Resting-State Functional Connectivity of the Central Executive Network Moderates the Relationship Between Neighborhood Violence and Proinflammatory Phenotype in Children

The central executive network moderates the relationship between posttraumatic stress symptom severity and gastrointestinal related issues

Although most adults experience at least one traumatic event in their lifetime, a smaller proportion will go on to be clinically diagnosed with post-traumatic stress disorder (PTSD). Persons diagnosed with PTSD have a greater likelihood of developing gastrointestinal (GI) disorders. However, the extent to which subclinical levels of post-traumatic stress (PTS) correspond with the incidence of GI issues in a normative sample is unclear. Resting state fMRI, medical history, psychological survey, and anthropometric data were acquired from the Enhanced Nathan Kline Institute-Rockland Sample (n = 378; age range 18-85.6 years). The primary aim of this study was to test the main effect of subclinical PTS symptom severity on the number of endorsed GI issues. The secondary aim was to test the moderating effect of high versus low resting state functional connectivity (rsFC) of the central executive network (CEN) on the relationship between PTS symptom severity and GI issues. Trauma Symptom Checklist-40 (TSC-40) scores were positively associated with the number of endorsed GI issues (b = -0.038, SE = .009, p < .001). The interaction between TSC-40 scores and rsFC within the CEN was significant on GI issues after controlling for sociodemographic and cardiometabolic variables (b = -0.031, SE = .016, p < .05), such that above average rsFC within the CEN buffered the effect of TSC-40 scores on GI issues. Our findings of higher rsFC within the CEN moderating the magnitude of coincidence in PTS and GI symptom severity may reflect the mitigating role of executive control processes in the putative stress signaling mechanisms that contribute to gut dysbiosis.

Annual Research Review: Neuroimmune network model of depression: a developmental perspective

Depression is a serious public health problem, and adolescence is an 'age of risk' for the onset of Major Depressive Disorder. Recently, we and others have proposed neuroimmune network models that highlight bidirectional communication between the brain and the immune system in both mental and physical health, including depression. These models draw on research indicating that the cellular actors (particularly monocytes) and signaling molecules (particularly cytokines) that orchestrate inflammation in the periphery can directly modulate the structure and function of the brain. In the brain, inflammatory activity heightens sensitivity to threats in the cortico-amygdala circuit, lowers sensitivity to rewards in the cortico-striatal circuit, and alters executive control and emotion regulation in the prefrontal cortex. When dysregulated, and particularly under conditions of chronic stress, inflammation can generate feelings of dysphoria, distress, and anhedonia. This is proposed to initiate unhealthy, self-medicating behaviors (e.g. substance use, poor diet) to manage the dysphoria, which further heighten inflammation. Over time, dysregulation in these brain circuits and the inflammatory response may compound each other to form a positive feedback loop, whereby dysregulation in one organ system exacerbates the other. We and others suggest that this neuroimmune dysregulation is a dynamic joint vulnerability for depression, particularly during adolescence. We have three goals for the present paper. First, we extend neuroimmune network models of mental and physical health to generate a developmental framework of risk for the onset of depression during adolescence. Second, we examine how a neuroimmune network perspective can help explain the high rates of comorbidity between depression and other psychiatric disorders across development, and multimorbidity between depression and stress-related medical illnesses. Finally, we consider how identifying neuroimmune pathways to depression can facilitate a 'next generation' of behavioral and biological interventions that target neuroimmune signaling to treat, and ideally prevent, depression in youth and adolescents.

