Impact of Stress on Brain Morphology: Insights into Structural Biomarkers of Stress-related Disorders

Long-term GABA supplementation mitigates anxiety by modulating complement and neuroinflammatory pathways

Anxiety disorders are among the most prevalent mental health conditions, often linked with neuroinflammation and imbalances in neurotransmitter systems. This study examined the anxiolytic effects of oral GABA in chronic restraint stress (CRS) mice. Mice were divided into control, CRS, and two GABA-treated groups (10 mg/kg, 20 mg/kg). After 14 days of administration, anxiety-like behaviors were assessed using elevated-plus maze and open-field tests. GABA levels in the prefrontal cortex were quantified via ELISA, while anti-inflammatory cytokines were measured using an antibody array. Proteomic analysis of the hippocampus identified differentially expressed proteins, validated through Parallel Reaction Monitoring and immunoblotting. Results showed that GABA significantly alleviated anxiety-like behaviors, increased GABA levels in the prefrontal cortex, and elevated anti-inflammatory factors IL-10 and TGF-β1. Proteomic analysis and validation revealed GABA reversed complement dysregulation (C3, C4b, Cfh, Cfi). These findings suggest GABA alleviates anxiety by modulating immune homeostasis and complement activation, highlighting its therapeutic potential.

Chronic stress-induced neuroplasticity in the prefrontal cortex: Structural, functional, and molecular mechanisms from development to aging

Chronic stress profoundly affects the structure and function of the prefrontal cortex (PFC), a brain region critical for executive functions and emotional regulation. This review synthesizes current knowledge on stress-induced PFC plasticity, encompassing structural, functional, and molecular changes. We examine how chronic stress leads to dendritic atrophy, spine loss, and alterations in neuronal connectivity within the PFC, particularly affecting the medial PFC. These structural changes are accompanied by disruptions in neurotransmitter systems, most notably glutamatergic and GABAergic signaling, and alterations in synaptic plasticity mechanisms. At the molecular level, we discuss the intricate interplay between stress hormones, neurotrophic factors, and epigenetic modifications that underlie these changes. The review highlights the significant behavioral and cognitive consequences of stress-induced PFC plasticity, including impairments in working memory, decision-making, and emotional regulation, which may contribute to the development of stress-related psychiatric disorders. We also explore individual differences in stress susceptibility, focusing on sex-specific effects and age-dependent variations in stress responses. The role of estrogens in conferring stress resilience in females and the unique vulnerabilities of the developing and aging PFC are discussed. Finally, we consider potential pharmacological and non-pharmacological interventions that may mitigate or reverse stress-induced changes in the PFC. The review concludes by identifying key areas for future research, including the need for more studies on the reversibility of stress effects and the potential of emerging technologies in unraveling the complexities of PFC plasticity. This comprehensive overview underscores the critical importance of understanding stress-induced PFC plasticity for developing more effective strategies to prevent and treat stress-related mental health disorders.

Models developed to explain the effects of stress on brain and behavior

There is an integral relationship between stress, brain function and behavior. Over the year's extensive research has led to the development of various models to explain the intricate intersection between brain and stress. This chapter delves into some of the theoretical frameworks that explains the neurobiological and behavioral responses to stress using key models of stress such as the allostatic load model, which is the most common model that describes how chronic stress affect brain structure and function resulting in long-term changes in regions such as the hippocampus, amygdala, and prefrontal cortex which phenotypically express as cognitive impairments, emotional dysfunction seen in various forms of neurological disorder. The neuro-endocrine model, follows the glucocorticoid cascade hypothesis, that associates prolonged stress exposure to hippocampal damage and cognitive decline via alteration in the hypothalamic-pituitary-adrenal (HPA) axis and the overproduction of stress hormones like cortisol which can induce hippocampal atrophy, impair learning and memory, and promote depressive-like behaviors. The neurobiological stress model addresses the role of the hypothalamic-pituitary-adrenal (HPA) axis and stress-related neurotransmitters in shaping behavioral responses, emphasizing alterations in neuroplasticity and synaptic function. These models demonstrate how chronic stress can alter neural plasticity, neurotransmitter systems, and synaptic connectivity, affecting behavior and cognitive function. Hence by integrating molecular, neurobiological, and behavioral perspectives, these models offer a comprehensive understanding of how stress alters brain activity and behavior. The chapter further showcase how these models direct the development of medical interventions, shedding light on potential therapies that target the underlying molecular mechanisms of stress-induced brain changes.

