Amygdala responses to threat in violence-exposed children depend on trauma context and maternal caregiving

Early life adversity is associated with greater similarity in neural representations of ambiguous and threatening stimuli

Exposure to early life adversity (ELA) is hypothesized to sensitize threat-responsive neural circuitry. This may lead individuals to overestimate threat in the face of ambiguity, a cognitive-behavioral phenotype linked to poor mental health. The tendency to process ambiguity as threatening may stem from difficulty distinguishing between ambiguous and threatening stimuli. However, it is unknown how exposure to ELA relates to neural representations of ambiguous and threatening stimuli, or how processing of ambiguity following ELA relates to psychosocial functioning. The current fMRI study examined multivariate representations of threatening and ambiguous social cues in 41 emerging adults (aged 18 to 19 years). Using representational similarity analysis, we assessed neural representations of ambiguous and threatening images within affective neural circuitry and tested whether similarity in these representations varied by ELA exposure. Greater exposure to ELA was associated with greater similarity in neural representations of ambiguous and threatening images. Moreover, individual differences in processing ambiguity related to global functioning, an association that varied as a function of ELA. By evidencing reduced neural differentiation between ambiguous and threatening cues in ELA-exposed emerging adults and linking behavioral responses to ambiguity to psychosocial wellbeing, these findings have important implications for future intervention work in at-risk, ELA-exposed populations.

Adverse childhood experiences and lifelong health

With the advent of the sustainable development goals, the field of global child health has shifted its focus from reducing mortality to improving health, nutrition and development outcomes - often measured as human capital. A growing knowledge of the biology of development and neuroscience has highlighted the importance of adverse environmental exposures, collectively termed adverse childhood experiences (ACEs) on health outcomes. ACEs are associated with short-term, medium-term and long-term negative consequences for health and development and their effects may be multiplicative, especially during critical periods of sensitivity and developmental plasticity. Some of these effects are compounded by emerging global threats such as climate change, conflict and population displacement. In this Review, we discuss the key mechanisms linking ACEs to health outcomes and consider promising strategies to prevent and mitigate their effects, highlighting evidence from programs in low-income and middle-income countries. Finally, we emphasize the need for early recognition of ACEs and delivery of packages of interventions spanning key sectors such as health, education, women's empowerment and social protection.

Interpersonal early adversity demonstrates dissimilarity from early socioeconomic disadvantage in the course of human brain development: A meta-analysis

It has been established that early-life adversity impacts brain development, but the role of development itself has largely been ignored. We take a developmentally-sensitive approach to examine the neurodevelopmental sequelae of early adversity in a preregistered meta-analysis of 27,234 youth (birth to 18-years-old), providing the largest group of adversity-exposed youth to date. Findings demonstrate that early-life adversity does not have an ontogenetically uniform impact on brain volumes, but instead exhibits age-, experience-, and region-specific associations. Relative to non-exposed comparisons, interpersonal early adversity (e.g., family-based maltreatment) was associated with initially larger volumes in frontolimbic regions until ∼10-years-old, after which these exposures were linked to increasingly smaller volumes. By contrast, socioeconomic disadvantage (e.g., poverty) was associated with smaller volumes in temporal-limbic regions in childhood, which were attenuated at older ages. These findings advance ongoing debates regarding why, when, and how early-life adversity shapes later neural outcomes.

Interpersonal early adversity demonstrates dissimilarity from early socioeconomic disadvantage in the course of human brain development: A meta-analysis

It has been established that early-life adversity impacts brain development, but the role of development itself has largely been ignored. We take a developmentally-sensitive approach to examine the neurodevelopmental sequelae of early adversity in a preregistered meta-analysis of 27,234 youth (birth to 18-years-old), providing the largest group of adversity-exposed youth to date. Findings demonstrate that early-life adversity does not have an ontogenetically uniform impact on brain volumes, but instead exhibits age-, experience-, and region-specific associations. Relative to non-exposed comparisons, interpersonal early adversity (e.g., family-based maltreatment) was associated with initially larger volumes in frontolimbic regions until ~10-years-old, after which these exposures were linked to increasingly smaller volumes. By contrast, socioeconomic disadvantage (e.g., poverty) was associated with smaller volumes in temporal-limbic regions in childhood, which were attenuated at older ages. These findings advance ongoing debates regarding why, when, and how early-life adversity shapes later neural outcomes.

