Trauma-associated anterior cingulate connectivity during reward learning predicts affective and anxiety states in young adults

How adverse childhood experiences get under the skin: A systematic review, integration and methodological discussion on threat and reward learning mechanisms

Adverse childhood experiences (ACEs) are a major risk factor for the development of multiple psychopathological conditions, but the mechanisms underlying this link are poorly understood. Associative learning encompasses key mechanisms through which individuals learn to link important environmental inputs to emotional and behavioral responses. ACEs may impact the normative maturation of associative learning processes, resulting in their enduring maladaptive expression manifesting in psychopathology. In this review, we lay out a systematic and methodological overview and integration of the available evidence of the proposed association between ACEs and threat and reward learning processes. We summarize results from a systematic literature search (following PRISMA guidelines) which yielded a total of 81 articles (threat: n=38, reward: n=43). Across the threat and reward learning fields, behaviorally, we observed a converging pattern of aberrant learning in individuals with a history of ACEs, independent of other sample characteristics, specific ACE types, and outcome measures. Specifically, blunted threat learning was reflected in reduced discrimination between threat and safety cues, primarily driven by diminished responding to conditioned threat cues. Furthermore, attenuated reward learning manifested in reduced accuracy and learning rate in tasks involving acquisition of reward contingencies. Importantly, this pattern emerged despite substantial heterogeneity in ACE assessment and operationalization across both fields. We conclude that blunted threat and reward learning may represent a mechanistic route by which ACEs may become physiologically and neurobiologically embedded and ultimately confer greater risk for psychopathology. In closing, we discuss potentially fruitful future directions for the research field, including methodological and ACE assessment considerations.

Genetic and inflammatory effects on childhood trauma and cognitive functioning in patients with schizophrenia and healthy participants

Recent studies have reported a negative association between exposure to childhood trauma, including physical neglect, and cognitive functioning in patients with schizophrenia. Childhood trauma has been found to influence immune functioning, which may contribute to the risk of schizophrenia and cognitive symptoms of the disorder. In this study, we aimed to test the hypothesis that physical neglect is associated with cognitive ability, and that this association is mediated by a combined latent measure of inflammatory response, and moderated by higher genetic risk for schizophrenia. The study included 279 Irish participants, comprising 102 patients and 177 healthy participants. Structural equation modelling was used to perform mediation and moderation analyses. Inflammatory response was measured via basal plasma levels of IL-6, TNF-α, and CRP, and cognitive performance was assessed across three domains: full-scale IQ, logical memory, and the emotion recognition task. Genetic variation for schizophrenia was estimated using a genome-wide polygenic score based on genome-wide association study summary statistics. The results showed that inflammatory response mediated the association between physical neglect and all measures of cognitive functioning, and explained considerably more variance than any of the inflammatory markers alone. Furthermore, genetic risk for schizophrenia was observed to moderate the direct pathway between physical neglect and measures of non-social cognitive functioning in both patient and healthy participants. However, genetic risk did not moderate the mediated pathway associated with inflammatory response. Therefore, we conclude that the mediating role of inflammatory response and the moderating role of higher genetic risk may independently influence the association between adverse early life experiences and cognitive function in patients and healthy participants.

Neurobehavioral Reward and Sleep-Circadian Profiles Predict Present and Next-Year Mania/Hypomania Symptoms

BACKGROUND

Heightened reward sensitivity/impulsivity, related neural activity, and sleep-circadian disruption are important risk factors for bipolar spectrum disorders, the defining feature of which is mania/hypomania. Our goal was to identify neurobehavioral profiles based on reward and sleep-circadian features and examine their specificity to mania/hypomania versus depression vulnerability.

