The brain on stress: vulnerability and plasticity of the prefrontal cortex over the life course

Quantification of Glutathione and Its Associated Spontaneous Neuronal Activity in Major Depressive Disorder and Obsessive-Compulsive Disorder

BACKGROUND

Glutathione (GSH) is a crucial antioxidant in the human brain. Although proton magnetic resonance spectroscopy using the Mescher-Garwood point-resolved spectroscopy sequence is highly recommended, limited literature has measured cortical GSH using this method in major psychiatric disorders.

METHODS

By combining magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging, we quantified brain GSH and glutamate in the medial prefrontal cortex and precuneus and explored relationships between GSH levels and intrinsic neuronal activity as well as clinical symptoms among healthy control (HC) participants (n = 30), people with major depressive disorder (MDD) (n = 28), and people with obsessive-compulsive disorder (OCD) (n = 28).

RESULTS

GSH concentrations were lower in the medial prefrontal cortex and precuneus in both the MDD and OCD groups than in the HC group. In the HC group, positive correlations were noted between GSH and glutamate levels and between GSH and fractional amplitude of low-frequency fluctuations in both regions. However, while these correlations were absent in both patient groups, there was a weak positive correlation between glutamate and fractional amplitude of low-frequency fluctuations. Moreover, GSH levels were negatively correlated with depressive and compulsive symptoms in MDD and OCD, respectively.

CONCLUSIONS

These findings suggest that reduced GSH levels and an imbalance between GSH and glutamate could increase oxidative stress and alter neurotransmitter signaling, thereby leading to disruptions in GSH-related neurochemical-neuronal coupling and psychopathologies across MDD and OCD. Understanding these mechanisms could provide valuable insights into the processes that underlie these disorders and potentially become a springboard for future directions and advancing our knowledge of their neurobiological foundations.

Association between sleep disorder and anhedonia in adolescence with major depressive disorder: the mediating effect of stress

BACKGROUND

Major depressive disorder (MDD) is a highly prevalent mental disorder with devastating consequences that often first manifest during adolescence. Anhedonia has emerged as one of the most promising symptoms of adolescent MDD, which means a longer time to remission， fewer depression-free days, and also increased risk of suicide ideas or actions. Research has shown that at least two-thirds of depressed adolescents have significant sleep-onset or sleep-maintenance problems. However, the association between sleep disorder and anhedonia, and the potential mediators are less understood.

METHODS

This is a cross-sectional study that includes 200 adolescents suffered from MDD between the ages of 12-17. We use Spearman's test to explore the relationship among main variables. To evaluate the mediating effects of stress, we applied regression models and used bootstrap method to validate the significance of effects.

RESULTS

Significant correlation exists among sleep disorder, stress, and anhedonia (P<0.05).The direct effect of sleep disorder on anhedonia was 0.214 (95% CI: 1.5235, 6.2073), while the total effect was 0.295 (95% CI: 2.9683, 7.6924). The indirect effect of sleep disorder on anhedonia mediated by stress was 0.081 (95% CI: 0.5842, 2.5268). Robustness of the regression analysis results has been verified by bootstrap test.

CONCLUSIONS

Our finding suggested a positive correlation between sleep disturbance and anhedonia in adMDD. Stress partially mediated the relationship between sleep disorder and anhedonia. Due to the deleterious effects of anhedonia on depressed adolescents, these findings provide impetus to investigate further the causal relationship between sleep problems and anhedonia.

TRIAL REGISTRATION

ChiCTR2200060176(Registration Date: 21/05/2022).

COVID-19 pandemic and its impact on medical interns' mental health of public and private hospitals in Guadalajara

INTRODUCTION

Burnout syndrome is a global burden characterized by exhaustion, work detachment, and a sense of ineffectiveness. It affects millions of individuals worldwide, with a particularly high prevalence among medical students. Factors such as demanding education, exposure to suffering, and the COVID-19 pandemic have contributed to elevated stress levels. Addressing this issue is crucial due to its impact on well-being and health-care quality.

MATERIALS AND METHODS

This cross-sectional survey study assessed fear of COVID-19 and burnout levels among medical student interns in hospitals in Guadalajara, Jalisco. The study used validated scales and collected data from September 2021 to September 2022. A snowball sampling method was employed and a minimum sample size of 198 participants was calculated.

RESULTS

This study included 311 medical students (62.1% female and 37.9% male with a mean age of 23.51 ± 2.21 years). The majority were in their second semester of internship (60.5%) and from public hospitals (89.1%). Most students believed that the COVID-19 pandemic affected the quality of their internship (82.6%). Female students had higher personal burnout scores, while male students had higher work-related burnout scores. The mean score for fear of COVID-19 was 13.71 ± 6.28, with higher scores among women (p = 0.004) and those from public hospitals (p = 0.009). A positive weak correlation was found between COVID-19 scores and burnout subscales.

CONCLUSION

Our study emphasizes the significant impact of various factors on burnout levels among medical students and health-care professionals during the COVID-19 pandemic. Prolonged exposure to COVID-19 patients, reduced staffing, and increased workload contributed to burnout, affecting well-being and quality of care. Targeted interventions and resilience-building strategies are needed to mitigate burnout and promote well-being in health-care settings.

Systemic Administration of a Site-Targeted Complement Inhibitor Attenuates Chronic Stress-Induced Social Behavior Deficits and Neuroinflammation in Mice

Chronic stress, a risk factor for many neuropsychiatric conditions, causes dysregulation in the immune system in both humans and animal models. Additionally, inflammation and synapse loss have been associated with deficits in social behavior. The complement system, a key player of innate immunity, has been linked to social behavior impairments caused by chronic stress. However, it is not known whether complement inhibition can help prevent neuroinflammation and behavioral deficits caused by chronic stress. In this study, we investigated the potential of a site-targeted complement inhibitor to ameliorate chronic stress-induced changes in social behavior and inflammatory markers in the prefrontal cortex (PFC) and hippocampus. Specifically, we investigated the use of C2-Crry, which comprises a natural antibody-derived single-chain antibody (ScFv) targeting domain-designated C2, linked to Crry, a C3 activation inhibitor. The C2 targeting domain recognizes danger-associated molecular patterns consisting of a subset of phospholipids that become exposed following cell stress or injury. We found that systemic administration of C2-Crry attenuated chronic stress-induced social behavioral impairments in mice. Furthermore, C2-Crry administration significantly decreased microglia/macrophage and astrocyte activation markers in the PFC and hippocampus. These findings suggest that site-targeted complement inhibition could offer a promising, safe, and effective strategy for treating chronic stress induced behavioral and immune function disorders.

Neuroprotective Role of Selenium Nanoparticles Against Behavioral, Neurobiochemical and Histological Alterations in Rats Subjected to Chronic Restraint Stress

Chronic stress induces changes in the prefrontal cortex and hippocampus. Selenium nanoparticles (SeNPs) showed promising results in several neurological animal models. The implementation of SeNPs in chronic restraint stress (CRS) remains to be elucidated. This study was done to determine the possible protective effects of selenium nanoparticles on behavioral changes and brain oxidative stress markers in a rat model of CRS. 50 rats were divided into three groups; control group (n = 10), untreated CRS group (n = 10) and CRS-SeNPs treated group (n = 30). Restraint stress was performed 6 h./day for 21 days. Rats of CRS-SeNPs treated group received 1, 2.5 or 5 mg/kg SeNPs (10 rats each) by oral gavage for 21 days. Rats were subjected to behavioral assessments and then sacrificed for biochemical and histological analysis of the prefrontal cortex and hippocampus. Prefrontal cortical and hippocampal serotonin levels, oxidative stress markers including malondialdehyde (MDA), reduced glutathione (GSH) and glutathione peroxidase (GPx), tumor necrosis factor alpha (TNF-α) and caspase-3 were assessed. Accordingly, different doses of SeNPs showed variable effectiveness in ameliorating disease parameters, with 2.5 mg/kg dose of SeNPs showing the best improving results in all studied parameters. The present study exhibited the neuroprotective role of SeNPs in rats subjected to CRS and proposed their antioxidant, anti-inflammatory and anti-apoptotic effects as the possible mechanism for increased prefrontal cortical and hippocampal serotonin level, ameliorated anxiety-like and depressive-like behaviors and improved prefrontal cortical and hippocampal histological architecture.

