties and, consequently, repetitive negative thinking as a dysfunctional coping strategy, when studying and intervening in sexual distress. Future research with clinical samples should be developed to establish better the significance of considering these two dimensions in assessment and therapeutic intervention. CONCLUSION: Future research should corroborate and expand upon these findings to advance our understanding of sexual distress and optimize interventions in this domain.

Optimism and pessimism in optimised replay.

The replay of task-relevant trajectories is known to contribute to memory consolidation and improved task performance. A wide variety of experimental data show that the content of replayed sequences is highly specific and can be modulated by reward as well as other prominent task variables. However, the rules governing the choice of sequences to be replayed still remain poorly understood. One recent theoretical suggestion is that the prioritization of replay experiences in decision-making problems is based on their effect on the choice of action. We show that this implies that subjects should replay sub-optimal actions that they dysfunctionally choose rather than optimal ones, when, by being forgetful, they experience large amounts of uncertainty in their internal models of the world. We use this to account for recent experimental data demonstrating exactly pessimal replay, fitting model parameters to the individual subjects' choices.

Real-Time fMRI Functional Connectivity Neurofeedback Reducing Repetitive Negative Thinking in Depression: A Double-Blind, Randomized, Sham-Controlled Proof-of-Concept Trial.

INTRODUCTION: Repetitive negative thinking (RNT) is a cognitive process focusing on self-relevant and negative experiences, leading to a poor prognosis of major depressive disorder (MDD). We previously identified that connectivity between the precuneus/posterior cingulate cortex (PCC) and right temporoparietal junction (rTPJ) was positively correlated with levels of RNT. OBJECTIVE: In this double-blind, randomized, sham-controlled, proof-of-concept trial, we employed real-time functional magnetic resonance imaging neurofeedback (rtfMRI-nf) to delineate the neural processes that may be causally linked to RNT and could potentially become treatment targets for MDD. METHODS: MDD-affected individuals were assigned to either active (n = 20) or sham feedback group (n = 19). RNT was measured by the Ruminative Response Scale-brooding subscale (RRS-B) before and 1 week after the intervention. RESULTS: Individuals in the active but not in the sham group showed a significant reduction in the RRS-B; however, a greater reduction in the PCC-rTPJ connectivity was unrelated to a greater reduction in the RRS-B. Exploratory analyses revealed that a greater reduction in the retrosplenial cortex (RSC)-rTPJ connectivity yielded a more pronounced reduction in the RRS-B in the active but not in the sham group. CONCLUSIONS: RtfMRI-nf was effective in reducing RNT. Considering the underlying mechanism of rtfMIR-nf, the RSC and rTPJ could be part of a network (i.e., default mode network) that might collectively affect the intensity of RNT. Understanding the relationship between the functional organization of targeted neural changes and clinical metrics, such as RNT, has the potential to guide the development of mechanism-based treatment of MDD.

Optimism and pessimism as predictors of seizure group among patients with intractable seizure disorders.

The purpose of this study was to investigate the validity of the Revised Optimism-Pessimism Scale (PSM-R) as a measure of attributional style, and the incremental utility of optimism and pessimism as predictors of seizure group, in an intractable seizure disorder sample. Participants included adult patients with epileptic seizures (ES; n = 151) and psychogenic nonepileptic seizures (PNES; n = 173) whose diagnoses were confirmed by prolonged video/EEG monitoring (PVEM). Optimism and pessimism scores were computed from abbreviated versions of the MMPI for all participants. Analyses were conducted to examine the relationships between optimism, pessimism, and MMPI clinical scale scores. Logistic regression analyses were conducted to generate a model for the prediction of seizure group. Results supported the validity of the PSM-R as a measure of attributional style in an intractable seizure disorder sample. Both optimism and pessimism provided significant incremental predictive utility over and above other predictors of seizure group. There are advantages of using the proposed prediction model over other alternative differential diagnostic procedures, including lower cost, greater availability, and increased standardization. Overall, results indicated that attributional style is a clinically relevant index of personality and cognitive response to stress among an intractable seizure disorder sample.

