Reward processing dysfunction in major depression, bipolar disorder and schizophrenia

Transdiagnostic phenomena of psychopathology in the context of the RDoC: protocol of a multimodal cross-sectional study

In the past, affective and cognitive processes related to psychopathology have been examined within the boundaries of phenotype-based diagnostic labels, which has led to inconsistent findings regarding their underlying operating principles. Investigating these processes dimensionally in healthy individuals and by means of multiple modalities may provide additional insights into the psychological and neuronal mechanisms at their core. The transdiagnostic phenomena Neuroticism and Rumination are known to be closely linked. However, the exact nature of their relationship remains to be elucidated. The same applies to the associations between Hedonic Capacity, Negativity Bias and different Emotion Regulation strategies.This multimodal cross-sectional study examines the relationship of the transdiagnostic phenomena Neuroticism and Rumination as well as Hedonic Capacity, the Negativity Bias and Emotion Regulation from a RDoC (Research Domain Criteria) perspective. A total of 120 currently healthy subjects (past 12 months) will complete several questionnaires regarding personality, emotion regulation, hedonic capacity, and psychopathologies as well as functional magnetic resonance imaging (fMRI) during cognitive and emotional processing, to obtain data on the circuit, behavioral and self-report level.This study aims to contribute to the understanding of the relationship between cognitive and affective processes associated with psychopathologies as well as their neuronal correlates. Ultimately, a grounded understanding of these processes could guide improvement of diagnostic labels and treatments. Limitations include the cross-sectional design and the limited variability in psychopathology scores due to the restriction of the sample to currently healthy subjects.

Dissociation of Cognitive Effort-Based Decision Making and Its Associations With Symptoms, Cognition, and Everyday Life Function Across Schizophrenia, Bipolar Disorder, and Depression

BACKGROUND

Anhedonia and amotivation are symptoms of many different mental health disorders that are frequently associated with functional disability, but it is not clear whether the same processes contribute to motivational impairments across disorders. This study focused on one possible factor, the willingness to exert cognitive effort, referred to as cognitive effort-cost decision making.

METHODS

We examined performance on the deck choice task as a measure of cognitive effort-cost decision making, in which people choose to complete an easy task for a small monetary reward or a harder task for larger rewards, in 5 groups: healthy control (n = 80), schizophrenia/schizoaffective disorder (n = 50), bipolar disorder with psychosis (n = 58), current major depression (n = 60), and past major depression (n = 51). We examined cognitive effort-cost decision making in relation to clinician and self-reported motivation symptoms, working memory and cognitive control performance, and life function measured by ecological momentary assessment and passive sensing.

RESULTS

We found a significant diagnostic group × reward interaction (F8,588 = 4.37, p < .001, ηp2 = 0.056). Compared with the healthy control group, the schizophrenia/schizoaffective and bipolar disorder groups, but not the current or past major depressive disorder groups, showed a reduced willingness to exert effort at the higher reward values. In the schizophrenia/schizoaffective and bipolar disorder groups, but not the major depressive disorder groups, reduced willingness to exert cognitive effort for higher rewards was associated with greater clinician-rated motivation impairments, worse working memory and cognitive control performance, and less engagement in goal-directed activities measured by ecological momentary assessment.

CONCLUSIONS

These findings suggest that the mechanisms contributing to motivational impairments differ among individuals with psychosis spectrum disorders versus depression.

The Addiction-Susceptibility TaqIA/Ankk1 Controls Reward and Metabolism Through D2 Receptor-Expressing Neurons

BACKGROUND

A large body of evidence highlights the importance of genetic variants in the development of psychiatric and metabolic conditions. Among these, the TaqIA polymorphism is one of the most commonly studied in psychiatry. TaqIA is located in the gene that codes for the ankyrin repeat and kinase domain containing 1 kinase (Ankk1) near the dopamine D2 receptor (D2R) gene. Homozygous expression of the A1 allele correlates with a 30% to 40% reduction of striatal D2R, a typical feature of addiction, overeating, and other psychiatric pathologies. The mechanisms by which the variant influences dopamine signaling and behavior are unknown.

METHODS

Here, we used transgenic and viral-mediated strategies to reveal the role of Ankk1 in the regulation of activity and functions of the striatum.

RESULTS

We found that Ankk1 is preferentially enriched in striatal D2R-expressing neurons and that Ankk1 loss of function in the dorsal and ventral striatum leads to alteration in learning, impulsivity, and flexibility resembling endophenotypes described in A1 carriers. We also observed an unsuspected role of Ankk1 in striatal D2R-expressing neurons of the ventral striatum in the regulation of energy homeostasis and documented differential nutrient partitioning in humans with or without the A1 allele.

CONCLUSIONS

Overall, our data demonstrate that the Ankk1 gene is necessary for the integrity of striatal functions and reveal a new role for Ankk1 in the regulation of body metabolism.

Examining social reinforcement learning in social anxiety

BACKGROUND AND OBJECTIVES

Reinforcement learning biases have been empirically linked to anhedonia in depression and theoretically linked to social anhedonia in social anxiety disorder, but little work has directly assessed how socially anxious individuals learn from social reward and punishment.

METHODS

N = 157 individuals high and low in social anxiety symptoms completed a social probabilistic selection task that involved selecting between pairs of neutral faces with varying probabilities of changing to a happy or angry face. Computational modeling was performed to estimate learning rates. Accuracy in choosing the more rewarding face was also analyzed.

RESULTS

No significant group differences were found for learning rates. Contrary to hypotheses, participants high in social anxiety showed impaired punishment learning accuracy; they were more accurate at choosing the most rewarding face than they were at avoiding the most punishing face, and their punishment learning accuracy was lower than that of participants low in social anxiety. Secondary analyses found that high (vs. low) social anxiety participants were less accurate at selecting the more rewarding face on more (vs. less) punishing face pairs.

LIMITATIONS

Stimuli were static, White, facial images, which lack important social cues (e.g., movement, sound) and diversity, and participants were largely non-Hispanic, White undergraduates, whose social reinforcement learning may differ from individuals at different developmental stages and those holding more marginalized identities.

CONCLUSIONS

Socially anxious individuals may be less accurate at learning to avoid social punishment, which may maintain negative beliefs through an interpersonal stress generation process.

Associations of negative affective biases and depressive symptoms in a community-based sample

BACKGROUND

Major depressive disorder (MDD) was previously associated with negative affective biases. Evidence from larger population-based studies, however, is lacking, including whether biases normalise with remission. We investigated associations between affective bias measures and depressive symptom severity across a large community-based sample, followed by examining differences between remitted individuals and controls.

METHODS

Participants from Generation Scotland (N = 1109) completed the: (i) Bristol Emotion Recognition Task (BERT), (ii) Face Affective Go/No-go (FAGN), and (iii) Cambridge Gambling Task (CGT). Individuals were classified as MDD-current (n = 43), MDD-remitted (n = 282), or controls (n = 784). Analyses included using affective bias summary measures (primary analyses), followed by detailed emotion/condition analyses of BERT and FAGN (secondary analyses).

RESULTS

For summary measures, the only significant finding was an association between greater symptoms and lower risk adjustment for CGT across the sample (individuals with greater symptoms were less likely to bet more, despite increasingly favourable conditions). This was no longer significant when controlling for non-affective cognition. No differences were found for remitted-MDD v. controls. Detailed analysis of BERT and FAGN indicated subtle negative biases across multiple measures of affective cognition with increasing symptom severity, that were independent of non-effective cognition [e.g. greater tendency to rate faces as angry (BERT), and lower accuracy for happy/neutral conditions (FAGN)]. Results for remitted-MDD were inconsistent.

CONCLUSIONS

This suggests the presence of subtle negative affective biases at the level of emotion/condition in association with depressive symptoms across the sample, over and above those accounted for by non-affective cognition, with no evidence for affective biases in remitted individuals.

Pushing the Frontiers: Optogenetics for Illuminating the Neural Pathophysiology of Bipolar Disorder

Bipolar disorder (BD), a disabling mental disorder, is featured by the oscillation between episodes of depression and mania, along with disturbance in the biological rhythms. It is on an urgent demand to identify the intricate mechanisms of BD pathophysiology. Based on the continuous progression of neural science techniques, the dysfunction of circuits in the central nervous system was currently thought to be tightly associated with BD development. Yet, challenge exists since it depends on techniques that can manipulate spatiotemporal dynamics of neuron activity. Notably, the emergence of optogenetics has empowered researchers with precise timing and local manipulation, providing a possible approach for deciphering the pathological underpinnings of mental disorders. Although the application of optogenetics in BD research remains preliminary due to the scarcity of valid animal models, this technique will advance the psychiatric research at neural circuit level. In this review, we summarized the crucial aberrant brain activity and function pertaining to emotion and rhythm abnormities, thereby elucidating the underlying neural substrates of BD, and highlighted the importance of optogenetics in the pursuit of BD research.

