Cognitive ability and decline after early life stress exposure

Impacts of age and environment on postnatal microglial activity: Consequences for cognitive function following early life adversity

Early life adversity (ELA) increases the likelihood of later-life neuropsychiatric disorders and cognitive dysfunction. Importantly, ELA, neuropsychiatric disorders, and cognitive deficits all involve aberrant immune signaling. Microglia are the primary neuroimmune cells and regulate brain development. Microglia are particularly sensitive to early life insults, which can program their responses to future challenges. ELA in the form of maternal separation (MS) in rats alters later-life microglial morphology and the inflammatory profile of the prefrontal cortex, a region important for cognition. However, the role of microglial responses during MS in the development of later cognition is not known. Therefore, here we aimed to determine whether the presence of microglia during MS mediates long-term impacts on adult working memory. Clodronate liposomes were used to transiently deplete microglia from the brain, while empty liposomes were used as a control. We hypothesized that if microglia mediate the long-term impacts of ELA on working memory in adulthood, then depleting microglia during MS would prevent these deficits. Importantly, microglial function shifts throughout the neonatal period, so an exploratory investigation assessed whether depletion during the early versus late neonatal period had different effects on adult working memory. Surprisingly, empty liposome treatment during the early, but not late, postnatal period induced microglial activity changes that compounded with MS to impair working memory in females. In contrast, microglial depletion later in infancy impaired later life working memory in females, suggesting that microglial function during late infancy plays an important role in the development of cognitive function. Together, these findings suggest that microglia shift their sensitivity to early life insults across development. Our findings also highlight the potential for MS to impact some developmental processes only when compounded with additional neuroimmune challenges in a sex-dependent manner.

Cognitive function following early life war-time stress exposure in a cohort of Vietnamese older adults

Although Alzheimer's Disease is a leading cause of death in Vietnam and other post-conflict, low- and middle-income countries, aside from studies of veterans in western populations, research on war-related violence and deprivation as risk factors for cognitive disorders remains sparse. Using data from the Vietnam Health and Aging Study, which relied upon a multistage probability sample of 2447 older adults residing in districts of northern Vietnam differentially exposed to wartime bombing and numerous war-related stressors, this paper investigates associations between early-life war-related stressors and later-life cognitive function in a cohort whose transition to adulthood took place during the American-Vietnam War. Relationships among experiences of severe childhood hunger, war-related violence and environmental hardships, military service, and cognitive function in an analytical sample of 2162 Vietnamese older adults are estimated using quantile regression. Cognitive function is assessed by a modified Mini-Mental State Examination (MMSE) score. Analyses also address posttraumatic stress disorder (PTSD), cardiovascular health, and health behaviors as potential mediators between early life war-related stressors and current cognitive function. Results indicate that experiences of severe hunger in childhood and environmental hardships are associated with poorer cognitive function in older adulthood. PTSD, cardiovascular risk (i.e., hypertension) and disease (i.e., stroke), each of which is heightened by exposure to wartime stressors, are associated with lower cognitive scores. Results suggest that certain war exposures, like involvement in combat duties, are associated with higher cognitive function scores, suggesting that military service either positively selects for cognitive function, or certain forms of service may impart cognitive resilience. Following recent calls to incorporate population-specific stressors to advance explanatory models of cognitive function, these findings suggest that it is critical to assess the enduring scars and resilience of armed conflict in global efforts to understand, prevent, and treat cognitive impairment, Alzheimer's Disease, and related dementias.

Early life stress modulates the genetic influence on brain structure and cognitive function in children

The enduring influence of early life stress (ELS) on brain and cognitive development has been widely acknowledged, yet the precise mechanisms underlying this association remain elusive. We hypothesize that ELS might disrupt the genome-wide influence on brain morphology and connectivity development, consequently exerting a detrimental impact on children's cognitive ability. We analyzed the multimodal data of DNA genotypes, brain imaging (structural and diffusion MRI), and neurocognitive battery (NIH Toolbox) of 4276 children (ages 9-10 years, European ancestry) from the Adolescent Brain Cognitive Development (ABCD) study. The genome-wide influence on cognitive function was estimated using the polygenic score (GPS). By using brain morphometry and tractography, we identified the brain correlates of the cognition GPSs. Statistical analyses revealed relationships for the gene-brain-cognition pathway. The brain structural variance significantly mediated the genetic influence on cognition (indirect effect = 0.016, PFDR < 0.001). Of note, this gene-brain relationship was significantly modulated by abuse, resulting in diminished cognitive capacity (Index of Moderated Mediation = -0.007; 95 % CI = -0.012 ∼ -0.002). Our results support a novel gene-brain-cognition model likely elucidating the long-lasting negative impact of ELS on children's cognitive development.

Membrane phospholipid peroxidation promotes loss of dopaminergic neurons in psychological stress-induced Parkinson's disease susceptibility

Parkinson's disease (PD) is a neurodegenerative disorder associated with α-synuclein aggregation and dopaminergic neuron loss in the midbrain. There is evidence that psychological stress promotes PD progression by enhancing glucocorticoids-related oxidative damage, however, the mechanisms involved are unknown. The present study demonstrated that plasma membrane phospholipid peroxides, as determined by phospholipidomics, triggered ferroptosis in dopaminergic neurons, which in turn contributed to stress exacerbated PD-like motor disorder in mice overexpressing mutant human α-synuclein. Using hormonomics, we identified that stress stimulated corticosteroid release and promoted 15-lipoxygenase-1 (ALOX15)-mediated phospholipid peroxidation. ALOX15 was upregulated by α-synuclein overexpression and acted as a fundamental risk factor in the development of chronic stress-induced parkinsonism and neurodegeneration. Further, we demonstrated the mechanism by which corticosteroids activated the PKC pathway and induced phosphatidylethanolamine-binding protein-1 (PEBP1) to form a complex with ALOX15, thereby facilitating ALOX15 to locate on the plasma membrane phospholipids. A natural product isolated from herbs, leonurine, was screened with activities of inhibiting the ALOX15/PEBP1 interaction and thereby attenuating membrane phospholipid peroxidation. Collectively, our findings demonstrate that stress increases the susceptibility of PD by driving membrane lipid peroxidation of dopaminergic neurons and suggest the ALOX15/PEBP1 complex as a potential intervention target.