Embracing complexity in psychiatry-from reductionistic to systems approaches

The understanding and treatment of psychiatric disorders present unique challenges due to these conditions' multifaceted nature, comprising dynamic interactions between biological, psychological, social, and environmental factors. Traditional reductionistic approaches often simplify these conditions into linear cause-and-effect relationships, overlooking the complexity and interconnectedness inherent in psychiatric disorders. Advances in complex systems approaches provide a comprehensive framework to capture and quantify the non-linear and emergent properties of psychiatric disorders. This Personal View emphasises the importance of identifying rules for generative models that govern brain and behaviour over time, which might contribute to personalised assessments and interventions for psychiatric disorders. For instance, mood fluctuations in bipolar disorder can be understood through dynamical systems modelling, which identifies modifiable parameters, such as circadian disruption, that can be addressed through targeted therapies such as light therapy. Similarly, recognition of depression as an emergent property arising from complex interactions highlights the need for integrated treatment strategies that enhance adaptive reactions in the individual. A framework for quantifying multilevel interactions and network dynamics can help researchers and clinicians to understand the interplay between neural circuits, behaviours, and social contexts. Probabilistic models and self-organisation concepts contribute to building concrete dynamical systems models of mental disorders, facilitating early identification of risk states and promoting resilience through adaptive interventions delivered with optimal timing. Embracing these complex systems approaches in psychiatry could capture the true nature of psychiatric disorders as properties of a dynamic complex system and not the manifestation of any lesion or insult. This line of thinking might improve diagnosis and treatment, offering new hope for individuals affected by psychiatric conditions and paving the way for more effective, personalised mental health care.

Near or mid-infra-red spectroscopy of the prefrontal cortex to identify previous stressful experience in an animal

Measuring the quality of life of an animal in a production system is difficult, time-consuming, and expensive. We tested the ability of both NIR and MIR spectroscopy, each combined with machine learning, to predict the prior exposure of pigs to long- and short-term life challenges when they are raised in an intensive system. Samples were obtained post-mortem from two locations in the prefrontal cortex. The analysis showed a clear separation between the gray and white matter from the prefrontal cortex with MIR spectroscopy. Exposure to long-term challenge was poorly predicted by the MIR or NIR spectra (< 45% correct classifications). By contrast, the correct classification of samples according to the exposure to a short-tern challenge before death was higher than 65%. These rates of classification, considering the complexity of the stimulus and the small sample size, support that vibrational spectroscopy could be used to assess the exposure to challenging events of an animal on post-mortem brain tissue.

The Impact of Adverse Childhood Experiences on Cognitive Control Across the Lifespan: A Systematic Review and Meta-analysis of Prospective Studies

Adverse childhood experiences (ACEs) are strongly associated with impaired cognitive control, yet research on ACEs' effects across cognitive control domains-working memory, cognitive flexibility, and inhibitory control-remains sparse. This systematic review and meta-analysis evaluated the overall impact of ACEs on each of these cognitive control domains and explored moderating factors such as age, gender, cognitive control paradigms, and ACEs subtypes based on the dimensional model of adversity and psychopathology. A database search was conducted in SCOPUS, MedLine, PsycINFO, and Web of Science. Only prospective studies were included to ensure temporal order inferences, with at least two data collection points, assessing ACEs at baseline (T1) and cognitive control during follow-up (T2). Thirty-two studies (N = 26,863) producing 124 effect sizes were analyzed. Three-level meta-analyses revealed small-to-medium negative associations between ACEs and overall cognitive control (g = -0.32), and in each domain: working memory (g = -0.28), cognitive flexibility (g = -0.28), and inhibitory control (g = -0.32). The negative associations between ACEs and cognitive control were consistent across age, gender, and cognitive control paradigms. ACEs subtypes moderated the association with cognitive flexibility (p = .04) but not working memory or inhibitory control. Specifically, the deprivation subtype exhibited a stronger negative association with cognitive flexibility compared to threat and threat-and-deprivation subtypes. These findings highlight the pervasive negative impact of ACEs on cognitive control across ages and emphasize the need for targeted interventions. Implications, current gaps, limitations in research, and future study recommendations are discussed.

Elder mistreatment and cognitive functioning among Chinese older adults in the U.S

Elder mistreatment disproportionately affects racial and ethnic minority older adults, particularly Chinese older adults in the U.S. who face increased risks due to cultural disparities, intergenerational conflicts, and socioeconomic disparities. This study investigated the longitudinal association of elder mistreatment with cognitive functioning among Chinese older adults in the Greater Chicago area (N = 2,811). Self-reported elder mistreatment and cognitive performance were assessed across four waves of the study. Latent growth curve modeling analysis showed that respondents reporting previous mistreatment instances at baseline exhibited better initial functioning status (B = 0.07, p < .05); however, those reporting mistreatment incidents at three follow-ups showed a faster cognitive decline compared to those without such reports (B = -0.04, p < .05). Recent and potentially cumulative experiences of elder mistreatment have a negative effect on cognitive decline. Sociocultural contexts need to be considered when addressing elder mistreatment issues within the Chinese minority community.

Evaluating the Effects of Different Cognitive Tasks on Autonomic Nervous System Responses: Implementation of a High-Precision, Low-Cost Complementary Method

INTRODUCTION

We developed a low-cost, user-friendly complementary research tool to evaluate autonomic nervous system (ANS) activity at varying levels of cognitive workload. This was achieved using visual stimuli as cognitive tasks, administered through a specially designed computer-based test battery.

METHODS

To assess sympathetic stress responses, skin conductance response (SCR) was measured, and electrocardiograms (ECG) were recorded to evaluate heart rate variability (HRV), an indicator of cardiac vagal tone. Twenty-five healthy adults participated in the study. SCR and ECG recordings were made during both tonic and phasic phases using a computer-based system designed for visual stimuli. Participants performed a button-pressing task upon seeing the target stimulus, and the relationship between reaction time (RT) and cognitive load was evaluated.

RESULTS

Analysis of the data showed higher skin conductance levels (SCLs) during tasks compared to baseline, indicating successful elicitation of sympathetic responses. RTs differed significantly between simple and cognitive tasks, increasing with mental load. Additionally, significant changes in vagally mediated HRV parameters during tasks compared to baseline highlighted the impact of cognitive load on the parasympathetic branch of the ANS, thereby influencing the brain-heart connection.

CONCLUSION

Our findings indicate that the developed research tool can successfully induce cognitive load, significantly affecting SCL, RTs, and HRV. This validates the tool's effectiveness in evaluating ANS responses to cognitive tasks.

Using a Biofeedback-Based Mindfulness Practice System to Enhance Mindfulness and Alleviate Anxiety in College Students: A Randomized Controlled Trial

Objective: College students experience intense anxiety, for which biofeedback mindfulness techniques show effectiveness in relief. However, typical biofeedback products often lead to user fatigue and boredom because of a single or fixed feedback and lack of focus on mindfulness enhancement. Materials and Methods: In this research, we developed Mindjourney, a VR-based respiratory feedback mindfulness system, designed to enhance mindfulness and alleviate anxiety through continuous/noncontinuous feedback and nonjudgmental reward/punishment for self-perception and attention management. A randomized controlled trial involved 72 college students, split equally into short-term (n = 34, age: 23.11 ± 1.729) and 4-week long-term (n = 38, age: 24.12 ± 1.408) groups, with equal randomization for intervention and control groups. Pre/postintervention tests were measured by using Trait Anxiety Inventory (TAI) and Five Facet Mindfulness Questionnaire (FFMQ) for long-term groups and Galvanic Skin Response and State Anxiety Inventory (SAI) for short-term groups. Results: Results showed that the long-term intervention group showed a significant increase in mindfulness (P = 0.001 for FFMQ total score). Furthermore, observe and act with awareness subscales showed significant increase after intervention (P = 0.034 for observe, P < 0.001 for act with awareness) compared with the control group. Both intervention groups demonstrated a significant decrease in anxiety levels compared with the control groups (P = 0.049 for SAI, P = 0.01 for TAI). Moreover, participants expressed high interest in this biofeedback mindfulness system and willingness for long-term usage. Conclusion: The proposed biofeedback mindfulness practice system could potentially facilitate mindfulness practice and serve as a convenient tool for anxiety relief in campus college students.

Spatial transcriptomics reveals modulation of transcriptional networks across brain regions after auditory threat conditioning

Prior research has demonstrated genome-wide transcriptional changes related to fear and anxiety across species, often focusing on individual brain regions or cell types. However, the extent of gene expression differences across brain regions and how these changes interact at the level of transcriptional connectivity remains unclear. To address this, we performed spatial transcriptomics RNAseq analyses in an auditory threat conditioning paradigm in mice. We generated a spatial transcriptomic atlas of a coronal mouse brain section covering cortical and subcortical regions, corresponding to histologically defined regions. Our finding revealed widespread transcriptional responses across all brain regions examined, particularly in the medial and lateral habenula, and the choroid plexus. Network analyses highlighted altered transcriptional connectivity between cortical and subcortical regions, emphasizing the role of steroidogenic factor 1. These results provide new insights into the transcriptional networks involved in auditory threat conditioning, enhancing our understanding of molecular and neural mechanisms underlying fear and anxiety disorders.

iPLA2β loss leads to age-related cognitive decline and neuroinflammation by disrupting neuronal mitophagy

BACKGROUND

During brain aging, disturbances in neuronal phospholipid metabolism result in impaired cognitive function and dysregulation of neurological processes. Mutations in iPLA2β are associated with neurodegenerative conditions that significantly impact brain phospholipids. iPLA2β deficiency exacerbates mitochondrial dysfunction and abnormal mitochondrial accumulation. We hypothesized that iPLA2β contributes to age-related cognitive decline by disrupting neuronal mitophagy.