The effects of esketamine and treatment expectation in acute major depressive disorder (Expect): study protocol for a pharmacological fMRI study using a balanced placebo design

BACKGROUND

Major depressive disorder (MDD) is a highly prevalent (8-15%), severely disabling disorder and is associated with enormous socioeconomic impact. Antidepressant medication for the treatment of MDD has proven effective in RCTs; however, placebo response is also substantial. Given the potential benefits of modulating the placebo response in patient care and pharmacological research, understanding the mechanisms underlying placebo response is of high clinical relevance. The placebo response is mediated by treatment expectation, i.e. an individual's belief about whether and how much they will improve as a consequence of their treatment. The mechanisms and moderators of treatment expectation effects in MDD are poorly understood. Initial brain imaging studies on placebo responses in MDD point towards the relevance of the lateral prefrontal cortex and the rostral anterior cingulate cortex (rACC). In this project, we will investigate the neural mechanisms underlying the antidepressant effects of treatment expectation associated with the fast-acting antidepressant esketamine in patients with MDD. Esketamine is an NMDA receptor antagonist inducing antidepressant effects within hours.

METHODS

We will employ a fully balanced placebo design with the factors "treatment" (i.v. esketamine / placebo) and verbally induced "expectation" (high / low) combined with fMRI (resting state, emotion and reward processing paradigms) to investigate the psychological and neural mechanisms underlying the antidepressant effects of expectation, and how these interact with the pharmacological effects of esketamine.

DISCUSSION

The insights gained by this project promise fundamental implications for clinical treatment and future drug trials. Unraveling the mechanisms underlying expectation effects on antidepressant treatment may inform (1) strategies to modulate these effects and thus improve assay sensitivity in RCTs and (2) novel treatment regiments aiming to maximize the synergistic effects of expectation and pharmacological treatment in the clinical care of patients with MDD.

TRIAL REGISTRATION

This trial has been prospectively registered with the EU Clinical Trials Register: EudraCT-No.: 2020-000784-23 (November 17, 2020).

Learning without contingencies: A loss of synergy between memory and reward circuits in schizophrenia

Motivational deficits in schizophrenia may interact with foundational cognitive processes including learning and memory to induce impaired cognitive proficiency. If such a loss of synergy exists, it is likely to be underpinned by a loss of synchrony between the brains learning and reward sub-networks. Moreover, this loss should be observed even during tasks devoid of explicit reward contingencies given that such tasks are better models of real world performance than those with artificial contingencies. Here we applied undirected functional connectivity (uFC) analyses to fMRI data acquired while participants engaged in an associative learning task without contingencies or feedback. uFC was estimated and inter-group differences (between schizophrenia patients and controls, n = 54 total, n = 28 patients) were assessed within and between reward (VTA and NAcc) and learning/memory (Basal Ganglia, DPFC, Hippocampus, Parahippocampus, Occipital Lobe) sub-networks. The task paradigm itself alternated between Encoding, Consolidation, and Retrieval conditions, and uFC differences were quantified for each of the conditions. Significantly reduced uFC dominated the connectivity profiles of patients across all conditions. More pertinent to our motivations, these reductions were observed within and across classes of sub-networks (reward-related and learning/memory related). We suggest that disrupted functional connectivity between reward and learning sub-networks may drive many of the performance deficits that characterize schizophrenia. Thus, cognitive deficits in schizophrenia may in fact be underpinned by a loss of synergy between reward-sensitivity and cognitive processes.

Parsing altered gray matter morphology of depression using a framework integrating the normative model and non-negative matrix factorization

The high inter-individual heterogeneity in individuals with depression limits neuroimaging studies with case-control approaches to identify promising biomarkers for individualized clinical decision-making. We put forward a framework integrating the normative model and non-negative matrix factorization (NMF) to quantitatively assess altered gray matter morphology in depression from a dimensional perspective. The proposed framework parses altered gray matter morphology into overlapping latent disease factors, and assigns patients distinct factor compositions, thus preserving inter-individual variability. We identified four robust disease factors with distinct clinical symptoms and cognitive processes in depression. In addition, we showed the quantitative relationship between the group-level gray matter morphological differences and disease factors. Furthermore, this framework significantly predicted factor compositions of patients in an independent dataset. The framework provides an approach to resolve neuroanatomical heterogeneity in depression.

Contextual influence of reinforcement learning performance of depression: evidence for a negativity bias?

BACKGROUNDS

Value-based decision-making impairment in depression is a complex phenomenon: while some studies did find evidence of blunted reward learning and reward-related signals in the brain, others indicate no effect. Here we test whether such reward sensitivity deficits are dependent on the overall value of the decision problem.

METHODS

We used a two-armed bandit task with two different contexts: one 'rich', one 'poor' where both options were associated with an overall positive, negative expected value, respectively. We tested patients (N = 30) undergoing a major depressive episode and age, gender and socio-economically matched controls (N = 26). Learning performance followed by a transfer phase, without feedback, were analyzed to distangle between a decision or a value-update process mechanism. Finally, we used computational model simulation and fitting to link behavioral patterns to learning biases.

RESULTS

Control subjects showed similar learning performance in the 'rich' and the 'poor' contexts, while patients displayed reduced learning in the 'poor' context. Analysis of the transfer phase showed that the context-dependent impairment in patients generalized, suggesting that the effect of depression has to be traced to the outcome encoding. Computational model-based results showed that patients displayed a higher learning rate for negative compared to positive outcomes (the opposite was true in controls).

CONCLUSIONS

Our results illustrate that reinforcement learning performances in depression depend on the value of the context. We show that depressive patients have a specific trouble in contexts with an overall negative state value, which in our task is consistent with a negativity bias at the learning rates level.

Distinctive alterations in the mesocorticolimbic circuits in various psychiatric disorders

AIM

Increasing evidence suggests that psychiatric disorders are linked to alterations in the mesocorticolimbic dopamine-related circuits. However, the common and disease-specific alterations remain to be examined in schizophrenia (SCZ), major depressive disorder (MDD), and autism spectrum disorder (ASD). Thus, this study aimed to examine common and disease-specific features related to mesocorticolimbic circuits.

METHODS

This study included 555 participants from four institutes with five scanners: 140 individuals with SCZ (45.0% female), 127 individuals with MDD (44.9%), 119 individuals with ASD (15.1%), and 169 healthy controls (HC) (34.9%). All participants underwent resting-state functional magnetic resonance imaging. A parametric empirical Bayes approach was adopted to compare estimated effective connectivity among groups. Intrinsic effective connectivity focusing on the mesocorticolimbic dopamine-related circuits including the ventral tegmental area (VTA), shell and core parts of the nucleus accumbens (NAc), and medial prefrontal cortex (mPFC) were examined using a dynamic causal modeling analysis across these psychiatric disorders.

RESULTS

The excitatory shell-to-core connectivity was greater in all patients than in the HC group. The inhibitory shell-to-VTA and shell-to-mPFC connectivities were greater in the ASD group than in the HC, MDD, and SCZ groups. Furthermore, the VTA-to-core and VTA-to-shell connectivities were excitatory in the ASD group, while those connections were inhibitory in the HC, MDD, and SCZ groups.

CONCLUSION

Impaired signaling in the mesocorticolimbic dopamine-related circuits could be an underlying neuropathogenesis of various psychiatric disorders. These findings will improve the understanding of unique neural alternations of each disorder and will facilitate identification of effective therapeutic targets.

Positive affect treatment targets reward sensitivity: A randomized controlled trial

OBJECTIVE

Determine whether a novel psychosocial treatment for positive affect improves clinical status and reward sensitivity more than a form of cognitive behavioral therapy that targets negative affect and whether improvements in reward sensitivity correlate with improvements in clinical status.

METHOD

In this assessor-blinded, parallel-group, multisite, two-arm randomized controlled clinical superiority trial, 85 treatment-seeking adults with severely low positive affect, moderate-to-severe depression or anxiety, and functional impairment received 15 weekly individual therapy sessions of positive affect treatment (PAT) or negative affect treatment (NAT). Clinical status measures were self-reported positive affect, interviewer-rated anhedonia, and self-reported depression and anxiety. Target measures were eleven physiological, behavioral, cognitive, and self-report measures of reward anticipation-motivation, response to reward attainment, and reward learning. All analyses were intent-to-treat.

RESULTS

Compared to NAT, individuals receiving PAT achieved superior improvements in the multivariate clinical status measures at posttreatment, b = .37, 95% CI [.15, .59], t(109) = 3.34, p = .001, q = .004, d = .64. Compared to NAT, individuals receiving PAT also achieved higher multivariate reward anticipation-motivation, b = .21, 95% CI [.05, .37], t(268) = 2.61, p = .010, q = .020, d = .32, and higher multivariate response to reward attainment, b = .24, 95% CI [.02, .45], t(266) = 2.17, p = .031, q = .041, d = .25, at posttreatment. Measures of reward learning did not differ between the two groups. Improvements in reward anticipation-motivation and in response to reward attainment correlated with improvements in the clinical status measures.