Association of childhood trauma with cognitive domains in adult patients with mental disorders and in non-clinical populations: a systematic review

Although the association between cognitive performances and the onset of psychiatric disorders has been widely investigated, limited research on the role of childhood trauma or early life stress (CT/ELS), and whether this role differs between clinical and non-clinical cohorts is available. This systematic review aims at filling this gap, testing whether the occurrence of CT/ELS and its subtypes are associated with cognitive domains (general cognitive ability, executive functions, working memory, attention, processing speed, verbal/visual memory) in patients with psychiatric disorders and in non-clinical populations. This study followed the PRISMA 2020 guidelines and the Newcastle-Ottawa scale for quality assessment. The search was performed until May 2022. Seventy-four studies were classified as eligible. The graphical representations of the results reported an association between exposure to CT/ELS and worse general cognitive ability, verbal/visual memory, processing speed and attention in patients affected by anxiety, mood and psychotic disorders, and that specific CT/ELS subtypes (physical neglect, physical/sexual abuse) can differentially influence specific cognitive abilities (executive functions, attention, working memory, verbal/visual memory). In non-clinical cohorts we found associations between CT/ELS exposure and impairments in executive functions, processing speed and working memory, while physical neglect was related to general cognitive ability and working memory. Concerning the emotional abuse/neglect subtypes in both populations, the results indicated their involvement in cognitive functioning; however, the few studies conducted are not enough to reach definitive conclusions. These findings suggest an association of CT/ELS with specific cognitive deficits and psychopathology.

Machine learning techniques for identifying mental health risk factor associated with schoolchildren cognitive ability living in politically violent environments

Introduction

Mental health and cognitive development are critical aspects of a child's overall well-being; they can be particularly challenging for children living in politically violent environments. Children in conflict areas face a range of stressors, including exposure to violence, insecurity, and displacement, which can have a profound impact on their mental health and cognitive development.

Methods

This study examines the impact of living in politically violent environments on the mental health and cognitive development of children. The analysis was conducted using machine learning techniques on the 2014 health behavior school children dataset, consisting of 6373 schoolchildren aged 10-15 from public and United Nations Relief and Works Agency schools in Palestine. The dataset included 31 features related to socioeconomic characteristics, lifestyle, mental health, exposure to political violence, social support, and cognitive ability. The data was balanced and weighted by gender and age.

Results

This study examines the impact of living in politically violent environments on the mental health and cognitive development of children. The analysis was conducted using machine learning techniques on the 2014 health behavior school children dataset, consisting of 6373 schoolchildren aged 10-15 from public and United Nations Relief and Works Agency schools in Palestine. The dataset included 31 features related to socioeconomic characteristics, lifestyle, mental health, exposure to political violence, social support, and cognitive ability. The data was balanced and weighted by gender and age.

Discussion

The findings can inform evidence-based strategies for preventing and mitigating the detrimental effects of political violence on individuals and communities, highlighting the importance of addressing the needs of children in conflict-affected areas and the potential of using technology to improve their well-being.

Early life adversity as a risk factor for cognitive impairment and Alzheimer's disease

Neurological conditions, including cognitive impairment and Alzheimer's disease (AD), impose a huge burden on society, affecting millions of people globally. In addition to genetic factors, recent studies indicate that environmental and experiential factors may contribute to the pathogenesis of these diseases. Early life adversity (ELA) has a profound impact on brain function and health later in life. In rodent models, exposure to ELA results in specific cognitive deficits and aggravated AD pathology. Extensive concerns have been raised regarding the higher risk of developing cognitive impairments in people with a history of ELA. In this review, we scrutinize findings from human and animal studies focusing on the connection of ELA with cognitive impairment and AD. These discoveries suggest that ELA, especially at early postnatal stages, increases susceptibility to cognitive impairment and AD later in life. In terms of mechanisms, ELA could lead to dysregulation of the hypothalamus-pituitary-adrenal axis, altered gut microbiome, persistent inflammation, oligodendrocyte dysfunction, hypomyelination, and aberrant adult hippocampal neurogenesis. Crosstalks among these events may synergistically contribute to cognitive impairment later in life. Additionally, we discuss several interventions that may alleviate adverse consequences of ELA. Further investigation into this crucial area will help improve ELA management and reduce the burden of related neurological conditions.

Quantification of Epistemic Capacity and Physical Frailty in Chronic Kidney Disease: Koch's Disease Co-infection

Background Chronic kidney disease (CKD) and tuberculosis (TB) co-infection devastates the affected individual physically and psychologically. Moreover, poor immune status and mental turmoil worsen cognition and quality of life. Hence, studying the cognitive function and quality of life among such patients is necessary. This study aimed to determine the changes in mini-mental state examination (MMSE) score and general health questionnaire (GHQ-12) score at six months from baseline. Methodology This prospective, observational study was conducted at Sriram Chandra Bhanja Medical College and Hospital, India, from February 2020 to December 2021. A total of 40 patients with stage 3-4 CKD and pulmonary TB were assessed with MMSE and GHQ-12 scales at baseline, two, and six months. The study population was grouped as ≤50 and >50 years of age. We used R software (version 4.1.1) for data analysis. Results In total, 40 (69%) of the 58 enrolled participants completed this study. The mean age of the study population was 50.93 ± 9.83 years. The baseline MMSE scores (≤50 years: 20.8 ± 2.1, >50 years: 20.1 ± 1.7, p = 0.17) were increased (≤50 years: 25.4 ± 1.8, >50 years: 22.4 ± 1.6, p = 0.08) at six months. The baseline GHQ-12 scores (≤50 years: 22.8 ± 2.6, >50 years: 23.1 ± 2.8, p = 0.56) were reduced (≤50 years: 17.9 ± 1.9, >50 years: 20.3 ± 2.3, p = 0.14) at six months. Conclusions The study participants' cognitive function and quality of life improved after six months of modified antitubercular drugs. Nevertheless, the intergroup differences were not statistically significant.