METHODS

At baseline, a transdiagnostic sample of 324 adults (18-25 years) completed trait measures of reward sensitivity (Behavioral Activation Scale), impulsivity (UPPS-P-Negative Urgency), and a functional magnetic resonance imaging card-guessing reward task (left ventrolateral prefrontal activity to reward expectancy, a neural correlate of reward motivation and impulsivity, was extracted). At baseline, 6-month follow-up, and 12-month follow-up, the Mood Spectrum Self-Report Measure - Lifetime Version assessed lifetime predisposition to subthreshold-syndromal mania/hypomania, depression, and sleep-circadian disturbances (insomnia, sleepiness, reduced sleep need, rhythm disruption). Mixture models derived profiles from baseline reward, impulsivity, and sleep-circadian variables.

RESULTS

Three profiles were identified: 1) healthy (no reward or sleep-circadian disruption; n = 162); 2) moderate-risk (moderate reward and sleep-circadian disruption; n = 109); and 3) high-risk (high impulsivity and sleep-circadian disruption; n = 53). At baseline, the high-risk group had significantly higher mania/hypomania scores than the other groups but did not differ from the moderate-risk group in depression scores. Over the follow-up period, the high-risk and moderate-risk groups exhibited elevated mania/hypomania scores, whereas depression scores increased at a faster rate in the healthy group than in the other groups.

CONCLUSIONS

Cross-sectional and next-year predisposition to mania/hypomania is associated with a combination of heightened reward sensitivity and impulsivity, related reward circuitry activity, and sleep-circadian disturbances. These measures can be used to detect mania/hypomania risk and provide targets to guide and monitor interventions.

Neurobiological correlates of resilience during childhood and adolescence - A systematic review

Research examining the neurobiological mechanisms of resilience has grown rapidly over the past decade. However, there is vast heterogeneity in research study design, methods, and in how resilience is operationalized, making it difficult to gauge what we currently know about resilience biomarkers. This preregistered systematic review aimed to review and synthesize the extant literature to identify neurobiological correlates of resilience to adversity during childhood and adolescence. Literature searches on MEDLINE and PsycINFO yielded 3834 studies and a total of 49 studies were included in the final review. Findings were synthesized based on how resilience was conceptualized (e.g., absence of psychopathology, trait resilience), and where relevant, the type of outcome examined (e.g., internalizing symptoms, post-traumatic stress disorder). Our synthesis showed that findings were generally mixed. Nevertheless, some consistent findings suggest that resilience neural mechanisms may involve prefrontal and subcortical regions structure/activity, as well as connectivity between these regions. Given substantial heterogeneity in the definition and operationalization of resilience, more methodological consistency across studies is required for advancing knowledge in this field.

Splitting the reward: Differences in inflammatory marker associations with neural connectivity between reward anticipation and reward outcome in adolescents at high risk for depression

BACKGROUND

Adolescent depression is associated with both dysfunction in neural reward processing and peripheral inflammatory markers (PIMs), such as interleukin-6 (IL-6), C-reactive-protein (CRP), and tumor-necrosis factor alpha (TNFα). Few adolescent studies have examined neural-inflammatory marker associations and associated behavioral correlates, which would contribute to a better understanding of developmental processes linked to depression.

METHODS

36 adolescents at high risk of depression completed an fMRI reward task (during anticipation and outcome), blood draw for PIMs (IL-6, CRP, and TNFα), and a behavioral task assessing motivation to expend effort. Analyses examined associations of task-dependent functional connectivity (FC; ventral striatum to frontal and default mode network brain regions), and if the interaction of PIMs and task-dependent FC predicted motivation to expend effort.

RESULTS

For anticipation contrast, TNFα was associated with increased task-dependent FC between the LVS and PCC/vmPFC. In moderation analyses, for anticipation contrasts, the combination of higher IL-6 and stronger FC (LVS-precuneus/PCC) was associated with lower motivation to expend effort, while for outcome contrasts, the combination of higher IL-6 and stronger FC (VS-precuneus/PCC) was associated with greater motivation to expend effort.

CONCLUSIONS

Our findings in adolescents during an important developmental time period suggest that PIMs are directly linked to greater FC between the VS and DMN brain regions during win anticipation, consistent with prior studies. Effects of PIMs on motivation to expend effort may vary the strength/type of neural reward processing (anticipation or outcome), which could guide better understanding how inflammatory markers and neural reward substrates contribute to development of depression in high-risk adolescents.