CONCLUSIONS

Targeting positive affect results in superior improvements in clinical status and reward sensitivity than targeting negative affect. This is the first demonstration of differential target engagement across two psychological interventions for anxious or depressed individuals with low positive affect. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A meta-analysis suggests that tACS improves cognition in healthy, aging, and psychiatric populations

Transcranial alternating current stimulation (tACS) has attracted interest as a technique for causal investigations into how rhythmic fluctuations in brain neural activity influence cognition and for promoting cognitive rehabilitation. We conducted a systematic review and meta-analysis of the effects of tACS on cognitive function across 102 published studies, which included 2893 individuals in healthy, aging, and neuropsychiatric populations. A total of 304 effects were extracted from these 102 studies. We found modest to moderate improvements in cognitive function with tACS treatment that were evident in several cognitive domains, including working memory, long-term memory, attention, executive control, and fluid intelligence. Improvements in cognitive function were generally stronger after completion of tACS ("offline" effects) than during tACS treatment ("online" effects). Improvements in cognitive function were greater in studies that used current flow models to optimize or confirm neuromodulation targets by stimulating electric fields generated in the brain by tACS protocols. In studies targeting multiple brain regions concurrently, cognitive function changed bidirectionally (improved or decreased) according to the relative phase, or alignment, of the alternating current in the two brain regions (in phase versus antiphase). We also noted improvements in cognitive function separately in older adults and in individuals with neuropsychiatric illnesses. Overall, our findings contribute to the debate surrounding the effectiveness of tACS for cognitive rehabilitation, quantitatively demonstrate its potential, and indicate further directions for optimal tACS clinical study design.

Differential responses from the left postcentral gyrus, right middle frontal gyrus, and precuneus to meal ingestion in patients with functional dyspepsia

Background

Functional dyspepsia (FD) is most often a meal-induced syndrome. Studies using resting-state functional magnetic resonance imaging (rs-fMRI) reported abnormal connectivity in areas related to pain processing in FD. However, only a few studies have attempted to determine how meal ingestion affects the brain's working patterns. Through rs-fMRI, this study observed how meal ingestion affected brain regions related to visceral hypersensitivity and emotional response networks in FD patients.

Methods

A total of 30 FD patients and 32 healthy controls (HC) were enrolled and underwent clinical investigations. Rs-fMRI was performed twice after a 4-h fast and 50 min after a meal. The mean functional connectivity strength (FCS) values were extracted from brain regions with significant differences to show the trend of changes related to meal ingestion after FCS analyses.

Results

Depression, anxiety, sleep disturbances, and weight loss were more common in FD patients (P ≤ 0.001). Compared with HCs (corrected cluster P-value < 0.05), FD patients had significantly higher FCS in the right middle frontal gyrus before meals and higher meal-induced FCS in the left postcentral gyrus. HCs had greater meal-induced activation in the right precuneus and anterior cingulate cortex. FD patients had a decreasing trend in the right inferior frontal gyrus compared to the increasing trend in HCs. We only found anxiety to be negatively correlated with FCS in the right inferior frontal gyrus in FD (r = -0.459, p = 0.048, uncorrected).

Conclusions

In this study, we discovered that FD patients have different perceptual and emotional responses to food intake in defined brain areas, providing promising impetus for understanding pathogenic brain mechanisms in FD.

Alpha Event-Related Desynchronization During Reward Processing in Schizophrenia

BACKGROUND

Alterations in the brain's reward system may underlie motivation and pleasure deficits in schizophrenia (SZ). Neuro-oscillatory desynchronization in the alpha band is thought to direct resource allocation away from the internal state, to prioritize processing salient environmental events, including reward feedback. We hypothesized reduced reward-related alpha event-related desynchronization (ERD) in SZ, consistent with less externally focused processing during reward feedback.

METHODS

Electroencephalography was recorded while participants with SZ (n = 54) and healthy control participants (n = 54) played a simple slot machine task. Total alpha band power (8-14 Hz), a measure of neural oscillation magnitude, was extracted via principal component analysis and compared between groups and reward outcomes. The clinical relevance of hypothesized alpha power alterations was examined by testing associations with negative symptoms within the SZ group and with trait rumination, dimensionally, across groups.

RESULTS

A group × reward outcome interaction (p = .018) was explained by healthy control participants showing significant posterior-occipital alpha power suppression to wins versus losses (p < .001), in contrast to participants with SZ (p > .1). Among participants with SZ, this alpha ERD was unrelated to negative symptoms (p > .1). Across all participants, less alpha ERD to reward outcomes covaried with greater trait rumination for both win (p = .005) and loss (p = .002) outcomes, with no group differences in slope.

CONCLUSIONS

These findings demonstrate alpha ERD alterations in SZ during reward outcome processing. Additionally, higher trait rumination was associated with less alpha ERD during reward feedback, suggesting that individual differences in rumination covary with external attention to reward processing, regardless of reward outcome valence or group membership.

Impact of membrane lipid polyunsaturation on dopamine D2 receptor ligand binding and signaling

Increasing evidence supports a relationship between lipid metabolism and mental health. In particular, the biostatus of polyunsaturated fatty acids (PUFAs) correlates with some symptoms of psychiatric disorders, as well as the efficacy of pharmacological treatments. Recent findings highlight a direct association between brain PUFA levels and dopamine transmission, a major neuromodulatory system implicated in the etiology of psychiatric symptoms. However, the mechanisms underlying this relationship are still unknown. Here we demonstrate that membrane enrichment in the n-3 PUFA docosahexaenoic acid (DHA), potentiates ligand binding to the dopamine D2 receptor (D2R), suggesting that DHA acts as an allosteric modulator of this receptor. Molecular dynamics simulations confirm that DHA has a high preference for interaction with the D2R and show that membrane unsaturation selectively enhances the conformational dynamics of the receptor around its second intracellular loop. We find that membrane unsaturation spares G protein activity but potentiates the recruitment of β-arrestin in cells. Furthermore, in vivo n-3 PUFA deficiency blunts the behavioral effects of two D2R ligands, quinpirole and aripiprazole. These results highlight the importance of membrane unsaturation for D2R activity and provide a putative mechanism for the ability of PUFAs to enhance antipsychotic efficacy.

Transdiagnostic brain correlates of self-reported trait impulsivity: A dimensional structure-symptom investigation

Impulsivity transcends psychiatric diagnoses and is often related to anhedonia. This ad hoc cross-sectional investigation explored 1) whether self-reported trait impulsivity mapped onto a common structural brain substrate across healthy controls (HCs) and psychiatric patients, and 2) in a more exploratory fashion, whether impulsivity and anhedonia were related to each other and shared overlapping brain correlates. Structural magnetic resonance imaging (sMRI) datasets from 234 participants including HCs (n = 109) and patients with opioid use disorder (OUD, n = 22), cocaine use disorder (CUD, n = 43), borderline personality disorder (BPD, n = 45) and schizophrenia (SZ, n = 15) were included. Trait impulsivity was measured with the Barratt Impulsiveness Scale (BIS-11) and anhedonia with a subscore of the Beck Depression Inventory (BDI). BIS-11 global score data were available for the entire sample, while data on the BIS-11 2nd order factors attentional, motor and non-planning were additionally in hand for a subsample consisting of HCs, OUD and BPD patients (n = 116). Voxel-based morphometry analyses were conducted for identifying dimensional associations between grey matter volume and impulsivity/anhedonia. Partial correlations were further performed to exploratory test the relationships between impulsivity and anhedonia and their corresponding volumetric brain substrates. Volume of the left opercular part of the inferior frontal gyrus (IFG) was negatively related to global impulsivity across the entire sample and specifically to motor impulsivity in the subsample of HCs, OUD and BPD patients. Across patients anhedonia expression was negatively correlated with left putamen volume. Although there was no relationship between global impulsivity and anhedonia across all patients, only across OUD and BPD patients anhedonia was positively associated with attentional impulsivity. Finally, also across OUD and BPD patients, motor impulsivity associated left IFG volume was positively linked with anhedonia-associated volume in the left putamen. Our findings suggest a critical role of left IFG volume in self-reported global impulsivity across healthy participants and patients with substance use disorder, BPD and SZ. Preliminary findings in OUD and BPD patients further suggests associations between impulsivity and anhedonia that are related to grey matter reductions in the left IFG and putamen.

