Seeding Stress Resilience through Inoculation

Interactions of the CSF3R polymorphism and early stress on future orientation: evidence for the differential model of stress-related growth

AIMS

This study aims to explore the concept of future orientation, which encompasses individuals' thoughts about the future, goal-setting, planning, response to challenges and behavioural adjustments in evolving situations. Often viewed as a psychological resource, future orientation is believed to be developed from psychological resilience. The study investigates the curvilinear relationship between childhood maltreatment and future orientation while examining the moderating effects of genotype.

METHODS

A total of 14,675 Chinese adults self-reported their experiences of childhood maltreatment and their future orientation. The influence of genetic polymorphism was evaluated through genome-wide interaction studies (GWIS; genome-wide association study [GWAS] using gene × environment interaction) and a candidate genes approach.

RESULTS

Both GWAS and candidate genes analyses consistently indicated that rs4498771 and its linked single-nucleotide polymorphisms, located in the intergenic area surrounding CSF3R, significantly interacted with early trauma to influence future orientation. Nonlinear regression analyses identified a quadratic or cubic association between future orientation and childhood maltreatment across some genotypes. Specifically, as levels of childhood maltreatment increased, future orientation declined for all genotypes. However, upon reaching a certain threshold, future orientation exhibited a rebound in individuals with specific genotypes.

CONCLUSIONS

The findings suggest that individuals with certain genotypes exhibit greater resilience to childhood maltreatment. Based on these results, we propose a new threshold model of stress-related growth.

Stress inoculation during adolescence attenuates social stress-induced increase in ethanol intake in adult male mice

Social stress exposure heightens the risk of substance abuse disorder development, especially when endured during adolescence, influencing long-term mental health. This study investigates early-life stress's potential to confer resilience against later-life stressors. To investigate this hypothesis, we examined the impact of a single social defeat (SD) incident during adolescent mice's lives on subsequent voluntary ethanol consumption following repeated adult social stress exposure. Half of the adolescent mice experienced SD at postnatal day 28. Three weeks later (postnatal day 49), defeated groups encountered four confrontations with aggressive residents every 72 h, while control groups were exposed to non-resident exploration. A day after the last SD, defeated mice were classified as resilient or susceptible based on their response to a social interaction test (SIT), a model for depressive behavior. To assess ethanol consumption during young adulthood, researchers used the 'drinking in the dark' and oral ethanol self-administration paradigms. Stress inoculation (IS) slightly increased resilient animals in the SIT. In mice without IS exposure during adolescence, susceptible defeated mice displayed higher ethanol consumption and motivation than control and resilient mice. IS in adolescence effectively counteracted this effect, as IS-SD groups, whether resilient or susceptible, showed no increase in ethanol intake. These groups also exhibited similar motivation to control, measured by the progressive ratio. Notably, elevated IL-6 levels seen in SD-S mice were absent in IS-exposed mice. Additionally, IS-exposed groups had lower prefrontal cortex IL-6 and CX3CL1 levels. These findings support the hypothesis that IS, induced by moderate-intensity stress during adolescence, can enhance resilience to more severe stressors in adulthood.

Neighborhood Disadvantage and Parenting in Early Adolescence Predict Epigenetic Aging and Mortality Risk in Adulthood

Youth who grow up in disadvantaged neighborhoods experience poorer health later in life, but little is known about the biological mechanisms underlying these effects and socioenvironmental factors that may protect youth from the biological embedding of neighborhood adversity. This study tests whether supportive and consistent parenting buffers associations between neighborhood disadvantage in early adolescence and epigenetic aging in adulthood. A community sample from Birmingham, Alabama, USA (N = 343; 57% female; 81% Black, 19% White) was assessed in early adolescence (T1; ages 11 and 13) and adulthood (T2; age 27). At T1, neighborhood poverty was derived from census data and neighborhood disorder was reported by caregivers. Both youth and parents reported on parental discipline and nurturance. At T2, methylation of salivary DNA was used to derive a mortality risk index and Hannum, Horvath, PhenoAge, and GrimAge epigenetic age estimators. Regression analyses revealed that neighborhood disadvantage was associated with accelerated epigenetic aging and/or mortality risk only when combined with high levels of harsh and inconsistent discipline and low child-reported parental nurturance. These findings identify epigenetic aging and mortality risk as relevant mechanisms through which neighborhood adversity experienced in adolescence may affect later health; they also point to the importance of supportive and consistent parenting for reducing the biological embedding of neighborhood adversity in early adolescence.

The promotive and protective effects of parents' perceived changes during the COVID-19 pandemic on emotional well-being among U.S. households with young children: an investigation of family resilience processes

Introduction

The COVID-19 pandemic may constitute a traumatic event for families with young children due to its acute onset, the unpredictable and ubiquitous nature, and the highly distressing disruptions it caused in family lives. Despite the prevalent challenges such as material hardships, child care disruptions, and social isolation, some families evinced remarkable resilience in the face of this potentially traumatic event. This study examined domains of changes perceived by parents of young children that were consistent with the post-traumatic growth (PTG) model as factors that facilitate family resilience processes.

