Associations between prenatal, childhood, and adolescent stress and variations in white-matter properties in young men

Early Adversity and Socioeconomic Factors in Pediatric Multiple Sclerosis: A Case-Control Study

BACKGROUND AND OBJECTIVES

Psychosocial adversity and stress, known to predispose adults to neurodegenerative and inflammatory immune disorders, are widespread among children who experience socioeconomic disadvantage, and the associated neurotoxicity and proinflammatory profile may predispose these children to multiple sclerosis (MS). We sought to determine associations of socioeconomic disadvantage and psychosocial adversity with odds of pediatric-onset MS (POMS), age at POMS onset, and POMS disease activity.

METHODS

This case-control study used data collected across 17 sites in the United States by the Environmental and Genetic Risk Factors for Pediatric Multiple Sclerosis Study. Cases (n = 381) were youth aged 3-21 years diagnosed with POMS or a clinically isolated demyelinating syndrome indicating high risk of MS. Frequency-matched controls (n = 611) aged 3-21 years were recruited from the same institutions. Prenatal and postnatal adversity and postnatal socioeconomic factors were assessed using retrospective questionnaires and zip code data. The primary outcome was MS diagnosis. Secondary outcomes were age at onset, relapse rate, and Expanded Disability Status Scale (EDSS). Predictors were maternal education, maternal prenatal stress events, child separation from caregivers during infancy and childhood, parental death during childhood, and childhood neighborhood disadvantage.

RESULTS

MS cases (64% female, mean age 15.4 years, SD 2.8) were demographically similar to controls (60% female, mean age 14.9 years, SD 3.9). Cases were less likely to have a mother with a bachelor's degree or higher (OR 0.42, 95% CI 0.22-0.80, p = 0.009) and were more likely to experience childhood neighborhood disadvantage (OR 1.04 for each additional point on the neighborhood socioeconomic disadvantage score, 95% CI 1.00-1.07; p = 0.025). There were no associations of the socioeconomic variables with age at onset, relapse rate, or EDSS, or of prenatal or postnatal adverse events with risk of POMS, age at onset, relapse rate, or EDSS.

DISCUSSION

Low socioeconomic status at the neighborhood level may increase the risk of POMS while high parental education may be protective against POMS. Although we did not find associations of other evaluated prenatal or postnatal adversities with POMS, future research should explore such associations further by assessing a broader range of stressful childhood experiences.

Through a teratological lens: A narrative review of exposure to stress and drugs of abuse during pregnancy on neurodevelopment

Teratological research shows that both prenatal stress and prenatal substance exposure have a significant impact on neurodevelopmental outcomes in children. Using human research, the purpose of this narrative review is to explore the degree to which these exposures may represent complex prenatal and postnatal risks for the development of cognition and behavior in children. An understanding of the HPA axis and its function during pregnancy as well as the types and operationalization of prenatal stress provide a context for understanding the direct and indirect mechanisms by which prenatal stress affects brain and behavior development. In turn, prenatal substance exposure studies are evaluated for their importance in understanding variables that indicate a potential interaction with prenatal stress including reactivity to novelty, arousal, and stress reactivity during early childhood. The similarities and differences between prenatal stress exposure and prenatal substance exposure on neurodevelopmental outcomes including arousal and emotion regulation, cognition, behavior, stress reactivity, and risk for psychopathology are summarized. Further considerations for teratological studies of prenatal stress and/or substance exposure include identifying and addressing methodological challenges, embracing the complexity of pre-and postnatal environments in the research, and the importance of incorporating parenting and resilience into future studies.

Brain structural and functional outcomes in the offspring of women experiencing psychological distress during pregnancy

In-utero exposure to maternal psychological distress is increasingly linked with disrupted fetal and neonatal brain development and long-term neurobehavioral dysfunction in children and adults. Elevated maternal psychological distress is associated with changes in fetal brain structure and function, including reduced hippocampal and cerebellar volumes, increased cerebral cortical gyrification and sulcal depth, decreased brain metabolites (e.g., choline and creatine levels), and disrupted functional connectivity. After birth, reduced cerebral and cerebellar gray matter volumes, increased cerebral cortical gyrification, altered amygdala and hippocampal volumes, and disturbed brain microstructure and functional connectivity have been reported in the offspring months or even years after exposure to maternal distress during pregnancy. Additionally, adverse child neurodevelopment outcomes such as cognitive, language, learning, memory, social-emotional problems, and neuropsychiatric dysfunction are being increasingly reported after prenatal exposure to maternal distress. The mechanisms by which prenatal maternal psychological distress influences early brain development include but are not limited to impaired placental function, disrupted fetal epigenetic regulation, altered microbiome and inflammation, dysregulated hypothalamic pituitary adrenal axis, altered distribution of the fetal cardiac output to the brain, and disrupted maternal sleep and appetite. This review will appraise the available literature on the brain structural and functional outcomes and neurodevelopmental outcomes in the offspring of pregnant women experiencing elevated psychological distress. In addition, it will also provide an overview of the mechanistic underpinnings of brain development changes in stress response and discuss current treatments for elevated maternal psychological distress, including pharmacotherapy (e.g., selective serotonin reuptake inhibitors) and non-pharmacotherapy (e.g., cognitive-behavior therapy). Finally, it will end with a consideration of future directions in the field.

