Neurobiological Markers of Resilience to Early-Life Adversity During Adolescence

Early-life stress impairs acquisition and retrieval of fear memories: sex-effects, corticosterone modulation, and partial prevention by targeting glucocorticoid receptors at adolescent age

The early postnatal period is a sensitive time window that is characterized by several neurodevelopmental processes that define neuronal architecture and function later in life. Here, we examined in young adult mice, using an auditory fear conditioning paradigm, whether stress during the early postnatal period 1) impacts fear acquisition and memory consolidation in male and female mice; 2) alters the fear responsiveness to corticosterone and 3) whether effects of early-life stress (ELS) can be prevented by treating mice with a glucocorticoid (GR) antagonist at adolescence. Male and female mice were exposed to a limited nesting and bedding model of ELS from postnatal day (PND) 2-9 and injected i.p with RU38486 (RU486) at adolescent age (PND 28-30). At two months of age, mice were trained in the fear conditioning (FC) paradigm (with and without post training administration of corticosterone - CORT) and freezing behavior during fear acquisition and contextual and auditory memory retrieval was scored. We observed that ELS impaired fear acquisition specifically in male mice and reduced both contextual and auditory memory retrieval in male and female mice. Acute post-training administration of CORT increased freezing levels during auditory memory retrieval in female mice but reduced freezing levels during the tone presentation in particular in control males. Treatment with RU486 prevented ELS-effects in acquisition in male mice and in females during auditory memory retrieval. In conclusion, this study highlights the long-lasting consequences of early-life stress on fear memory processing and further illustrates 1) the potential of a glucocorticoid antagonist intervention during adolescence to mitigate these effects and 2) the partial modulation of the auditory retrieval upon post training administration of CORT, with all these effects being sex-dependent.

Early life adversity impacts alterations in brain structure and food addiction in individuals with high BMI

Obesity and food addiction are associated with distinct brain signatures related to reward processing, and early life adversity (ELA) also increases alterations in these same reward regions. However, the neural mechanisms underlying the effect of early life adversity on food addiction are unknown. Therefore, the aim of this study was to examine the interactions between ELA, food addiction, and brain morphometry in individuals with obesity. 114 participants with high body mass index (BMI) underwent structural MRIs, and completed several questionnaires (e.g., Yale Food Addiction Scale (YFAS), Brief Resilience Scale (BRS), Early Traumatic Inventory (ETI)). Freesurfer 6 was applied to generate the morphometry of brain regions. A multivariate pattern analysis was used to derive brain morphometry patterns associated with food addiction. General linear modeling and mediation analyses were conducted to examine the effects of ELA and resilience on food addiction in individuals with obesity. Statistical significance was determined at a level of p < 0.05. High levels of ELA showed a strong association between reward control brain signatures and food addiction (p = 0.03). Resilience positively mediated the effect of ELA on food addiction (B = 0.02, p = 0.038). Our findings suggest that food addiction is associated with brain signatures in motivation and reward processing regions indicative of dopaminergic dysregulation and inhibition of cognitive control regions. These mechanistic variabilities along with early life adversity suggest increased vulnerability to develop food addiction and obesity in adulthood, which can buffer by the neuroprotective effects of resilience, highlighting the value of incorporating cognitive appraisal into obesity therapeutic regimens.

A gut (microbiome) feeling about addiction: Interactions with stress and social systems

In recent years, an increasing attention has given to the intricate and diverse connection of microorganisms residing in our gut and their impact on brain health and central nervous system disease. There has been a shift in mindset to understand that drug addiction is not merely a condition that affects the brain, it is now being recognized as a disorder that also involves external factors such as the intestinal microbiota, which could influence vulnerability and the development of addictive behaviors. Furthermore, stress and social interactions, which are closely linked to the intestinal microbiota, are powerful modulators of addiction. This review delves into the mechanisms through which the microbiota-stress-immune axis may shape drug addiction and social behaviors. This work integrates preclinical and clinical evidence that demonstrate the bidirectional communication between stress, social behaviors, substance use disorders and the gut microbiota, suggesting that gut microbes might modulate social stress having a significance in drug addiction.

Transcutaneous auricular vagus nerve stimulation ameliorates adolescent depressive- and anxiety-like behaviors via hippocampus glycolysis and inflammation response

BACKGROUND

Transcutaneous auricular vagus nerve stimulation (taVNS) is a crucial neuromodulation therapy for depression, yet its molecular mechanism remains unclear. Here, we aim to unveil the underlying mechanisms of antidepression by systematically evaluating the change of gene expression in different brain regions (i.e., hippocampus, anterior cingulate cortex, and medial prefrontal cortex).