Neural activations to loss anticipation mediates the association between difficulties in emotion regulation and screen media activities among early adolescent youth: A moderating role for depression

BACKGROUND

Screen media activities (SMAs; e.g., watching videos, playing videogames) have become increasingly prevalent among youth as ways to alleviate or escape from negative emotional states. However, neural mechanisms underlying these processes in youth are incompletely understood.

METHOD

Seventy-nine youth aged 11-15 years completed a monetary incentive delay task during fMRI scanning. Neural correlates of reward/loss processing and their associations with SMAs were explored. Next, brain activations during reward/loss processing in regions implicated in the processing of emotions were examined as potential mediating factors between difficulties in emotion regulation (DER) and engagement in SMAs. Finally, a moderated mediation model tested the effects of depressive symptoms in such relationships.

RESULT

The emotional components associated with SMAs in reward/loss processing included activations in the left anterior insula (AI) and right dorsolateral prefrontal cortex (DLPFC) during anticipation of working to avoid losses. Activations in both the AI and DLPFC mediated the relationship between DER and SMAs. Moreover, depressive symptoms moderated the relationship between AI activation in response to loss anticipation and SMAs.

CONCLUSION

The current findings suggest that DER link to SMAs through loss-related brain activations implicated in the processing of emotions and motivational avoidance, particularly in youth with greater levels of depressive symptoms. The findings suggest the importance of enhancing emotion-regulation tendencies/abilities in youth and, in particular, their regulatory responses to negative emotional situations in order to guide moderate engagement in SMAs.

Medial Prefrontal Cortex Activity to Reward Outcome Moderates the Association Between Victimization Due to Sexual Orientation and Depression in Youth

BACKGROUND

Sexual minority youth (SMY) are 3 times more likely to experience depression than heterosexual peers. Minority stress theory posits that this association is explained by sexual orientation victimization, which acts as a stressor to impact depression. For those vulnerable to the effects of stress, victimization may worsen depression by altering activity in neural reward systems. This study examines whether neural reward systems moderate the influence of sexual orientation victimization, a common and distressing experience in SMY, on depression.

METHODS

A total of 81 participants ages 15 to 22 years (41% SMY, 52% marginalized race) reported sexual orientation victimization, depression severity, and anhedonia severity, and underwent a monetary reward functional magnetic resonance imaging task. Significant activation to reward > neutral outcome (p_{familywise error} < .05) was determined within a meta-analytically derived Neurosynth reward mask. A univariate linear model examined the impact of reward activation and identity on victimization-depression relationships.

RESULTS

SMY reported higher depression (p < .001), anhedonia (p = .03), and orientation victimization (p < .001) than heterosexual youth. The bilateral ventral striatum, medial prefrontal cortex (mPFC), anterior cingulate cortex, and right orbitofrontal cortex were significantly active to reward. mPFC activation moderated associations between sexual orientation victimization and depression (p = .03), with higher depression severity observed in those with a combination of higher mPFC activation and greater orientation victimization.

CONCLUSIONS

Sexual orientation victimization was related to depression but only in the context of higher mPFC activation, a pattern observed in depressed youth. These novel results provide evidence for neural reward sensitivity as a vulnerability factor for depression in SMY, suggesting mechanisms for disparities, and are a first step toward a clinical neuroscience understanding of minority stress in SMY.