Reciprocal relationships between stress and depressive symptoms: the essential role of the nucleus accumbens

BACKGROUND

Stress and depression have a reciprocal relationship, but the neural underpinnings of this reciprocity are unclear. We investigated neuroimaging phenotypes that facilitate the reciprocity between stress and depressive symptoms.

METHODS

In total, 22 195 participants (52.0% females) from the population-based UK Biobank study completed two visits (initial visit: 2006-2010, age = 55.0 ± 7.5 [40-70] years; second visit: 2014-2019; age = 62.7 ± 7.5 [44-80] years). Structural equation modeling was used to examine the longitudinal relationship between self-report stressful life events (SLEs) and depressive symptoms. Cross-sectional data were used to examine the overlap between neuroimaging correlates of SLEs and depressive symptoms on the second visit among 138 multimodal imaging phenotypes.

RESULTS

Longitudinal data were consistent with significant bidirectional causal relationship between SLEs and depressive symptoms. In cross-sectional analyses, SLEs were significantly associated with lower bilateral nucleus accumbal volume and lower fractional anisotropy of the forceps major. Depressive symptoms were significantly associated with extensive white matter hyperintensities, thinner cortex, lower subcortical volume, and white matter microstructural deficits, mainly in corticostriatal-limbic structures. Lower bilateral nucleus accumbal volume were the only imaging phenotypes with overlapping effects of depressive symptoms and SLEs (B = -0.032 to -0.023, p = 0.006-0.034). Depressive symptoms and SLEs significantly partially mediated the effects of each other on left and right nucleus accumbens volume (proportion of effects mediated = 12.7-14.3%, p < 0.001-p = 0.008). For the left nucleus accumbens, post-hoc seed-based analysis showed lower resting-state functional connectivity with the left orbitofrontal cortex (cluster size = 83 voxels, p = 5.4 × 10-5) in participants with high v. no SLEs.

CONCLUSIONS

The nucleus accumbens may play a key role in the reciprocity between stress and depressive symptoms.

Long-term associations between early-life family functioning and preadolescent white matter microstructure

BACKGROUND

Causes of childhood behavior problems remain poorly understood. Enriched family environments and corresponding brain development may reduce the risk of their onset, but research investigating white matter neurodevelopmental pathways explaining associations between the family environment and behavior remains limited. We hypothesized that more positive prenatal and mid-childhood family functioning - a measure of a family's problem solving and supportive capacity - would be associated with two markers of preadolescent white matter neurodevelopment related to reduced behavior problems: higher global fractional anisotropy (FA) and lower global mean diffusivity (MD).

METHODS

Data are from 2727 families in the Generation R Study, the Netherlands. Mothers reported family functioning (McMaster Family Assessment Device, range 1-4, higher scores indicate healthier functioning) prenatally and in mid-childhood (mean age 6.1 years). In preadolescence (mean age 10.1), the study collected diffusion-weighted scans. We computed standardized global MD and FA values by averaging metrics from 27 white matter tracts, and we fit linear models adjusting for possible confounders to examine global and tract-specific outcomes.

RESULTS

Prenatal and mid-childhood family functioning scores were moderately correlated, r = 0.38. However, only prenatal family functioning - and not mid-childhood functioning - was associated with higher global FA and lower global MD in preadolescence in fully adjusted models: βglobal FA = 0.11 (95% CI 0.00, 0.21) and βglobal MD = -0.15 (95% CI -0.28, -0.03) per one-unit increase in functioning score. Sensitivity and tract-specific analyses supported these global findings.

CONCLUSIONS

These results suggest high-functioning prenatal or perinatal family environments may confer lasting white matter neurodevelopmental benefits into preadolescence.

Associations between Stressful Life Events and Increased Physical and Psychological Health Risks in Adolescents: A Longitudinal Study

Stressful life events (SLEs) are understood as risk factors for mental and physical health problems, particularly in the vulnerable period of adolescence. Using a longitudinal approach, this study investigated associations between SLE and several negative health outcomes in adolescents. Moderating effects of sociodemographic factors were considered. We analyzed the data of a healthy adolescent sample from the LIFE Child study in Leipzig, Germany (n = 2024, aged 10-18 years). SLEs were measured by a questionnaire, addressing SLEs in the family and the social environment domain. Health-related quality of life (HrQoL), behavioral difficulties and BMI were compared before and after an SLE had occurred. Moderator effects of socioeconomic status (SES), age, and sex were investigated using linear regression models. All considered health parameters had, on average, deteriorated after the occurrence of an SLE in the social environment. Differences in HrQoL before and after an SLE were significantly stronger in girls. Higher SES functioned as a slight protective factor against decreased well-being after an SLE. The findings suggest that SLEs function as risk factors for mental and physical health disadvantages in adolescents. Prevention programs should seek to support adolescents in all age and SES groups affected by SLEs, with a specific focus on girls.