METHODS

The adolescent depression rat model was established by chronic unpredictable mild stress (CUMS), followed by the taVNS treatment for 3 weeks. The open field test (OFT), forced swimming test (FST), elevated plus maze test (EPM), and new object recognition (NOR) test were used to evaluate depressive- and anxiety-like behaviors. Gene expression analysis of three brain regions was conducted by RNA sequencing (RNA-seq) and further bioinformatics methods.

RESULTS

The depressive- and anxiety-like behaviors in CUMS-exposed rats were manifested by decreased spontaneous locomotor activity of OFT, increased immobility time of FST, increased entries and time in the closed arms of EPM, and decreased new object index of NOR. Furthermore, CUMS exposure also led to alterations in gene expression within the hippocampus (HIP), anterior cingulate cortex (ACC), and medial prefrontal cortex (mPFC), suggesting a potential link between adolescent stress and pathological changes within these brain regions. TaVNS could significantly ameliorate depressive- and anxiety-like behaviors. Its effects on these three brain regions were found related to regulation of the metabolism, and there were some brain region-specific findings. Compared with ACC and mPFC, taVNS has a more concrete effect on HIP by regulating the inflammation response and glycolysis.

CONCLUSION

taVNS is capable of ameliorating adolescent depressive- and anxiety-like behaviors by regulating plenty of genes in the three brain regions. Suppressed level of inflammatory response and enhanced glycolysis manifests the dominant role of taVNS in HIP, which provides a theoretical foundation and data support for the molecular mechanism of antidepression by taVNS.

COVID-19-related stress exacerbates the effect of child maltreatment on negative affect via increased identity confusion during adolescence

INTRODUCTION

Exposure to childhood maltreatment may undermine the crucial developmental task of identity formation in adolescence, placing them at risk for developing negative affect. The current study investigated whether COVID-19-related stress intensified the indirect link between child maltreatment and adolescents' negative affect through identity confusion.

METHOD

Using multidimensional assessments of child maltreatment (threat vs. deprivation), the study included a sample of 124 adolescents (Mage  = 12.89, SD = 0.79; 52% female) assessed before (January 2018 to March 2020) and during the pandemic (May to October 2020) in Georgia, United States. The majority of the participants were European American (78.8%), followed by African American (11.5%), Hispanic (3.8%), Asian/Pacific Islander (1.0%), and other (4.8%). We used structural equation modeling to test (a) the mediating role of identity confusion in the link between childhood maltreatment and negative affect and (b) whether COVID-19-related stress moderated these indirect effects. Simple slopes and Johnson-Neyman plots were generated to probe regions of significant interaction effects.

RESULTS

Threat and deprivation predicted an increase in adolescent identity confusion. Additionally, childhood threat and deprivation were indirectly linked to adolescents' negative affect through increased levels of identity confusion. COVID-19-related stress significantly exacerbated the link between identity confusion and negative affect.

CONCLUSION

Identity confusion is a mechanism underlying the link between child maltreatment and the development of negative affect in adolescence. Our results inform prevention and intervention programs that aim to reduce negative affect among adolescents who experience threatening and depriving rearing environments.

Role of body mass index in the relationship between adverse childhood experiences, resilience, and mental health: a multivariate analysis

OBJECTIVES

Depression among adolescents is a global concern. Adverse childhood experiences (ACEs) have been correlated with negative physical and mental health such as obesity and depression; however, increasing evidence has suggested that their correlation might be moderated by BMI and resilience. In this study, we aim to explore (1) whether resilience moderate the risk of mental health by ACEs; (2) whether BMI is a moderator of this relationship.

STUDY DESIGN

Adolescents were obtained from 4 grade college students by a multi-stage convenience sampling method in the period of May to Jun, 2022.

METHODS

We use the Connor-Davidson Resilience scale, Depression, Anxiety and Stress Scale-21 Item (DASS-21) questionnaires to measure the ACEs, BMI, resilience and mental health. The primary exposure was ACEs and the primary outcome was mental health; while resilience and BMI were moderators. Multivariable linear regression model was used to establish the relationship of ACEs, resilience and BMI against mental health status. Moderate analysis was employed by PROCESS method to explore the relationship between these variables.