Effects of stress on cognitive performance

Stress remains a pervasive challenge in modern life, exerting significant impacts on cognitive performance and overall well-being by triggering release of stress hormones like adrenaline and cortisol. It has profound implications for education, work performance, and everyday life, impacting cognitive performance, health outcomes, and social relationships. It does this by impacting memory, attention and focus, informed decision-making, developmental and cognitive performance, work and educational performance, genetic and epigenetic influence, and public health. When a stressor is perceived, the hypothalamus in the brain signals the pituitary gland to release adrenocorticotropic hormone, hence adrenaline is quickly released into the bloodstream, causing immediate physiological changes and thus releasing cortisol gradually to help maintain the body's response to stress over a longer period through the hypothalamic-pituitary-adrenal and sympathetic-adrenomedullar axis. The impacts can be short-term or long-term focusing on the working memory, pre-frontal cortex, amygdala, and hippocampus. By recognizing these implications and implementing targeted interventions, we can foster environments that support resilience, optimize performance, and enhance overall well-being across diverse contexts. This chapter also highlighted some mitigation strategies to reduce stress-related activities and improve cognitive performance, such as cognitive-behavioral therapy, mindfulness-based stress reduction, healthy lifestyle adoption, pet therapy, time management and prioritization, and workplace interventions.

Caregiver-reported emotional-behavioral symptoms in Spanish youth during the COVID-19 pandemic: a longitudinal study

BACKGROUND

COVID-19 pandemic stressors affected youth's mental health. This longitudinal study aims to explore these effects while considering predictive factors such as age and sex.

METHODS

An initial sample of 1502 caregivers answered a longitudinal survey evaluating their youths' (4-17 years of age) emotional/behavioral symptoms using the Pediatric Symptom Checklist (PSC) screening tool. First assessment in May-July 2020 included the prior year's retrospective (TR) and since-lockdown-start (T0) PSC, followed by monthly evaluations until February 2021.

RESULTS

A positive screening PSC (PSC+) was reported in 13.09% of cases at TR and 35.01% at T0, but the likelihood of PSC+ quickly decreased over time. At T0, a more pronounced impact was found on children (39.7%) compared to adolescents (25.4%); male children exhibited higher risk for a PSC+ at T0 and longitudinally than females. Adolescents presented a weaker effect of time-improvement. PSC+ at TR, experienced stressors, and caregiver's stress/depressive symptoms positively predicted PSC+ at T0 and longitudinally; adolescents' unproductive coping style predicted PSC+ at T0. CONCLUSION: The study shows a caregiver-reported increase in emotional/behavioral symptoms in youths during the COVID-19 pandemic, affecting predominantly younger children in the early stages and showing gradual improvement over time, albeit possibly slower in adolescents.

IMPACT

The results show the anticipated surge in emotional and behavioral symptoms during the COVID-19 lockdown in youth reported by caregivers, followed by subsequent amelioration. Of greater significance, the study reveals a heightened impact on young children initially, yet it suggests a slower improvement trajectory in adolescents. The study also identifies risk factors linked to emotional and behavioral symptoms within each age group. Alongside the longitudinal approach, the authors underscore the remarkable inclusion of a significant representation of young children, an unusual feature in such surveys.

Investigating amygdala nuclei volumes in military personnel with post-traumatic stress disorder, major depressive disorder, and adjustment disorder: A retrospective cross-sectional study using clinical routine data

BACKGROUND

Post-traumatic Stress Disorder (PTSD), Major Depressive Disorder (MDD), and Adjustment Disorder (AdjD) are highly prevalent among military personnel, often presenting diagnostic challenges due to overlapping symptoms and reliance on self-reporting. The amygdala, particularly the basolateral complex involved in fear-related memory formation and extinction recall, plays a crucial role in emotional processing. Abnormalities in these amygdala nuclei are implicated in PTSD and may distinguish it from other disorders like MDD and AdjD, where these mechanisms are less central. Investigating structural differences in specific amygdala nuclei could enhance diagnostic precision and inform targeted interventions.

GOAL

This study aimed to explore volumetric differences in amygdala nuclei among patients with PTSD, MDD, comorbid PTSD and MDD (PTSD+MDD), and AdjD using routine clinical MRI data. We hypothesized that patients with PTSD would exhibit distinct amygdala nuclei volumes compared to those with MDD or AdjD. Additionally, we examined the influence of symptom duration, prior medication, and psychotherapeutic experience on amygdala volumes.