Adolescent Alcohol and Stress Exposure Rewires Key Cortical Neurocircuitry

Human adolescence is a period of development characterized by wide ranging emotions and behavioral risk taking, including binge drinking (Konrad et al., 2013). These behavioral manifestations of adolescence are complemented by growth in the neuroarchitecture of the brain, including synaptic pruning (Spear, 2013) and increases in overall white matter volume (Perrin et al., 2008). During this period of profound physiological maturation, the adolescent brain has a unique vulnerability to negative perturbations. Alcohol consumption and stress exposure, both of which are heightened during adolescence, can individually and synergistically alter these neurodevelopmental trajectories in positive and negative ways (conferring both resiliency and susceptibility) and influence already changing neurotransmitter systems and circuits. Importantly, the literature is rapidly changing and evolving in our understanding of basal sex differences in the brain, as well as the interaction between biological sex and life experiences. The animal literature provides the distinctive opportunity to explore sex-specific stress- and alcohol- induced changes in neurocircuits on a relatively rapid time scale. In addition, animal models allow for the investigation of individual neurons and signaling molecules otherwise inaccessible in the human brain. Here, we review the human and rodent literature with a focus on cortical development, neurotransmitters, peptides, and steroids, to characterize the field's current understanding of the interaction between adolescence, biological sex, and exposure to stress and alcohol.

Caught in vicious circles: a perspective on dynamic feed-forward loops driving oxidative stress in schizophrenia

A growing body of evidence has emerged demonstrating a pathological link between oxidative stress and schizophrenia. This evidence identifies oxidative stress as a convergence point or "central hub" for schizophrenia genetic and environmental risk factors. Here we review the existing experimental and translational research pinpointing the complex dynamics of oxidative stress mechanisms and their modulation in relation to schizophrenia pathophysiology. We focus on evidence supporting the crucial role of either redox dysregulation, N-methyl-D-aspartate receptor hypofunction, neuroinflammation or mitochondria bioenergetics dysfunction, initiating "vicious circles" centered on oxidative stress during neurodevelopment. These processes would amplify one another in positive feed-forward loops, leading to persistent impairments of the maturation and function of local parvalbumin-GABAergic neurons microcircuits and myelinated fibers of long-range macrocircuitry. This is at the basis of neural circuit synchronization impairments and cognitive, emotional, social and sensory deficits characteristic of schizophrenia. Potential therapeutic approaches that aim at breaking these different vicious circles represent promising strategies for timely and safe interventions. In order to improve early detection and increase the signal-to-noise ratio for adjunctive trials of antioxidant, anti-inflammatory and NMDAR modulator drugs, a reverse translation of validated circuitry approach is needed. The above presented processes allow to identify mechanism based biomarkers guiding stratification of homogenous patients groups and target engagement required for successful clinical trials, paving the way towards precision medicine in psychiatry.

Glucocorticoid treatment for non-cerebral diseases in children and adolescents is associated with differences in uncinate fasciculus microstructure

BACKGROUND

Evidence suggests that fronto-limbic brain regions and connecting white matter fibre tracts in the left hemisphere are more sensitive to glucocorticoids than in the right hemisphere. It is unknown whether treatment with glucocorticoids in childhood is associated with microstructural differences of the uncinate fasciculus and cingulum bundle, which connect fronto-limbic brain regions. Here, we tested the hypothesis that prior glucocorticoid treatment would be associated with differences in fractional anisotropy (FA) of the left relative to right uncinate fasciculus and cingulum bundle.

METHODS

We performed diffusion-weighted imaging in 28 children and adolescents aged 7-16 years previously treated with glucocorticoids for nephrotic syndrome or rheumatic disease and 28 healthy controls.

RESULTS

Patients displayed significantly different asymmetry in the microstructure of uncinate fasciculus with higher left but similar right uncinate fasciculus FA and axial diffusivity compared to controls. No apparent differences were observed for the cingulum. Notably, higher cumulative glucocorticoid doses were significantly associated with higher uncinate fasciculus FA and axial diffusivity bilaterally.

CONCLUSIONS

Our findings indicate that previous glucocorticoid treatment for non-cerebral diseases in children and adolescents is associated with long-term changes in the microstructure of the uncinate fasciculi, and that higher cumulative glucocorticoid doses have a proportional impact on the microstructure.