Biochemical clusters predict mortality and reported inability to work 10 ​years later

BACKGROUND

Chronic systemic inflammation has been linked to premature mortality and limited somatic as well as mental health with consequences for capability to work and everyday functioning. We recently identified three biochemical clusters of endocrine and immune parameters (C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, cortisol and creatinine) in participants, age 35-81 years, of the open access Midlife in the United States Study (MIDUS) dataset. These clusters have been validated in an independent cohort of Japanese mid-life adults. Among these clusters, the one characterized by high inflammation coupled with low cortisol and creatinine concentrations was associated with the highest disease burden, referred to as high-risk cluster in the following. The current study aims to further examine the nature of this cluster and specifically whether it predicts mortality and the reported inability to work the last 30 days 10 years after the biomarker assessment.

METHODS AND FINDINGS

Longitudinally assessed health data from N ​= ​1234 individuals were analyzed in the current study. Logistic regression analyses were performed to predict mortality within one decade after first assessment (T0 ​= ​first assessment; T1 ​= ​second assessment). General linear models were used to predict the number of days study participants were unable to work due to health issues in the last 30 days (assessed at T1, analyses restricted to individuals <70 years of age). Biological sex, disease burden, and age at T0 were used as covariates in all analyses. Individuals in the previously identified high-risk cluster had a higher risk for mortality (22% of individuals deceased between T0 and T1 versus 10% respectively 9% in the two other clusters). Logistic regression models predicting mortality resulted in a significant difference between individuals from the high-risk cluster compared to those from an identified reference cluster (indicator method, p ​= ​.012), independently of age and disease burden. Furthermore, individuals in the high-risk cluster reported a higher number of disability days during the past 30 days (3.4 days in the high-risk cluster versus 1.5 respectively 1.0 days in the reference clusters) assessed at T1. All pairwise comparisons involving the high-risk cluster were significant (all ps ​< ​.001).

CONCLUSIONS

Immune-endocrine profiles are predictive of mortality within the following decade over and above age and disease burden. The findings thus highlight the importance of biomarker-based risk profiling that may provide new targets for interventions in the context of preventive medicine in the transition from health to disease and disease-related mortality.

Addressing the biological embedding of early life adversities (ELA) among adults through mindfulness: Proposed mechanisms and review of converging evidence

Early life adversities (ELA) are prevalent and have a profound and adverse impact across the lifespan, including on age-related health outcomes, yet interventions to remediate its adverse impact are scarce. This paper presents evidence for mindfulness training to reduce the elevated mental and physical health risks linked to ELA among adults by targeting biological mechanisms of ELA leading to these adverse health outcomes. We first provide a brief overview of ELA, its adverse health impacts, and mechanisms that might be responsible. Next, we review converging evidence that demonstrates that mindfulness training influences key biological pathways involved in ELA-linked negative health consequences, including (a) brain networks involved in self-regulation, (b) immunity and inflammation, (c) telomere biology, and (d) epigenetic modifications. Further, we review preliminary evidence from mindfulness-based trials that focused on populations impacted by ELA. We discuss limitations of this review and provide recommendations for future research. If effective, a mindfulness-based approach could be an important public health strategy for remediating the adverse mental and physical health consequences of ELA.

Acting Before; A Combined Strategy to Counteract the Onset and Progression of Dementia

Brain aging and aging-related neurodegenerative disorders are posing a significant challenge for health systems worldwide. To date, most of the therapeutic efforts aimed at counteracting dementiarelated behavioral and cognitive impairment have been focused on addressing putative determinants of the disease, such as β-amyloid or tau. In contrast, relatively little attention has been paid to pharmacological interventions aimed at restoring or promoting the synaptic plasticity of the aging brain. The review will explore and discuss the most recent molecular, structural/functional, and behavioral evidence that supports the use of non-pharmacological approaches as well as cognitive-enhancing drugs to counteract brain aging and early-stage dementia.

Stress effects on cognitive function in patients with major depressive disorder: Does childhood trauma play a role?

Impaired cognitive functioning constitutes an important symptom of major depressive disorder (MDD), potentially associated with elevated cortisol levels. Adverse childhood experiences (ACE) enhance the risk for MDD and can contribute to disturbances in the stress systems, including cortisol and cognitive functions. In healthy participants, cortisol administration as well as acute stress can affect cognitive performance. In the current study, we tested cognitive performance in MDD patients with (N = 32) and without (N = 52) ACE and healthy participants with (N = 22) and without (N = 37) ACE after psychosocial stress induction (Trier Social Stress Test, TSST) and a control condition (Placebo-TSST). MDD predicted lower performance in verbal learning and both selective and sustained attention, while ACE predicted lower performance in psychomotoric speed and working memory. There were no interaction effects of MDD and ACE. After stress, MDD patients were more likely to show lower performance in working memory as well as in selective and sustained attention compared with participants without MDD. Individuals with ACE were more likely to show lower performance in verbal memory after stress compared with individuals without ACE. Our results indicate negative effects of MDD and ACE on distinct cognitive domains. Furthermore, MDD and/or ACE seem to enhance susceptibility for stress-related cognitive impairments.