METHODOLOGY

We used aged wild-type (WT) mice and iPLA2β-/- mice as natural aging models to assess cognitive performance, iPLA2β expression in the cortex, levels of chemokines and inflammatory cytokines, and mitochondrial dysfunction, with a specific focus on mitophagy and the mitochondrial phospholipid profile. To further elucidate the role of iPLA2β, we employed adeno-associated virus (AAV)-mediated iPLA2β overexpression in aged mice and re-evaluated these parameters.

RESULTS

Our findings revealed a significant reduction in iPLA2β levels in the prefrontal cortex of aged brains. Notably, iPLA2β-deficient mice exhibited impaired learning and memory. Loss of iPLA2β in the PFC of aged mice led to increased levels of chemokines and inflammatory cytokines. This damage was associated with altered mitochondrial morphology, reduced ATP levels due to dysregulation of the parkin-independent mitophagy pathway, and changes in the mitochondrial phospholipid profile. AAV-mediated overexpression of iPLA2β alleviated age-related parkin-independent mitophagy pathway dysregulation in primary neurons and the PFC of aged mice, reduced inflammation, and improved cognitive function.

CONCLUSIONS

Our study suggests that age-related iPLA2β loss in the PFC leads to cognitive decline through the disruption of mitophagy. These findings highlight the potential of targeting iPLA2β to ameliorate age-related neurocognitive disorders.

GABAergic implications in anxiety and related disorders

Evidence indicates that anxiety disorders arise from an imbalance in the functioning of brain circuits that govern the modulation of emotional responses to possibly threatening stimuli. The circuits under consideration in this context include the amygdala's bottom-up activity, which signifies the existence of stimuli that may be seen as dangerous. Moreover, these circuits encompass top-down regulatory processes that originate in the prefrontal cortex, facilitating the communication of the emotional significance associated with the inputs. Diverse databases (e.g., Pubmed, ScienceDirect, Web of Science, Google Scholar) were searched for literature using a combination of different terms e.g., "anxiety", "stress", "neuroanatomy", and "neural circuits", etc. A decrease in GABAergic activity is present in both anxiety disorders and severe depression. Research on cerebral functional imaging in depressive individuals has shown reduced levels of GABA within the cortical regions. Additionally, animal studies demonstrated that a reduction in the expression of GABAA/B receptors results in a behavioral pattern resembling anxiety. The amygdala consists of inhibitory networks composed of GABAergic interneurons, responsible for modulating anxiety responses in both normal and pathological conditions. The GABAA receptor has allosteric sites (e.g., α/γ, γ/β, and α/β) which enable regulation of neuronal inhibition in the amygdala. These sites serve as molecular targets for anxiolytic medications such as benzodiazepine and barbiturates. Alterations in the levels of naturally occurring regulators of these allosteric sites, along with alterations to the composition of the GABAA receptor subunits, could potentially act as mechanisms via which the extent of neuronal inhibition is diminished in pathological anxiety disorders.

MiR-186-5p inhibition restores synaptic transmission and neuronal network activity in a model of chronic stress

Chronic stress exerts profound negative effects on cognitive and emotional behaviours and is a major risk factor for the development of neuropsychiatric disorders. However, the molecular links between chronic stress and its deleterious effects on neuronal and synaptic function remain elusive. Here, using a combination of in vitro and in vivo approaches, we demonstrate that the upregulation of miR-186-5p triggered by chronic stress may be a key mediator of such changes, leading to synaptic dysfunction. Our results show that the expression levels of miR-186-5p are increased both in the prefrontal cortex (PFC) of mice exposed to chronic stress and in cortical neurons chronically exposed to dexamethasone. Additionally, viral overexpression of miR-186-5p in the PFC of naïve mice induces anxiety- and depressive-like behaviours. The upregulation of miR-186-5p through prolonged glucocorticoid receptor activation in vitro, or in a mouse model of chronic stress, differentially affects glutamatergic and GABAergic synaptic transmission, causing an imbalance in excitation/inhibition that leads to altered neuronal network activity. At glutamatergic synapses, we observed both a reduction in synaptic AMPARs and synaptic transmission, whereas GABAergic synaptic transmission was strengthened. These changes could be rescued in vitro by a miR-186-5p inhibitor. Overall, our results establish a novel molecular link between chronic glucocorticoid receptor activation, the upregulation of miR-186-5p and the synaptic changes induced by chronic stress, that may be amenable to therapeutic intervention.

Social experience in adolescence shapes prefrontal cortex structure and function in adulthood

During adolescence, the prefrontal cortex (PFC) undergoes dramatic reorganization. PFC development is profoundly influenced by the social environment, disruptions to which may prime the emergence of psychopathology across the lifespan. We investigated the neurobehavioral consequences of isolation experienced in adolescence in mice, and in particular, the long-term consequences that were detectable even despite normalization of the social milieu. Isolation produced biases toward habit-like behavior at the expense of flexible goal seeking, plus anhedonic-like reward deficits. Behavioral phenomena were accompanied by neuronal dendritic spine over-abundance and hyper-excitability in the ventromedial PFC (vmPFC), which was necessary for the expression of isolation-induced habits and sufficient to trigger behavioral inflexibility in socially reared controls. Isolation activated cytoskeletal regulatory pathways otherwise suppressed during adolescence, such that repression of constituent elements prevented long-term isolation-induced neurosequelae. Altogether, our findings unveil an adolescent critical period and multi-model mechanism by which social experiences facilitate prefrontal cortical maturation.

A Preliminary Analysis of Stress Burden and Cognitive Function and Clinically Adjudicated Cognitive Outcomes in Black American Adults

BACKGROUND

The combination of exposure to multiple stressors and psychological distress may contribute to the disproportionate burden of dementia risk among Black Americans. This study estimates the effect of an index of stress and psychological distress (ie, "stress burden") on cognitive function and clinically adjudicated cognitive outcomes among older Black American adults, and examines sleep as a mediator.

METHODS

The sample included 204 Black adults (79% female; mean age = 64 years) from Pittsburgh, PA, USA. Stress burden comprised 3 self-reported stress and distress measures assessed in 2016: discrimination, psychological distress, and posttraumatic stress. Potential mediators included actigraphy-assessed sleep duration and efficiency from 2018. Cognitive battery and clinical adjudication in 2019 assessed cognitive function and clinically adjudicated outcomes. Causal mediation analysis estimated the direct effect between stress burden and cognitive outcomes, and indirect effects through sleep, after adjusting for sociodemographics and hypertension.

RESULTS

Higher stress burden had a significant direct effect on lower executive functioning and visuospatial performance. However, there were no significant indirect effects (ie, mediation) by sleep disturbances on any domain of cognitive function assessed. Also, there were no significant direct or indirect effects on clinically adjudicated outcomes.

CONCLUSIONS

Multiple stressors often co-occur and may contribute to racial disparities in cognitive health. Findings suggest that higher stress burden had negative effects on functioning in executive and visuospatial domains in this community-based sample of older Black American adults. However, there was no evidence of mediation by sleep. Findings highlight the importance of continued work to identify modifiable pathways between stress burden and cognitive health disparities.

Antidepressant effects of activation of infralimbic cortex via upregulation of BDNF and β-catenin in an estradiol withdrawal model

RATIONALE

Clinical and preclinical studies have demonstrated that estradiol withdrawal after delivery is one of important factors involved in the pathogenesis of postpartum depression (PPD). The infralimbic cortex (IL) is related to anxiety and mood disorders. Whether IL neurons mediate PPD is still unclear.

OBJECTIVES

This study was to observe the antidepressant effect and expression of BDNF and β-catenin in IL by allopregnanolone (ALLO) treatment or the selective activation or inhibition of IL neurons using a chemogenetic approach in a pseudopregnancy model of PPD.

METHODS

Administration of estradiol combined with progesterone and the abrupt withdrawal of estradiol simulated the pregnancy and early postpartum periods to induce depression in ovariectomized rats. The relative expression levels of β-catenin and BDNF were observed by western blotting.

RESULTS

Immobility time was significantly increased in the forced swim test and open-arm movement was reduced in the elevated plus maze test in the estradiol-withdrawn rats. After ALLO treatment, the immobility time were lower and open-arm traveling times higher than those of the estradiol-withdrawn rats. Meanwhile, the expression level of BDNF or β-catenin in the IL was reduced significantly in estradiol-withdrawn rats, which was prevented by treatment with ALLO. The hM3Dq chemogenetic activation of pyramidal neurons in the IL reversed the immobility and open-arm travel time trends in the estradiol-withdrawal rat model, but chemogenetic inhibition of IL neurons failed to affect this. Upregulated BDNF and β-catenin expression and increased c-Fos in the basolateral amygdala were found following IL neuron excitation in model rats.