IMPACT

It is unknown if treatment with glucocorticoids in childhood have long-term effects on fronto-limbic white matter microstructure. The study examined if children and adolescents previously treated with glucocorticoids for nephrotic syndrome or rheumatic disorder differed in fronto-limbic white matter microstructure compared to healthy controls. The nephrotic and rheumatic patients had higher left but similar right uncinate fasciculus FA and axial diffusivity. Higher bilateral uncinate fasciculus FA and axial diffusivity was associated with higher cumulative glucocorticoid doses. We revealed new evidence suggesting that previous glucocorticoid treatment for non-cerebral diseases in children and adolescents is associated with long-term changes in uncinate fasciculi microstructure.

A dynamic relation between whole-brain white matter microstructural integrity and anxiety symptoms in preadolescent females with pathological anxiety

Pathological anxiety typically emerges during preadolescence and has been linked to alterations in white matter (WM) pathways. Because myelination is critical for efficient neuronal communication, characterizing associations between WM microstructure and symptoms may provide insights into pathophysiological mechanisms associated with childhood pathological anxiety. This longitudinal study examined 182 girls enrolled between the ages of 9-11 that were treatment-naïve at study entry: healthy controls (n = 49), subthreshold-anxiety disorders (AD) (n = 82), or meeting DSM-5 criteria for generalized, social, and/or separation ADs (n = 51), as determined through structured clinical interview. Anxiety severity was assessed with the Clinical Global Impression Scale and Screen for Child Anxiety and Related Emotional Disorders (SCARED). Participants (n = 182) underwent clinical, behavioral, and diffusion tensor imaging (DTI) assessments at study entry, and those with pathological anxiety (subthreshold-AD and AD, n = 133) were followed longitudinally for up to 3 additional years. Cross-sectional ANCOVAs (182 scans) examining control, subthreshold-AD, and AD participants found no significant relations between anxiety and DTI measurements. However, in longitudinal analyses of girls with pathological anxiety (343 scans), linear mixed-effects models demonstrated that increases in anxiety symptoms (SCARED scores) were associated with reductions in whole-brain fractional anisotropy, independent of age (Std. β (95% CI) = -0.06 (-0.09 to -0.03), F(1, 46.24) = 11.90, P = 0.001). Using a longitudinal approach, this study identified a dynamic, within-participant relation between whole-brain WM microstructural integrity and anxiety in girls with pathological anxiety. Given the importance of WM microstructure in modulating neural communication, this finding suggests the possibility that WM development could be a viable target in the treatment of anxiety-related psychopathology.

Inflammation, Anxiety, and Stress in Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent and serious neurodevelopmental disorder characterized by symptoms of inattention and/or hyperactivity/impulsivity. Chronic and childhood stress is involved in ADHD development, and ADHD is highly comorbid with anxiety. Similarly, inflammatory diseases and a pro-inflammatory state have been associated with ADHD. However, while several works have studied the relationship between peripheral inflammation and stress in affective disorders such as depression or bipolar disorder, fewer have explored this association in ADHD. In this narrative review we synthetize evidence showing an interplay between stress, anxiety, and immune dysregulation in ADHD, and we discuss the implications of a potential disrupted neuroendocrine stress response in ADHD. Moreover, we highlight confounding factors and limitations of existing studies on this topic and critically debate multidirectional hypotheses that either suggest inflammation, stress, or anxiety as a cause in ADHD pathophysiology or inflammation as a consequence of this disease. Untangling these relationships will have diagnostic, therapeutic and prognostic implications for ADHD patients.

White matter integrity moderates the relation between experienced childhood maltreatment and fathers' behavioral response to infant crying

The ability to provide appropriate responses to infant distress is vital to paternal care, but may be affected by fathers' experiences of childhood maltreatment. Detrimental effects of childhood maltreatment have been found in the adult brain's white matter fibers, accompanied with impaired emotional and cognitive functioning. In the current study (N = 121), we examined new and expectant fathers' childhood maltreatment experiences (i.e. emotional and physical abuse and neglect), current behavioral responses (i.e. handgrip force) to infant cry sounds, and white matter integrity using diffusion tensor imaging. First, more exposure to childhood maltreatment was associated with more use of excessive handgrip force in response to infant crying by fathers. Second, the association between experienced childhood maltreatment and white matter integrity was not significant in whole-brain analyses. Lastly, we found that the association between maltreatment exposure and excessive handgrip force during infant crying was absent in fathers with high tract integrity in the bilateral uncinate fasciculus. These findings possibly point to insufficient behavioral inhibition or emotional dysregulation in fathers who experienced childhood maltreatment, but buffering for this effect in those with larger integrity in brain fibers connecting the amygdala and prefrontal cortex.