Early stressful experiences are associated with reduced neural responses to naturalistic emotional and social content in children

How do children's experiences relate to their naturalistic emotional and social processing? Because children can struggle with tasks in the scanner, we collected fMRI data while 4-to-11-year-olds watched a short film with positive and negative emotional events, and rich parent-child interactions (n = 70). We captured broad, normative stressful experiences by examining socioeconomic status (SES) and stressful life events, as well as children's more proximal experiences with their parents. For a sub-sample (n = 30), parenting behaviors were measured during a parent-child interaction, consisting of a picture book, a challenging puzzle, and free play with novel toys. We characterized positive parenting behaviors (e.g., warmth, praise) and negative parenting behaviors (e.g., harsh tone, physical control). We found that higher SES was related to greater activity in medial orbitofrontal cortex during parent-child interaction movie events. Negative parenting behaviors were associated with less activation of the ventral tegmental area and cerebellum during positive emotional events. In a region-of-interest analysis, we found that stressful life events and negative parenting behaviors were associated with less activation of the amygdala during positive emotional events. These exploratory results demonstrate the promise of using movie fMRI to study how early experiences may shape emotional, social, and motivational processes.

Neighborhood Disadvantage Associated With Blunted Amygdala Reactivity to Predictable and Unpredictable Threat in a Community Sample of Youth

BACKGROUND

Childhood socioeconomic disadvantage is a form of adversity associated with alterations in critical frontolimbic circuits involved in the pathophysiology of psychiatric disorders. Most work has focused on individual-level socioeconomic position, yet individuals living in deprived communities typically encounter additional environmental stressors that have unique effects on the brain and health outcomes. Notably, chronic and unpredictable stressors experienced in the everyday lives of youth living in disadvantaged neighborhoods may impact neural responsivity to uncertain threat.

METHODS

A community sample of children (N = 254) ages 8 to 15 years (mean = 12.15) completed a picture anticipation task during a functional magnetic resonance imaging scan, during which neutral and negatively valenced photos were presented in a temporally predictable or unpredictable manner. Area Deprivation Index (ADI) scores were derived from participants' home addresses as an index of relative neighborhood disadvantage. Voxelwise analyses examined interactions of ADI, valence, and predictability on neural response to picture presentation.

RESULTS

There was a significant ADI × valence interaction in the middle temporal gyrus, anterior cingulate cortex, hippocampus, and amygdala. Higher ADI was associated with less amygdala activation to negatively valenced images. ADI also interacted with predictability. Higher ADI was associated with greater activation of lingual and calcarine gyri for unpredictably presented stimuli. There was no three-way interaction of ADI, valence, and predictability.

CONCLUSIONS

Neighborhood disadvantage may impact how the brain perceives and responds to potential threats. Future longitudinal work is critical for delineating how such effects may persist across the life span and how health outcomes may be modifiable with community-based interventions and policies.

Addressing Mental Health Concerns in Refugees and Displaced Populations: Is Enough Being Done?

There are over 82.4 million forcibly displaced people worldwide, about a quarter of whom are resettling as refugees. In the wake of the global refugee crisis spurred by conflict, religious and political persecution, human rights violations, and climate disasters, a mental health has crisis followed. Not only does trauma experienced in home countries and as part of forced migration affect mental health, so too do post-migration traumatic events, discrimination, lack of access to quality and affordable healthcare and housing, and acculturation. To address mental health concerns in refugees and displaced populations, collective action is needed not only from health care providers but also from mental health researchers, funders, journals, resettlement agencies, government entities, and humanitarian organizations. The present review highlights the work of numerous scholars and organizations with the goal of understanding the mental health concerns of forcibly displaced persons within and across ecological systems. The present review seeks to bring attention to the experiences of forcibly displaced persons, summarize the growing body of research understanding the acute and chronic effects of forced displacement and possible interventions, and give a call to action for all members of the global community at every level to engage in joint efforts to improve mental health in refugees and displaced persons. Notably, there is a need for more interventions at the familial and community level that serve not only as treatment but also as prevention. Smartphone-based interventions, mind-body modalities, and interventions delivered by lay and non-clinician community members hold promise. Numerous strides could be made in refugee mental health and treatment when funding agencies include these goals in their research priorities. Despite the challenges they have faced, persons who resettle as refugees are incredibly resilient and deserve to be afforded every right, opportunity, dignity, and respect.