Methods

This study drew data from the RAPID project, a large ongoing national study that used frequent online surveys to examine the pandemic impact on U.S. households with young children. A subsample of 669 families was leveraged for the current investigation, including 8.07% Black, 9.57% Latino(a), 74.44% non-Latino(a) White families, and 7.92% households of other racial/ethnic backgrounds. In this subsample, 26.36% were below 200% federal poverty level.

Results

Approximately half of the parents reported moderate-to-large degrees of changes during the pandemic, and the most prevalent domain of change was appreciation of life, followed by personal strengths, new possibilities, improved relationships, and spiritual growth. Black and Latino(a) parents reported more changes in all five domains than White parents and more spiritual growth than parents of the other racial/ethnic groups. Moreover, parent-reported improved relationships were found to indirectly reduce young children's overall fussiness/defiance and fear/anxiety symptoms through reducing parents' emotional distress. Perceived changes in the new possibilities, personal strengths, and appreciation of life domains were found to serve as protective factors that buffered the indirect impacts of material hardship mean levels on child behavioral symptoms via mitigating parents' emotional distress.

Discussion

These findings shed light on resilience processes of a family system in a large-scale, disruptive, and stressful socio-historical event such as the COVID-19 pandemic. The five PTG domains could inform therapeutic and intervention practices in the face of future similar events. Importantly, these findings and the evinced family resilience should not negate the urgent needs of policy and program efforts to address material hardships, financial instabilities, and race/ethnicity-based structural inequalities for families of young children.

Maternal stress during the third trimester of pregnancy and the neonatal microbiome

OBJECTIVES

Preliminary research suggests that maternal prenatal stress may alter the development of the fetal microbiome and resulting microbial composition after birth. However, the findings of existing studies are mixed and inconclusive. The purpose of this exploratory study was to assess whether maternal stress during pregnancy is associated with the overall number and diversity of various microbial species in the infant gut microbiome or the abundance of specific bacterial taxa.

METHODS

Fifty-one women were recruited during their third trimester of pregnancy. The women completed a demographic questionnaire and Cohen's Perceived Stress Scale at recruitment. A stool sample was collected from their neonate at one month of age. Data on potential confounders, such as gestational age and mode of delivery, were extracted from medical records to control for their effects. 16s rRNA gene sequencing was used to identify the diversity and abundance of microbial species, along with multiple linear regression models to examine the effects of prenatal stress on microbial diversity. We employed negative binomial generalized linear models to test for differential expression of various microbial taxa among infants exposed to prenatal stress and those not exposed to prenatal stress.

RESULTS

More severe symptoms of prenatal stress were associated with a greater diversity of microbial species in the gut microbiome of neonates (β = .30, p = .025). Certain microbial taxa, such as Lactobacillus and Bifidobacterium, were enriched among infants exposed to greater maternal stress in utero, while others, such as Bacteroides and Enterobacteriaceae, were depleted in contrast to infants exposed to less stress.

CONCLUSIONS

Findings suggest that mild to moderate stress exposure in utero could be associated with a microbial environment in early life that is more optimally prepared to thrive in a stressful postnatal environment. Adaptation of gut microbiota under conditions of stress may involve upregulation of bacterial species, including certain protective microorganisms (e.g. Bifidobacterium), as well as downregulation of potential pathogens (e.g. Bacteroides) via epigenetic or other processes within the fetal/neonatal gut-brain axis. However, further research is needed to understand the trajectory of microbial diversity and composition as infant development proceeds and the ways in which both the structure and function of the neonatal microbiome may mediate the relationship between prenatal stress and health outcomes over time. These studies may eventually yield microbial markers and gene pathways that are biosignatures of risk or resilience and inform targets for probiotics or other therapies in utero or during the postnatal period.

Changes in perceived ageism during the COVID-19 pandemic: impact on quality of life and mental well-being among Dutch adults aged 55 and older

Objectives: The COVID-19 pandemic brought ageism to the forefront of public discourse. Negative ageism incurs more negative self-perceptions of aging, which affects physical and mental functioning. Whether negative ageism as perceived and experienced by older adults has worsened as the pandemic lingered, and how such changes impact quality of life (QoL) and mental well-being (MWB), remain urgent questions.Method: In a sample of adults aged 55 or older (n = 500), we aimed to address this by administering the Perceived Ageism Questionnaire twice during the pandemic (T1: between October 2020 and May 2021; T2: on average 45 wk after T1).Results: Higher levels of perceived negative ageism were associated with lower QoL and MWB, at least partially through its unfavorable effects on self-perceptions of aging, even after controlling for ageism experiences in the preceding year (at T2, corrected for T1). Furthermore, we found that perceived negative ageism increased from T1 to T2, which had negative implications for QoL/MWB. Opposite effects were found for perceived positive ageism, although less consistently.Conclusion: These patterns reveal that ageism as perceived and experienced by adults of 55 or older became stronger and more negative throughout the COVID-19 pandemic, which had detrimental implications for individuals' QoL and MWB. These disconcerting findings emphasize the importance of combatting negative ageism in our society.