CONCLUSIONS

Our results demonstrated that pseudopregnancy and estradiol withdrawal produced depressive-like behavior and anxiety. ALLO treatment or specific excitement of IL pyramidal neurons relieved abnormal behaviors and upregulated BDNF and β-catenin expression in the IL in the PPD model, suggesting that hypofunction of IL neurons may be involved in the pathogenesis of PPD.

Corticosterone disrupts spatial working memory during retention testing when highly taxed, which positively correlates with depressive-like behavior in middle-aged, ovariectomized female rats

Major Depressive Disorder affects 8.4 % of the U.S. population, particularly women during perimenopause. This study implemented a chronic corticosterone manipulation (CORT, a major rodent stress hormone) using middle-aged, ovariectomized female rats to investigate depressive-like behavior, anxiety-like symptoms, and cognitive ability. CORT (400 μg/ml, in drinking water) was administered for four weeks before behavioral testing began and continued throughout all behavioral assessments. Compared to vehicle-treated rats, CORT significantly intensified depressive-like behaviors: CORT decreased sucrose preference, enhanced immobility on the forced swim test, and decreased sociability on a choice task between a novel conspecific female rat and an inanimate object. Moreover, CORT enhanced anxiety-like behavior on a marble bury task by reducing time investigating tabasco-topped marbles. No effects were observed on novelty suppressed feeding or the elevated plus maze. For spatial working memory using an 8-arm radial arm maze, CORT did not alter acquisition but disrupted performance during retention. CORT enhanced the errors committed during the highest working memory load following a delay and during the last trial requiring the most items to remember; this cognitive metric positively correlated with a composite depressive-like score to reveal that as depressive-like symptoms increased, cognitive performance worsened. This protocol allowed for the inclusion of multiple behavioral assessments without stopping the CORT treatment needed to produce a MDD phenotype and to assess a battery of behaviors. Moreover, that when middle-age was targeted, chronic CORT produced a depressive-like phenotype in ovariectomized females, who also comorbidly expressed aspects of anxiety and cognitive dysfunction.

Early-life prefrontal cortex inhibition and early-life stress lead to long-lasting behavioral, transcriptional, and physiological impairments

Early-life stress has been linked to multiple neurodevelopmental and neuropsychiatric deficits. Our previous studies have linked maternal presence/absence from the nest in developing rat pups to changes in prefrontal cortex (PFC) activity. Furthermore, we have shown that these changes are modulated by serotonergic signaling. Here we test whether changes in PFC activity during early life affect the developing cortex leading to behavioral alterations in the adult. We show that inhibiting the PFC of mouse pups leads to cognitive deficits in the adult comparable to those seen following maternal separation. Moreover, we show that activating the PFC during maternal separation can prevent these behavioral deficits. To test how maternal separation affects the transcriptional profile of the PFC we performed single-nucleus RNA-sequencing. Maternal separation led to differential gene expression almost exclusively in inhibitory neurons. Among others, we found changes in GABAergic and serotonergic pathways in these interneurons. Interestingly, both maternal separation and early-life PFC inhibition led to changes in physiological responses in prefrontal activity to GABAergic and serotonergic antagonists that were similar to the responses of more immature brains. Prefrontal activation during maternal separation prevented these changes. These data point to a crucial role of PFC activity during early life in behavioral expression in adulthood.

Dynamic quantitative monitoring of cerebrospinal fluid monoamine neurotransmitter markers during the modeling process of chronic stress-induced depression in monkeys (Macaca mulatta)

BACKGROUND

Depression is known as the "mental cold" and is also considered a major cause of disability worldwide. It is estimated that over 300 million people worldwide suffer from severe depression, equivalent to 4.4% of the world's population. The monoamine hypothesis of depression predicts the underlying pathophysiological mechanisms of depression, but in-depth research has failed to find convincing evidence.

METHOD

In this study, we will dynamically and strictly quantitatively monitor the concentration changes of monoamine transmitters in the cerebrospinal fluid (CSF) of macaques, based on our previous work. In the experiment, timed and quantitative collection of CSF samples from macaques was performed and the concentration of monoamine transmitters was determined.

RESULT

The results showed that after 2 months of chronic stress, the concentrations of high vanillin acid (HVA) and 3,4-dihydroxy-phenylacetic acid were significantly higher in the maternal separation (MS) group, whereas there was no significant difference in dopamine and 5-hydroxyindoleacetic acid.

CONCLUSION

This study is the first to observe the long-term dynamic relationship between early adversity, chronic stress, adolescent depression, and CSF monoamine concentrations. The research suggests that MS and chronic stress play an undeniable role in the pathogenesis of depression and that concentrations of HVA and dihydroxyphenylacetic acid are likely to serve as early markers of depressive-like symptoms in macaques.

A process model of parental executive functioning as a spillover mechanism linking interparental conflict and parenting difficulties across parenting domains

There is a well-documented interdependency between destructive interparental conflict (IPC) and parenting difficulties (i.e., spillover effect), yet little is known about the mechanisms that "carry" spillover between IPC and parenting. Guided by a cascade model framework, the current study used a longitudinal, multimethod, multi-informant design to examine a process model of spillover that tested whether parental executive functioning (working memory, cognitive flexibility, inhibitory control) served as a mediator of the prospective associations between IPC and subsequent changes in parenting over a 2-year period. Mothers and fathers were separated into differentiated models and multiple domains of parenting were examined (i.e., authoritarian discipline and scaffolding behavior). Participants included 231 families (both mothers and fathers of preschoolers). Race was reported as White (62%), Black (21%), Mixed (8%), Asian (3%), or Other (6%) and 14% considered their ethnicity to be Hispanic/Latino. Median household income was $65,000. Results indicated that for fathers, IPC indirectly predicted domain-general parenting difficulties (increased authoritarian parenting and decreased scaffolding) via deficits in paternal cognitive flexibility (but not inhibitory control or working memory). In mothers, IPC directly predicted domain-specific parenting difficulties (decreased scaffolding only) that did not operate via maternal executive functions. Notably, these effects occurred over and above the influence of parental socioeconomic status. This study constitutes a first step toward documenting parental executive functioning as a mechanism underlying the spillover of IPC to the parent-child relationship. Family interventions intended to interrupt IPC spillover should emphasize father involvement and consider targeting parental executive functions as change mechanisms. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Childhood adversity is associated with reduced BOLD response in inhibitory control regions amongst preadolescents from the ABCD study

Adolescence is characterized by dynamic neurodevelopment, which poses opportunities for risk and resilience. Adverse childhood experiences (ACEs) confer additional risk to the developing brain, where ACEs have been associated with alterations in functional magnetic resonance imaging (fMRI) BOLD signaling in brain regions underlying inhibitory control. Socioenvironmental factors like the family environment may amplify or buffer against the neurodevelopmental risks associated with ACEs. Using baseline to Year 2 follow-up data from the Adolescent Brain Cognitive Development (ABCD) Study, the current study examined how ACEs relate to fMRI BOLD signaling during successful inhibition on the Stop Signal Task in regions associated with inhibitory control and examined whether family conflict levels moderated that relationship. Results showed that greater ACEs were associated with reduced BOLD response in the right opercular region of the inferior frontal gyrus and bilaterally in the pre-supplementary motor area, which are key regions underlying inhibitory control. Further, greater BOLD response was correlated with less impulsivity behaviorally, suggesting reduced activation may not be behaviorally adaptive at this age. No significant two or three-way interactions with family conflict levels or time were found. Findings highlight the continued utility of examining the relationship between ACEs and neurodevelopmental outcomes and the importance of intervention/prevention of ACES.

Minimizing Variability in Developmental Fear Studies in Mice: Toward Improved Replicability in the Field

In rodents, the first weeks of postnatal life feature remarkable changes in fear memory acquisition, retention, extinction, and discrimination. Early development is also marked by profound changes in brain circuits underlying fear memory processing, with heightened sensitivity to environmental influences and stress, providing a powerful model to study the intersection between brain structure, function, and the impacts of stress. Nevertheless, difficulties related to breeding and housing young rodents, preweaning manipulations, and potential increased variability within that population pose considerable challenges to developmental fear research. Here we discuss several factors that may promote variability in studies examining fear conditioning in young rodents and provide recommendations to increase replicability. We focus primarily on experimental conditions, design, and analysis of rodent fear data, with an emphasis on mouse studies. The convergence of anatomical, synaptic, physiological, and behavioral changes during early life may increase variability, but careful practice and transparency in reporting may improve rigor and consensus in the field. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC.