Pubertal Testosterone and the Structure of the Cerebral Cortex in Young Men

Adolescence is a period of brain maturation that may involve a second wave of organizational effects of sex steroids on the brain. Rodent studies suggest that, overall, organizational effects of gonadal steroid hormones decrease from the prenatal/perinatal period to adulthood. Here we used multimodal magnetic resonance imaging to investigate whether 1) testosterone exposure during adolescence (9-17 years) correlates with the structure of cerebral cortex in young men (n = 216, 19 years of age); 2) this relationship is modulated by the timing of testosterone surge during puberty. Our results showed that pubertal testosterone correlates with structural properties of the cerebral cortex, as captured by principal component analysis of T1 and T2 relaxation times, myelin water fraction, magnetization transfer ratio, fractional anisotropy and mean diffusivity. Many of the correlations between pubertal testosterone and the cortical structure were stronger in individuals with earlier (vs. later) testosterone surge. We also demonstrated that the strength of the relationship between pubertal testosterone and cortical structure across the cerebral cortex varies as a function of inter-regional profiles of gene expression specific to dendrites, axonal cytoskeleton, and myelin. This finding suggests that the cellular substrate underlying the relationships between pubertal testosterone and cerebral cortex involves both dendritic arbor and axon.

Pubertal Testosterone and Brain Response to Faces in Young Adulthood: An Interplay between Organizational and Activational Effects in Young Men

According to the organizational-activational hypothesis, the organizational effects of testosterone during (prenatal) brain development moderate the activational effects of adult testosterone on behavior. Accumulating evidence supports the notion that adolescence is another period during which sex hormones organize the nervous system. Here we investigate how pubertal sex hormones moderate the activational effects of adult sex hormones on social cognition in humans. To do so, we recruited a sample of young men (n = 507; age, ∼19 years) from a longitudinal birth cohort and investigated whether testosterone exposure during adolescence (from 9 to 17 years of age) moderates the relation between current testosterone and brain response to faces in young adulthood, as assessed with functional magnetic resonance imaging (fMRI). Our results showed that the cumulative exposure to testosterone during adolescence moderated the relation between adult testosterone and both the mean fMRI response and functional connectivity (i.e., node strength). Specifically, in participants with low exposure to testosterone during puberty, we observed a positive relationship between current testosterone and the brain response to faces; this was not the case for participants with medium and high pubertal testosterone. Furthermore, we observed a stronger relationship between the brain response and current testosterone in parts of the angry-face network associated with (vs without) motion in the eye region of an observed (angry) face. We speculate that pubertal testosterone modulates the relationship between current testosterone and brain response to social cues carried by the eyes and signaling a potential threat.SIGNIFICANCE STATEMENT Accumulating evidence supports the organizational effects of pubertal testosterone, but the body of literature examining these effects on social cognition in humans is in its infancy. With a sample of young men from a longitudinal birth cohort, we showed that the cumulative exposure to testosterone during adolescence moderated the relation between adult testosterone and both the mean BOLD signal change and functional connectivity. Specifically, we observed a positive relationship between adult testosterone and the brain response to faces in participants with low exposure to testosterone during puberty, but not in participants with medium and high pubertal testosterone. Results of further analysis suggest that sensitivity to cues carried by the eyes might underlie the relationship between testosterone and brain response to faces, especially in the context of a potential threat.

Physical Activity, Sedentary Behavior, and White Matter Microstructure in Children with Overweight or Obesity

PURPOSE

This study aimed to investigate the associations of objectively measured and self-reported physical activity (PA) and sedentary behavior with white matter microstructure in children with overweight or obesity.

METHODS

In a sample of 103 participants (age, 10.02 ± 1.15 yr; 42 girls) from the ActiveBrains project, we assessed PA and sedentary behavior using accelerometers (GT3X+; ActiGraph, Pensacola, FL), and the Youth Activity Profile-Spain questionnaire. Objectively measured PA and sedentary behavior were classified into different intensities following the hip- and wrist-based cutoff points for the Euclidean Norm Minus One metric by Hildebrand et al., wrist-based cutoff points for counts metric by Chandler et al., and hip-based cutoff points for counts metric for Romanzini et al. and Evenson et al. Magnetic resonance imaging of white matter microstructure, fractional anisotropy (FA), and mean diffusivity (MD) were derived from diffusion tensor imaging. Linear regression models were used to examine the associations of objectively measured and self-reported PA and sedentary behavior with global and tract-specific FA and MD.

RESULTS

Self-reported total PA was positively associated with global FA (β = 0.236, P = 0.038), whereas watching television was negatively associated with global FA (β = -0.270, P = 0.014). In regard to the objective measures, using single regression models, light PA (β = 0.273, P = 0.016), moderate-to-vigorous PA (β = 0.257, P = 0.035), and total PA (β = 0.294, P = 0.013) were positively associated with global FA only when Hildebrand-Euclidean Norm Minus One hip cut points were used for analyses. Lastly, no association was found between PA and sedentary behavior and FA and MD within individual tracts.

CONCLUSIONS

Our results suggest that PA and watching television are related to white matter microstructure in children with overweight or obesity. However, longitudinal large-scale studies are needed to confirm and expand these findings.