The critical role of the hippocampal NLRP3 inflammasome in social isolation-induced cognitive impairment in male mice

Early life stress exerts detrimental effects on cognitive function, but the mechanism by which this occurs is unknown. The NLRP3 inflammasome-mediated inflammatory response has emerged as a prominent contributor to cognitive impairment induced by chronic stress. In the present study, we showed that 8-week chronic social isolation (SI) led to cognitive impairment in mice, remarkably increasing expression of the hippocampal NLRP3 inflammasome. Furthermore, the 8-week SI procedure significantly increased the levels of hippocampal IL-1β and IL-18 without significant alteration of the level of serum IL-1β, suggesting a central mechanism for IL-1β-related CNS inflammation. Moreover, inflammatory microglial and expression of AMPAR were reduced in the hippocampus of SI mice. Minocycline is an antibiotic that limits microglia responses, and previous study also showed that minocycline could prevent stress-induced pro-inflammatory cytokine expression in the brain. Our experiment found that minocycline improved cognitive behavior in SI mice. Minocycline also prevented expression of the hippocampal NLRP3 inflammasome, indicating that microglia might be the primary contributor to SI-induced hippocampal NLRP3 inflammasome activation. Furthermore, alterations in SI mice were also restored by chronic treatment with the NLRP3 inhibitor MCC950. These results indicate that the microglia-derived NLRP3 inflammasome may be primarily involved in the inflammatory response to social isolation and that specific NLRP3 inflammasome inhibition using MCC950 may represent a promising therapeutic approach for early stress induced cognitive impairment.

Maternal sleep quality during pregnancy is associated with neonatal auditory ERPs

Poor maternal sleep quality during pregnancy may act as a prenatal stress factor for the fetus and associate with neonate neurocognition, for example via fetal programming. The impacts of worsened maternal sleep on neonatal development and, more specifically on neonatal auditory brain responses, have not been studied. A total of 155 mother-neonate dyads drawn from the FinnBrain Birth Cohort Study participated in our study including maternal self-report questionnaires on sleep at gestational week 24 and an event-related potential (ERP) measurement among 1-2-day-old neonates. For sleep quality assessment, the Basic Nordic Sleep Questionnaire (BNSQ) was used and calculated scores for (1) insomnia, (2) subjective sleep loss and (3) sleepiness were formed and applied in the analyses. In the auditory ERP protocol, three emotionally uttered pseudo words (in happy, angry and sad valence) were presented among neutrally uttered pseudo words. To study the relations between prenatal maternal sleep quality and auditory emotion-related ERP responses, mixed-effects regression models were computed for early (100–200 ms) and late (300–500 ms) ERP response time-windows. All of the selected BNSQ scores were associated with neonatal ERP responses for happy and angry emotion stimuli (sleep loss and sleepiness in the early, and insomnia, sleep loss and sleepiness in the late time-window). For sad stimuli, only maternal sleep loss predicted the neonatal ERP response in the late time-window, likely because the overall ERP was weakest in the sad condition. We conclude that maternal sleep quality during pregnancy is associated with changes in neonatal auditory ERP responses.

Characterization of astrocytes throughout life in wildtype and APP/PS1 mice after early-life stress exposure

Background

Early-life stress (ES) is an emerging risk factor for later life development of Alzheimer’s disease (AD). We have previously shown that ES modulates amyloid-beta pathology and the microglial response to it in the APPswe/PS1dE9 mouse model. Because astrocytes are key players in the pathogenesis of AD, we studied here if and how ES affects astrocytes in wildtype (WT) and APP/PS1 mice and how these relate to the previously reported amyloid pathology and microglial profile.

Methods

We induced ES by limiting nesting and bedding material from postnatal days (P) 2–9. We studied in WT mice (at P9, P30, and 6 months) and in APP/PS1 mice (at 4 and 10 months) (i) GFAP coverage, cell density, and complexity in hippocampus (HPC) and entorhinal cortex (EC); (ii) hippocampal gene expression of astrocyte markers; and (iii) the relationship between astrocyte, microglia, and amyloid markers.

Results

In WT mice, ES increased GFAP coverage in HPC subregions at P9 and decreased it at 10 months. APP/PS1 mice at 10 months exhibited both individual cell as well as clustered GFAP signals. APP/PS1 mice when compared to WT exhibited reduced total GFAP coverage in HPC, which is increased in the EC, while coverage of the clustered GFAP signal in the HPC was increased and accompanied by increased expression of several astrocytic genes. While measured astrocytic parameters in APP/PS1 mice appear not be further modulated by ES, analyzing these in the context of ES-induced alterations to amyloid pathology and microglial shows alterations at both 4 and 10 months of age.

Conclusions

Our data suggest that ES leads to alterations to the astrocytic response to amyloid-β pathology.

Annual Research Review: Rethinking childhood trauma-new research directions for measurement, study design and analytical strategies

Childhood trauma is a key modifiable risk factor for psychopathology. Despite significant scientific advances, traumatised children still have poorer long-term outcomes than nontraumatised children. New research paradigms are, thus, needed. To this end, the review examines three dominant assumptions about measurement, design and analytical strategies. Current research warns against using prospective and retrospective measures of childhood trauma interchangeably; against interpreting cross-sectional differences in putative mediating mechanisms between adults with or without a history of childhood trauma as evidence of longitudinal changes from pre-trauma conditions; and against directly applying explanatory models of resilience or vulnerability to psychopathology in traumatised children to forecast individual risk in unseen cases. The warnings equally apply to research on broader measures of adverse childhood experiences (ACEs). Further research examining these assumptions can generate new insights on how to prevent childhood trauma and its detrimental effects.

The Effects of Early Life Stress, Postnatal Diet Modulation, and Long-Term Western-Style Diet on Later-Life Metabolic and Cognitive Outcomes

Early life stress (ES) increases the risk to develop metabolic and brain disorders in adulthood. Breastfeeding (exclusivity and duration) is associated with improved metabolic and neurocognitive health outcomes, and the physical properties of the dietary lipids may contribute to this. Here, we tested whether early life exposure to dietary lipids mimicking some physical characteristics of breastmilk (i.e., large, phospholipid-coated lipid droplets; Concept Nuturis® infant milk formula (N-IMF)), could protect against ES-induced metabolic and brain abnormalities under standard circumstances, and in response to prolonged Western-style diet (WSD) in adulthood. ES was induced by exposing mice to limited nesting material from postnatal day (P) 2 to P9. From P16 to P42, male offspring were fed a standard IMF (S-IMF) or N-IMF, followed by either standard rodent diet (SD) or WSD until P230. We then assessed body composition development, fat mass, metabolic hormones, hippocampus-dependent cognitive function, and neurogenesis (proliferation and survival). Prolonged WSD resulted in an obesogenic phenotype at P230, which was not modulated by previous ES or N-IMF exposure. Nevertheless, ES and N-IMF modulated the effect of WSD on neurogenesis at P230, without affecting cognitive function, highlighting programming effects of the early life environment on the hippocampal response to later life challenges at a structural level.