RESULTS

A total of 3600 individuals were initially enrolled, after excluding 22 with invalid questionnaires, 3578 adolescents were finally included. The mean age was (20.53 ± 1.65) years old. After adjusted for covariates, multivariable linear regression suggest that the high level ACEs (, β =0.58, , 95%CI:0.54,0.62, P < 0.01), resilience (, β=-0.27, 95%CI: , 95%CI: -0.28,-0.26, P < 0.01) were associated with higher depression symptoms, and BMI (, β =0.073, 95%CI: 0.002-0.15, P < 0.05) was associated with higher depression symptoms. There is also the interaction between resilience, ACEs and mental health (depression, anxiety and stress symptoms). In the relationship between ACEs and mental health, resilience and BMI played a moderator role.

CONCLUSIONS

The moderate analysis also provided further evidence of a link between resilience, ACEs, BMI and mental health. The findings shed new light on potential mechanisms between ACEs and mental health, including the effects of the co-interaction of resilience and BMI, adding to previous literature. ACEs may be a profound variable to measure adolescents' psychosocial environment to influence mental health, and resilience moderate this effect and is also moderated by BMI.

Integrating the pattern of negative emotion processing and acute stress response with childhood stress among healthy young adults

Background: Childhood adversity might impair corticolimbic brain regions, which play a crucial role in emotion processing and the acute stress response. The dimensional model of childhood adversity proposed that deprivation and threat dimensions might associated with individuals' development through different mechanisms. However, few studies have explored the relationship between different dimensions of childhood stress, emotion processing, and acute stress reactivity despite the overlapping brain regions of the last two. With the aid of event-related potentials technique, we explore whether negative emotion processing, which might be particularly relevant for adaptive stress responding among individuals with adverse childhood experience, mediates the relationship between dimensional childhood stress and acute stress response. Method: Fifty-one young adults completed a free-viewing task to evaluate neural response to negative stimuli measured by late positive potential (LPP) of ERPs (Event-related potentials). On a separate day, heart rate and salivary cortisol were collected during a social-evaluative stress challenge (i.e., TSST, Trier Social Stress Test). After the TSST, childhood trauma questionnaire was measured to indicate the level of abuse (as a proxy of threat) and neglect (as a proxy of deprivation) dimensions. Multiple linear regression and mediation analysis were used to explore the relationship among the childhood stress, emotion processing and acute stress response. Results: Higher level of childhood abuse (but not neglect) was distinctly related to smaller LPP amplitudes to negative stimuli, as well as smaller heart rate reactivity to acute stress. For these participants, smaller LPP amplitudes were linked with smaller heart rate reactivity to acute stress. Furthermore, decreased LPP amplitudes to negative stimuli mediated the relationship between higher level of childhood abuse and blunted heart rate reactivity to stress. Conclusions: Consistent with the dimensional model of childhood stress, our study showed that childhood abuse is distinctly associated with neural as well as physiological response to threat. Furthermore, the blunted neural response to negative stimuli might be the underlying mechanism in which childhood abuse leads to the blunted acute stress response. Considering that all the participants are healthy in the present study, the blunted processing of negative stimuli might rather reflect adaptation instead of vulnerability, in order to prevent stress overshooting in the face of early-life threatening experiences.

Prolonged Rather Than Early Childhood Parent-Child Separation Predicts Change in Molecular Markers of Cellular Aging: A Consideration of the Role of Adolescence

Early life adversity is a major risk factor for the onset of psychopathology, and cellular aging may be a mechanism underlying these associations. It is unknown whether and how the pattern (timing and duration) of parent-child separation is associated with accelerated cellular aging, particularly with respect to functional aging and replicative senescence, indexed by mitochondrial DNA copy number (mtDNAcn) elevation and telomere length (TL) attrition. This cohort study included 252 rural adolescents (mean age 11.62 years, SD: 1.56). Nearly one in five participants were persistently separated from both parents since birth. Compared with participants who never separated from their parents, adolescents with prolonged parent-child separation had higher acceleration both in functional aging and replicative senescence of cells. However, that was not the case in adolescents who experienced parent-child separation in early childhood but regained stable parental care during adolescence. These findings indicate that pubertal development reopens a window of opportunity for buffering the adverse biological effect based on significant improvements in the supportiveness of the caregiving environment relative to that in childhood. Translating such knowledge to inform intervention and prevention strategies for youths exposed to adversity is a critical goal for the field.