Population neuroimaging: generation of a comprehensive data resource within the ALSPAC pregnancy and birth cohort

Neuroimaging offers a valuable insight into human brain development by allowing in vivo assessment of structure, connectivity and function. Multimodal neuroimaging data have been obtained as part of three sub-studies within the Avon Longitudinal Study of Parents and Children, a prospective multigenerational pregnancy and birth cohort based in the United Kingdom. Brain imaging data were acquired when offspring were between 18 and 24 years of age, and included acquisition of structural, functional and magnetization transfer magnetic resonance, diffusion tensor, and magnetoencephalography imaging. This resource provides a unique opportunity to combine neuroimaging data with extensive phenotypic and genotypic measures from participants, their mothers, and fathers.

Effects of maternal stress and nutrient restriction during gestation on offspring neuroanatomy in humans

Cognitive and mental health are major determinants of quality of life, allowing integration into society at all ages. Human epidemiological and animal studies indicate that in addition to genetic factors and lifestyle, prenatal environmental influences may program neuropsychiatric disorders in later life. While several human studies have examined the effects of prenatal stress and nutrient restriction on brain function and mental health in later life, potentially mediating effects of prenatal stress and nutrient restriction on offspring neuroanatomy in humans have been studied only in recent years. Based on neuroimaging and anatomical data, we comprehensively review the studies in this emerging field. We relate prenatal environmental influences to neuroanatomical abnormalities in the offspring, measured in utero and throughout life. We also assess the relationship between neuroanatomical abnormalities and cognitive and mental disorders. Timing- and gender-specific effects are considered, if reported. Our review provides evidence for adverse effects of an unfavorable prenatal environment on structural brain development that may contribute to the risk for cognitive, behavioral and mental health problems throughout life.

Stress-Induced Microstructural Alterations Correlate With the Cognitive Performance of Rats: A Longitudinal in vivo Diffusion Tensor Imaging Study

Background: Stress-induced cellular changes in limbic brain structures contribute to the development of various psychopathologies. In vivo detection of these microstructural changes may help us to develop objective biomarkers for psychiatric disorders. Diffusion tensor imaging (DTI) is an advanced neuroimaging technique that enables the non-invasive examination of white matter integrity and provides insights into the microstructure of pathways connecting brain areas.

Objective: Our aim was to examine the temporal dynamics of stress-induced structural changes with repeated in vivo DTI scans and correlate them with behavioral alterations.

Methods: Out of 32 young adult male rats, 16 were exposed to daily immobilization stress for 3 weeks. Four DTI measurements were done: one before the stress exposure (baseline), two scans during the stress (acute and chronic phases), and a last one 2 weeks after the end of the stress protocol (recovery). We used a 4.7T small-animal MRI system and examined 18 gray and white matter structures calculating the following parameters: fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). T2-weighted images were used for volumetry. Cognitive performance and anxiety levels of the animals were assessed in the Morris water maze, novel object recognition, open field, and elevated plus maze tests.

Results: Reduced FA and increased MD and RD values were found in the corpus callosum and external capsule of stressed rats. Stress increased RD in the anterior commissure and reduced MD and RD in the amygdala. We observed time-dependent changes in several DTI parameters as the rats matured, but we found no evidence of stress-induced volumetric alterations in the brains. Stressed rats displayed cognitive impairments and we found numerous correlations between the cognitive performance of the animals and between various DTI metrics of the inferior colliculus, corpus callosum, anterior commissure, and amygdala.

Conclusions: Our data provide further support to the translational value of DTI studies and suggest that chronic stress exposure results in similar white matter microstructural alterations that have been documented in stress-related psychiatric disorders. These DTI findings imply microstructural abnormalities in the brain, which may underlie the cognitive deficits that are often present in stress-related mental disorders.

Childhood socio-economic disadvantage predicts reduced myelin growth across adolescence and young adulthood

Socio-economic disadvantage increases exposure to life stressors. Animal research suggests early life stressors impact later neurodevelopment, including myelin developmental growth. To determine how early life disadvantage may affect myelin growth in adolescence and young adulthood, we analysed data from an accelerated longitudinal neuroimaging study measuring magnetisation transfer (MT), a myelin-sensitive marker, in 288 participants (149 female) between 14 and 25 years of age at baseline. We found that early life economic disadvantage before age 12, measured by a neighbourhood poverty index, was associated with slower myelin growth. This association was observed for magnetization transfer in cortical, subcortical and core white matter regions, and also in key subcortical nuclei. Participant IQ at baseline, alcohol use, body mass index, parental occupation and self-reported parenting quality did not account for these effects, but parental education did so partially. Specifically, positive parenting moderated the effect of socio-economic disadvantage in a protective manner. Thus, early socioeconomic disadvantage appears to alter myelin growth across adolescence. This finding has potential translational implications, including clarifying whether reducing socio-economic disadvantage during childhood, and increasing parental education and positive parenting, promote normal trajectories of brain development in economically disadvantaged contexts.

