Post-traumatic stress disorder: clinical and translational neuroscience from cells to circuits

Cholinergic signaling to CA1 astrocytes controls fear extinction

Fear extinction is an evolutionarily conserved biological process that allows an organism to better re-adapt; its deficits can lead to psychiatric disorders. Fear extinction is considered to rely mostly on neuronal function. However, whether and how astrocytes contribute to fear extinction is largely unknown. Here, we show that hippocampal CA1 astrocytes exhibit de novo Ca2+ dynamics during fear extinction. Inhibition of these astrocytic Ca2+ dynamics impairs, while their activation facilitates, fear extinction. In this regulation of fear extinction, the posterior basal forebrain (pBF) cholinergic input to hippocampus drives CA1 astrocytic Ca2+ dynamics through the activation of α4 and α7 subunits of nicotinic acetylcholine receptors. Clinically used acetylcholinesterase inhibitor donepezil increases CA1 astrocytic Ca2+ dynamics and facilitates fear extinction. Thus, our findings demonstrate a previously unrecognized and crucial pathway from pBF cholinergic neurons to CA1 astrocytes that governs natural fear extinction. This neuron-glia signaling pathway may constitute a promising target for treatment of fear- and anxiety-related disorders.

Poly ADP-ribosylation regulates Arc expression and promotes adaptive stress-coping

RATIONALE

Rapid adaptation to stressful events is essential for survival and requires acute stress response and stress-coping strategy. However, the molecular mechanisms that govern this coping strategy have yet to be fully discovered.

OBJECTIVES

This study aims to investigate the effects of poly ADP-ribosylation (PARylation) on stress-coping strategies following acute stress and to identify the target genes influenced by Parp1-induced histone PARylation.

METHODS

Mice were subjected to a forced swim test, a well-established acute stress paradigm, to evaluate cortical PARylation and assess the expression of activity-dependent genes. The pharmacological inhibition of Parp1 was conducted using ABT888 (Veliparib) to determine its effects on stress-coping behavior and related molecular changes.

RESULTS

The forced swim test increased cortical PARylation and upregulated the expression of activity-dependent genes. Systemic inhibition of Parp1 with ABT888 led to impaired stress-coping behavior, evidenced by a reduced immobility response during a subsequent forced swim test done 24 hours later. This impairment was associated with decreased chromatin PARylation and histone H4 acetylation at the Arc promoter and reduced Arc expression observed one hour after Parp1 inhibition.

CONCLUSION

Our findings indicate that chromatin PARylation at the Arc promoters regulates histone H4 acetylation and Arc gene expression, and a subsequent impact on successful stress-coping behavior in response to acute stress.

Unexpected mechanisms of sex-specific memory vulnerabilities to acute traumatic stress

It is increasingly recognized that severe acute traumatic events (e.g., mass shooting, natural disasters) can provoke enduring memory disturbances, and these problems are more common in women. We probed the fundamental sex differences underlying memory vulnerability to acute traumatic stress (ATS), focusing on the role of the sex hormone, estrogen (17β-estradiol) and its receptor signaling in hippocampus. Surprisingly, high physiological hippocampal estrogen levels were required for ATS-induced episodic memory disruption and the concurrent sensitization and generalization of fear memories in both male and female mice. Pharmacological and transgenic approaches demonstrated signaling via estrogen receptor (ER)α in males and, in contrast, ERβ in females, as the mechanisms for these memory problems. Finally, identify distinct hippocampal chromatin states governed by sex and estrogen levels, which may confer an enduring vulnerability to post-traumatic memory disturbances in females.

Identifying behavior regulatory leverage over mental disorders transcriptomic network hubs toward lifestyle-dependent psychiatric drugs repurposing

BACKGROUND

There is a vast prevalence of mental disorders, but patient responses to psychiatric medication fluctuate. As food choices and daily habits play a fundamental role in this fluctuation, integrating machine learning with network medicine can provide valuable insights into disease systems and the regulatory leverage of lifestyle in mental health.