Examining intra- and inter-personal health effects of optimism and pessimism: The role of subjective well-being in romantic couples.

INTRODUCTION: Recent meta-analytic research suggests that the absence of pessimism could be a stronger predictor of physical health than the presence of optimism. The present study examined the role of subjective well-being in the effects of optimism and pessimism on physical health in romantic couples. It was hypothesized that pessimism would be more strongly associated with both well-being and health than optimism, intra- and interpersonally. Subjective well-being was also expected to explain variance in the associations between optimism, pessimism, and health. METHODS: A baseline sample of 153 opposite-sex couples completed various measures of subjective well-being (e.g., life satisfaction, positive and negative affect, and depressive symptoms) and physical health (e.g., subjective health, sleep efficiency, physical symptoms, cold symptoms, and chronic illness). RESULTS: Results of actor-partner interdependence models showed that the absence of pessimism, but not the presence of optimism, was associated with better physical health at baseline and over time. Pessimism was also a stronger predictor than optimism of baseline levels in some indicators of subjective well-being. These effects were obtained intra- and interpersonally. Finally, subjective well-being explained variance in some of the effects of pessimism on levels of physical health. Implications for theory, research, and practice are discussed.

A Personalized, Transdiagnostic Smartphone Intervention (Mello) Targeting Repetitive Negative Thinking in Young People With Depression and Anxiety: Pilot Randomized Controlled Trial.

BACKGROUND: Repetitive negative thinking (RNT) is a key transdiagnostic mechanism underpinning depression and anxiety. Using "just-in-time adaptive interventions" via smartphones may disrupt RNT in real time, providing targeted and personalized intervention. OBJECTIVE: This pilot randomized controlled trial evaluates the feasibility, acceptability, and preliminary clinical outcomes and mechanisms of Mello-a fully automated, personalized, transdiagnostic, and mechanistic smartphone intervention targeting RNT in young people with depression and anxiety. METHODS: Participants with heightened depression, anxiety, and RNT were recruited via social media and randomized to receive Mello or a nonactive control over a 6-week intervention period. Assessments were completed via Zoom sessions at baseline and at 3 and 6 weeks after baseline. RESULTS: The findings supported feasibility and acceptability, with high rates of recruitment (N=55), uptake (55/64, 86% of eligible participants), and retention (52/55, 95% at 6 weeks). Engagement was high, with 90% (26/29) and 59% (17/29) of the participants in the Mello condition still using the app during the third and sixth weeks, respectively. Greater reductions in depression (Cohen d=0.50), anxiety (Cohen d=0.61), and RNT (Cohen d=0.87) were observed for Mello users versus controls. Mediation analyses suggested that changes in depression and anxiety were accounted for by changes in RNT. CONCLUSIONS: The results indicate that mechanistic, targeted, and real-time technology-based solutions may provide scalable and effective interventions that advance the treatment of youth mental ill health. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12621001701819; http://tinyurl.com/4d3jfj9f.

Using spreading activation to understand repetitive negative thinking.

Repetitive negative thinking (RNT) describes a recursive, unproductive pattern of thought that is commonly observed in individuals who experience anxiety and depression. Past research on RNT has primarily relied on self-report, which fails to capture the potential mechanisms that underlie the persistence of maladaptive thought. We investigated whether RNT may be maintained by a negatively biased semantic network. The present study used a modified free association task to assess state RNT. Following the presentation of a valenced (positive, neutral, negative) cue word, participants generated a series of free associates, which allowed for the dynamic progression of responses. State RNT was conceptualised as the length of consecutive, negatively valenced free associates (i.e. chains). Participants also completed two self-report measures that assessed trait RNT and trait negative affect. Within a structural equation model, negative (but not positive or neutral) response chain length positively predicted trait RNT and negative affect, and this was only the case for positive (but not negative or neutral) cue words. These results suggest that RNT tendencies may be reflected in semantic retrieval and can be assessed without self-report.