METHODS

We conducted a retrospective cross-sectional study with 185 military personnel (162 men, 23 women) diagnosed with PTSD (n = 50), MDD (n = 70), PTSD+MDD (n = 38), and AdjD (n = 27). High-resolution T1-weighted MRI scans were obtained using a 3T Siemens Skyra scanner. Amygdala subfields were automatically segmented and volumetrized using FreeSurfer software. Analysis of covariance (ANCOVA) models compared amygdala nuclei volumes across diagnostic groups, controlling for estimated total intracranial volume (eTIV), age, and gender. Exploratory analyses included symptom duration, medication use, and prior psychotherapy as additional covariates. Sensitivity analyses further examined the impact of depressive episode type (first vs. recurrent), severity (mild, moderate, severe), and AdjD symptom duration.

RESULTS

The main analyses revealed no significant differences in the volumes of the basolateral and medial amygdala nuclei among the PTSD, MDD, PTSD+MDD, and AdjD groups. Exploratory analyses did not identify significant associations between amygdala volumes and symptom duration, medication use, or prior psychotherapy. Sensitivity analyses also showed no significant volumetric differences related to depressive episode type, severity, or AdjD symptom duration.

CONCLUSION

Our findings suggest that, within this military population, amygdala nuclei volumes measured using routine clinical MRI data do not significantly differ among patients with PTSD, MDD, PTSD+MDD, and AdjD. This indicates that structural amygdala volumetry alone may not suffice to distinguish between these stress-related disorders in clinical settings. The study highlights the complexity of diagnosing overlapping mental health conditions and underscores the need for comprehensive approaches that integrate neuroimaging with clinical assessments. Future research should include healthy control groups, consider additional brain regions and functional connectivity, and employ longitudinal designs to better understand the temporal dynamics of amygdala changes and their relation to symptomatology.

Current Status and Future Directions of Artificial Intelligence in Post-Traumatic Stress Disorder: A Literature Measurement Analysis

This study aims to explore the current state of research and the applicability of artificial intelligence (AI) at various stages of post-traumatic stress disorder (PTSD), including prevention, diagnosis, treatment, patient self-management, and drug development. We conducted a bibliometric analysis using software tools such as Bibliometrix (version 4.1), VOSviewer (version 1.6.19), and CiteSpace (version 6.3.R1) on the relevant literature from the Web of Science Core Collection (WoSCC). The analysis reveals a significant increase in publications since 2017. Kerry J. Ressler has emerged as the most influential author in the field to date. The United States leads in the number of publications, producing seven times more papers than Canada, the second-ranked country, and demonstrating substantial influence. Harvard University and the Veterans Health Administration are also key institutions in this field. The Journal of Affective Disorders has the highest number of publications and impact in this area. In recent years, keywords related to functional connectivity, risk factors, and algorithm development have gained prominence. The field holds immense research potential, with AI poised to revolutionize PTSD management through early symptom detection, personalized treatment plans, and continuous patient monitoring. However, there are numerous challenges, and fully realizing AI's potential will require overcoming hurdles in algorithm design, data integration, and societal ethics. To promote more extensive and in-depth future research, it is crucial to prioritize the development of standardized protocols for AI implementation, foster interdisciplinary collaboration-especially between AI and neuroscience-and address public concerns about AI's role in healthcare to enhance its acceptance and effectiveness.

Macrostructural Brain Morphology as Moderator of the Relationship Between Pandemic-Related Stress and Internalizing Symptomology During COVID-19 in High-Risk Adolescents

BACKGROUND

According to person-by-environment models, individual differences in traits may moderate the association between stressors and the development of psychopathology; however, findings in the literature have been inconsistent and little literature has examined adolescent brain structure as a moderator of the effects of stress on adolescent internalizing symptoms. The COVID-19 pandemic presented a unique opportunity to examine the associations between stress, brain structure, and psychopathology. Given links of cortical morphology with adolescent depression and anxiety, the current study investigated whether cortical morphology moderated the relationship between stress from the COVID-19 pandemic and the development of internalizing symptoms in familial high-risk adolescents.

METHODS

Prior to the COVID-19 pandemic, 72 adolescents (27 male) completed a measure of depressive and anxiety symptoms and underwent magnetic resonance imaging. T1-weighted images were acquired to assess cortical thickness and surface area. Approximately 6 to 8 months after COVID-19 was declared a global pandemic, adolescents reported their depressive and anxiety symptoms and pandemic-related stress.

RESULTS

Adjusting for pre-pandemic depressive and anxiety symptoms and stress, increased pandemic-related stress was associated with increased depressive but not anxiety symptoms. This relationship was moderated by cortical thickness and surface area in the anterior cingulate and cortical thickness in the medial orbitofrontal cortex such that increased stress was only associated with increased depressive and anxiety symptoms among adolescents with lower cortical surface area and higher cortical thickness in these regions.

CONCLUSIONS

Results further our understanding of neural vulnerabilities to the associations between stress and internalizing symptoms in general and during the COVID-19 pandemic in particular.