Pro-inflammatory markers are related to cortical network connectivity in women exposed to interpersonal trauma with PTSD

Exposure to interpersonal violence affects a significant number of individuals each year and further increases the risk for developing Posttraumatic Stress Disorder (PTSD). A growing body of research suggests that immune system dysfunction, in particular elevated inflammation, may contribute to the pathophysiology of PTSD. However, few studies have examined the neurobiological correlates of inflammation in women with PTSD using resting-state fMRI. The present study explored the relationship between pro-inflammatory cytokine levels, C-reactive protein (CRP), tumor necrosis factor alpha TNF-alpha), and interleukin-6 (IL-6), and resting-state functional connectivity patterns in three major cortical networks (default mode network (DMN), central executive network (CEN), and salience network (SN)) in a sample of women (N=18) exposed to interpersonal violence with PTSD. Results indicated that higher CRP levels were associated with stronger functional connectivity between the SN and visual areas, but weaker functional connectivity between the CEN and visual areas. These findings suggest that pro-inflammatory markers are related to connectivity of task-positive networks in women with PTSD. Further, our results provide evidence for potential neurobiological markers of inflammation in PTSD.

Neuroimmune mechanisms connecting violence with internalizing symptoms: A high-dimensional multimodal mediation analysis

Violence exposure is associated with worsening anxiety and depression symptoms among adolescents. Mechanistically, social defeat stress models in mice indicate that violence increases peripherally derived macrophages in threat appraisal regions of the brain, which have been causally linked to anxious behavior. In the present study, we investigate if there is a path connecting violence exposure with internalizing symptom severity through peripheral inflammation and amygdala connectivity. Two hundred and thirty-three adolescents, ages 12-15, from the Chicago area completed clinical assessments, immune assays and neuroimaging. A high-dimensional multimodal mediation model was fit, using violence exposure as the predictor, 12 immune variables as the first set of mediators and 288 amygdala connectivity variables as the second set, and internalizing symptoms as the primary outcome measure. 56.2% of the sample had been exposed to violence in their lifetime. Amygdala-hippocampus connectivity mediated the association between violence exposure and internalizing symptoms (ζ ̂ Hipp π ̂ Hipp = 0.059 $$ {\hat{\zeta}}_{\mathrm{Hipp}}{\hat{\pi}}_{\mathrm{Hipp}}=0.059 $$ ,95 % CI boot = 0.009,0.134 $$ 95\%{\mathrm{CI}}_{\mathrm{boot}}=\left[\mathrm{0.009,0.134}\right] $$ ). There was no evidence that inflammation or inflammation and amygdala connectivity in tandem mediated the association. Considering the amygdala and the hippocampus work together to encode, consolidate, and retrieve contextual fear memories, violence exposure may be associated with greater connectivity between the amygdala and the hippocampus because it could be adaptive for the amygdala and the hippocampus to be in greater communication following violence exposure to facilitate evaluation of contextual threat cues. Therefore, chronic elevations of amygdala-hippocampal connectivity may indicate persistent vigilance that leads to internalizing symptoms.

Flexible Resources Key to Neighborhood Resilience for Children: A Scoping Review

Neighborhoods have been the focus of health researchers seeking to develop upstream strategies to mitigate downstream disease development. In recent years, neighborhoods have become a primary target in efforts to promote health and resilience following deleterious social conditions such as the climate crisis, extreme weather events, the global pandemic, and supply chain disruptions. Children are often the most vulnerable populations after experiencing unexpected shocks. To examine and describe conceptually the construct of Neighborhood Resilience, we conducted a comprehensive scoping review using the terms ("resilience" or "resiliency" or "resilient") AND ("neighborhood"), utilizing MEDLINE (through PubMed) and CINAHL (through EBSCOhost) databases, to assess overall neighborhood themes that impact resilience. A total of 57 articles were extracted that met inclusion criteria. Extracted characteristics included study purpose, country of origin, key findings, environmental protective/risk factors. The analysis revealed a positive relationship between neighborhood resource density, neighborhood resiliency, and individual resiliency. This study reports the finding for studies with a population focus of pre-school age and school age children (1.5-18 years of age). Broadly, we identified that the primary goals regarding neighborhood resilience for childhood can be conceptualized as all activities and resources that (a) prevent trauma during childhood development and/or (b) mitigate or heal childhood trauma once it has occurred. This goal conceptually encompasses antecedents that increase protective factors and reduces risk factors for children and their families. This comprehensive look at the literature showed that a neighborhood's ability to build, promote, and maintain resiliency is often largely dependent on the flexible resources (i.e., knowledge, money, power, prestige, and beneficial social connections) that are available.