Enduring effect of abuse: Childhood maltreatment links to altered theory of mind network among adults

Childhood maltreatment (CM) confers a great risk of maladaptive development outcomes later in life, however, the neurobiological mechanism underlying this vulnerability is still unclear. The present study aimed to investigate the long-term consequences of CM on neural connectivity while controlling for psychiatric conditions, medication, and, substance abuse. A sample including adults with (n = 40) and without CM (n = 50) completed Childhood Trauma Questionnaire (CTQ), personality questionnaires, and resting-state functional magnetic resonance imaging scan were recruited for the current study. The whole-brain functional connectivity (FC) was evaluated using an unbiased, data-driven, multivariate pattern analysis method. Relative to controls, adults with CM suffered a higher level of temperament and impulsivity and showed decreased FC between the insula and superior temporal gyrus (STG) and between inferior parietal lobule (IPL) and middle frontal gyrus, STG, and dorsal anterior cingulate cortex (dACC), while increased FC between IPL and cuneus and superior frontal gyrus (SFG) regions. The FCs of IPL with dACC and SFG were correlated with the anxious and cyclothymic temperament and attentional impulsivity. Moreover, these FCs partially mediated the relationship between CM and attentional impulsivity. Our results suggest that CM has a significant effect on the modulation of FC within theory of mind (ToM) network even decades later in adulthood, and inform a new framework to account for how CM results in the development of impulsivity. The novel findings reveal the neurobiological consequences of CM and provide new clues to the prevention and intervention strategy to reduce the risk of the development of psychopathology.

A systematic review of the association between biological markers and environmental stress risk factors for adolescent depression

INTRODUCTION

Although the aetiology and pathophysiology of depression are multifactorial, to date most studies have examined either biological or environmental mechanisms without looking at the integration of both; with most studies conducted in high-income countries (HICs). Therefore, we conducted a systematic review of worldwide studies investigating the relationship between biological and environmental stress risk factors for major depressive disorder (MDD) in adolescence.

METHODS

We searched MEDLINE (via Ovid), PsycINFO, Cochrane Database of Systematic Reviews, Web of Science (Core Collection), Lilacs, African Journals Online and Global Health for prospective and cross-sectional studies that examined the association between biological markers and environmental stress risk factors in MDD during adolescence.

FINDINGS

Of 11,089 articles identified, 21 were included, with only two from middle-income countries. Increased inflammation, telomere length and brain abnormalities, including blunted reward-related activity, white matter disruptions, and altered volume of limbic brain regions, were associated with increased risk for MDD mainly in the context of early life adversity. There is little evidence suggesting that the neurobiological changes investigated were associated with MDD in the context of recent life stress.

INTERPRETATION

The developmental trajectory of depression appears to start with early life adversities and occurs in the context of immune and brain abnormalities. Understanding these biopsychosocial processes will help to improve our ability to detect individuals at risk of developing depression in adolescence. However, generalizability is limited by few studies examining both biological and environmental stress risk factors and a lack of studies on adolescents and young adults in low-and-middle-income countries (LMICs).

The contributions of the endocannabinoid system and stress on the neural processing of reward stimuli

The brain's endocannabinoid system plays a crucial role in reward processes by mediating appetitive learning and encoding the reinforcing properties of substances. Evidence also suggests that endocannabinoids are an important constituent of neuronal substrates involved in emotional responses to stress. Thus, it is critical to understand how the endocannabinoid system and stress may affect reward processes given their importance in substance use disorders. We examined the relationship between factors that regulate endocannabinoid system signaling (i.e., cannabinoid receptor genes and prolonged cannabis exposure) and stress on fMRI BOLD response to reward cues using multivariate statistical analysis. We found that proxies for endocannabinoid system signaling (i.e., endocannabinoid genes and chronic exposure to cannabis) and stress have differential effects on neural response to cannabis cues. Specifically, a single nucleotide polymorphism (SNP) variant in the cannabinoid receptor 1 (CNR1) gene, early life stress, and current perceived stress modulated reward responsivity in long-term, heavy cannabis users, while a variant in the fatty acid amide hydrolase (FAAH) gene and current perceived stress modulated cue-elicited response in non-using controls. These associations were related to distinct neural responses to cannabis-related cues compared to natural reward cues. Understanding the contributions of endocannabinoid system factors and stress that lead to downstream effects on neural mechanisms underlying sensitivity to rewards, such as cannabis, will contribute towards a better understanding of endocannabinoid-targeted therapies as well as individual risks for cannabis use disorder.