Sex-dependent effects of paternal deprivation and chronic variable stress on novel object recognition in adult California mice (Peromyscus californicus)

Early-life stress exposure can confer vulnerability for development of psychiatric illnesses and impaired cognition in adulthood. It is well-known that early-life stress can dysregulate the hypothalamic-pituitary-adrenal (HPA) axis in a sex-dependent manner. Specifically, uniparental rodent models of prolonged disrupted mother-offspring relationships (e.g., maternal separation) have demonstrated greater alterations in stress responsivity in adult males, compared to females. Also, chronic early-life stressors (e.g., limited bedding model) impair cognitive function in males more than females. However, the sex-dependent effects of early-life stress and later-life chronic HPA axis activation on cognition have not been well-characterized. Here, we utilized the biparental California mouse (Peromyscus californicus) to model the early-life adversity of paternal deprivation (PD). Fathers either remained in the nest (biparental care) or were permanently removed (PD) on postnatal day (PND) 1. Adult offspring were exposed to daily handling (control) or chronic variable stress (CVS; three stressors for seven days). Twenty-four hours after the final stressor, the novel object recognition (NOR) task commenced, followed by serum collection for corticosterone (CORT) analysis. Independent of sex or rearing, CVS increased CORT. Exploration during acquisition for the NOR task was increased as a result of CVS and PD. During NOR testing, non-stressed females exhibited greater difference scores (i.e., increased recognition memory), compared to non-stressed males. However, the addition of CVS diminished difference scores in females - an effect not observed in CVS-exposed males. Overall, these data suggest that neonatal paternal experience, sex, and chronic stress contribute to exploratory behavior, cognition, and stress hormone concentrations in a biparental species.

The connection between microbiome and schizophrenia

There has been an accumulation of knowledge about the human microbiome, some detailed investigations of the gastrointestinal microbiota and its functions, and the highlighting of complex interactions between the gut, the gut microbiota, and the central nervous system. That assumes the involvement of the microbiome in the pathogenesis of various CNS diseases, including schizophrenia. Given this information and the fact, that the gut microbiota is sensitive to internal and environmental influences, we have speculated that among the factors that influence the formation and composition of gut microbiota during life, possible key elements in the schizophrenia development chain are hidden where gut microbiota is a linking component. This article aims to describe and understand the developmental relationships between intestinal microbiota and the risk of developing schizophrenia.

Measurement of heart rate variability and cognitive abilities based on attachment styles in children with chronic medical conditions

Recognizing the biopsychosocial dimensions of chronic medical conditions in children and preparing them to adapt to medical processes is one of the most significant issues in the field of health psychology. The aim of this study was to measure heart rate variability and cognitive abilities based on attachment style in children with chronic medical conditions. To this end, 45 children aged 12-15 years who had received a diagnosis of a chronic medical disease and were matched with the inclusion/exclusion criteria, were entered the study using available sampling method. These children were assigned to three groups of secure, avoidance and anxiety attachment style based on the Collins and Reid Attachment Scale. These groups had been demographically homogeneous. Then heart rate variability and cognitive abilities were measured. One-way ANOVA results showed a significant difference between the three groups in the heart rate variability and cognitive abilities. Post hoc test showed that children with secure attachment style had higher efficiency in heart rate variability and cognitive abilities. These results indicate that attachment style is one of the factors influencing the health status of children with chronic medical illness. These findings highlight the importance of paying attention to psychological factors, especially attachment and its role in the health status of children with chronic medical conditions.

Socioeconomic position in childhood and cognitive aging in Europe

OBJECTIVES

We aimed to investigate whether socioeconomic position (SEP) in childhood has an effect on the level of cognitive performance and the rate of cognitive decline in older adults.

METHODS

We performed a prospective cohort study of individuals enrolled in a multicenter population-based study, SHARE (Survey of Health, Ageing and Retirement in Europe). Interviews were conducted in 6 waves at approximately 2-year intervals and included examinations of cognitive performance (memory, verbal fluency, delayed recall) and measurements of childhood SEP (participants' household characteristics at the age of 10 years). We estimated the associations of SEP with the level of cognitive performance using linear regression and the relation to the rate of cognitive decline with mixed-effects models.

RESULTS

This study included 20,244 participants from 16 European countries (median age at baseline 71 years, 54% women). Adverse childhood SEP was associated with a lower level of baseline cognitive performance. This association was attenuated after adjustment for clinical and social risk factors but remained statistically significant. Childhood SEP was not related to the rate of cognitive decline.

CONCLUSIONS

Variation in childhood SEP helps to explain differences in cognitive performance between older people, but not the rate of decline from their previous level of cognition. Strategies to protect cognitive aging should be applied early in life.

Stress-related deficits of older adults' spatial working memory: an EEG investigation of occipital alpha and frontal-midline theta activities

Studies highlight cumulative life stress as a significant predictor of accelerated cognitive aging. This study paired electrophysiological with behavioral measures to explore how cumulative stress affects attentional and maintenance processes underpinning working memory retention. We collected electroencephalographic recordings from 60 individuals (30 older, 30 younger) reporting high or low levels of cumulative stress during the performance of a spatial Sternberg task. We measured mid-occipital alpha (8-12 Hz) and frontal-midline theta (4-6 Hz) as indicators of attentional and maintenance processes. Older, high-stress participants' behavioral performance lay significantly below than that of younger adults and low-stress older individuals. Impaired task performance coincided with reduced event-related synchronization in alpha and theta frequency ranges during memory maintenance. Electrophysiological findings suggest that older adults' reduced performance results from a stress-related impact on their ability to retain a stimulus in working memory and inhibit extraneous information from interfering with maintenance. Our results demonstrate the wide-ranging impact of cumulative stress on cognitive health and provide insight into the functional mechanisms disrupted by its influence.