Gender-specific differences in white matter microstructure in healthy adults exposed to mild stress

Stress is a powerful moderator of brain plasticity and may affect several physiological functions such as the endocrine and the immune system. The impact of stress can be protective or detrimental according to several factors such as level of the stressor and age of occurrence. Also, the impact may differ in males and females. We aim to analyze the effect of mild levels of early and recent stress on white matter microstructure in healthy volunteers. MRI acquisition of diffusion tensor images with a 3.0 T scanner was performed on 130 healthy subjects (71 males and 59 females). Severity of early and recent stress was rated, respectively, on the Risky Families Questionnaire and on the Schedule of Recent Experiences; subjects were divided into low stress and mild stress groups. Mild early stress associated with lower fractional anisotropy (FA) in the cingulate gyrus compared to low early stress. Females reported reduced FA compared to males in the low-stress group in the internal capsule, posterior corona radiata, posterior thalamic radiation, superior longitudinal fasciculus, and sagittal stratum whereas no difference was observed in the mild stress group. An additive effect of early and recent stress was observed in posterior corona radiata, retrolenticular part of the internal capsule, and superior longitudinal fasciculus. The impact of early stress on WM microstructure in healthy subjects is different in males and females. While males seem to be more sensitive to early stress, an additive effect of early and recent stress manifests itself in females.Layman summaryMild levels of early stress associate with lower white matter integrity measured by fractional anisotropy.Females and males show differences in white matter integrity when exposed to low levels of early stress with females showing lower white matter integrity compared to males.No difference in white matter integrity was observed for males and females exposed to mild levels of stress.Mild stress in females is associated with higher white matter integrity.Males seem to be more sensitive to early stress while females are more affected when early stress is followed by stress in adult life.

The Long-Term Effects of Adolescent Social Defeat Stress on Oligodendrocyte Lineage Cells and Neuroinflammatory Mediators in Mice

OBJECTIVE

Adverse childhood and adolescent experiences are associated with the emergences of psychopathology later in life and have negative consequences on white matter integrity. However, this adversity-induced white matter impairment remains not fully investigated.

METHODS

Adolescent Balb/c mice were subjected to intermittent social defeat stress once a day during postnatal days 25 to 40. Then, the subjects were allowed to recover for three weeks before sacrifice. At the end, oligodendrocyte (OL) lineage cells, cell proliferation, and microglia activation, as well as myelin basic protein (MBP) levels in frontal cortex and hippocampus were evaluated. The levels of interleukin (IL)-1β and IL-6 in the brain regions were assessed.

RESULTS

MBP protein level in frontal cortex, but not in the hippocampus of defeated mice, decreased significantly compared to controls. The numeral densities of mature OLs, oligodendrocyte progenitor cells, and proliferating cells in medial prefrontal cortex were comparable between the defeated mice and controls. The defeated mice, however, showed significantly higher IL-1β level, although IL-6 level and numeral density of microglia in frontal cortex did not change relative to controls.

CONCLUSION

These results indicate that effects of intermittent social defeat stress on the white matter integrity and OL lineage cells in mouse brain are region- and developmental stage-specific. Upregulated IL-1β may contribute to this negative consequence though the underlying mechanism remains to be investigated.

Cohort profile: the Neonatal Intensive Care Unit Hospital Exposures and Long-Term Health (NICU-HEALTH) cohort, a prospective preterm birth cohort in New York City

PURPOSE

The Neonatal Intensive Care Unit Hospital Exposures and Long-Term Health (NICU-HEALTH) longitudinal preterm birth cohort studies the impact of the NICU exposome on early-life development. NICU-HEALTH collects multiple biospecimens, complex observational and survey data and comprehensive multisystem outcome assessments to allow measurement of the impact of modifiable environmental exposures during the preterm period on neurodevelopmental, pulmonary and growth outcomes.

PARTICIPANTS

Moderately preterm infants without genetic or congenital anomalies and their mothers are recruited from an urban academic medical centre level IV NICU in New York City, New York, USA. Recruitment began in 2011 and continues through multiple enrolment phases to the present with goal enrolment of 400 infants. Follow-up includes daily data collection throughout the NICU stay and six follow-up visits in the first 2 years. Study retention is 77% to date, with the oldest patients turning age 8 in 2019.

FINDINGS TO DATE

NICU-HEALTH has already contributed significantly to our understanding of phthalate exposure in the NICU. Phase I produced the first evidence of the clinical impact of phthalate exposure in the NICU population. Further study identified specific sources of exposure to clinically relevant phthalate mixtures in the NICU.

FUTURE PLANS

Follow-up from age 3 to 12 is co-ordinated through integration with the Environmental Influences on Child Health Outcomes (ECHO) programme. The NICU-HEALTH cohort will generate a wealth of biomarker, clinical and outcome data from which future studies of the impact of early-life chemical and non-chemical environmental exposures can benefit. Findings from study of this cohort and other collaborating environmental health cohorts will likely translate into improvements in the hospital environment for infant development.