Multilayer network associations between the exposome and childhood brain development

Growing up in a high poverty neighborhood is associated with elevated risk for academic challenges and health problems. Here, we take a data-driven approach to exploring how measures of children's environments relate to the development of their brain structure and function in a community sample of children between the ages of 4 and 10 years. We constructed exposomes including measures of family socioeconomic status, children's exposure to adversity, and geocoded measures of neighborhood socioeconomic status, crime, and environmental toxins. We connected the exposome to two structural measures (cortical thickness and surface area, n = 170) and two functional measures (participation coefficient and clustering coefficient, n = 130). We found dense connections within exposome and brain layers and sparse connections between exposome and brain layers. Lower family income was associated with thinner visual cortex, consistent with the theory that accelerated development is detectable in early-developing regions. Greater neighborhood incidence of high blood lead levels was associated with greater segregation of the default mode network, consistent with evidence that toxins are deposited into the brain along the midline. Our study demonstrates the utility of multilayer network analysis to bridge environmental and neural explanatory levels to better understand the complexity of child development.

Multi-omics approach to socioeconomic disparity in metabolic syndrome reveals roles of diet and microbiome

The epidemy of metabolic syndrome (MetS) is typically preceded by adoption of a "risky" lifestyle (e.g., dietary habit) among populations. Evidence shows that those with low socioeconomic status (SES) are at an increased risk for MetS. To investigate this, we recruited 123 obese subjects (body mass index [BMI] ≥ 30) from Chicago. Multi-omic data were collected to interrogate fecal microbiota, systemic markers of inflammation and immune activation, plasma metabolites, and plasma glycans. Intestinal permeability was measured using the sugar permeability testing. Our results suggest a heterogenous metabolic dysregulation among obese populations who are at risk of MetS. Systemic inflammation, linked to poor diet, intestinal microbiome dysbiosis, and gut barrier dysfunction may explain the development of MetS in these individuals. Our analysis revealed 37 key features associated with increased numbers of MetS features. These features were used to construct a composite metabolic-inflammatory (MI) score that was able to predict progression of MetS among at-risk individuals. The MI score was correlated with several markers of poor diet quality as well as lower levels of gut microbial diversity and abnormalities in several species of bacteria. This study reveals novel targets to reduce the burden of MetS and suggests access to healthy food options as a practical intervention.

Transdiagnostic indicators predict developmental changes in cognitive control resting-state networks

Over the past decade, transdiagnostic indicators in relation to neurobiological processes have provided extensive insight into youth's risk for psychopathology. During development, exposure to childhood trauma and dysregulation (i.e., so-called AAA symptomology: anxiety, aggression, and attention problems) puts individuals at a disproportionate risk for developing psychopathology and altered network-level neural functioning. Evidence for the latter has emerged from resting-state fMRI studies linking mental health symptoms and aberrations in functional networks (e.g., cognitive control (CCN), default mode networks (DMN)) in youth, although few of these investigations have used longitudinal designs. Herein, we leveraged a three-year longitudinal study to identify whether traumatic exposures and concomitant dysregulation trigger changes in the developmental trajectories of resting-state functional networks involved in cognitive control (N = 190; 91 females; time 1 Mage = 11.81). Findings from latent growth curve analyses revealed that greater trauma exposure predicted increasing connectivity between the CCN and DMN across time. Greater levels of dysregulation predicted reductions in within-network connectivity in the CCN. These findings presented in typically developing youth corroborate connectivity patterns reported in clinical populations, suggesting there is predictive utility in using transdiagnostic indicators to forecast alterations in resting-state networks implicated in psychopathology.

Residence in High-Crime Neighborhoods Moderates the Association between Interleukin-6 and Social and Non-Social Reward Brain Responses

Background

Residence in high-crime neighborhoods, especially in childhood, is linked to mental health issues later. Detecting distinct neurobiological processes underlying the effects of this environmental stressor may be critical to identifying prevention and intervention targets. This study examined the relationships of levels of a circulating inflammatory protein with social and monetary reward–related brain function among adolescents who lived in high- versus low-crime neighborhoods during childhood.