The human cerebellum in reward anticipation and reward outcome processing: An activation likelihood estimation meta-analysis

The cerebellum generates internal prediction models and actively compares anticipated and actual outcomes in order to reach a desired end state. In this process, reward can serve as a reinforcer that shapes internal prediction models, enabling context-appropriate behavior. While the involvement of the cerebellum in reward processing has been established in animals, there is no detailed account of which cerebellar regions are involved in reward anticipation and reward outcome processing in humans. To this end, an activation likelihood estimation meta-analysis of functional neuroimaging studies was performed to investigate cerebellar functional activity patterns associated with reward anticipation and reward outcome processing in healthy adults. Results showed that reward anticipation (k=31) was associated with regional activity in the bilateral anterior lobe, bilateral lobule VI, left Crus I and the posterior vermis, while reward outcome (k=16) was associated with regional activity in the declive and left lobule VI. The findings of this meta-analysis show distinct involvement of the cerebellum in reward anticipation and reward outcome processing as part of a predictive coding routine.

Opportunities and limitations for studying neuropsychiatric disorders using patient-derived induced pluripotent stem cells

Neuropsychiatric disorders affect a large proportion of the global population and there is an urgent need to understand the pathogenesis and to develop novel and improved treatments of these devastating disorders. However, the diverse symptomatology combined with complex polygenic etiology, and the limited access to disorder-relevant cell types in human brains represent a major obstacle for mechanistic disease research. Conventional animal models, such as rodents, are limited by inherent species differences in brain development, architecture, and function. Advances in human induced pluripotent stem cells (hiPSCs) technologies have provided platforms for new discoveries in neuropsychiatric disorders. First, hiPSC-based disease models enable unprecedented investigation of psychiatric disorders at the molecular, cellular, and structural levels. Second, hiPSCs derived from patients with known genetics, symptoms, and drug response profiles offer an opportunity to recapitulate pathogenesis in relevant cell types and provide novel approaches for understanding disease mechanisms and for developing effective treatments. Third, genome-editing technologies have extended the potential of hiPSCs for generating models to elucidate the genetic basis of rare monogenetic and complex polygenic psychiatric disorders and to establish the causality between genotype and phenotype. Here we review opportunities and limitations for studying psychiatric disorders using various hiPSC-derived model systems.

Risk factors for the intergenerational transmission of depression in women and girls: Understanding neural correlates of major depressive disorder and the role of early-onset maternal depression

Deficits in neural reward processing have been implicated in the etiology of depression and have been observed in high-risk individuals. However, depression is a heterogeneous disorder, and not all depressed individuals exhibit blunted neural reward response, suggesting the need to examine more specific depression phenotypes. Early-onset depression, a well-defined phenotype, has been associated with greater intergenerational transmission of depression and appears more closely linked to neural reward processing deficits. The present study examined whether a maternal history of early-onset depression was associated with neural reward response among mothers and their daughters. Mothers with and without a history of depression, as well as their biological, adolescent daughters (N = 109 dyads), completed a monetary reward guessing task while electroencephalogram was collected. Analyses focused on the Reward Positivity (RewP), an event-related potential following reward receipt. Adjusting for current depressive symptoms, maternal early-onset depression was associated with a blunted RewP in the mothers and a numerically smaller RewP in their never-depressed, adolescent daughters. Maternal adult-onset depression was not statistically associated with a blunted RewP in mothers or daughters. Thus, a blunted RewP appears to be a trait-like vulnerability marker for depression that emerges before depression onset and relates to more specific depression phenotypes (e.g., early-onset depression). These findings have implications for early identification of individuals at risk of depression and for developing more targeted interventions.

The association of CNR1 genetic variants with resting-state functional connectivity in youth bipolar disorder

Cannabinoid 1 receptors coded by the CNR1 gene are implicated in mood disorders and addiction. Given the prevalence and negative correlates of cannabis use in bipolar disorder (BD), we examined CNR1 polymorphism rs1324072 in relation to resting-state functional connectivity (rsFC) in youth BD. Participants included 124 youth, ages 13-20 years: 17 BD G-carriers, 48 BD non-carriers, 16 healthy controls (HC) G-carriers, and 43 HC non-carriers. rsFC was obtained using 3T-MRI. General linear models examined main effects of diagnosis, gene, and diagnosis-by-gene interaction, controlling for age, sex, and race. Regions-of-interests in seed-to-voxel analyses included: bilateral amygdala, hippocampus, nucleus accumbens (NAc), and orbitofrontal cortex (OFC). Main effects of diagnosis were observed for rsFC between the right amygdala seed and right occipital pole, and between the left NAc seed and left superior parietal lobe. Interaction analyses identified 6 significant clusters. G-allele was associated with negative connectivity in BD and positive connectivity in HC for: left amygdala seed with right intracalcarine cortex; right NAc seed with left inferior frontal gyrus; and right hippocampal seed with bilateral cuneal cortex (all p<0.001). G-allele was associated with positive connectivity in BD and negative connectivity in HC for: right hippocampal seed with left central opercular cortex (p = 0.001), and left NAc seed with left middle temporal cortex (p = 0.002). In conclusion, CNR1 rs1324072 was differentially associated with rsFC in youth with BD in regions relevant to reward and emotion. Future studies powered to integrate CNR1 alongside cannabis use are warranted to examine the inter-relationship between rs1324072 G-allele, cannabis use, and BD.

Opposite effects of positive and negative symptoms on resting-state brain networks in schizophrenia

Schizophrenia is a severe psychotic disorder characterized by positive and negative symptoms, but their neural bases remain poorly understood. Here, we utilized a nested-spectral partition (NSP) approach to detect hierarchical modules in resting-state brain functional networks in schizophrenia patients and healthy controls, and we studied dynamic transitions of segregation and integration as well as their relationships with clinical symptoms. Schizophrenia brains showed a more stable integrating process and a more variable segregating process, thus maintaining higher segregation, especially in the limbic system. Hallucinations were associated with higher integration in attention systems, and avolition was related to a more variable segregating process in default-mode network (DMN) and control systems. In a machine-learning model, NSP-based features outperformed graph measures at predicting positive and negative symptoms. Multivariate analysis confirmed that positive and negative symptoms had opposite effects on dynamic segregation and integration of brain networks. Gene ontology analysis revealed that the effect of negative symptoms was related to autistic, aggressive and violent behavior; the effect of positive symptoms was associated with hyperammonemia and acidosis; and the interaction effect was correlated with abnormal motor function. Our findings could contribute to the development of more accurate diagnostic criteria for positive and negative symptoms in schizophrenia.

Tensorial independent component analysis reveals social and reward networks associated with major depressive disorder

Major depressive disorder (MDD) has been associated with changes in functional brain connectivity. Yet, typical analyses of functional connectivity, such as spatial independent components analysis (ICA) for resting-state data, often ignore sources of between-subject variability, which may be crucial for identifying functional connectivity patterns associated with MDD. Typically, methods like spatial ICA will identify a single component to represent a network like the default mode network (DMN), even if groups within the data show differential DMN coactivation. To address this gap, this project applies a tensorial extension of ICA (tensorial ICA)-which explicitly incorporates between-subject variability-to identify functionally connected networks using functional MRI data from the Human Connectome Project (HCP). Data from the HCP included individuals with a diagnosis of MDD, a family history of MDD, and healthy controls performing a gambling and social cognition task. Based on evidence associating MDD with blunted neural activation to rewards and social stimuli, we predicted that tensorial ICA would identify networks associated with reduced spatiotemporal coherence and blunted social and reward-based network activity in MDD. Across both tasks, tensorial ICA identified three networks showing decreased coherence in MDD. All three networks included ventromedial prefrontal cortex, striatum, and cerebellum and showed different activation across the conditions of their respective tasks. However, MDD was only associated with differences in task-based activation in one network from the social task. Additionally, these results suggest that tensorial ICA could be a valuable tool for understanding clinical differences in relation to network activation and connectivity.

The impact of ADHD symptom severity on reinforcement and punishment learning among adults

Introduction: Aberrations in feedback learning are hypothesised to contribute to the behavioural disruptions and impairment of attention-deficit/hyperactivity disorder (ADHD). However, few studies have evaluated the relation of reward/punishment feedback and ADHD symptom severity on learning. The current study evaluates the differential effects of reward and punishment feedback on learning among adults with elevated ADHD. Methods: One hundred five participants self-reported their level of current ADHD symptoms and completed an innovative instrumental learning task. Results: Consistent with predictions, participants with low self-reported ADHD symptom severity benefitted equally from reward and punishment feedback during the learning task, whereas participants with high self-reported symptom severity performed better (indexed by accuracy on learning task) from reward than punishment feedback trials. Conclusions: Overall, adults with high self-reported symptom severity of ADHD learned more from reward-based feedback, which provides critical implications for motivational theories about ADHD, as well as for treatment protocols. Future work should examine the translatability of results within a treatment setting.

Anhedonia and dysregulation of an angular gyrus-centred and dynamic functional network in adolescent-onset depression

BACKGROUND

Anhedonia is an important aspect of adolescent-onset major depressive disorder (MDD) and is associated with increased risk of suicidal behaviors and poor treatment outcomes. However, the neural circuitry underlying this deficit has not been well defined. This study aims to identify the relationships between anhedonia and changes in static and dynamic functional connectivity (FC) in adolescent-onset MDD patients compared with healthy control subjects (HCs) and adult-onset MDD patients.