The Wither or Thrive Model of Resilience: an Integrative Framework of Dynamic Vulnerability and Resilience in the Face of Repeated Stressors During the COVID-19 Pandemic

During the first 2 years of the COVID-19 pandemic, empirical efforts in the psychological sciences have been unequivocally focused on understanding the psychosocial impact on resilience and vulnerability. While current empirical work is guided by different existing theoretical models of resilience and vulnerability, the emerging datasets have also pointed to a necessity for an update of these models. Due to the unique features and developments specific to the current pandemic such as the occurrence of repeated collective stressors of varying durations, in the current position paper, we introduce the Wither or Thrive model of Resilience (With:Resilience). It integrates key aspects of prevailing psychological resilience frameworks within the context of the COVID-19 pandemic, and extends them by (1) moving away from single scale approaches towards a higher-order latent expression of resilience and vulnerability incorporating also non-clinical mental health markers, (2) proposing different trajectories of resilience-vulnerability emerging across repeated stressors over long periods of time, and (3) by incorporating multiple influencing factors including aspects of the socio-economic concept of social cohesion as well as separate mediating processing mechanisms. We propose that With:Resilience will enable a more nuanced approach and appropriate analytical investigation of the vast incoming data on mental health and resilience during the COVID-19 pandemic, and we suggest some concrete methodological approaches. This framework will assist in the development of actionable public health guidelines for society in the present and future pandemic contexts as well as aid policy making and the interventional sciences aimed at protecting the most vulnerable amongst us.

Neurodevelopmental origins of substance use disorders: Evidence from animal models of early-life adversity and addiction

Addiction is a chronic relapsing disorder with devastating personal, societal, and economic consequences. In humans, early-life adversity (ELA) such as trauma, neglect, and resource scarcity are linked with increased risk of later-life addiction, but the brain mechanisms underlying this link are still poorly understood. Here, we focus on data from rodent models of ELA and addiction, in which causal effects of ELA on later-life responses to drugs and the neurodevelopmental mechanisms by which ELA increases vulnerability to addiction can be determined. We first summarize evidence for a link between ELA and addiction in humans, then describe how ELA is commonly modeled in rodents. Since addiction is a heterogeneous disease with many individually varying behavioral aspects that may be impacted by ELA, we next discuss common rodent assays of addiction-like behaviors. We then summarize the specific addiction-relevant behavioral phenotypes caused by ELA in male and female rodents and discuss some of the underlying changes in brain reward and stress circuits that are likely responsible. By better understanding the behavioral and neural mechanisms by which ELA promotes addiction vulnerability, we hope to facilitate development of new approaches for preventing or treating addiction in those with a history of ELA.

Emotion Regulation as a Pathway Connecting Early Life Adversity and Inflammation in Adulthood: a Conceptual Framework

Chronic inflammation is implicated in a variety of diseases (e.g., cardiovascular disease and cancer). Much evidence suggests that early life adversity (ELA), such as maltreatment or neglect, can increase risk for inflammation in adulthood. ELA may program proinflammatory activity via its effects on brain areas involved in emotion regulation. Of multiple emotion regulation strategies, some are considered maladaptive (e.g., expressive suppression), while others are generally adaptive (e.g., cognitive reappraisal). We propose a conceptual framework for how emotion regulation tendencies may affect vulnerability or resilience to inflammation in adults who experienced adversity in childhood and/or adolescence. In support of this framework, we summarize evidence for the relationships between emotion dysregulation and higher inflammation (i.e., vulnerability), as well as between cognitive reappraisal and lower inflammation (i.e., resilience), in healthy adults with a history of ELA. Plausible neurobiological, physiological, psychosocial, and ELA-specific factors, as well as interventions, contributing to these associations are discussed. Strengths and limitations of the extant research, in addition to ideas for future directions, are presented.

Emotion regulation strategy usage explains links between institutional caregiving and elevated internalizing symptoms

Early adversity, including institutional orphanage care, is associated with the development of internalizing disorders. Previous research suggests that institutionalization can disrupt emotion regulation processes, which contribute to internalizing symptoms. However, no prior work has investigated how early orphanage care shapes emotion regulation strategy usage (e.g., cognitive reappraisal, expressive suppression) and whether the said strategy usage contributes to internalizing symptoms. This study probed emotion regulation strategy usage and internalizing symptoms in a sample of 36 previously institutionalized and 58 comparison youth. As hypothesized, previously institutionalized youth exhibited higher rates of internalizing symptoms than comparison youth, and more frequent use of suppression partially accounted for the relationship between early institutional care and elevated internalizing symptoms. Contrary to our initial hypotheses, reappraisal use did not buffer previously institutionalized or comparison youth against internalizing symptoms. Our findings highlight the potential utility of targeting emotion regulation strategy usage in adversity-exposed youth in future intervention work.