Task MRI-Based Functional Brain Network of Major Depression

This chapter will focus on task magnetic resonance imaging (MRI) to understand the biological mechanisms and pathophysiology of brain in major depressive disorder (MDD), which would have minor alterations in the brain function. Therefore, the functional study, such as task MRI functional connectivity, would play a crucial role to explore the brain function in MDD. Different kinds of tasks would determine the alterations in functional connectivity in task MRI studies of MDD. The emotion-related tasks are linked with alterations in anterior cingulate cortex, insula, and default mode network. The emotional memory task is linked with amygdala-hippocampus alterations. The reward-related task would be related to the reward circuit alterations, such as fronto-straital. The cognitive-related tasks would be associated with frontal-related functional connectivity alterations, such as the dorsolateral prefrontal cortex, anterior cingulate cortex, and other frontal regions. The visuo-sensory characteristics of tasks might be associated with the parieto-occipital alterations. The frontolimbic regions might be major components of task MRI-based functional connectivity in MDD. However, different scenarios and tasks would influence the representations of results.

Trauma Affects Prospective Relationships Between Reward-Related Ventral Striatal and Amygdala Activation and 1-Year Future Hypo/Mania Trajectories

BACKGROUND

Trauma exposure is associated with a more severe, persistent course of affective and anxiety symptoms. Markers of reward neural circuitry function, specifically activation to reward prediction error (RPE), are impacted by trauma and predict the future course of affective symptoms. This study's purpose was to determine how lifetime trauma exposure influences relationships between reward neural circuitry function and the course of future affective and anxiety symptoms in a naturalistic, transdiagnostic observational context.

METHODS

A total of 59 young adults aged 18-25 (48 female and 11 male participants, mean ± SD = 21.5 ± 2.0 years) experiencing psychological distress completed the study. Participants were evaluated at baseline, 6, and 12 months. At baseline, the participants reported lifetime trauma events and completed a monetary reward functional magnetic resonance imaging task. Affective and anxiety symptoms were reported at each visit, and trajectories were calculated using MPlus. Neural activation during RPE and other phases of reward processing were determined using SPM8. Trauma and reward neural activation were entered as predictors of symptom trajectories.

RESULTS

Trauma exposure moderated prospective relationships between left ventral striatum (β = -1.29, p = .02) and right amygdala (β = 0.58, p = .04) activation to RPE and future hypo/mania severity trajectory: the interaction between greater trauma and greater left ventral striatum activation to RPE was associated with a shallower increase in hypo/mania severity, whereas the interaction between greater trauma and greater right amygdala activation to RPE was associated with increasing hypo/mania severity.

CONCLUSIONS

Trauma exposure affects prospective relationships between markers of reward circuitry function and affective symptom trajectories. Evaluating trauma exposure is thus crucial in naturalistic and treatment studies aiming to identify neural predictors of future affective symptom course.

Investigation of functional brain network reconfiguration during vocal emotional processing using graph-theoretical analysis

Vocal expression is essential for conveying the emotion during social interaction. Although vocal emotion has been explored in previous studies, little is known about how perception of different vocal emotional expressions modulates the functional brain network topology. In this study, we aimed to investigate the functional brain networks under different attributes of vocal emotion by graph-theoretical network analysis. Functional magnetic resonance imaging (fMRI) experiments were performed on 36 healthy participants. We utilized the Power-264 functional brain atlas to calculate the interregional functional connectivity (FC) from fMRI data under resting state and vocal stimuli at different arousal and valence levels. The orthogonal minimal spanning trees method was used for topological filtering. The paired-sample t-test with Bonferroni correction across all regions and arousal-valence levels were used for statistical comparisons. Our results show that brain network exhibits significantly altered network attributes at FC, nodal and global levels, especially under high-arousal or negative-valence vocal emotional stimuli. The alterations within/between well-known large-scale functional networks were also investigated. Through the present study, we have gained more insights into how comprehending emotional speech modulates brain networks. These findings may shed light on how the human brain processes emotional speech and how it distinguishes different emotional conditions.