METHODS

A total of 157 participants completed the Snaith-Hamilton Pleasure Scale (SHAPS) to assess hedonic capacity. Resting-state functional imaging scans were analysed using graph theoretical analysis, network-based statistics (NBS) and sliding window correlation analysis to explore the potential patterns of neural network brain disruptions in adolescent-onset MDD. Pearson correlations and support vector machines regression (SVR) were used to explore correlations and predict network measures with SHAPS scores.

RESULTS

Compared with those with adult-onset MDD, adolescent-onset MDD patients showed decreased FC in 7 nodes and 6 connections, with the right angular gyrus (AG), left AG and left paracentral lobule having the largest number of connected edges (P = 0.0396, NBS-corrected). Their average FC and SHAPS scores were positively correlated (r = 0.309, P = 0.035). Regarding dynamic FC, compared with HCs, adolescent-onset MDD patients showed a tendency towards a decreased frequency in moderate-intensity brain FC states (P = 0.014), which was significantly and positively correlated with SHAPS scores (r = 0.425, P = 0.003). SVR also revealed AG-centred FC and dynamic FC could predict SHAPS scores (MSE = 27.233, P = 0.001).

CONCLUSIONS

These findings provide distinct evidence on the physiological mechanisms of adolescent-onset MDD and anhedonia.

Inflammation-Related Functional and Structural Dysconnectivity as a Pathway to Psychopathology

Findings from numerous laboratories and across neuroimaging modalities have consistently shown that exogenous administration of cytokines or inflammatory stimuli that induce cytokines disrupts circuits and networks involved in motivation and motor activity, threat detection, anxiety, and interoceptive and emotional processing. While inflammatory effects on neural circuits and relevant behaviors may represent adaptive responses promoting conservation of energy and heightened vigilance during immune activation, chronically elevated inflammation may contribute to symptoms of psychiatric illnesses. Indeed, biomarkers of inflammation such as cytokines and acute phase reactants are reliably elevated in a subset of patients with unipolar or bipolar depression, anxiety-related disorders, and schizophrenia and have been associated with differential treatment responses and poor clinical outcomes. A growing body of literature also describes higher levels of endogenous inflammatory markers and altered, typically lower functional or structural connectivity within these circuits in association with transdiagnostic symptoms such as anhedonia and anxiety in psychiatric and at-risk populations. This review presents recent evidence that inflammation and its effects on the brain may serve as one molecular and cellular mechanism of dysconnectivity within anatomically and/or functionally connected cortical and subcortical regions in association with transdiagnostic symptoms. We also discuss the need to establish reproducible methods to assess inflammation-associated dysconnectivity in relation to behavior for use in translational studies or biomarker-driven clinical trials for novel pharmacological or behavioral interventions targeting inflammation or its effects on the brain.

How negative mood hinders belief updating in depression: results from two experimental studies

BACKGROUND

In two experimental studies, we tested the hypothesis that negative mood would hinder the revision of negative beliefs in response to unexpectedly positive information in depression, whereas positive mood was expected to enhance belief updating.

METHODS

In study 1 (N = 101), we used a subclinical sample to compare the film-based induction of sad v. happy mood with a distraction control group. Subsequently, participants underwent a well-established paradigm to examine intra-individual changes in performance-related expectations after unexpectedly positive performance feedback. In study 2, we applied the belief-updating task from study 1 to an inpatient sample (N = 81) and induced sad v. happy mood via film-clips v. recall of autobiographic events.

RESULTS

The results of study 1 showed no significant group differences in belief updating; the severity of depressive symptoms was a negative predictor of belief revision, though, and there was a non-significant trend suggesting that the presence of sad mood hindered belief updating in the subgroup of participants with a diagnosed depressive episode. Study 2 revealed that participants updated their expectations significantly less in line with positive feedback when they underwent the induction of negative mood prior to feedback, relative to positive mood.

CONCLUSIONS

By indicating that the presence of negative mood can hinder the revision of negative beliefs in clinically depressed people, our findings suggest that learning from new experiences can be hampered if state negative mood is activated. Thus, interventions relying on learning from novel positive experiences should aim at reducing state negative mood in depression.

Sleep and Healthy Aging Research on Depression (SHARE-D) randomized controlled trial: Protocol overview of an experimental model of depression with insomnia, inflammation, and affect mechanisms in older adults

Depression, one of the most common diseases in older adults, carries significant risk for morbidity and mortality. Because of the burgeoning population of older adults, the enormous burden of late-life depression, and the limited efficacy of current antidepressants in older adults, biologically plausible models that translate into selective depression prevention strategies are needed. Insomnia predicts depression recurrence and is a modifiable target to prevent incident and recurrent depression in older adults. Yet, it is not known how insomnia gets converted into biological- and affective risk for depression, which is critical for identification of molecular targets for pharmacologic interventions, and for refinement of insomnia treatments that target affective responding to improve efficacy. Sleep disturbance activates inflammatory signaling and primes immune responses to subsequent inflammatory challenge. In turn, inflammatory challenge induces depressive symptoms, which correlate with activation of brain regions implicated in depression. This study hypothesizes that insomnia serves as a vulnerability factor for inflammation-related depression; older adults with insomnia will show heightened inflammatory- and affective responding to inflammatory challenge as compared to those without insomnia. To test this hypothesis, this protocol paper describes a placebo-controlled, randomized, double-blind study of low dose endotoxin in older adults (n = 160; 60-80 y) with insomnia vs. comparison controls without insomnia. The aims of this study are to examine differences in depressive symptoms, measures of negative affective responding, and measures of positive affective responding as a function of insomnia and inflammatory challenge. If the hypotheses are confirmed, older adults with two "hits", insomnia and inflammatory activation, would represent a high risk group to be prioritized for monitoring and for depression prevention efforts using treatments that target insomnia or inflammation. Moreover, this study will inform the development of mechanism-based treatments that target affect responses in addition to sleep behaviors, and which might also be coupled with efforts to reduce inflammation to optimize efficacy of depression prevention.

Perimenopausal Effects of Estradiol on Anhedonia and Psychosis Study (PEEPs): study protocol for a neural and molecular mechanistic clinical trial

BACKGROUND

The perimenopausal transition is accompanied by psychiatric symptoms in over 10% of women. Symptoms commonly include depressed mood and anhedonia and less commonly include psychosis. Psychiatric symptoms have been linked to the depletion and/or variability of circulating estradiol, and estradiol treatment reduces perimenopausal anhedonia and psychosis in some women. Estrogen fluctuations may disrupt function in the mesolimbic reward system in some women, leading to psychiatric symptoms like anhedonia or psychosis. The Perimenopausal Effects of Estradiol on Anhedonia and Psychosis Study (PEEPs) is a mechanistic clinical trial that aims to (1) identify relationships between perimenopausal-onset anhedonia and psychosis and neuromolecular markers of mesolimbic reward responses and (2) determine the extent to which estradiol treatment-induced changes in mesolimbic reward responses are associated with alleviation of perimenopausal onset anhedonia or psychosis.

METHODS

This study will recruit 100 unmedicated women ages 44-55 in the late-stage perimenopausal transition, sampling across the range of mild-to-high anhedonia and absent-to-moderate psychosis symptoms. Patients will be randomized to receive either estradiol or placebo treatment for 3 weeks. Clinical outcome measures will include symptoms of anhedonia (measured with Snaith-Hamilton Pleasure Scale; SHAPS) and psychosis (measured with Brief Psychiatric Rating Scale; BPRS psychosis subscale) as well as neural markers of mesolimbic reward system functioning, including reward-related fMRI activation and PET-derived measure of striatal dopamine binding. Pre-treatment associations between (1) SHAPS/BPRS scores and (2) reward-related striatal dopamine binding/BOLD activation will be examined. Furthermore, longitudinal mixed models will be used to estimate (1) symptom and neuromolecular trajectories as a function of estradiol vs. placebo treatment and (2) how changes in reward-related striatal dopamine binding and BOLD activation predict variability in symptom trajectories in response to estradiol treatment.

DISCUSSION

This clinical trial will be the first to characterize neural and molecular mechanisms by which estradiol treatment ameliorates anhedonia and psychosis symptoms during the perimenopausal transition, thus laying the groundwork for future biomarker research to predict susceptibility and prognosis and develop targeted treatments for perimenopausal psychiatric symptoms. Furthermore, in alignment with the National Institute for Mental Health Research Domain Criteria initiative, this trial will improve our understanding of a range of disorders characterized by anhedonia, psychosis, and reward system dysfunction.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05282277.