Prolonged HPA axis dysregulation in postpartum depression associated with adverse early life experiences: A cross-species translational study

Childhood and adolescent stress increase the risk of postpartum depression (PPD), often providing an increased probability of treatment refractoriness. Nevertheless, the mechanisms linking childhood/adolescent stress to PPD remain unclear. Our study investigated the longitudinal effects of adolescent stress on the hypothalamic-pituitary-adrenal (HPA) axis and postpartum behaviors in mice and humans. Adolescent social isolation prolonged glucocorticoid elevation, leading to long-lasting postpartum behavioral changes in female mice. These changes were unresponsive to current PPD treatments but improved with post-delivery glucocorticoid receptor antagonist treatment. Childhood/adolescent stress significantly impacted HPA axis dysregulation and PPD in human females. Repurposing glucocorticoid receptor antagonists for some cases of treatment-resistant PPD may be considered.

Tryptophan metabolic pathway plays a key role in the stress-induced emotional eating

Chronic stress disrupts the emotional and energetic balance, which may lead to abnormal behaviors such as binge eating. This overeating behavior alleviating the negative emotions is called emotional eating, which may exacerbate emotional instability and lead to obesity. It is a complex and multifaceted process that has not yet been fully understood. In this study, we constructed an animal model of chronic mild stress (CMS)-induced emotional eating. The emotional eating mice were treated with tryptophan for 21 days to reveal the key role of tryptophan. Furthermore, serum-targeted metabolomics, immunohistochemical staining, qPCR and ELISA were performed. The results showed that CMS led to the binge eating behavior, accompanied by the disturbed intestinal tryptophan-derived serotonin (5-hydroxytryptamine; 5-HT) metabolic pathways. Then we found that tryptophan supplementation improved depression and anxiety-like behaviors as well as abnormal eating behaviors. Tryptophan supplementation improved the abnormal expression of appetite regulators (e.g., AgRP, OX1R, MC4R), and tryptophan supplementation also increased the tryptophan hydroxylase 2 (tph2) and 5-HT receptors in the hypothalamus of CMS mice, which indicates that the 5-HT metabolic pathway influences feeding behavior. In vitro experiments confirmed that 5-HT supplementation ameliorated corticosterone-induced aberrant expression of appetite regulators, such as AgRP and OX1R, in the hypothalamic cell line. In conclusion, our findings revealed that the tryptophan-derived 5-HT pathway plays an important role in emotional eating, especially in providing targeted therapy for stress-induced obesity.

Klinefelter Syndrome: A Genetic Disorder Leading to Neuroendocrine Modifications and Psychopathological Vulnerabilities in Children-A Literature Review and Case Report

Klinefelter syndrome (KS), characterized by an additional X-chromosome in males, manifests in a wide range of neuroendocrine and psychiatric symptoms. Individuals with KS often face increased risks of hormonal dysfunction, leading to depression and anxiety, although extended research during pediatric and adolescent age is still limited. This critical phase, decisive for KS children, is influenced by a combination of genetic, environmental and familial factors, which impact brain plasticity. In this report, we reviewed, in a narrative form, the crucial KS psychopathological hallmarks in children. To better describe neuroendocrine and neuropsychiatric outcomes in children with KS, we presented the case of an 11-year-old prepubertal child with mosaic KS who was referred to our Center of Developmental Psychopathology due to a decline in his academic performance, excessive daytime fatigue and increased distractibility over the past few months. Family history revealed psychiatric conditions among first- and second-degree relatives, including recently divorced parents and a 15-year-old sister. Early-onset persistent depressive disorder and anxious traits were diagnosed. Timely identification of susceptible children, with thorough examination of familial psychiatric history, environmental influences and neurocognitive profile, alongside targeted interventions, could potentially mitigate lifelong psychopathology-related disabilities in pediatric and adolescent KS cases, including those with mosaic KS.

Distress and neuroticism as mediators of the effect of childhood and adulthood adversity on cognitive performance in the UK Biobank study

Childhood adversity and adulthood adversity affect cognition later in life. However, the mechanism through which adversity exerts these effects on cognition remains under-researched. We aimed to investigate if the effect of adversity on cognition was mediated by distress or neuroticism. The UK Biobank is a large, population-based, cohort study designed to investigate risk factors of cognitive health. Here, data were analysed using a cross-sectional design. Structural equation models were fitted to the data with childhood adversity or adulthood adversity as independent variables, distress and neuroticism as mediators and executive function and processing speed as latent dependent variables that were derived from the cognitive scores in the UK Biobank. Complete data were available for 64,051 participants in the childhood adversity model and 63,360 participants in the adulthood adversity model. Childhood adversity did not show a direct effect on processing speed. The effect of childhood adversity on executive function was partially mediated by distress and neuroticism. The effects of adulthood adversity on executive function and processing speed were both partially mediated by distress and neuroticism. In conclusion, distress and neuroticism mediated the deleterious effect of childhood and adulthood adversity on cognition and may provide a mechanism underlying the deleterious consequences of adversity.

Neural Mechanisms of Nonauditory Effects of Noise Exposure on Special Populations

Due to the abnormal structure and function of brain neural networks in special populations, such as children, elderly individuals, and individuals with mental disorders, noise exposure is more likely to have negative psychological and cognitive nonauditory effects on these individuals. There are unique and complex neural mechanisms underlying this phenomenon. For individuals with mental disorders, there are anomalies such as structural atrophy and decreased functional activation in brain regions involved in emotion and cognitive processing, such as the prefrontal cortex (PFC). Noise exposure can worsen these abnormalities in relevant brain regions, further damaging neural plasticity and disrupting normal connections and the transmission of information between the PFC and other brain areas by causing neurotransmitter imbalances. In the case of children, in a noisy environment, brain regions such as the left inferior frontal gyrus and PFC, which are involved in growth and development, are more susceptible to structural and functional changes, leading to neurodegenerative alterations. Furthermore, noise exposure can interrupt auditory processing neural pathways or impair inhibitory functions, thus hindering children's ability to map sound to meaning in neural processes. For elderly people, age-related shrinkage of brain regions such as the PFC, as well as deficiencies in hormone, neurotransmitter, and nutrient levels, weakens their ability to cope with noise. Currently, it is feasible to propose and apply coping strategies to improve the nonauditory effects of noise exposure on special populations based on the plasticity of the human brain.

Acute stress impairs intentional memory suppression through aberrant prefrontal cortex activation in high trait ruminators

Objective

Research shows that the effect of acute stress on intentional memory suppression could be modulated by individual differences in psychological traits. However, whether acute stress distinctly affects intentional memory suppression in high trait ruminators, a high at-risk group of stress-related disorders, and the neural correlations, remains unclear.

Method

55 healthy college students were divided into high and low trait ruminators (HTR and LTR), Following stress manipulation, a Think/No Think task assessed the memory suppression performance. Functional near-infrared spectroscopy was applied to explore the neural correlates. Psychophysiological interaction analyses were used to assess how the functional connectivity between a seed region and another brain region was modulated by tasks during memory suppression, further mediating memory suppression performance and state rumination.

Results

The HTR exhibited poorer memory suppression performance than the LTR under the stress condition. Aberrant activation patterns and task-modulated functional connectivity in the dorsal prefrontal cortex (DLPFC) and superior temporal gyrus (STG) were observed only in the HTR during memory suppression under the stress condition. The effect of memory suppression performance on the state rumination of individuals was significantly mediated by the task-modulated functional connectivity between the DLPFC and STG.

Conclusions

The findings could provide insights for prevention or early intervention in the development of stress-related disorders in HTR.

GABAergic synapses from the ventral lateral septum to the paraventricular nucleus of hypothalamus modulate anxiety

Emotional disorders, such as anxiety and depression, represent a major societal problem; however, the underlying neurological mechanism remains unknown. The ventral lateral septum (LSv) is implicated in regulating processes related to mood and motivation. In this study, we found that LSv GABAergic neurons were significantly activated in mice experiencing chronic social defeat stress (CSDS) after exposure to a social stressor. We then controlled LSv GABAergic neuron activity using a chemogenetic approach. The results showed that although manipulation of LSv GABAergic neurons had little effect on anxiety-like behavioral performances, the activation of LSv GABAergic neurons during CSDS worsened social anxiety during a social interaction (SI) test. Moreover, LSv GABAergic neurons showed strong projections to the paraventricular nucleus (PVN) of the hypothalamus, which is a central hub for stress reactions. Remarkably, while activation of GABAergic LSv-PVN projections induced social anxiety under basal conditions, activation of this pathway during CSDS alleviated social anxiety during the SI test. On the other hand, the chemogenetic manipulation of LSv GABAergic neurons or LSvGABA-PVN projections had no significant effect on despair-like behavioral performance in the tail suspension test. Overall, LS GABAergic neurons, particularly the LSv GABAergic-PVN circuit, has a regulatory role in pathological anxiety and is thus a potential therapeutic target for the treatment of emotional disorders.