Anhedonia Reduction and the Association Between Left Ventral Striatal Reward Response and 6-Month Improvement in Life Satisfaction Among Young Adults

IMPORTANCE

Anhedonia is a symptom of multiple psychiatric conditions in young adults that is associated with poorer mental health and psychosocial function and abnormal ventral striatum reward processing. Aberrant function of neural reward circuitry is well documented in anhedonia and other psychiatric disorders. Longitudinal studies to identify potential biomarkers associated with a reduction in anhedonia are necessary for the development of novel treatment targets.

OBJECTIVE

To identify neural reward-processing factors associated with improved psychiatric symptoms and psychosocial function in a naturalistic, observational context.

DESIGN, SETTING, AND PARTICIPANTS

A longitudinal cohort follow-up study was conducted from March 1, 2014, to June 5, 2018, at the University of Pittsburgh Medical Center after baseline functional magnetic resonance imaging in 52 participants between the ages of 18 and 25 years who were experiencing psychological distress.

MAIN OUTCOMES AND MEASURES

Participants were evaluated at baseline and 6 months. At baseline, participants underwent functional magnetic resonance imaging during a card-guessing monetary reward task. Participants completed measures of affective symptoms and psychosocial function at each visit. Neural activation during reward prediction error (RPE), a measure of reward learning, was determined using Statistical Parametric Mapping software. Neural reward regions with significant RPE activation were entered as regions associated with future symptoms in multiple linear regression models.

RESULTS

A total of 52 young adults (42 women and 10 men; mean [SD] age, 21.4 [2.2] years) completed the study. Greater RPE activation in the left ventral striatum was associated with a decrease in anhedonia symptoms during a 6-month period (β = -6.152; 95% CI, -11.870 to -0.433; P = .04). The decrease in anhedonia between baseline and 6 months mediated the association between left ventral striatum activation to RPE and improvement in life satisfaction between baseline and 6 months (total [c path] association: β = 0.245; P = .01; direct [c' path] association: β = 0.133; P = .16; and indirect [ab path] association: 95% CI, 0.026-0.262). Results were not associated with psychotropic medication use.

CONCLUSIONS AND RELEVANCE

Greater left ventral striatum responsiveness to RPE may serve as a biomarker or potential target for novel treatments to improve the severity of anhedonia, overall mental health, and psychosocial function.

Dissociation between Cerebellar and Cerebral Neural Activities in Humans with Long-Term Bilateral Sensorineural Hearing Loss

Abnormal neural activity in the cerebellum has been implicated in hearing impairments, but the effects of long-term hearing loss on cerebellar function are poorly understood. To further explore the role of long-term bilateral sensorineural hearing loss on cerebellar function, we investigated hearing loss-induced changes among neural networks within cerebellar subregions and the changes in cerebellar-cerebral connectivity patterns using resting-state functional MRI. Twenty-one subjects with long-term bilateral moderate-to-severe sensorineural hearing loss and 21 matched controls with clinically normal hearing underwent MRI scanning and a series of neuropsychological tests targeting cognition and emotion. Voxel-wise functional connectivity (FC) analysis demonstrated decreased couplings between the cerebellum and other cerebral areas, including the temporal pole (TP), insula, supramarginal gyrus, inferior frontal gyrus (IFG), medial frontal gyrus, and thalamus, in long-term bilateral sensorineural hearing loss patients. An ROI-wise FC analysis found weakened interregional connections within cerebellar subdivisions. Moreover, there was a negative correlation between anxiety and FC between the left cerebellar lobe VI and left insula. Hearing ability and anxiety scores were also correlated with FC between the left cerebellar lobe VI and left TP, as well as the right cerebellar lobule VI and left IFG. Our results suggest that sensorineural hearing loss disrupts cerebellar-cerebral circuits, some potentially linked to anxiety, and interregional cerebellar connectivity. The findings contribute to a growing body showing that auditory deprivation caused by cochlear hearing loss disrupts not only activity with the classical auditory pathway but also portions of the cerebellum that communicates with other cortical networks.