Development and initial validation of the Retrospective Indigenous Childhood Enrichment scale (RICE)

ABSTRACTBackground:Years of education is the most commonly used proxy measure of cognitive reserve. Other forms of cognitive stimulation in childhood may provide similar protection against cognitive decline, particularly in Indigenous groups, where education may have been lacking in quality or quantity. The Retrospective Indigenous Childhood Enrichment (RICE) scale was developed to measure non-school-based activities and environmental stimulation during childhood that are likely to have enhanced cognitive reserve. The aim of the study was to assess the validity and reliability of the RICE scale with a group of older Aboriginal Australians.

METHODS

294 Aboriginal Australian people (60-92 years), living in urban or regional areas of NSW, completed the RICE scale as part of a longer face-to-face interview. Additional data was collected on their formal education, childhood environment, and childhood trauma (Study 1). Test-retest, inter-method and inter-rater reliability were assessed in a convenience sample of a further 38 participants by re-administration of the RICE scale at two time points, approximately 14 days apart (M = 14.11, SD = 6.78) (Study 2).

RESULTS

Factor analyses reduced the scale from 21 items to 18 and identified three factors: (1) Traditional, (2) Intellectual, and (3) Community. Higher scores on the RICE scale were related to higher years of formal education and lower scores on a childhood trauma questionnaire. The RICE scale had good internal consistency (Cronbach's α 0.79), and excellent test-retest reliability (ICC = 0.95, 95% CI 0.90-0.97) and inter-rater reliability (0.99, CI 95% 0.997-0.999).

CONCLUSIONS

The RICE is, to our knowledge, the first standardized measure that assesses the level of childhood environmental stimulation in older Aboriginal Australians. This could provide an important supplementary measure, in addition to formal education, to investigate cognitive reserve and dementia risk in this population and enhance understanding of the links between childhood experiences and late-life cognitive decline.

Association between breastfeeding and better preserved cognitive ability in an elderly cohort of Finnish men

BACKGROUND

Being breastfed in infancy has been shown to benefit neurodevelopment. However, whether the benefits persist to old age remains unclear.

METHODS

We examined the associations between breastfeeding and its duration on cognitive ability in young adulthood and old age, and on aging-related cognitive change over five decades. In total, 931 men from the Helsinki Birth Cohort Study born in 1934-1944 in Finland took the Finnish Defence Forces Basic Intellectual Ability Test (total and verbal, arithmetic and visuospatial subtest scores) twice, at ages 20.2 and 67.9 years, and had data on breastfeeding (yes v. no) and its duration ('never breastfed', 'up to 3', '3 to 6' and '6 or more months'). Linear and mixed model regressions tested the associations.

RESULTS

At 20.2 years, breastfed men had higher cognitive ability total and visuospatial subtest scores [mean differences (MDs) ranged between 3.0-3.9, p values < 0.013], and its longer duration predicted higher cognitive ability total and arithmetic and visuospatial subtest scores (MDs ranged between 3.0 and 4.8, p values < 0.039). At 67.9 years, breastfed men had higher total cognitive ability and all subtest scores (MDs ranged between 2.6 and 3.4, p values < 0.044) and its longer duration predicted all cognitive ability scores (MDs ranged between 3.1 and 4.7, p values < 0.050). Verbal subtest scores decreased over five decades in men who were never breastfed or were breastfed for 3 months or less, and increased in those breastfed for longer than 3 months.

CONCLUSIONS

Neurodevelopmental advantages of breastfeeding and its longer duration persist into old age, and longer duration of breastfeeding may benefit aging-related change, particularly in verbal reasoning ability.

The impact of early-life stress on the expression of HPA-associated genes in the adult murine brain

Early life is an important period for the development of the nervous system and for the programming of behavioural phenotypes in adulthood. In our study, two types of early-life stress were used: prolonged separation of pups from their mothers (for 3 h/day, maternal separation (MS)) and brief separation (for 15 min/day, handling (HD)). We analysed the effects of early-life stress on behaviour and the expression of HPA-associated genes in the hypothalamus, hippocampus, and frontal cortex of male mice. Adult mice in the MS group demonstrated reduced locomotor activity and deficiencies in spatial long-term memory, while the HD showed no significant changes. Additionally, early-life MS resulted in reduced hippocampal Crhr1 mRNA, increased MR/GR mRNA in the hippocampus and hypothalamus. Both groups, HD and MS, showed increased Avp mRNA in the hypothalamus. Thus, prolonged maternal separation but not brief leads to adverse behavioural changes and influences the expression of HPA-associated genes in a brain region-specific manner.

Examining the influence of perceived stress on developmental change in memory and perceptual speed for adopted and nonadopted individuals

The present study prospectively evaluated cumulative early life perceived stress in relation to differential change in memory and perceptual speed from middle childhood to early adulthood. We aimed to identify periods of cognitive development susceptible to the effects of perceived stress among both adopted and nonadopted individuals. The sample consisted of participants in the Colorado Adoption Project (CAP, N = 690). Structured latent growth curves were fit to 4 memory outcomes as well as 1 perceptual speed outcome, which described nonlinear change between ages 9 and 30. Both adoption status and cumulative perceived stress indices served as predictors of the latent curves. The perceived stress indices were constructed from the Brooks-Gunn Life Events Scale for Adolescents, and reflected "upsettingness" ratings associated with the occurrence of particular life events during middle childhood (ages 9 to 12) and adolescence (ages 13 to 16). For memory and perceptual speed, cumulative perceived stress did not predict differential cognitive gains. However, differences in perceptual speed trajectories between nonadopted and adopted individuals were observed, with adopted individuals showing smaller gains. Although these findings provide no evidence that emergent variability in memory and perceptual speed trajectories by age 30 are explained by cumulative perceptions of stress in childhood and adolescence, further investigations regarding potential vulnerability across the life span are warranted. (PsycINFO Database Record