Age-related impact of social isolation in mice: Young vs middle-aged

Social isolation is a chronic mild stressor and a significant risk factor for mental health disorders. Herein we explored the impact of social isolation on depression- and anxiety-like behaviours, as well as spatial memory impairments, in middle-aged male mice compared to post-weaning mice. We aimed to quantify and correlate social isolation-induced behaviour discrepancies with changes in hippocampal glial cell reactivity and pro-inflammatory cytokine levels. Post-weaning and middle-aged C57BL7/J6 male mice were socially isolated for a 3-week period and behavioural tests were performed on the last five days of isolation. We found that 3 weeks of social isolation led to depressive-like behaviour in the forced swim test, anxiety-like behaviour in the open field test, and spatial memory impairment in the Morris water maze paradigm in middle-aged male mice. These behavioural alterations were not observed in male mice after post-weaning social isolation, indicating resilience to isolation-mediated stress. Increased Iba-1 expression and NLRP3 priming were both observed in the hippocampus of socially isolated middle-aged mice, suggesting a role for microglia and NLRP3 pathway in the detrimental effects of social isolation on cognition and behaviour. Young socially isolated mice also demonstrated elevated NLRP3 priming compared to controls, but no differences in Iba-1 levels and no significant changes in behaviour. Ageing-induced microglia activation and enhancement of IL-1β, TNF-α and IL-6 proinflammatory cytokines, known signs of a chronic low-grade inflammatory state, were also detected. Altogether, data suggest that social isolation, in addition to inflammaging, contributes to stress-related cognitive impairment in middle-aged mice.

Granulocyte macrophage colony-stimulating factor-induced macrophages of individuals with autism spectrum disorder adversely affect neuronal dendrites through the secretion of pro-inflammatory cytokines

BACKGROUND

A growing body of evidence suggests that immune dysfunction and inflammation in the peripheral tissues as well as the central nervous system are associated with the neurodevelopmental deficits observed in autism spectrum disorder (ASD). Elevated expression of pro-inflammatory cytokines in the plasma, serum, and peripheral blood mononuclear cells of ASD has been reported. These cytokine expression levels are associated with the severity of behavioral impairments and symptoms in ASD. In a prior study, our group reported that tumor necrosis factor-α (TNF-α) expression in granulocyte-macrophage colony-stimulating factor-induced macrophages (GM-CSF MΦ) and the TNF-α expression ratio in GM-CSF MΦ/M-CSF MΦ (macrophage colony-stimulating factor-induced macrophages) was markedly higher in individuals with ASD than in typically developed (TD) individuals. However, the mechanisms of how the macrophages and the highly expressed cytokines affect neurons remain to be addressed.

METHODS

To elucidate the effect of macrophages on human neurons, we used a co-culture system of control human-induced pluripotent stem cell-derived neurons and differentiated macrophages obtained from the peripheral blood mononuclear cells of five TD individuals and five individuals with ASD. All participants were male and ethnically Japanese.

RESULTS

Our results of co-culture experiments showed that GM-CSF MΦ affect the dendritic outgrowth of neurons through the secretion of pro-inflammatory cytokines, interleukin-1α and TNF-α. Macrophages derived from individuals with ASD exerted more severe effects than those derived from TD individuals.

LIMITATIONS

The main limitations of our study were the small sample size with a gender bias toward males, the use of artificially polarized macrophages, and the inability to directly observe the interaction between neurons and macrophages from the same individuals.

CONCLUSIONS

Our co-culture system revealed the non-cell autonomous adverse effects of GM-CSF MΦ in individuals with ASD on neurons, mediated by interleukin-1α and TNF-α. These results may support the immune dysfunction hypothesis of ASD, providing new insights into its pathology.

Examining a Healthy Lifestyle as a Moderator of the Relationship between Psychological Distress and Cognitive Decline among Older Adults in the NuAge Study

INTRODUCTION

The objective of this study was to examine whether a healthy lifestyle composite score of social engagement, physical activity, and Mediterranean diet adherence moderates the association between psychological distress and global cognitive decline among cognitively healthy older adults (67+ years of age at baseline).

METHODS

A total of 1,272 cognitively intact older adults (Mage = 74.1 ± 4.1 years, 51.9% female) in the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge) completed a series of self-reported questionnaires to measure psychological distress and lifestyle behaviors, and the Modified Mini-Mental Examination (3MS) to assess cognitive performance at baseline and annually over 3 years.

RESULTS

Controlling for sociodemographic and health-related characteristics, greater psychological distress was associated with steeper cognitive decline over time among males (B = -0.07, 95% CI: [-0.12, -0.02]), but not females (B = 0.008, 95% CI: [0.03, 0.04]). Although a healthy lifestyle composite score did not statistically significantly moderate the distress-cognition relationship (B = -0.005, 95% CI: [-0.02, 0.01]), there was an association between higher psychological distress and greater cognitive decline at low levels of social engagement (B = -0.05, 95% CI: [-0.09, -0.006]), but not at high levels of social engagement (B = 0.02, 95% CI: [-0.03, 0.07]).

CONCLUSION

This study suggests that the potentially harmful impact of stress on cognitive function may be malleable through specific healthy lifestyle behaviors and emphasizes the importance of taking a sex-based approach to cognitive aging research.

Transcriptomic analyses of rats exposed to chronic mild stress: Modulation by chronic treatment with the antipsychotic drug lurasidone

Exposure to stressful experiences accounts for almost half of the risk for mental disorders. Hence, stress-induced alterations represent a key target for pharmacological interventions aimed at restoring brain function in affected individuals. We have previously demonstrated that lurasidone, a multi-receptor antipsychotic drug approved for the treatment of schizophrenia and bipolar depression, can normalize the functional and molecular impairments induced by stress exposure, representing a valuable tool for the treatment of stress-induced mental illnesses. However, the mechanisms that may contribute to the therapeutic effects of lurasidone are still poorly understood. Here, we performed a transcriptomic analysis on the prefrontal cortex (PFC) of adult male rats exposed to the chronic mild stress (CMS) paradigm and we investigated the impact of chronic lurasidone treatment on such changes. We found that CMS exposure leads to an anhedonic phenotype associated with a down-regulation of different pathways associated to neuronal guidance and synaptic plasticity within the PFC. Interestingly, a significant part of these alterations (around 25%) were counteracted by lurasidone treatment. In summary, we provided new insights on the transcriptional changes relevant for the therapeutic intervention with lurasidone, which may ultimately promote resilience.

Emotion regulation shows an age- and sex-specific moderating effect on the relationship between chronic stress and cognitive performance

Despite the extensive knowledge about the effects of chronic stress on cognition, the underlying mechanisms remain unclear. We conducted a cross-sectional moderation analysis on a population-based sample of 596 adults to examine the age- and sex-specific role of emotion regulation (ER) in the relationship between chronic stress and cognitive performance using validated self-report questionnaires. While women showed no direct or moderated relationship between stress and cognition, men displayed a distinct age-related pattern where stress was negatively associated with poorer cognitive performance at older ages, and the onset of this relationship was detected earlier in men with ER problems. These results showed that suppression of emotions and lack of executive control of ER amplify the negative consequences of chronic stress and suggest that there are sex-specific differences in the decline of ability to cope with long-term exposure to stressors.

The brain, gut, and bladder health nexus: A conceptual model linking stress and mental health disorders to overactive bladder in women

OBJECTIVE

A small, but growing literature links stressors and mental health disorders (MHDs) across the life course to overactive bladder (OAB) and urinary incontinence symptoms. Mechanisms by which stressors and MHDs may impact bladder health are not fully understood, limiting novel prevention and treatment efforts. Moreover, potential biopsychosocial mechanisms involving the brain and gut have not been considered in an integrated, comprehensive fashion.

METHODS

Members of the prevention of lower urinary tract symptoms Research Consortium developed conceptual models to inform research on biopsychosocial mechanisms through which stress and MDHs may impact bladder health among girls and women, focusing on brain and gut physiology.

RESULTS

Two conceptual models were developed-one to explain central (brain-based) and peripheral (gut-based) mechanisms linking stressors and MHDs to OAB and bladder health, and one to highlight bidirectional communication between the brain, gut, and bladder. Traumatic events, chronic stressors, and MHDs may lead to a maladaptive stress response, including dysregulated communication and signaling between the brain, gut, and bladder. Gut bacteria produce molecules and metabolites that alter production of neurotransmitters, amino acids, short-chain fatty acids, and inflammatory immune response molecules that mediate communication between the gut and brain. Microbiota signal neurogenesis, microglia maturation, and synaptic pruning; they also calibrate brain-gut-bladder axis communication through neurotransmission and synaptogenesis, potentially influencing bladder symptom development. Life course trajectories of risk may be prevented or interrupted by central and peripheral resources for neuropsychological resilience.

CONCLUSIONS

Depicted pathways, including brain-gut-bladder communication, have implications for research and development of novel prevention and treatment approaches.

Abnormal changes of dynamic topological characteristics in patients with major depressive disorder

BACKGROUND

Most studies have detected abnormalities of static topological characteristics in major depressive disorder (MDD). However, whether dynamic alternations in brain topology are influenced by MDD remains unknown.

METHODS

An approach was proposed to capture the dynamic topological characteristics with sliding-window and graph theory for a large data sample from the REST-meta-MDD project.