Stress regulates Alzheimer's disease progression via selective enrichment of CD8+ T cells

This study investigates stress's impact on Alzheimer's disease (AD) using male APP/PS1 transgenic mice. Negative stressors (chronic social defeat, restraint) and positive hedonia (environmental enrichment, EE) were applied. Stress worsens AD pathology, while EE slows progression. Brain RNA sequencing reveals interleukin-6 (IL-6) and IL-10 as key stress-related AD regulators. Flow cytometry shows that the CD8+/CD4+ T cell ratio shifts in response to stress exposure and EE. Stress exposure increases CD8+/CD4+ ratio, opposite to EE. Depletion and enrichment of CD8+ T cells both accelerate AD, indicating immune intervention's negative impact. Stress management and balanced immunity may aid AD therapy, highlighting novel potential treatment.

The mental health impact of the COVID-19 pandemic on older adults: a systematic review and meta-analysis

BACKGROUND

Early in the COVID-19 pandemic, many experts pointed to potential adverse mental health effects for older adults. By contrast, many studies in young to middle-aged adults found older age to be associated with reduced mental burden. However, a systematic review on older adults is missing.

OBJECTIVES

To comprehensively assess the pandemic's mental health impact on older adults.

DATA SOURCES

We searched nine databases from December 2019 to April 2022.

STUDY SELECTION

We included longitudinal and repeated cross-sectional studies assessing pre- and/or peri-pandemic mental distress and/or positive mental health indicators (e.g. wellbeing) on at least two occasions.

DATA SYNTHESIS

We identified 108 studies comprising 102,136 participants (≥60 years). After removal of outliers, there was a small increase in mental distress from pre-to-peri-pandemic assessments, standardised mean difference (SMD) = 0.10, 95% confidence interval (CI) [0.01, 0.18]. Furthermore, a small peri-pandemic decrease in anxiety symptoms was observed, whereas other symptoms remained unchanged. For positive mental health indicators, wellbeing and quality of life showed an initial decrease, whereas overall positive mental health increased during the pandemic, SMD = 0.08, 95% CI [0.01, 0.15]. Being female was related to larger peri-pandemic increases in mental distress.

CONCLUSIONS

Based on many studies, this review demonstrated small decreases in mental health during early stages of the pandemic in older adults, with evidence for later recovery. These findings are similar to those for younger adults and correct earlier claims that older adults are at particular risk for negative mental health consequences. The results ask for further research into resilience and adaptation processes in older adults.

Responses to Reduced Feeding Frequency in Captive-Born Cheetahs (Acinonyx jubatus): Implications for Behavioural and Physiological Stress and Gastrointestinal Health

Unnatural diet composition and frequent feeding regimes may play an aetiological role in the multiple diseases prevalent in captive cheetahs. This study investigated the responses of captive-born (hand-reared) cheetahs (n = 6) to a reduced feeding frequency schedule distinguished by offering larger quantities of food less frequently. The study cheetahs were fed four once-daily meals per week during the 3-week treatment period, followed by a 3-week control period in which they were fed two daily rations six days a week. Total weekly food intake was maintained throughout the study. Variations in behaviour, faecal consistency score (FCS), and faecal glucocorticoid metabolite concentration were measured. Less frequent feeding resulted in higher FCS (p < 0.01) and locomotory behaviour (p < 0.05) among the studied cheetahs. Faecal glucocorticoid metabolite concentration demonstrated an initial acute stress response to the change in feeding frequency (p < 0.05) and subsequent adaptation. The results of the FCS analysis suggest that the more natural feeding pattern could have benefited the studied cheetahs' gastrointestinal health without a significant behavioural or physiological stress response overall to the change in feeding frequency.

Transient Elevation of Plasma Glucocorticoids Supports Psilocybin-Induced Anxiolysis in Mice

While correlations between drug-induced cortisol elevation, self-reported anxiety, and treatment outcomes have been reported for human studies during psilocybin-assisted psychotherapy, the mechanistic relationship between psychedelic-associated alterations in plasma glucocorticoid responses and the time course of anxious responsiveness remains unclear. Using rodents, both time-bound manipulation of glucocorticoid concentrations and assessment of anxiety-like behaviors can be achieved. Here, 3 mg/kg IP psilocybin was found to have anxiolytic-like effects in C57BL/6 male mice at 4 h after treatment. These effects were not altered by pretreatment with a 5-HT2A antagonist but were blunted by pretreatment with a glucocorticoid receptor antagonist or suppression of psilocybin-induced corticosterone elevations. Anxiolytic-like effects were also observed at 4 h following treatment with the nonpsychedelic 5-HT2A agonist lisuride at a dose causing a similar increase in plasma glucocorticoids as that seen with psilocybin, as well as following stress-induced (via repeated injection) glucocorticoid release alone. Psilocybin's anxiolytic-like effects persisted at 7 days following administration. The long-term anxiolytic effects of psilocybin were lost when psilocybin was administered to animals with ongoing chronic elevations in plasma corticosterone concentrations. Overall, these experiments indicate that acute, resolvable psilocybin-induced glucocorticoid release drives the postacute anxiolytic-like effects of psilocybin in mice and that its long-term anxiolytic-like effects can be abolished in the presence of chronically elevated plasma glucocorticoid elevations.