The association between high levels of cumulative life stress and aberrant resting state EEG dynamics in old age

Cumulative experienced stress produces shortcomings in old adults' cognitive performance. These are reflected in electrophysiological changes tied to task execution. This study explored whether stress-related aberrations in older adults' electroencephalographic (EEG) activity were also apparent in the system at rest. To this effect, the amount of stressful life events experienced by 60 young and 60 elderly participants were assessed in conjunction with resting state power changes in the delta, theta, alpha, and beta frequencies during a resting EEG recording. Findings revealed elevated levels of delta power among elderly individuals reporting high levels of cumulative life stress. These differed significantly from young high and low stress individuals and old adults with low levels of stress. Increases of delta activity have been linked to the emergence of conditions such as Alzheimer's Disease and Mild Cognitive Impairment. Thus, a potential interpretation of our findings associates large amounts of cumulative stress with an increased risk of developing age-related cognitive pathologies in later life.

The Origins of Cognitive Deficits in Victimized Children: Implications for Neuroscientists and Clinicians

OBJECTIVE

Individuals reporting a history of childhood violence victimization have impaired brain function. However, the clinical significance, reproducibility, and causality of these findings are disputed. The authors used data from two large cohort studies to address these research questions directly.

METHOD

The authors tested the association between prospectively collected measures of childhood violence victimization and cognitive functions in childhood, adolescence, and adulthood among 2,232 members of the U.K. E-Risk Study and 1,037 members of the New Zealand Dunedin Study who were followed up from birth until ages 18 and 38 years, respectively. Multiple measures of victimization and cognition were used, and comparisons were made of cognitive scores for twins discordant for victimization.

RESULTS

Individuals exposed to childhood victimization had pervasive impairments in clinically relevant cognitive functions, including general intelligence, executive function, processing speed, memory, perceptual reasoning, and verbal comprehension in adolescence and adulthood. However, the observed cognitive deficits in victimized individuals were largely explained by cognitive deficits that predated childhood victimization and by confounding genetic and environmental risks.

CONCLUSIONS

Findings from two population-representative birth cohorts totaling more than 3,000 individuals and born 20 years and 20,000 km apart suggest that the association between childhood violence victimization and later cognition is largely noncausal, in contrast to conventional interpretations. These findings support the adoption of a more circumspect approach to causal inference in the neuroscience of stress. Clinically, cognitive deficits should be conceptualized as individual risk factors for victimization as well as potential complicating features during treatment.

Adverse early life environment increases hippocampal microglia abundance in conjunction with decreased neural stem cells in juvenile mice

BACKGROUND

Adverse maternal lifestyle resulting in adverse early life environment (AELE) increases risks for neuropsychiatric disorders in offspring. Neuropsychiatric disorders are associated with impaired neurogenesis and neuro-inflammation in the hippocampus (HP). Microglia are neuro-inflammatory cells in the brain that regulate neurogenesis via toll-like receptors (TLR). TLR-9 is implicated in neurogenesis inhibition and is responsible for stress-related inflammatory responses. We hypothesized that AELE would increase microglia cell count and increase TLR-9 expression in juvenile mouse HP. These increases in microglia cell count and TLR-9 expression would be associated with decrease neural stem cell count and neuronal cell count.

METHODS

We developed a mouse model of AELE combining Western diet and a stress environment. Stress environment consisted of random change from embryonic day 13 (E13) to E17 as well as static change in maternal environment from E13 to postnatal day 21(P21). At P21, we measured hippocampal cell numbers of microglia, neural stem cell and neuron, as well as hippocampal TLR-9 expression.

RESULTS

AELE significantly increased total microglia number and TLR-9 expression in the hippocampus. Concurrently, AELE significantly decreased neural stem cell and neuronal numbers.

CONCLUSIONS

AELE increased the neuro-inflammatory cellular response in the juvenile HP. We speculate that increased neuro-inflammatory responses may contribute to impaired neurogenesis seen in this model.

Cognitive impairment effects of early life stress in adolescents can be predicted with early biomarkers: Impacts of sex, experience, and cytokines

Childhood adversity increases vulnerability to psychiatric disorders that emerge in adolescence, in a sex-dependent manner. Early adversity modeled in rodents with maternal separation (MS) affects cognition and medial prefrontal cortex (mPFC) circuitry. Humans and animals exposed to early life adversity also display heightened circulating inflammatory cytokines, however the predictive relationship of these early measures with later behavioral deficits is unknown. Here, male and female rats were exposed to MS or control rearing during the postnatal period (P2-21). Blood samples were taken at distinct developmental time points for analysis of the pro-inflammatory cytokine IL-1β and the anti-inflammatory cytokines IL-4, and IL-10, followed by win-shift cognitive testing and analysis of mPFC parvalbumin (PVB) immunofluorescent interneurons in adolescence. Regression analyses were conducted to explore the relationship between early cytokines and adolescent behavioral measures. We observed sex- and age-dependent effects of MS on circulating cytokines. MS also yielded adolescent decreases in mPFC PVB and cognitive deficits, which were predicted by early cytokine expression in a sex- and experience-dependent manner. Taken together, the present data reveals that circulating cytokines and PVB levels are predictive of adolescent cognitive deficits, and therefore provide compelling evidence for a putative role of early biomarkers in mediating MS-induced behavioral dysfunction. Importantly, predictive relationships often depended on sex and on MS history, suggesting that early life experiences may yield individualistic mechanisms of vulnerability compared to the general population.