Methods

A total of 70 participants (mean age = 16.3 years; 57% female) completed measures of inflammatory markers, depression history, and health and 2 functional magnetic resonance imaging tasks assessing responsivity to monetary and social rewards. Multivariate linear regression tested whether individuals with higher interleukin 6, an inflammatory cytokine, who also lived in neighborhoods with higher crime had distinct orbitofrontal cortex and nucleus accumbens activation to monetary reward and social acceptance.

Results

For adolescents who lived in neighborhoods with more crime, higher interleukin 6 was associated with higher nucleus accumbens responses to social acceptance. We did not detect significant moderating effects of neighborhood crime rates on the associations of interleukin 6 with orbitofrontal cortex responses to social acceptance or orbitofrontal cortex/nucleus accumbens activation during monetary reward anticipation or outcome. These results were obtained before and after adjusting for neighborhood income and other covariates. We did not detect significant moderating effects of neighborhood income.

Conclusions

High-threat residence environment and specific demands of the social context in childhood may have shaped the effect of peripheral immune activation on reward-related neural function in adolescence. The prevailing view that inflammation-associated behaviors are characterized by blunted responsiveness to reward may be oversimplistic.

Discrimination and Inflammation in Adolescents of Color

Background

This study examined how experiences with discrimination relate to inflammation, a key biological pathway in mental and physical illnesses, and whether associations are moderated by gender across two samples of adolescents of color.

Methods

Study 1 was a longitudinal study of 419 African American adolescents assessed on discrimination (ages 19-20), with trajectories of biomarkers of low-grade inflammation (C-reactive protein and soluble urokinase plasminogen activator receptor) measured from ages 25 to 29. Study 2 was a cross-sectional study of 201 eighth graders of color assessed on discrimination and mechanistic indicators of a proinflammatory phenotype: 1) in vitro studies of immune cells' inflammatory cytokine responses to stimuli; 2) in vitro studies of cells' sensitivity to anti-inflammatory agents; 3) circulating numbers of classical monocytes, key cellular drivers of low-grade inflammation; and 4) a composite of six biomarkers of low-grade inflammation.

Results

Interactions of discrimination by gender were found across both studies. In study 1, African American males experiencing high discrimination showed increasing trajectories of soluble urokinase plasminogen activator receptor over time (p < .001). In study 2, adolescent boys of color experiencing greater discrimination evinced a more proinflammatory phenotype: larger cytokine responses to stimuli (p = .003), lower sensitivity to anti-inflammatory agents (p = .003), higher numbers of classical monocytes (p = .008), and more low-grade inflammation (p = .003). No such associations were found in females.

Conclusions

Discrimination is a pressing societal issue that will need to be addressed in efforts to promote health equity. This study suggests that adolescent males of color may be particularly vulnerable to its effects on mental health-relevant inflammatory processes.

Childhood Violence Exposure, Inflammation, and Cardiometabolic Health

Exposure to interpersonal violence during childhood, a severe and often traumatic form of social stress, is an enduring problem that an emerging body of work suggests may be relevant to cardiometabolic health and the progression of cardiovascular disease (CVD) across the life course. Less is known about this association causally, and consequently, the biological mechanisms that may confer risk for, and resilience to, poor health outcomes in the aftermath of violence are not well understood. Drawing on recent theoretical insights and empirical research in both humans and non-human animal models, the current paper articulates a hypothesis for one way that childhood violence could get "under the skin" to influence CVD. Based on this emerging literature, one plausible way that childhood violence exposure could increase susceptibility to CVD in later life is by sensitizing stress-response neurobiology and immune processes that regulate and promote inflammation, which is a key pathogenic mechanism in CVD. This is inherently a developmental process that begins in early life and that unfolds across the life course, although less is known about the specific mechanisms through which this occurs. The goal of this paper is to articulate some of these plausible mechanisms and to suggest areas for future research that aims to reduce the burden of disease among individuals who are exposed to violence.