METHODS

This study analyzed coexpression network modules of MDD and PTSD blood transcriptomic profile using modularity optimization method, the first runner-up of Disease Module Identification DREAM challenge. The top disease genes of both MDD and PTSD modules were detected using random forest model. Afterward, the regulatory signature of two predominant habitual phenotypes, diet-induced obesity and smoking, were identified. These transcription/translation regulating factors (TRFs) signals were transduced toward the two disorders' disease genes. A bipartite network of drugs that target the TRFS together with PTSD or MDD hubs was constructed.

RESULTS

The research revealed one MDD hub, the CENPJ, which is known to influence intellectual ability. This observation paves the way for additional investigations into the potential of CENPJ as a novel target for MDD therapeutic agents development. Additionally, most of the predicted PTSD hubs were associated with multiple carcinomas, of which the most notable was SHCBP1. SHCBP1 is a known risk factor for glioma, suggesting the importance of continuous monitoring of patients with PTSD to mitigate potential cancer comorbidities. The signaling network illustrated that two PTSD and three MDD biomarkers were co-regulated by habitual phenotype TRFs. 6-Prenylnaringenin and Aflibercept were identified as potential candidates for targeting the MDD and PTSD hubs: ATP6V0A1 and PIGF. However, habitual phenotype TRFs have no leverage over ATP6V0A1 and PIGF.

CONCLUSION

Combining machine learning and network biology succeeded in revealing biomarkers for two notoriously spreading disorders, MDD and PTSD. This approach offers a non-invasive diagnostic pipeline and identifies potential drug targets that could be repurposed under further investigation. These findings contribute to our understanding of the complex interplay between mental disorders, daily habits, and psychiatric interventions, thereby facilitating more targeted and personalized treatment strategies.

The evolving neurobiology of early-life stress

Because early-life stress is common and constitutes a strong risk factor for cognitive and mental health disorders, it has been the focus of a multitude of studies in humans and experimental models. Yet, we have an incomplete understanding of what is perceived as stressful by the developing brain, what aspects of stress influence brain maturation, what developmental ages are particularly vulnerable to stress, which molecules mediate the effects of stress on brain operations, and how transient stressful experiences can lead to enduring emotional and cognitive dysfunctions. Here, we discuss these themes, highlight the challenges and progress in resolving them, and propose new concepts and avenues for future research.

Fear conditioning: Insights into learning, memory and extinction and its relevance to clinical disorders

Fear, whether innate or learned, is an essential emotion required for survival. The learning, and subsequent memory, of fearful events enhances our ability to recognise and respond to threats, aiding adaptation to new, ever-changing environments. Considerable research has leveraged associative learning protocols such as contextual or auditory forms of fear conditioning in rodents, to understand fear learning, memory consolidation and extinction phases of memory. Such assays have led to detailed characterisation of the underlying neurocircuitry and neurobiology supporting fear learning processes. Given fear processing is conserved across rodents and humans, fear conditioning experiments provide translational insights into fundamental memory processes and fear-related pathologies. This review examines associative learning protocols used to measure fear learning, memory and extinction, before providing an overview on the underlying complex neurocircuitry including the amygdala, hippocampus and medial prefrontal cortex. This is followed by an in-depth commentary on the neurobiology, particularly synaptic plasticity mechanisms, which regulate fear learning, memory and extinction. Next, we consider how fear conditioning assays in rodents can inform our understanding of disrupted fear memory in human disorders such as post-traumatic stress disorder (PTSD), anxiety and psychiatric disorders including schizophrenia. Lastly, we critically evaluate fear conditioning protocols, highlighting some of the experimental and theoretical limitations and the considerations required when conducting such assays, alongside recent methodological advancements in the field. Overall, rodent-based fear conditioning assays remain central to making progress in uncovering fundamental memory phenomena and understanding the aetiological mechanisms that underpin fear associated disorders, alongside the development of effective therapeutic strategies.