Experienced stress produces inhibitory deficits in old adults' Flanker task performance: First evidence for lifetime stress effects beyond memory

Studies regarding aged individuals' performance on the Flanker task differ with respect to reporting impaired or intact executive control. Past work has explained this discrepancy by hypothesising that elderly individuals use increased top-down control mechanisms advantageous to Flanker performance. This study investigated this mechanism, focussing on cumulative experienced stress as a factor that may impact on its execution, thereby leading to impaired performance. Thirty elderly and thirty young participants completed a version of the Flanker task paired with electroencephalographic recordings of the alpha frequency, whose increased synchronisation indexes inhibitory processes. Among high stress elderly individuals, findings revealed a general slowing of reaction times for congruent and incongruent stimuli, which correlated with alpha desynchronisation for both stimulus categories. Results found high performing (low stress) elderly revealed neither a behavioural nor electrophysiological difference compared to young participants. Therefore, rather than impacting on top-down compensatory mechanisms, findings indicate that stress may affect elderly participants' inhibitory control in attentional and sensorimotor domains.

Reproducibility and Temporal Structure in Weekly Resting-State fMRI over a Period of 3.5 Years

Resting-state functional MRI (rs-fMRI) permits study of the brain’s functional networks without requiring participants to perform tasks. Robust changes in such resting state networks (RSNs) have been observed in neurologic disorders, and rs-fMRI outcome measures are candidate biomarkers for monitoring clinical trials, including trials of extended therapeutic interventions for rehabilitation of patients with chronic conditions. In this study, we aim to present a unique longitudinal dataset reporting on a healthy adult subject scanned weekly over 3.5 years and identify rs-fMRI outcome measures appropriate for clinical trials. Accordingly, we assessed the reproducibility, and characterized the temporal structure of, rs-fMRI outcome measures derived using independent component analysis (ICA). Data was compared to a 21-person dataset acquired on the same scanner in order to confirm that the values of the single-subject RSN measures were within the expected range as assessed from the multi-participant dataset. Fourteen RSNs were identified, and the inter-session reproducibility of outcome measures—network spatial map, temporal signal fluctuation magnitude, and between-network connectivity (BNC)–was high, with executive RSNs showing the highest reproducibility. Analysis of the weekly outcome measures also showed that many rs-fMRI outcome measures had a significant linear trend, annual periodicity, and persistence. Such temporal structure was most prominent in spatial map similarity, and least prominent in BNC. High reproducibility supports the candidacy of rs-fMRI outcome measures as biomarkers, but the presence of significant temporal structure needs to be taken into account when such outcome measures are considered as biomarkers for rehabilitation-style therapeutic interventions in chronic conditions.

The impact of experienced stress on aged spatial discrimination: Cortical overreliance as a result of hippocampal impairment

A large body of neuroscientific work indicates that exposure to experienced stress causes damage to both cortical and hippocampal cells and results in impairments to cognitive abilities associated with these structures. Similarly, work within the domain of cognitive aging demonstrates that elderly participants who report experiencing greater amounts of stress show reduced levels of cognitive functioning. The present article attempted to combine both findings by collecting data from elderly and young participants who completed a spatial discrimination paradigm developed by Reagh and colleagues [Reagh et al. (2013) Hippocampus 24:303-314] to measure hippocampal-mediated cognitive processes. In order to investigate the effect of stress on the cortex and, indirectly, the hippocampus, it paired the paradigm with electroencephalographic recordings of the theta frequency band, which is thought to reflect cortical/hippocampal interactions. Findings revealed that elderly participants with high levels of experienced stress performed significantly worse on target recognition and lure discrimination and demonstrated heightened levels of cortical theta synchronization compared with young and elderly low stress counterparts. Results therefore provided further evidence for the adverse effect of stress on cognitive aging and indicate that impaired behavioral performance among high stress elderly may coincide with an overreliance on cortical cognitive processing strategies as a result of early damage to the hippocampus.

Alteration of somatosensory response in adulthood by early life stress

Early life stress is well-known as a critical risk factor for mental and cognitive disorders in adulthood. Such disorders are accompanied by altered neuro- (synapto-) genesis and gene expression. Because psychosomatic disorders induced by early life stress (e.g., physical and/or sexual abuse, and neglect) have become a socio-economic problem, it is very important to clarify the mechanisms underlying these changes. However, despite of intensive clinical and animal studies, such mechanisms have not yet been clarified. Although the disturbance of glucocorticoid and glutamate homeostasis by stress has been well-documented, it has not yet been clarified whether such disturbance by early life stress persists for life. Furthermore, since previous studies have focused on the detection of changes in specific brain regions, such as the hippocampus and prefrontal cortex, it has not been clarified whether early life stress induced changes in the sensory/motor system. Thus, in this review, we introduce recent studies on functional/structural changes in the somatosensory cortex induced by early life stress. We believe that this review provides new insights into the functional alteration of the somatosensory system induced by early life stress. Such information may have clinical relevance in terms of providing effective therapeutic interventions to early life stressed individuals.

Epigenomic profiling of men exposed to early-life stress reveals DNA methylation differences in association with current mental state

Early-life stress (ELS) is known to be associated with an increased risk of neuropsychiatric and cardiometabolic disease in later life. One of the potential mechanisms underpinning this is through effects on the epigenome, particularly changes in DNA methylation. Using a well-phenotyped cohort of 83 men from the Helsinki Birth Cohort Study, who experienced ELS in the form of separation from their parents during childhood, and a group of 83 matched controls, we performed a genome-wide analysis of DNA methylation in peripheral blood. We found no differences in DNA methylation between men who were separated from their families and non-separated men; however, we did identify differences in DNA methylation in association with the development of at least mild depressive symptoms over the subsequent 5-10 years. Notably, hypomethylation was identified at a number of genes with roles in brain development and/or function in association with depressive symptoms. Pathway analysis revealed an enrichment of DNA methylation changes in pathways associated with development and morphogenesis, DNA and transcription factor binding and programmed cell death. Our results support the concept that DNA methylation differences may be important in the pathogenesis of psychiatric disease.