RESULTS

It was shown that patients with MDD were characterized by decreased nodal efficiency of the left orbitofrontal cortex. The temporal variability of topological characteristics was focused on the left opercular part of inferior frontal gyrus, and the right part of middle frontal gyrus, inferior parietal gyrus, precuneus and thalamus.

LIMITATIONS

Future studies need larger and diverse samples to explore the relationship between dynamic topological network characteristics and MDD symptoms.

CONCLUSIONS

The results support that the altered dynamic topology in cortex of frontal and parietal lobes and thalamus during resting-state activity may be involved in the neuropathological mechanism of MDD.

Targeting Human Glucocorticoid Receptors in Fear Learning: A Multiscale Integrated Approach to Study Functional Connectivity

Fear extinction is a phenomenon that involves a gradual reduction in conditioned fear responses through repeated exposure to fear-inducing cues. Functional brain connectivity assessments, such as functional magnetic resonance imaging (fMRI), provide valuable insights into how brain regions communicate during these processes. Stress, a ubiquitous aspect of life, influences fear learning and extinction by changing the activity of the amygdala, prefrontal cortex, and hippocampus, leading to enhanced fear responses and/or impaired extinction. Glucocorticoid receptors (GRs) are key to the stress response and show a dual function in fear regulation: while they enhance the consolidation of fear memories, they also facilitate extinction. Accordingly, GR dysregulation is associated with anxiety and mood disorders. Recent advancements in cognitive neuroscience underscore the need for a comprehensive understanding that integrates perspectives from the molecular, cellular, and systems levels. In particular, neuropharmacology provides valuable insights into neurotransmitter and receptor systems, aiding the investigation of mechanisms underlying fear regulation and potential therapeutic targets. A notable player in this context is cortisol, a key stress hormone, which significantly influences both fear memory reconsolidation and extinction processes. Gaining a thorough understanding of these intricate interactions has implications in terms of addressing psychiatric disorders related to stress. This review sheds light on the complex interactions between cognitive processes, emotions, and their neural bases. In this endeavor, our aim is to reshape the comprehension of fear, stress, and their implications for emotional well-being, ultimately aiding in the development of therapeutic interventions.

Accumulation and neuroprotective effects of lithium on hepatocellular carcinoma mice model

AIM

The peripheral tumor growth is accompanied by the accumulation of inflammatory mediators in the blood that can negatively influence blood-brain barrier function and neuronal structure and develop the cancer-associated depression. The aim of the study was to evaluate the neurobiological effects of lithium on hepatocellular carcinoma mice model.

METHODS

In this study we analyzed the locomotor activity of lithium-treated tumor-bearing mice using the Phenomaster instrument. Inductively coupled plasma mass-spectral analysis was used to determine lithium levels in blood, brain, liver, kidneys, tumors and muscle tissues. The prefrontal cortex neurons ultrastructure was assessed by transmission electron microscopy. Expression of BDNF, GRP78, EEA1, LAMP1, and LC3 beta in neurons was determined by immunohistochemical analysis.

RESULTS

A decrease in locomotor activity was found in animals with tumors. At the same time, the low expression levels of the neurotrophic factor BDNF and early endosomal marker EEA1 were revealed, as well as the decreased amount of synaptic vesicles and synapses was shown. Signs of endoplasmic reticulum stress and autophagy development in neurons of animals with tumors were noted. Lithium carbonate administration had a corrective effect on animal's behavior and the prefrontal cortex neurons structure.

CONCLUSIONS

In summary, lithium can restore the neuronal homeostasis in tumor-bearing mice.

A maternal high-fat diet during pregnancy and lactation induced depression-like behavior in offspring and myelin-related changes in the rat prefrontal cortex

In accordance with the developmental origins of health and disease, early-life environmental exposures, such as maternal diet, can enhance the probability and gravity of health concerns in their offspring in the future. Over the past few years, compelling evidence has emerged suggesting that prenatal exposure to a maternal high-fat diet (HFD) could trigger neuropsychiatric disorders in the offspring, such as depression. The majority of brain development takes place before birth and during lactation. Nevertheless, our understanding of the impact of HFD on myelination in the offspring's brain during both gestation and lactation remains limited. In the present study, we investigated the effects of maternal HFD (60% energy from fat) on depressive-like and myelin-related changes in adolescent and adult rat offspring. Maternal HFD increased immobility time during the forced swimming test in both adolescent and adult offspring. Correspondingly, the depressive-like phenotype in offspring correlated with dysregulation of several genes and proteins in the prefrontal cortex, especially of myelin-oligodendrocyte glycoprotein (MOG), myelin and lymphocyte protein (MAL), 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase), kallikrein 6, and transferrin in male offspring, as well as of MOG and kallikrein 6 in female offspring, which persist even into adulthood. Maternal HFD also induced long-lasting adaptations manifested by the reduction of immature and mature oligodendrocytes in the prefrontal cortex in adult offspring. In summary, maternal HFD-induced changes in myelin-related genes are correlated with depressive-like behavior in adolescent offspring, which persists even to adulthood.

Prolonged stress-induced depression-like behaviors in aged rats are mediated by endoplasmic reticulum stress and apoptosis in the hippocampus

Structural and functional recovery from stress-induced depression is impaired in the context of aging brain. Since investigating the molecular substrates that facilitate behavioral recovery may have important implications for understanding brain plasticity and resilience of individuals, we studied depressive-like behaviors in young and aged rats 6 weeks after chronic stress exposure as a recovery period and examined the levels of TNF-α and IL-6 inflammatory cytokines, NADH oxidase activity, NADPH oxidase, endoplasmic reticulum (ER) stress markers, and apoptosis in the hippocampus. Young (3 months old) and aged (22 months old) male Wistar rats were divided into four groups; young control (Young), depression model of young rats that received chronic stress procedure followed by a 6-week recovery period (Young+S), aged control (Aged), and depression model of aged rats that received chronic stress procedure followed by a 6-week recovery period (Aged+S). After the recovery period, aged but not young rats showed depression-like behaviors, evaluated by the sucrose preference test (SPT) and forced swimming test (FST), coincided with the altered levels of TNF-α, IL-6, NADH oxidase activity, NADPH oxidase, GRP78, CHOP, and cleaved caspase-12 in the hippocampus of these animals. These data suggested that oxidative and ER stress-induced apoptosis in the aging hippocampus may affect the recovery-related outcomes after the stress paradigm.

Socioeconomic Disparities in Hypothalamic-Pituitary-Adrenal Axis Regulation and Prefrontal Cortical Structure

Socioeconomic disadvantage during childhood predicts an increased risk for mental health problems across the life span. Socioeconomic disadvantage shapes multiple aspects of children's proximal environments and increases exposure to chronic stressors. Drawing from multiple literatures, we propose that childhood socioeconomic disadvantage may lead to adaptive changes in the regulation of stress response systems including the hypothalamic-pituitary-adrenal (HPA) axis. These changes, in turn, affect the development of prefrontal cortical (PFC) circuitry responsible for top-down control over cognitive and emotional processes. Translational findings indicate that chronic stress reduces dendritic complexity and spine density in the medial PFC and anterior cingulate cortex, in part through altered HPA axis regulation. Socioeconomic disadvantage has frequently been associated with reduced gray matter in the dorsolateral and ventrolateral PFC and anterior cingulate cortex and lower fractional anisotropy in the superior longitudinal fasciculus, cingulum bundle, and uncinate fasciculus during middle childhood and adolescence. Evidence of socioeconomic disparities in hair cortisol concentrations in children has accumulated, although null findings have been reported. Coupled with links between cortisol levels and reduced gray matter in the PFC and anterior cingulate cortex, these results support mechanistic roles for the HPA axis and these PFC circuits. Future longitudinal studies should simultaneously consider multiple dimensions of proximal factors, including cognitive stimulation, while focusing on epigenetic processes and genetic moderators to elucidate how socioeconomic context may influence the HPA axis and PFC circuitry involved in cognitive and emotional control. These findings, which point to modifiable factors, can be harnessed to inform policy and more effective prevention strategies.

Alzheimer's Disease Prevention and Treatment Based on Population-Based Approaches

The development of effective prevention and treatment strategies for Alzheimer's disease (AD) and dementia is hindered by limited knowledge of the underlying biological and environmental causes. While certain genetic factors have been associated with AD, and various lifestyle and environmental factors have been linked to dementia risk, the interactions between genes and the environment are not yet fully understood. To identify new avenues for dementia prevention, coordinated global efforts are needed to utilize existing cohorts and resources effectively and efficiently. This chapter provides an overview of current research on risk and protective factors for AD and dementia and discusses the opportunities and challenges associated with population-based approaches.

A Glucocorticoid-Sensitive Hippocampal Gene Network Moderates the Impact of Early-Life Adversity on Mental Health Outcomes

BACKGROUND

Early stress increases the risk for psychiatric disorders. Glucocorticoids are stress mediators that regulate transcriptional activity and morphology in the hippocampus, which is implicated in the pathophysiology of multiple psychiatric conditions. We aimed to establish the relevance of hippocampal glucocorticoid-induced transcriptional activity as a mediator of the effects of early life on later psychopathology in humans.