Reorganization of Brain Networks as a Substrate of Resilience: An Analysis of Cytochrome c Oxidase Activity in Rats

The unpredictable chronic mild stress (UCMS) model has been used to induce depressive-like symptoms in animal models, showing adequate predictive validity. Our work aims to evaluate the effects of environmental enrichment (EE) on resilience in this experimental model of depression. We also aim to assess changes in brain connectivity using cytochrome c oxidase histochemistry in cerebral regions related to cognitive-affective processes associated with depressive disorder: dorsal hippocampus, prefrontal cortex, amygdala, accumbens, and habenula nuclei. Five groups of rats were used: UCMS, EE, EE + UCMS (enrichment + stress), BG (basal level of brain activity), and CONT (behavioral tests only). We assessed the hedonic responses elicited by sucrose solution using a consumption test; the anxiety level was evaluated using the elevated zero maze test, and the unconditioned fear responses were assessed by the cat odor test. The behavioral results showed that the UCMS protocol induces elevated anhedonia and anxiety. But these responses are attenuated previous exposure to EE. Regarding brain activity, the UCMS group showed greater activity in the habenula compared to the EE + UCMS group. EE induced a functional reorganization of brain activity. The EE + UCMS and UCMS groups showed different patterns of connections between brain regions. Our results showed that EE favors greater resilience and could reduce vulnerability to disorders such as depression and anxiety, modifying metabolic brain activity.

Trajectories of resilience and mental distress to global major disruptions

The COVID-19 pandemic has resulted in a major societal disruption, raising the question of how people can maintain or quickly regain their mental health (i.e., be resilient) during such times. Researchers have used the pandemic as a use case for studying resilience in response to a global, synchronously starting, and chronic set of stressors on the individual and societal level. Our review of this recent literature reveals that mental distress trajectories during the pandemic largely resemble mental distress responses to individual-level macro-stressors, except for a lower prevalence of recovery trajectories. Results suggest more resilient responses in older adults, but trajectories are less consistent for younger and older ages compared with middle-aged adults. We call for more research integrating state-of-the-art operationalizations of resilience and using these to study resilience over the lifespan.

Brief Maternal Separation Inoculates Against the Effects of Social Stress on Depression-Like Behavior and Cocaine Reward in Mice

Exposure to intermittent repeated social defeat (IRSD) increases the vulnerability of mice to the rewarding effects of cocaine in the conditioned place preference (CPP) paradigm. According to the "inoculation of stress" hypothesis, a brief period of maternal separation (MS) can provide protection against the negative effects of IRSD. The aim of the present study was to assess whether exposure to a brief episode of MS prevents the subsequent short-term effects of IRSD on depression- and anxiety-like behaviors and to explore its long-term effects on cocaine CPP in mice. Four groups of male C57BL/6 mice were employed; two groups were separated from their mother [6 h on postnatal day (PND) 9], while the other two groups were not (controls). On PND 47, 50, 53 and 56, mice that had experienced MS were exposed to social defeat in the cage of an aggressive resident mouse (MS + IRSD group) or were allowed to explore an empty cage (MS + EXPL group). The same procedure was performed with control mice that had not experienced MS (CONTROL + IRSD and CONTROL + EXPL groups). On PND57-58, all the mice performed the elevated plus maze and the hole-board, social interaction and splash tests. Three weeks after the last episode of defeat, all the mice underwent the CPP procedure with cocaine (1 mg/kg). Irrespective of whether or not MS had taken place, a reduction in open arms measures, dips, and social interaction was observed in mice that experienced IRSD. A higher latency of grooming and acquisition of cocaine-induced CPP were observed only in mice exposed to IRSD alone (CONTROL + IRSD). These results suggest that exposure to a brief episode of stress early in life increases the subsequent resilience of animals to the effects of social stress on vulnerability to cocaine.

Interactions Between Experience, Genotype and Sex in the Development of Individual Coping Strategies

Coping strategies, the first line of defense against adversities, develop through experience. There is consistent evidence that both genotype and sex contribute to the development of dysfunctional coping, leading to maladaptive outcomes of adverse experiences or to adaptive coping that fosters rapid recovery even from severe stress. However, how these factors interact to influence the development of individual coping strategies is just starting to be investigated. In the following review, we will consider evidence that experience, sex, and genotype influence the brain circuits and neurobiological processes involved in coping with adversities and discuss recent results pointing to the specific effects of the interaction between early experiences, genotype, and stress in the development of functional and dysfunctional coping styles.