Optimism and pessimism are antithetically associated with post-operative knee function in patients' undergoing total knee arthroplasty.

PURPOSE: Personality traits, such as dispositional optimism and pessimism, have impact on a variety of health-related problems. Influence on outcome in total knee arthroplasty (TKA) could only be shown for other personality trait concepts, but not for dispositional optimism/pessimism. This study aims to examine the association of dispositional optimism/pessimism with pre-operative joint function and post-operative outcome in TKA. METHODS: Data were acquired in a multicentre, cross-sectoral, prospective study (the PROMISE Trial). Patients were followed for 12 months post-operatively. Dispositional optimism/pessimism was measured pre-operatively via the revised Life Orientation Test (LOT-R), pre- and post-operative function was measured via the 12 Item Knee-osteoarthritis outcome Scores (KOOS-12). Log-linear regression models considering known confounders and t-test were carried out to show the association of LOT-R scores with pre- and post-operative KOOS-12 scores. RESULTS: 740 patients were analyzed. Optimistic LOT-R was significantly positively associated to the mean scores of KOOS-12 pre- and post-operative, while pessimistic LOT-R was significantly associated negatively (pre-operative: optimistic p = 0.001, pessimistic p = 0.001; post-operative optimistic: 3M p = 0.001, 6M p = 0.001, 12M p = 0.001; post-operative pessimistic: 3M p = 0.01, 6M p = 0.004, 12M p = 0.001). CONCLUSION: Optimism was positively associated with pre-operative joint function and, more importantly, post-operative functional outcome in TKA, while pessimism was associated with the opposite. Assessing patients' general personality traits prior to surgery to identify pessimistic patients, hence being at risk for poor outcome in TKA, should be considered to react to the patients' special needs and possible pessimistic expectations, i.e., through a cognitive-behavioral intervention, to potentially increase optimism and hereby post-operative outcome in TKA. LEVEL OF EVIDENCE: Prognostic Level III.

Minority stress, repetitive negative thinking, and internalizing symptoms in sexual minorites: Does cognitive content matter?

BACKGROUND: The Psychological Mediation Framework theorizes that repetitive negative thinking (RNT) mediates the relationship between minority stress and mental health, and this theory has been consistently supported by previous research. Yet, it is unclear whether the process or content of RNT is more important in the development of internalizing symptoms in sexual minorities. Consequently, the goal of the current study was to use structural equation modeling to determine whether there are significant indirect effects of repetitive negative thought content in the relationship between minority stress and internalizing psychopathology. METHODS: Measures of RNT, internalizing symptoms, and proximal minority stress were completed online by 205 cisgender sexual minority adults. Structural equation modeling was used to examine indirect effects of proximal stress on internalizing symptoms through content-independent RNT, depressive rumination, and sexual orientation-related rumination. RESULTS: Significant direct effects of proximal minority stress on internalizing symptoms were observed. Indirect effects of proximal stress on internalizing symptoms were observed for content-independent RNT and depressive rumination, but not sexual orientation-related rumination. CONCLUSIONS: The current study provides evidence that the process and affective valence of RNT contributes more to internalizing symptoms in sexual minorities when compared with sexual orientation-related content. Theoretical and clinical implications are discussed.

Can a Pessimistic Outlook Moderate the Victimization-Delinquency Relationship?

This study was designed to shed light on the relationship between victimization and offending, a pattern commonly known as the victim-offender overlap, by exploring whether victimization and pessimism toward the future interact in association with self-reported delinquency. This study was performed on 1,300 (444 males, 645 females, and 211 sex not identified) members of the 2018 High School Senior Monitoring the Future cross-sectional study. Multiple regression analysis was conducted using a maximum likelihood estimator and bias-corrected bootstrapped 95% confidence intervals. The analysis revealed that victimization and the victimization × pessimism interaction correlated significantly with delinquency, after controlling for a series of demographic, family, and peer factors. These results indicate that pessimism toward the future may exacerbate the already strong relationship known to exist between victimization and delinquency.