METHODS

RNA sequencing was performed with anterior and posterior hippocampal dentate gyrus from adult female macaques (n = 12/group) that were chronically treated with betamethasone (glucocorticoid receptor agonist) or vehicle. Coexpression network analysis identified a preserved gene network in the posterior hippocampal dentate gyrus that was strongly associated with glucocorticoid exposure. The single nucleotide polymorphisms in the genes in this network were used to create an expression-based polygenic score in humans.

RESULTS

The expression-based polygenic score significantly moderated the association between early adversity and psychotic disorders in adulthood (UK Biobank, women, n = 44,519) and on child peer relations (ALSPAC [Avon Longitudinal Study of Parents and Children], girls, n = 1666 for 9-year-olds and n = 1594 for 11-year-olds), an endophenotype for later psychosis. Analyses revealed that this network was enriched for glucocorticoid-induced epigenetic remodeling in human hippocampal cells. We also found a significant association between single nucleotide polymorphisms from the expression-based polygenic score and adult brain gray matter density.

CONCLUSIONS

We provide an approach for the use of transcriptomic data from animal models together with human data to study the impact of environmental influences on mental health. The results are consistent with the hypothesis that hippocampal glucocorticoid-related transcriptional activity mediates the effects of early adversity on neural mechanisms implicated in psychiatric disorders.

Hippocampal subfield volumes predict treatment response to oral ketamine in people with suicidality

Ongoing stress results in hippocampal neuro-structural alterations which produce pathological consequences, including depression and suicidality. Ketamine may ameliorate stress related illnesses, including suicidality, via neuroplasticity processes. This novel study sought to determine whether oral ketamine treatment specifically affects hippocampal (whole and subfield) volumes in patients with chronic suicidality and MDD. It was hypothesised that oral ketamine treatment would differentially alter hippocampal volumes in trial participants categorised as ketamine responders, versus those who were non-responders. Twenty-eight participants received 6 single, weekly doses of oral ketamine (0.5-3 mg/kg) and underwent MRI scans at pre-ketamine (week 0), post-ketamine (week 6), and follow up (week 10). Hippocampal subfield volumes were extracted using the longitudinal pipeline in FreeSurfer. Participants were grouped according to ketamine response status and then compared in terms of grey matter volume (GMV) changes, among 10 hippocampal regions, over 6 and 10 weeks. Mixed ANOVAs were used to analyse interactions between time and group. Post treatment analysis revealed a significant main effect of group for three left hippocampal GMVs as well in the left and right whole hippocampus. Ketamine acute responders (Week 6) showed increased GMVs in both left and right whole hippocampus and in three subfields compared to acute non-responders, across all three timepoints, suggesting that pre-treatment increased hippocampal GMVs (particularly left hemisphere) may be predictive biomarkers of acute treatment response. Future studies should further investigate the potential of hippocampal volumes as a biomarker of ketamine treatment response.

Chronic stress-induced anxiety-like behavior, hippocampal oxidative, and endoplasmic reticulum stress are reversed by young plasma transfusion in aged adult rats

Objectives

Aging and stress synergistically induce behavioral dysfunctions associated with oxidative and endoplasmic reticulum (ER) stress in brain regions. Considering the rejuvenating effects of young plasma on aging brain function, in the current study, we examined the effects of young plasma administration on anxiety-like behavior, NADH oxidase, NADPH oxidase, and ER stress markers in the hippocampus of old male rats.

Materials and Methods

Young (3 months old) and aged (22 months old) rats were randomly assigned into five groups: young control (Y), aged control (A), aged rats subjected to chronic stress for four weeks (A+S), aged rats subjected to chronic stress and treated with old plasma (A+S+OP), and aged rats subjected to chronic stress and treated with young plasma (A+S+YP). Systemic injection of (1 ml) young and old plasma was performed for four weeks (3 times/week).

Results

Young plasma transfusion significantly improved anxiety-like behavior in aged rats and modulated oxidative stress in the hippocampus, evidenced by the increased NADH oxidase (NOX) activity and the reduced NADPH oxidase. In addition, the levels of C/EBP homologous protein (CHOP) and Glucose-Regulated Protein 78 (GRP-78), as ER stress markers, markedly reduced in the hippocampus following the administration of young plasma.

Conclusion

These findings suggest that young plasma transfusion could reverse anxiety-like behavior in stress-exposed aged rats by modulating the hippocampal oxidative and ER stress markers.

Prenatal exposure to per-and polyfluoroalkyl substances and child executive function: Evidence from the Shanghai birth cohort study

BACKGROUND

Per-and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and accumulate in humans. Toxicological studies have indicated the potential neurotoxicity of PFAS during the fetal development. However, in epidemiological studies, the association between prenatal exposure to PFAS and executive function in offspring remains unclear.

OBJECTIVES

To investigate the association between prenatal exposure to PFAS and executive function in offspring.

METHOD

This study included 1765 mother-child pairs in the Shanghai Birth Cohort, a prospective birth cohort enrolled during 2013-2016. The levels of 10 PFAS were measured in maternal plasma samples collected during early gestation. Child executive function was assessed at 4 years of age using the parent-reported Behavior Rating Inventory of Executive Function-Preschool version (BRIEF-P), which provided 4 composite measures: Inhibitory Self-Control Index, Flexibility Index, Emergent Metacognition Index, and Global Executive Composite. We used multivariable linear regression to examine the associations between individual PFAS and BRIEF-P scores. Bayesian kernel machine regression (BKMR) was employed to evaluate the joint effects. We also investigated whether these associations were modified by sex.

RESULT

We found no significant associations between prenatal PFAS exposure and BRIEF-P scores when the child was 4 years old. BKMR analysis showed no joint effect of the PFAS mixture on child executive function. RCS analysis indicated that the majority of relationships between PFAS and BRIEF-P did not deviate from the linear relationship, even though there was a nonlinear association between PFUA and EMI. Additionally, the associations were not modified by sex.

CONCLUSION

Overall, our findings showed that there were no associations between prenatal exposure to PFAS and child executive function at 4 years of age.

Adopting a child perspective for exposome research on mental health and cognitive development - Conceptualisation and opportunities

Mental disorders among children and adolescents pose a significant global challenge. The exposome framework covering the totality of internal, social and physical exposures over a lifetime provides opportunities to better understand the causes of and processes related to mental health, and cognitive functioning. The paper presents a conceptual framework on exposome, mental health, and cognitive development in children and adolescents, with potential mediating pathways, providing a possibility for interventions along the life course. The paper underscores the significance of adopting a child perspective to the exposome, acknowledging children's specific vulnerability, including differential exposures, susceptibility of effects and capacity to respond; their susceptibility during development and growth, highlighting neurodevelopmental processes from conception to young adulthood that are highly sensitive to external exposures. Further, critical periods when exposures may have significant effects on a child's development and future health are addressed. The paper stresses that children's behaviour, physiology, activity pattern and place for activities make them differently vulnerable to environmental pollutants, and calls for child-specific assessment methods, currently lacking within today's health frameworks. The importance of understanding the interplay between structure and agency is emphasized, where agency is guided by social structures and practices and vice-versa. An intersectional approach that acknowledges the interplay of social and physical exposures as well as a global and rural perspective on exposome is further pointed out. To advance the exposome field, interdisciplinary efforts that involve multiple scientific disciplines are crucial. By adopting a child perspective and incorporating an exposome approach, we can gain a comprehensive understanding of how exposures impact children's mental health and cognitive development leading to better outcomes.

Restorative effect of NitroSynapsin on synaptic plasticity in an animal model of depression

In the search for new options for the pharmacological treatment of major depressive disorder, compounds with a rapid onset of action and high efficacy but lacking a psychotomimetic effect are of particular interest. In the present study, we evaluated the antidepressant potential of NitroSynapsin (NS) at behavioural, structural, and functional levels. NS is a memantine derivative and a dual allosteric N-methyl-d-aspartate receptors (NMDAR) antagonist using targeted delivery by the aminoadamantane of a warhead nitro group to inhibitory redox sites on the NMDAR. In a chronic restraint stress (CRS) mouse model of depression, five doses of NS administered on three consecutive days evoked antidepressant-like activity in the chronically stressed male C57BL/6J mice, reversing CRS-induced behavioural disturbances in sucrose preference and tail suspension tests. CRS-induced changes in morphology and density of dendritic spines in cerebrocortical neurons in the medial prefrontal cortex (mPFC) were also reversed by NS. Moreover, CRS-induced reduction in long-term potentiation (LTP) in the mPFC was found to be prevented by NS based on the electrophysiological recordings. Our study showed that NS restores structural and functional synaptic plasticity and reduces depressive behaviour to the level found in naïve animals. These results preliminarily revealed an antidepressant-like potency of NS.