Your smile won't affect me: Association between childhood maternal antipathy and adult neural reward function in a transdiagnostic sample

Aberrant activation in the ventral striatum (VS) during reward anticipation may be a key mechanism linking adverse childhood experiences (ACE) to transdiagnostic psychopathology. This study aimed to elucidate whether retrospectively reported ACE, specifically maternal antipathy, relate to monetary and social reward anticipation in a transdiagnostic adult sample. A cross-sectional neuroimaging study was conducted in 118 participants with varying levels of ACE, including 25 participants with posttraumatic stress disorder (PTSD), 32 with major depressive disorder (MDD), 29 with somatic symptom disorder (SSD), and 32 healthy volunteers (HVs). Participants underwent functional magnetic resonance imaging during a monetary and social incentive delay task, and completed a self-report measure of ACE, including maternal antipathy. Neural correlates of monetary and social reward anticipation and their association with ACE, particularly maternal antipathy, were analyzed. Participants showed elevated activation in brain regions underlying reward processing, including the VS, only while anticipating social, but not monetary rewards. Participants reporting higher levels of maternal antipathy exhibited reduced activation in the brain reward network, including the VS, only during social, but not monetary reward anticipation. Group affiliation moderated the association between maternal antipathy and VS activation to social reward anticipation, with significant associations found in participants with PTSD and HVs, but not in those with MDD and SSD. Results were not associated with general psychopathology or psychotropic medication use. Childhood maternal antipathy may confer risk for aberrant social reward anticipation in adulthood, and may thus be considered in interventions targeting reward expectations from social interactions.

Data driven clusters derived from resting state functional connectivity: Findings from the EMBARC study

BACKGROUND

To address the clinical heterogeneity of Major Depressive Disorder (MDD), this investigation determined whether resting state functional magnetic resonance imaging (fMRI) could be deployed to identify circuit based homogeneous subgroups, and whether subgroups identified show differential treatment outcomes.

METHODS

Pretreatment resting state fMRIs obtained from 278 outpatients with nonpsychotic MDD from Establishing Moderators and Biosignatures of Antidepressant Response for Clinical Care for Depression Study were used to create data-driven subgroups using CLICK clustering. These subgroups were then compared using baseline clinical data, as well as baseline-to-week 8 changes in depression severity measured using the 17-item Hamilton Rating Scale for Depression (HAMD17) and response/remission rates by treatment group.

RESULTS

Three subgroups were identified. Cluster-1 was characterized by overallhyperconnectivity coupled with profound hypoconnectivity between the supramarginal gyrus (executive control network; ECN) and the superior frontal cortex (dorsal attention network; DAN). Cluster-2 was characterized by overall hypoconnectivity coupled with hyperconnectivity between supramarginal gyrus (ECN) and superior frontal cortex (DAN). Cluster-3 showed hypoconnectivity, especially profound between the angular cortex (default mode network; DMN) and middle frontal cortex (ECN). While baseline clinical measures did not differentiate the three clusters, Cluster-3 had the remission rate (51.6%) compared to Cluster-1 and Cluster-2 (32.7% and 31.9%) when treated with sertraline.

LIMITATIONS

Due to the exploratory nature of these analyses, there were no adjustments for multiple comparisons.

CONCLUSIONS

Baseline functional connectivity can be used to subgroup patients with MDD that differ in acute phase treatment outcomes. Measures of connectivity may address the heterogeneity of MDD.

Corporal Punishment Is Uniquely Associated With a Greater Neural Response to Errors and Blunted Neural Response to Rewards in Adolescence

BACKGROUND

Although corporal punishment is a common form of punishment with known negative impacts on health and behavior, how such punishment affects neurocognitive systems is relatively unknown.

METHODS

To address this issue, we examined how corporal punishment affected neural measures of error and reward processing in 149 adolescent boys and girls of ages 11 to 14 years (mean age [SD] = 11.02 [1.16]). Corporal punishment experienced over the lifetime was assessed using the Stress and Adversity Inventory. In addition, participants completed a flankers task and a reward task to measure the error-related negativity and reward positivity, respectively, as well as measures of anxiety and depressive symptoms.

RESULTS

As hypothesized, participants who experienced lifetime corporal punishment reported more anxiety and depressive symptoms. Experiencing corporal punishment was also related to a larger error-related negativity and blunted reward positivity. Importantly, corporal punishment was independently related to a larger error-related negativity and a more blunted reward positivity beyond the impact of harsh parenting and lifetime stressors.

CONCLUSIONS

Corporal punishment appears to potentiate neural response to errors and decrease neural response to rewards, which could increase risk for anxiety and depressive symptoms.

Error-related brain activity in pediatric major depressive disorder: An ERP and time-frequency investigation

BACKGROUND

The error-related negativity (ERN) reflects individual differences in error monitoring. However, findings on the ERN in adult and adolescent depression have been inconsistent. Analyzing electroencephalographic (EEG) data in both the time- and time-frequency domain can be useful to better quantify neural response to errors. The present study aimed at examining electrocortical measures of error monitoring in early adolescents with and without depression.

METHOD

EEG activity was collected during an arrowhead version of the flanker task in 29 (25 females) early adolescents with depression and 34 without MDD (29 females).

RESULTS

The depression group showed reduced ERN amplitude, reduced error-related theta power and increased error-related beta power compared to the control group. When all variables that related to MDD diagnosis were considered simultaneously, both theta and beta power, but not the ERN, were independently related to an increased likelihood of being diagnosed with depression.

CONCLUSIONS

By examining both time-domain and separate time-frequency measures, the present study provided novel evidence on error monitoring alterations in youth depression, suggesting that depression during adolescence may be characterized by reduced error monitoring (i.e., reduced ERN and error-related theta) and post-error inhibition (i.e., greater error-related beta power). These results support that time-frequency measures might be better suited for examining error-related neural activity in MDD relative to time-domain measures.

Preliminary evidence that fatigue contributes to anhedonia in stable individuals diagnosed with schizophrenia

Objectives

Anhedonia and fatigue are trans-diagnostic symptoms commonly observed in schizophrenia. Anhedonia is a core negative symptom with a strong relationship with depression and is associated with diminished global functioning. Similarly, fatigue is also associated to depression and research across psychiatric illnesses indicate that fatigue may persist even when primary symptoms are treated. Although fatigue is common in people diagnosed with schizophrenia, it is under studied within this population. The objective of this exploratory study was to investigate the association of fatigue and anhedonia by controlling for depression in a sample of individuals diagnosed with schizophrenia.

Method

Fifty-one stable individuals diagnosed with schizophrenia from the University Department of Adult Psychiatry in Montpellier took part in this study. Participants completed questionnaires on fatigue impact and depression, and were assessed for symptom severity. Following data collection, statistical analyses were conducted in order to explore associations between clinical variables and fatigue impact. Based on the results obtained, a hierarchical linear regression was conducted in order to investigate whether fatigue impact contributed to the variance of negative symptoms.

Results

The hierarchical linear regression indicated that when controlling for depression, fatigue impact contributes to ~20% of the variance of anhedonia. Together the social impact of fatigue and depression contribute to 24% of the variation of anhedonia.

Conclusion

To the best of our knowledge, this exploratory study is the first to investigate and show that fatigue impact may contribute to anhedonia. We recommend further research to investigate fatigue, its impact on symptomatology, and better categorization of negative symptoms in hopes of developing targeted fatigue treatment interventions.

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

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

Cognitive-affective processes and suicidality in response to repetitive transcranial magnetic stimulation for treatment resistant depression

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) can elicit 45-55 % response rates and may alleviate suicidality symptoms in treatment resistant depression (TRD). Blunted anticipatory reward sensitivity and negatively biased self-referential processing may predict trajectories of depressive and suicidality symptoms in rTMS for TRD and be modulated during treatment.

METHODS

Fifty-five individuals with TRD received four weeks of low-frequency rTMS applied to the right dorsolateral prefrontal cortex (LFR-rTMS) and were followed until 17 weeks post-baseline. Participants completed behavioral measures of anticipatory reward sensitivity and self-referential processing at baseline and five weeks post-baseline (approximately one-week post-treatment). We examined whether baseline anticipatory reward sensitivity and self-referential processing predicted trajectories of depressive and suicidality symptoms from baseline to follow-up and whether these cognitive-affective variables showed change from baseline to week five.

RESULTS

Anticipatory reward sensitivity and negative self-referential encoding at baseline were associated with higher overall depressive symptoms and suicidality from baseline to 17 weeks post-baseline. At week five, participants self-attributed a higher number of positive traits and a lower number of negative traits and had a lesser tendency to remember negative relative to positive traits they had self-attributed, compared to baseline.

LIMITATIONS

The specificity of these results to LFR-rTMS is unknown in the absence of a comparison group, and our relatively small sample size precluded the interpretation of null results.

CONCLUSIONS

Baseline blunted anticipatory reward sensitivity and negative biases in self-referential processing may be risk factors for higher depressive symptoms and suicidality during and after LFR-rTMS, and LFR-rTMS may modulate self-referential processing.