Early life stress induces anxiety-like behavior during adulthood through dysregulation of neuronal plasticity in the basolateral amygdala

AIMS

Early life stress (ELS) increases the risk of psychiatric diseases such as anxiety disorders and depression in later life. Hyperactivation of the basolateral amygdala (BLA) neurons plays a pivotal role in the pathogenesis of stress-related diseases. However, the functional roles of BLA neurons in ELS-induced anxiety disorders are not completely understood.

MAIN METHODS

Mice were subjected to maternal separation (MS) during postnatal days 3 to 21 to mimic ELS. Anxiety-like behavior was tested by open field test (OFT), elevated plus maze (EPM), and novelty suppressed feeding (NSF). Then, c-fos expression, a proxy for neuronal activity, was evaluated by immunofluorescence. Finally, synaptic transmission and intrinsic excitability were measured by whole-cell patch-clamp recordings.

KEY FINDINGS

MS significantly increased anxiety-like behavior in adulthood, as indicated by less time spent in the center area of the OFT, less time spent in and fewer entries to the open arms of the EPM, and increased latency to feed in NSF. Mechanistically, MS increased the expression of c-fos in BLA. MS enhanced the excitatory, but not inhibitory, synaptic transmission onto BLA projection neurons (PNs), which was caused by enhanced presynaptic glutamate release. Moreover, MS also markedly increased the intrinsic neuronal excitability of BLA PNs, probably due to the reduced medium afterhyperpolarization (mAHP) in BLA PNs.

SIGNIFICANCE

Our results suggest that the changes of neuronal activity and synaptic transmission in the BLA PNs may play a crucial role in ELS-induced anxiety-like behavior, and these findings provide new insights into the pathological mechanisms of stress-related anxiety disorders.

Cardinal role of the environment in stress induced changes across life stages and generations

The stress response in rodents and humans is exquisitely dependent on the environmental context. The interactive element of the environment is typically studied by creating laboratory models of stress-induced plasticity manifested in behavior or the underlying neuroendocrine mediators of the behavior. Here, we discuss three representative sets of studies where the role of the environment in mediating stress sensitivity or stress resilience is considered across varying windows of time. Collectively, these studies testify that environmental variation at an earlier time point modifies the relationship between stressor and stress response at a later stage. The metaplastic effects of the environment on the stress response remain possible across various endpoints, including behavior, neuroendocrine regulation, region-specific neural plasticity, and regulation of receptors. The timescale of such variation spans adulthood, across stages of life history and generational boundaries. Thus, environmental variables are powerful determinants of the observed diversity in stress response. The predominant role of the environment suggests that it is possible to promote stress resilience through purposeful modification of the environment.

Sex differences in the effects of physical and sexual abuse on the odds of past 30-day opioid misuse among Florida justice-involved children

AIM

Opioid misuse is a severe threat to justice-involved children and adolescents. Identifying risk factors and sex differences is critical to design accurate risk assessments and person-centered interventions. Stress theory and research posit that abuse may be linked to opioid misuse, and the consequences may be harsher for females. The study tests the hypothesis that physical and sexual abuse will individually and cumulatively increase the risk for opioid misuse, and females will have a higher risk than males.

METHODS

A statewide sample of 79,960 justice-involved children in Florida were examined. Opioid misuse, illicit and non-medical use, was measured by urine analysis or self-disclosure within the past-30 days. Bivariate and multivariate logistic regression analyses were employed. Marginal effects were estimated to investigate the interaction between abuse and sex.

RESULTS

Over 2000 youth met the criteria for opioid misuse. One-third of female opioid users experienced both physical and sexual abuse. Compared to those with no history of physical or sexual abuse, those who were physically abused had 43% higher odds of opioid misuse, those who were sexually abuse had 78% higher odds, and those who experienced both had twice as high odds of opioid misuse. The individual and combined effects of these abuse types were higher for females. For example, female youth who were sexually abused had 2.7-times higher odds of opioid misuse than males who were sexually abused.

CONCLUSION

Intervention efforts can be improved by integrating physical and sexual abuse into risk assessments and tailoring assessments by sex.

Corticosterone after acute stress prevents the delayed effects on the amygdala

Even a single 2-hour episode of immobilization stress is known to trigger anxiety-like behavior and increase spine-density in the basolateral amygdala (BLA) of rats 10 days later. This delayed build-up of morphological and behavioral effects offers a stress-free time window of intervention after acute stress, which we used to test a protective role for glucocorticoids against stress. We observed that post-stress corticosterone, given 1 day after acute stress in drinking water, reversed enhanced anxiety-like behavior 10 days later. Quantification of spine-density on Golgi-stained BLA principal neurons showed that the same intervention also prevented the increase in spine numbers in the amygdala, at the same delayed time-point. Further, stress elevated serum corticosterone levels in rats that received vehicle in the drinking water. However, when stress was followed 24 h later by corticosterone in the drinking water, the surge in corticosterone was prevented. Together, these observations suggest that corticosterone, delivered through drinking water even 24 h after acute stress, is capable of reversing the delayed enhancing effects on BLA synaptic connectivity and anxiety-like behavior. Strikingly, although the immobilization-induced surge in corticosterone by itself has delayed detrimental effects on amygdalar structure and function, there exists a window of opportunity even after stress to mitigate its impact with a second surge of exogenously administered corticosterone. This provides a framework in the amygdala for analyzing how the initial physiological and endocrine processes triggered by traumatic stress eventually give rise to debilitating emotional symptoms, as well as the protective effects of glucocorticoids against their development.