TRIAL REGISTRATION NUMBERS

This observational cohort is registered with ClinicalTrials.gov (NCT01420029 and NCT01963065).

Timing of Early-Life Stress and the Development of Brain-Related Capacities

Early-life stress (ELS) poses risks for developmental and mental health problems throughout the lifespan. More research is needed regarding how specific ELS experiences influence specific aspects of neurodevelopment. We examined the association between ELS, defined as severe adversity (e.g., domestic violence, caregiver drug use) and severe relational poverty (e.g., caregiver neglect, lack of caregiver attunement), occurring during the first 2 months of life and a variety of brain-related, clinician-rated functions, including self-regulation and relational capacities. Interdisciplinary clinicians using the Neurosequential Model of Therapeutics (NMT), an approach to clinical problem solving, reported on the timing and type of treatment-seeking children’s (N = 2,155; 8–10 years) stressful experiences during four developmental periods: Perinatal (0–2 months), Infancy (2–12 months), Early Childhood (13 months to 4 years), and Childhood (4–11 years). They also reported on children’s current functioning in 32 brain-related domains (e.g., sleep, arousal, impulsivity, empathy, concrete cognition). Non-negative matrix factorization (NMF) was conducted on the 32 brain-related domains to identify latent factors, yielding four factors comprising Sensory Integration, Self-Regulation, Relational, and Cognitive functioning. Regularized hierarchical models were then used to identify associations between ELS and each latent factor while controlling for stress occurring during subsequent developmental periods, and children’s current degree of relational health. ELS (stress occurring during the first 2 months of life), specifically a severe lack of positive relational experiences (e.g., caregiver neglect, lack of caregiver attunement), was associated with the Sensory Integration and Self-Regulation factors. The Relational factor was better explained by stress occurring during childhood, and the Cognitive factor by stress occurring during infancy and childhood. Implications for how the timing and type of stress experiences may influence brain-related outcomes that are observed in clinical settings are discussed. Future directions include longitudinal follow-ups and greater specification of environmental variables, such as types of interventions received and when they were received, that may interact with ELS experiences to influence brain-related outcomes.

Characterizing adverse prenatal and postnatal experiences in children

BACKGROUND

Prenatal and postnatal adversities, including prenatal alcohol exposure (PAE), prenatal exposure to other substances, toxic stress, lack of adequate resources, and postnatal abuse or neglect, often co-occur. These exposures can have cumulative effects, or interact with each other, leading to worse outcomes than single exposures. However, given their complexity and heterogeneity, exposures can be difficult to characterize. Clinical services and research often overlook additional exposures and attribute outcomes solely to one factor.

METHODS

We propose a framework for characterizing adverse prenatal and postnatal exposures and apply it to a cohort of 77 children. Our approach considers type, timing, and frequency to quantify PAE, other prenatal substance exposure, prenatal toxic stress, postnatal threat (harm or threat of harm), and postnatal deprivation (failure to meet basic needs) using a 4-point Likert-type scale. Postnatal deprivation and harm were separated into early (<24 months of age) and late (≥24 months) time periods, giving seven exposure variables. Exposures were ascertained via health records, child welfare records, interviews with birth parents, caregivers, and/or close family/friends.

RESULTS

Nearly all children had co-occurring prenatal exposures, and two-thirds had both prenatal and postnatal adversities. Children with high PAE were more likely to experience late postnatal adversities, and children with other prenatal substance exposure were more likely to have early postnatal deprivation. Postnatal adversities were more likely to co-occur.

CONCLUSION

This framework provides a comprehensive picture of a child's adverse exposures, which can inform assessment and intervention approaches and policy and will be useful for future research.

Developmental origins of depression-related white matter properties: Findings from a prenatal birth cohort

Depression is the leading cause of years lost due to disability worldwide. Still, the mechanisms underlying its development are not well understood. This study aimed to evaluate white-matter properties associated with depressive symptomatology in young adulthood and their developmental origins. Diffusion tensor imaging and assessment of depressive symptomatology were conducted in 128 young adults (47% male, age 23-24) from a prenatal birth cohort (European Longitudinal Study of Pregnancy and Childhood). For a subset of these individuals, the database included information on prenatal stress (n = 93) and depressive symptoms during adolescence (assessed repeatedly at age 15 and 19). Depressive symptoms in young adulthood were associated with lower fractional anisotropy in the left and right cingulum and higher fractional anisotropy in the right corticospinal tract and superior longitudinal fasciculus. Further analyses revealed that prenatal stress and depressive symptomatology during adolescence were independent predictors of altered white-matter properties in the cingulum in young adulthood. We conclude that typically developing young adults with more depressive symptoms already exhibit tract-specific alterations in white-matter properties and that prenatal stress and depressive symptomatology during adolescence might contribute to their development.