Neurofunctional differences and similarities between persistent postural-perceptual dizziness and anxiety disorder

INTRODUCTION

Persistent postural-perceptual dizziness (PPPD) (ICD-11) and anxiety disorders (ANX) share behavioural symptoms like anxiety, avoidance, social withdrawal, hyperarousal, or palpitation as well as neurological symptoms like vertigo, stance and gait disorders. Furthermore, previous studies have shown a bidirectional link between vestibulo-spatial and anxiety neural networks. So far, there have been no neuroimaging-studies comparing these groups.

OBJECTIVES

The aim of this explorative study was to investigate differences and similarities of neural correlates between these two patient groups and to compare their findings with a healthy control group.

METHODS

63 participants, divided in two patient groups (ANX = 20 and PPPD = 14) and two sex and age matched healthy control groups (HC-A = 16, HC-P = 13) were included. Anxiety and dizziness related pictures were shown during fMRI-measurements in a block-design in order to induce emotional responses. All subjects filled in questionnaires regarding vertigo (VSS, VHQ), anxiety (STAI), depression (BDI-II), alexithymia (TAS), and illness-perception (IPQ). After modelling the BOLD response with a standard canonical HRF, voxel-wise t-tests between conditions (emotional-negative vs neutral stimuli) were used to generate statistical contrast maps and identify relevant brain areas (pFDR < 0.05, cluster size >30 voxels). ROI-analyses were performed for amygdala, cingulate gyrus, hippocampus, inferior frontal gyrus, insula, supramarginal gyrus and thalamus (p ≤ 0.05).

RESULTS

Patient groups differed from both HC groups regarding anxiety, dizziness, depression and alexithymia scores; ratings of the PPPD group and the ANX group did differ significantly only in the VSS subscale 'vertigo and related symptoms' (VSS-VER). The PPPD group showed increased neural responses in the vestibulo-spatial network, especially in the supramarginal gyrus (SMG), and superior temporal gyrus (STG), compared to ANX and HC-P group. The PPPD group showed increased neural responses compared to the HC-P group in the anxiety network including amygdala, insula, lentiform gyrus, hippocampus, inferior frontal gyrus (IFG) and brainstem. Neuronal responses were enhanced in visual structures, e.g. fusiform gyrus, middle occipital gyrus, and in the medial orbitofrontal cortex (mOFC) in healthy controls compared to patients with ANX and PPPD, and in the ANX group compared to the PPPD group.

CONCLUSIONS

These findings indicate that neuronal responses to emotional information in the PPPD and the ANX group are comparable in anxiety networks but not in vestibulo-spatial networks. Patients with PPPD revealed a stronger neuronal response especially in SMG and STG compared to the ANX and the HC group. These results might suggest higher sensitivity and poorer adaptation processes in the PPPD group to anxiety and dizziness related pictures. Stronger activation in visual processing areas in HC subjects might be due to less emotional and more visual processing strategies.

Increased Inflammation and Treatment of Depression: From Resistance to Reuse, Repurposing, and Redesign

Based on mounting clinical and translational evidence demonstrating the impact of exogenously administered inflammatory stimuli on the brain and behavior, increased endogenous inflammation has received attention as one pathophysiologic process contributing to psychiatric illnesses and particularly depression. Increased endogenous inflammation is observed in a significant proportion of depressed patients and has been associated with reduced responsiveness to standard antidepressant therapies. This chapter presents recent evidence that inflammation affects neurotransmitters and neurocircuits to contribute to specific depressive symptoms including anhedonia, motor slowing, and anxiety, which may preferentially improve after anti-cytokine therapies in patients with evidence of increased inflammation. Existing and novel pharmacological strategies that target inflammation or its downstream effects on the brain and behavior will be discussed in the context of a need for intelligent trial design in order to meaningfully translate these concepts and develop more precise therapies for depressed patients with increased inflammation.

Individual- and Connectivity-Based Real-Time fMRI Neurofeedback to Modulate Emotion-Related Brain Responses in Patients with Depression: A Pilot Study

INTRODUCTION

Individual real-time functional magnetic resonance imaging neurofeedback (rtfMRI NF) might be a promising adjuvant in treating depressive symptoms. Further studies showed functional variations and connectivity-related changes in the dorsolateral prefrontal cortex (dlPFC) and the insular cortex.

OBJECTIVES

The aim of this pilot study was to investigate whether individualized connectivity-based rtfMRI NF training can improve symptoms in depressed patients as an adjunct to a psychotherapeutic programme. The novel strategy chosen for this was to increase connectivity between individualized regions of interest, namely the insula and the dlPFC.

METHODS

Sixteen patients diagnosed with major depressive disorder (MDD, ICD-10) and 19 matched healthy controls (HC) participated in a rtfMRI NF training consisting of two sessions with three runs each, within an interval of one week. RtfMRI NF was applied during a sequence of negative emotional pictures to modulate the connectivity between the dlPFC and the insula. The MDD REAL group was divided into a Responder and a Non-Responder group. Patients with an increased connectivity during the second NF session or during both the first and the second NF session were identified as "MDD REAL Responder" (N = 6). Patients that did not show any increase in connectivity and/or a decreased connectivity were identified as "MDD REAL Non-Responder" (N = 7).

RESULTS

Before the rtfMRI sessions, patients with MDD showed higher neural activation levels in ventromedial PFC and the insula than HC; by contrast, HC revealed increased hemodynamic activity in visual processing areas (primary visual cortex and visual association cortex) compared to patients with MDD. The comparison of hemodynamic responses during the first compared to during the last NF session demonstrated significantly increased BOLD-activation in the medial orbitofrontal cortex (mOFC) in patients and HC, and additionally in the lateral OFC in patients with MDD. These findings were particularly due to the MDD Responder group, as the MDD Non-Responder group showed no increase in this region during the last NF run. There was a decrease of neural activation in emotional processing brain regions in both groups in the last NF run compared to the first: HC showed differences in the insula, parahippocampal gyrus, basal ganglia, and cingulate gyrus. Patients with MDD demonstrated deceased responses in the parahippocampal gyrus. There was no significant reduction of BDI scores after NF training in patients.

CONCLUSIONS

Increased neural activation in the insula and vmPFC in MDD suggests an increased emotional reaction in patients with MDD. The activation of the mOFC could be associated with improved control-strategies and association-learning processes. The increased lOFC activation could indicate a stronger sensitivity to failed NF attempts in MDD. A stronger involvement of visual processing areas in HC may indicate better adaptation to negative emotional stimuli after repeated presentation. Overall, the rtfMRI NF had an impact on neurobiological mechanisms, but not on psychometric measures in patients with MDD.

Aberrant reward processing to positive versus negative outcomes across psychotic disorders

Several studies of reward processing in schizophrenia have shown reduced sensitivity to positive, but not negative, outcomes although inconsistencies have been reported. In addition, few studies have investigated whether patients show a relative deficit to social versus nonsocial rewards, whether deficits occur across the spectrum of psychosis, or whether deficits relate to negative symptoms and functioning. This study examined probabilistic implicit learning via two visually distinctive slot machines for social and nonsocial rewards in 101 outpatients with diverse psychotic disorders and 48 community controls. The task consisted of two trial types: positive (optimal to choose a positive vs. neutral machine) and negative (optimal to choose a neutral vs. negative machine), with two reward conditions: social (faces) and nonsocial (money) reward conditions. A significant group X trial type interaction indicated that controls performed better on positive than negative trials, whereas patients showed the opposite pattern of better performance on negative than positive trials. In addition, both groups performed better for social than nonsocial stimuli, despite lower overall task performance in patients. Within patients, worse performance on negative trials showed significant, small-to-moderate correlations with motivation and pleasure-related negative symptoms and social functioning. The current findings suggest reward processing disturbances, particularly decreased sensitivity to positive outcomes, extend beyond schizophrenia to a broader spectrum of psychotic disorders and relate to important clinical outcomes.

Shared and distinct neural activity during anticipation and outcome of win and loss: A meta-analysis of the monetary incentive delay task

Reward and punishment motivate decision making and behavioral changes. Numerous studies have examined regional activities during anticipation and outcome of win and loss in the monetary incentive delay task (MIDT). However, the great majority of studies reported findings of anticipation or outcome and of win or loss alone. It remains unclear how the neural correlates share and differentiate amongst these processes. We conducted an Activation Likelihood Estimation meta-analysis of 81 studies of the MIDT (5,864 subjects), including 24 published since the most recent meta-analysis, to identify and, with conjunction and subtraction, contrast regional responses to win anticipation, loss anticipation, win outcome, and loss outcome. Win and loss anticipation engaged a shared network of bilateral anterior insula (AI), striatum, thalamus, supplementary motor area (SMA), and precentral gyrus. Win and loss outcomes did not share regional activities. Win and loss outcome each engaged higher activity in medial orbitofrontal cortex (mOFC) and dorsal anterior cingulate cortex. Bilateral striatum and right occipital cortex responded to both anticipation and outcome of win, and right AI to both phases of loss. Win anticipation vs. outcome engaged higher activity in bilateral AI, striatum, SMA and precentral gyrus and right thalamus, and lower activity in bilateral mOFC and posterior cingulate cortex as well as right inferior frontal and angular gyri. Loss anticipation relative to outcome involved higher activity in bilateral striatum and left AI. These findings collectively suggest shared and distinct regional responses during monetary wins and losses. Delineating the neural correlates of these component processes may facilitate empirical research of motivated behaviors and dysfunctional approach and avoidance in psychopathology.