Differential impact of stress and environmental enrichment on corticolimbic circuits

Stress exposure can produce profound changes in physiology and behavior that can impair health and well-being. Of note, stress exposure is linked to anxiety disorders and depression in humans. The widespread impact of these disorders warrants investigation into treatments to mitigate the harmful effects of stress. Pharmacological treatments fail to help many with these disorders, so recent work has focused on non-pharmacological alternatives. One of the most promising of these alternatives is environmental enrichment (EE). In rodents, EE includes social, physical, and cognitive stimulation for the animal, in the form of larger cages, running wheels, and toys. EE successfully reduces the maladaptive effects of various stressors, both as treatment and prophylaxis. While we know that EE can have beneficial effects under stress conditions, the morphological and molecular mechanisms underlying these behavioral effects are still not well understood. EE is known to alter neurogenesis, dendrite development, and expression of neurotrophic growth factors, effects that vary by type of enrichment, age, and sex. To add to this complexity, EE has differential effects in different brain regions. Understanding how EE exerts its protective effects on morphological and molecular levels could hold the key to developing more targeted pharmacological treatments. In this review, we summarize the literature on the morphological and molecular consequences of EE and stress in key emotional regulatory pathways in the brain, the hippocampus, prefrontal cortex, and amygdala. The similarities and differences among these regions provide some insight into stress-EE interaction that may be exploited in future efforts toward prevention of, and intervention in, stress-related diseases.

Female rats are resilient to the behavioral effects of maternal separation stress and exhibit stress-induced neurogenesis

Early-life stress causes anxiogenesis and sensitivity of stress endocrine axis, facilitated by changes in the basolateral amygdala and hippocampal neurogenesis. In this report, we examined if male-like relationship between early-life stress and anxiety was recapitulated in female rats, along with related neurobiological substrates of the amygdala and the hippocampus. Maternal separation, a paradigm consistently utilized in male rats in most previously published scripts, did not cause similar behavioral consequences in females. Maternal separation caused an increase in adult hippocampal neurogenesis in females without causing substantial differences in dendritic arbors of the basolateral amygdala. Thus, female rats displayed remarkable resilience in the emotional consequences of early-life stress.

Prefrontal-hippocampus plasticity reinstated by an enriched environment during stress

Chronic stress causes dendritic atrophy of neurons within the hippocampus and medial prefrontal cortex. In this report, we show that chronic stress leads to reduced long-term potentiation in the pathway from the hippocampus to the medial prefrontal cortex of rats; and that such reduction is rescued by enriched housing environment. Connectivity between the hippocampus and medial prefrontal cortex is proposed to be an essential substrate that is often compromised in several psychiatric disorders. Our observations suggest that a short period of complexity in the housing environment has the potential to protect the functional integrity of this important connection.

Meditation and Yoga Practices as Potential Adjunctive Treatment of SARS-CoV-2 Infection and COVID-19: A Brief Overview of Key Subjects

Editor's Note: As an acute condition quickly associated with multiple chronic susceptibilities, COVID-19 has rekindled interest in, and controversy about, the potential role of the host in disease processes. While hundreds of millions of research dollars have been funneled into drug and vaccine solutions that target the external agent, integrative practitioners tuned to enhancing immunity faced a familiar mostly unfunded task. First, go to school on the virus. Then draw from the global array of natural therapies and practices with host-enhancing or anti-viral capabilities to suggest integrative treatment strategies. The near null-set of conventional treatment options propels this investigation. In this paper, researchers from the Massachusetts Institute of Technology, University of California-San Diego, Chopra Library for Integrative Studies, and Harvard University share one such exploration. Their conclusion, that "certain meditation, yoga asana (postures), and pranayama (breathing) practices may possibly be effective adjunctive means of treating and/or preventing SARS-CoV-2 infection" underscores the importance of this rekindling. At JACM, we are pleased to have the opportunity to publish this work. We hope that it might help diminish in medicine and health the polarization that, like so much in the broader culture, seems to be an obstacle to healing. -John Weeks, Editor-in-Chief, JACM.

How Early Life Adversity Influences Defensive Circuitry

Childhood maltreatment increases the likelihood of developing anxiety disorders in humans. Early life adversity (ELA) paradigms in rodents produce lasting increases in avoidant and inhibitory responses to both immediate and nonspecific threats, collectively referred to as defensive behaviors. This approach provides an opportunity to thoroughly investigate the underlying mechanisms, an effort that is currently under way. In this review, we consider the growing literature indicating that ELA alters the rhythmic firing of neurons in brain regions associated with defensive behavior, as well as potential neuronal, glial, and extracellular matrix contributions to functional changes in this circuitry. We also consider how ELA studies in rodents may inform us about both susceptible and resilient outcomes in humans.