Reward sensitivity and internalizing symptoms during the transition to puberty: An examination of 9-and 10-year-olds in the ABCD Study

Early pubertal timing has been linked to increased risk for internalizing psychopathology in adolescents. Work in older adolescents and adults suggests that heightened reward sensitivity may buffer risk for internalizing symptoms. However, few studies have investigated these associations during the early transition to puberty, a window of vulnerability to mental health risk. In this preregistered study, we investigated the associations among pubertal timing, internalizing symptoms, and reward sensitivity in a large, population-based sample of 11,224 9-10 year-olds from the ABCD Study®. Using split-half analysis, we tested for within-sample replications of hypothesized effects across two age- and sex-matched subsets of the sample. Early pubertal timing was associated with higher internalizing symptoms in female and male participants across samples, with 9-10 year-olds in the mid-pubertal stage at the highest risk for internalizing symptoms. Additionally, early pubertal timing was robustly associated with greater self-reported reward sensitivity in both female and male participants. We observed inconsistent evidence for a moderating role of reward sensitivity across measurement domains (self-report, behavioral, and fMRI data), several of which differed by sex, but none of these interactions replicated across samples. Together, these findings provide unique insights into early indicators of risk for internalizing psychopathology during the transition to puberty in a large, population-based, demographically diverse sample of youth.

The importance of a multidimensional approach to the preclinical study of major depressive disorder and apathy

Both the neuropsychiatric syndrome of apathy and major depressive disorder comprise a heterogenous cluster of symptoms which span multiple behavioural domains. Despite this heterogeneity, there is a tendency in the preclinical literature to conclude a MDD or apathy-like phenotype from a single dimensional behavioural task used in isolation, which may lead to inaccurate phenotypic interpretation. This is significant, as apathy and major depressive disorder are clinically distinct with different underlying mechanisms and treatment approaches. At the clinical level, apathy and major depressive disorder can be dissociated in the negative valence (loss) domain of the Research Domain Criteria. Symptoms of MDD in the negative valence (loss) domain can include an exaggerated response to emotionally salient stimuli and low mood, while in contrast apathy is characterised by an emotionally blunted state. In this article, we highlight how using a single dimensional approach can limit psychiatric model interpretation. We discuss how integrating behavioural findings from both the positive and negative (loss) valence domains of the Research Domain Criteria can benefit interpretation of findings. We focus particularly on behaviours relating to the negative valence (loss) domain, which may be used to distinguish between apathy and major depressive disorder at the preclinical level. Finally, we consider how future approaches using home cage monitoring may offer a new opportunity to detect distinct behavioural profiles and benefit the overall translatability of findings.

Decreased miR-15b-5p/miR-155-5p levels and increased miR-134-5p/miR-652-3p levels among BD patients under lithium treatment

BACKGROUND

There is an increasing interest about the role of miRNAs in the pathogenesis of bipolar disorder (BD). In this study, we aimed to examine the role of miRNAs as potential diagnostic and clinical biomarkers in BD.

METHODS

Fifteen miRNAs in plasmas obtained from BD patients (n = 66) and from the healthy control group (n = 66) were analyzed by a qPCR test. Clinical variables including lithium treatment response were assessed with various test batteries. The correlation of the miRNA levels with the clinical variables and scale scores was examined. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using the DIANA-miRPath v.3.0 software to identify the possible target genes.

RESULTS

The miR-132, miR-134, miR-152, miR-607, miR-633, and miR-652 levels were significantly increased, whereas the miR-15b and miR-155 levels were found to be significantly decreased in the patient group compared to the controls. The miR-15b-5p and miR-155-5p levels and increases in the miR-134-5p and miR-652-3p levels were calculated to have 83.3 % sensitivity and 78.8 % specificity in determining the risk of BD. miR-155-5p was associated with the disease burden and severity. Fatty acid biosynthesis and metabolism, viral carcinogenesis, the EBV infection, and extracellular matrix and adhesion pathways were highlighted as target pathways.

CONCLUSION

We can conclude that miRNAs may play a role in the pathophysiology of BD through various biological pathways and that miRNAs may be used as a screening test to distinguish bipolar patients from healthy controls. Our findings will provide a basis for long-term follow-up studies with larger samples.

The Central Nervous Mechanism of Stress-Promoting Cancer Progression

Evidence shows that stress can promote the occurrence and development of tumors. In recent years, many studies have shown that stress-related hormones or peripheral neurotransmitters can promote the proliferation, survival, and angiogenesis of tumor cells and impair the body’s immune response, causing tumor cells to escape the “surveillance” of the immune system. However, the perception of stress occurs in the central nervous system (CNS) and the role of the central nervous system in tumor progression is still unclear, as are the underlying mechanisms. This review summarizes what is known of stress-related CNS-network activation during the stress response and the influence of the CNS on tumors and discusses available adjuvant treatment methods for cancer patients with negative emotional states, such as anxiety and depression.

Adapted Behavioural Activation for Bipolar Depression: A Randomised Multiple Baseline Case Series

Behavioural Activation (BA) is associated with a substantial evidence base for treatment of acute unipolar depression, and has promise as an easily disseminable psychological intervention for bipolar depression. Using a randomised multiple baseline case series design we examined the feasibility and acceptability of an adapted version of BA in a U.K. outpatient sample of 12 adults with acute bipolar depression. Participants were allocated at random to a 3–8 week wait period before being offered up to 20 sessions of BA. They completed outcome measures at intake, pre- and post-treatment and weekly symptom measures across the study period. Retention in therapy was high (11/12 participants completed the target minimum number of sessions), and all participants returning acceptability measures reported high levels of satisfaction with the intervention. No therapy-related serious adverse events were reported, nor were there exacerbations in manic symptoms that were judged to be a result of the intervention. The pattern of change on outcome measures is consistent with the potential for clinical benefit; six of the nine participants with a stable baseline showed clinically significant improvement on the primary outcome measure. The findings suggest adapted BA for bipolar depression is a feasible and acceptable approach that merits further investigation.

The effect of salience of rewards on effort-based decision making in psychotic disorders

BACKGROUND

Although motivational negative symptoms account for reduced functioning and quality of life in individuals with psychotic disorders, the underlying mechanisms are yet not fully understood. Neuroimaging studies suggest that an impaired perception of reward cues could result in a lack of incentive value that then leads to a decrease in goal-directed behavior. Therefore, the aim of this study was to test the effect of increasing the salience of reward cues on goal-directed behavior.

METHODS

We recruited a sample of n = 30 participants with a psychotic disorder and at least mild negative symptoms and n = 30 healthy controls. We used the Balloon Effort Task, an effort-based decision-making paradigm, to assess amotivation on a behavioral level. We manipulated the salience of rewards in the paradigm by highlighting the monetary rewards in half of the trials.

RESULTS

Total effort expenditure did not differ between participants with and without psychotic disorders, but participants with psychotic disorders showed a significantly reduced effort allocation to the level of rewards. The salience of rewards manipulation significantly increased effort expenditure both in participants with psychotic disorders and in the healthy controls, but had no impact on effort allocation.

CONCLUSIONS

Increasing the salience of reward cues promotes goal-directed behavior. This opens up new possibilities for interventions addressing amotivation in individuals with negative symptoms by facilitating the perception of reward cues.

Decision value signals in the ventromedial prefrontal cortex and motivational and hedonic symptoms across mood and psychotic disorders

Deficits in motivation and pleasure are common across many psychiatric disorders, and manifest as symptoms of amotivation and anhedonia, which are prominent features of both mood and psychotic disorders. Here we provide evidence for an association between neural value signals and symptoms of amotivation and anhedonia across adults with major depression, bipolar disorder, schizophrenia, or no psychiatric diagnosis. We found that value signals in the ventromedial prefrontal cortex (vmPFC) during intertemporal decision-making were dampened in individuals with greater motivational and hedonic deficits, after accounting for primary diagnosis. This relationship remained significant while controlling for diagnosis-specific symptoms of mood and psychosis, such as depression as well as positive and negative symptoms. Our results demonstrate that dysfunction in the vmPFC during value-based decision-making is specifically linked to motivational and hedonic impairments. These findings provide a quantitative neural target for the potential development of novel treatments for amotivation and anhedonia.