Moderate maternal separation mitigates the altered synaptic transmission and neuronal activation in amygdala by chronic stress in adult mice

Exposure to moderate level of stress during the perinatal period helps the organisms to cope well with stressful events in their later life, an effect known as stress inoculation. Amygdala is one of the kernel brain regions mediating stress-coping in the brain. However, little is known about whether early life stress may affect amygdala to have its inoculative effect. Here, we observed that moderate maternal separation (MS) from postnatal day 3 to day 21 (D3–21, 1 h per day) significantly alleviated the increased anxiety-like behavior induced by chronic social defeat stress (CSDS) in adulthood, suggesting an obvious inoculative effect of moderate MS. Further studies revealed that MS prevented CSDS-evoked augmentation of glutamatergic transmission onto principal neurons (PNs) in the basolateral amygdala (BLA) by inhibiting presynaptic glutamate release. By contrast, it did not affect GABAergic transmission in BLA PNs, as indicated by unaltered frequency and amplitude of miniature inhibitory postsynaptic currents (mIPSCs). Moreover, the CSDS-induced increase of neuronal excitability was also mitigated by MS in BLA PNs. In conclusion, our results suggest that MS may have its inoculative effect through alleviating the influences of later life stress on the glutamatergic transmission and neuronal activity in amygdala neurons.

Modelling resilience in adolescence and adversity: a novel framework to inform research and practice

Recent conceptualisations of resilience have advanced the notion that it is a dynamic and multifaceted construct. However, its adaptive components, especially those forged by adversity, have not been fully realised, and its neurobiological and psychosocial underpinnings are yet to be meaningfully integrated. In part, this is because a developmental perspective is often neglected in the formulation of resilience. In this review, we consider the findings of resilience research, with a specific emphasis on the developmental period of adolescence. To bridge the gaps in our current understanding, we propose a model of resilience that is predicated on experiencing adversity. Specifically, our model provides a sophisticated insight into the components of resilience, which, together with intrinsic features, involves facilitation of, and skill acquisition via strengthening processes we term tempering and fortification. The model also points to the potential trajectories of adversity-driven resilience and forms the basis of a framework that allows for individual variance in resilience, and the identification of both neurobiological and psychosocial targets for prevention and therapeutic interventions.

Cognitive Appraisal and Stress Performance: The Threat/Challenge Matrix and Its Implications on Performance

BACKGROUND

Stress has the potential to improve performance through increased focus and strength or negatively impact performance through distraction and decreased fine motor control. The first step in the distinction between success or failure in a stressful situation is making the decision to engage in the process or withdraw. Cognitive appraisal describes the process of evaluating a stimulus as either a challenge to be met or an overwhelming obstacle from which to retreat.

OBJECTIVE

Providers in the air medical community are required to perform in inherently stressful and unpredictable situations that may threaten to devastate personal resources. This paper is a literary meta-analysis of existing literature on stress performance, threat assessment, and cognitive appraisal in the medical environment.

FINDINGS

Preparing for stressful situations is not only accomplished through the practice of skills and rehearsal of knowledge, but also cognitive readiness, mindfulness, and encouragement of team members. Positive cognitive appraisals is practiced through simulation, case study, and purposeful mental practice. Deciding to actively engage in problem solving through the lens of overcoming obstacles and meeting challenges with confidence provides the mental framework that recruits the inevitable sympathetic surge for benefit rather than impairment.

IMPLICATION

Cognitive appraisal describes the decision to focus on the challenge rather than threat of the situation based on the skills, knowledge, and experience of the team. Establishing a positive narrative and actively engaging in challenges increased confidence and improves performance of medical providers.

Early life stress is associated with reduced avoidance of threatening facial expressions

Early neglect or maltreatment has been associated with changes in children's processing of emotional facial expressions, including a hypersensitivity to the emotion of anger. This may facilitate the avoidance of danger in a maltreating environment. However, few studies have examined whether experiences of early life stress (ELS) are associated with atypical avoidance responses towards emotional facial expressions, or whether the effects of ELS can be observed in adult participants. The present study therefore examined the effects of ELS on adults' approach-avoidance tendencies towards angry, happy, and neutral facial expressions. Surprisingly, higher levels of ELS were associated with reduced avoidance of angry facial expressions among individuals with no evidence of mental illness. In contrast, there was no evidence of a relationship between ELS and avoidance of angry facial expressions among individuals with experience of mental illness. These novel findings suggest that ELS-related changes in social cognition can be observed years after the ELS itself occurred.

Biological and Psychological Perspectives of Resilience: Is It Possible to Improve Stress Resistance?

The term “resilience” refers to the ability to adapt successfully to stress, trauma and adversity, enabling individuals to avoid stress-induced mental disorders such as depression, posttraumatic stress disorder (PTSD) and anxiety. Here, we review evidence from both animal models and humans that is increasingly revealing the neurophysiological and neuropsychological mechanisms that underlie stress susceptibility, as well as active mechanisms underlying the resilience phenotype. Ultimately, this growing understanding of the neurobiological mechanisms of resilience should result in the development of novel interventions that specifically target neural circuitry and brain areas that enhance resilience and lead to more effective treatments for stress-induced disorders. Stress resilience can be improved, but the outcomes and effects depend on the type of intervention and the species treated.

Adversity and Resilience Are Associated with Outcome after Mild Traumatic Brain Injury in Military Service Members

The objective of this study was to assess the associations between resilience, adversity, post-concussion symptoms, and post-traumatic stress symptom reporting after mild traumatic brain injury (mTBI). We hypothesized that resilience would be associated with less symptom reporting, and adversity would be associated with greater symptom reporting. This was a cross-sectional study of retrospective data collected for an ongoing TBI repository. United States military service members who screened positive for mTBI during a primary care visit completed the Trauma History Screen (THS), Connor-Davidson Resilience Scale (CD-RISC), Neurobehavioral Symptom Inventory (NSI), and post-traumatic stress disorder (PTSD) Checklist-Civilian Version (PCL-C). Data collected from February 2015 to August 2016 were used for the present study. Only participants with complete data for the above measures were included, yielding a sample size of 165 participants. Adversity (THS) and resilience (CD-RISC) scores were each correlated significantly with post-concussion (NSI) and traumatic stress (PCL-C) total and subscale scores in the hypothesized direction. Interactions between adversity and resilience were absent for all measures except the NSI sensory subscale. Four traumatic event types were significantly associated positively with most NSI and PCL-C total and subscale scores, but the age at which traumatic events were first experienced showed few and mixed significant associations. In conclusion, resilience and adversity were significantly associated with symptom endorsement after mTBI. Screening for cumulative adversity may identify individuals at greater risk of developing persistent post-concussion symptoms and/or PTSD, and interventions that increase resilience may reduce symptom severity.

Stressful life events and posttraumatic growth among police officers: A cross-sectional study

Police officers often continue to face numerous threats and stressors in the aftermath of a disaster. To date, posttraumatic growth (PTG) has been studied primarily in the context of significant trauma; thus, it is not known whether stressful life events are associated with PTG. This study investigated the development of PTG among 113 police officers working in the New Orleans area following Hurricane Katrina. Hierarchical regression was used to evaluate if gratitude, social support, and satisfaction with life moderated the relationship between stressful life events (as measured by the total life stress score) and PTG, after adjustment for age, sex, race, level of involvement in Hurricane Katrina, and alcohol intake. Results indicate that stressful life events are independently associated with PTG. Gratitude, satisfaction with life, and social support were seen to moderate this relationship; as stressful life events increased so too did PTG-particularly among officers with higher levels of gratitude (B = 0.002, p ≤ .05), satisfaction with life (B = 0.002, p ≤ .05), and social support (B = 0.001, p ≤ .05). These findings suggest that promoting satisfaction with life, interpersonal support, and gratitude may be beneficial to those who are regularly at risk of trauma exposure.

Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance

Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change.  Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasmagondii -induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma gondii infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma gondii are dependent on variables in the environment that often go unreported in the published literature.

Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance

Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change.  Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasma-induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma are dependent on variables in the environment that often go unreported in the published literature.

Susceptibility or resilience? Prenatal stress predisposes male rats to social subordination, but facilitates adaptation to subordinate status

Mood disorders such as major depressive disorder (MDD) affect a significant proportion of the population. Although progress has been made in the development of therapeutics, a large number of individuals do not attain full remission of symptoms and adverse side effects affect treatment compliance for some. In order to develop new therapies, there is a push for new models that better reflect the multiple risk factors that likely contribute to the development of depressive illness. We hypothesized that early life stress would exacerbate the depressive-like phenotype that we have previously observed in socially subordinate (SUB) adult male rats in the visible burrow system (VBS), a semi-natural, ethologically relevant environment in which males in a colony form a dominance hierarchy. Dams were exposed to chronic variable stress (CVS) during the last week of gestation, resulting in a robust and non-habituating glucocorticoid response that did not alter maternal food intake, body weight or litter size and weight. As adults, one prenatal CVS (PCVS) and one non-stressed (NS) male were housed in the VBS with adult females. Although there were no overt differences between PCVS and NS male offspring prior to VBS housing, a greater percentage of PCVS males became SUB. However, the depressive-like phenotype of SUB males was not exacerbated in PCVS males; rather, they appeared to better cope with SUB status than NS SUB males. They had lower basal plasma corticosterone than NS SUB males at the end of VBS housing. In situ hybridization for CRH in the PVN and CeA did not reveal any prenatal treatment or status effects, while NPY expression was higher within the MeA of dominant and subordinate males exposed to the VBS in comparison with controls, but with no effect of prenatal treatment. These data suggest that prenatal chronic variable stress may confer resilience to offspring when exposed to social stress in adulthood.