The neuroscientific basis of post-traumatic stress disorder (PTSD): From brain to treatment

Post-traumatic stress disorder (PTSD) is a debilitating mental health condition resulting from exposure to traumatic events, marked by persistent psychological distress and impairment in daily functioning. Risk factors for PTSD include genetic predispositions, neurobiological factors, as well as psychosocial and environmental influences. Specific demographic groups, such as veterans, first responders, and individuals in high-risk environments, are more susceptible to developing the disorder. Despite growing research, there remain gaps in understanding the full pathophysiology of PTSD, and existing diagnostic methods and treatments are not universally effective, contributing to a significant public health burden. This chapter explores the pathophysiology of PTSD, focusing on its underlying mechanisms, associated risk factors, and high-risk populations. Biological biomarkers such as neuroimaging findings, hormonal imbalances, genetic predispositions, and physiological indicators are discussed in the context of their role in PTSD diagnosis and understanding. Both pharmacological treatments and non-pharmacological interventions, including Cognitive Behavioral Therapy (CBT), Eye Movement Desensitization and Reprocessing (EMDR), and mindfulness-based techniques, are reviewed for their effectiveness in symptom management. Further research is essential to advance individualized diagnostic techniques and optimize treatment strategies, ensuring more personalized care for PTSD patients.

Biological treatments for co-occurring eating disorders and psychological trauma: a systematic review

Introduction

Many people with eating disorders report having experienced childhood maltreatment or a traumatic event prior to developing an eating disorder. Although many people with eating disorders have significant traumatic exposure or symptoms of post-traumatic stress disorder, very little research has examined the effects of combined treatments for this group. The purpose of this systematic review was to synthesize all existing research on biological treatments for those with eating disorders and psychological trauma, evaluate their safety, and identify future areas of research in this area to support patients with eating disorders and psychological trauma.

Method

A multi-step literature search, according to an a priori protocol was performed on PubMed, Embase, APA PsycINFO, Web of Science, Scopus and Cochrane Central. Studies needed to include a biological intervention and report on at least one eating disorder or psychological trauma outcome. Given the limited research in this area, minimal exclusion criteria were applied. A quality assessment of all included studies was completed using the Risk of Bias in Non-Randomized Studies-or Interventions (ROBINS-I) tool.

Results

After removing duplicates, 2623 article titles and abstracts were screened, with 43 articles selected for a full-text review. Following the full-text review, 11 articles met the inclusion criteria. The biological treatments examined included repurposed medications (n = 3), ketamine (n = 2), repetitive transcranial magnetic stimulation (rTMS; n = 2), deep brain stimulation (n =1) electroconvulsive therapy (ECT; n = 1), 3,4-methylenedioxymethamphetamine (MDMA; n = 1), and neurofeedback (n = 1). All studies reported on some improvement in either eating disorder or trauma pathology, with the strongest effect for repetitive transcranial magnetic stimulation and MDMA. While some effects were promising, missing data and selective reporting limited the interpretability of the findings. Adverse events across interventions were common.

Conclusion

Although psychological trauma is common in those with eating disorders, very few treatments have been evaluated in this population. Future work should aim to investigate biological treatments for those with co-occurring eating disorders and psychological trauma, as these evolving treatments show potential benefits for this complex group.

Critically Assessing the Unanswered Questions of How, Where, and When to Induce Plasticity in the Posttraumatic Stress Disorder Network With Transcranial Magnetic Stimulation

Extinction of traumatic memory, a primary treatment approach (termed exposure therapy) in posttraumatic stress disorder (PTSD), occurs through relearning and may be subserved at the molecular level by long-term potentiation of relevant circuits. In parallel, repetitive transcranial magnetic stimulation (TMS) is thought to work through long-term potentiation-like mechanisms and may provide a novel, safe, and effective treatment for PTSD. In a recent failed randomized controlled trial we emphasized the necessity of correctly identifying cortical targets, the directionality of TMS protocols, and the role of memory activation. Here, we provide a systematic review of TMS for PTSD to further identify how, where, and when TMS treatment should be delivered to alleviate PTSD symptoms. We conducted a systematic review of the literature by searching for repetitive TMS clinical trials involving patients with PTSD and outcomes. We searched MEDLINE through October 25, 2023, for "TMS and PTSD" and "transcranial magnetic stimulation and posttraumatic stress disorder." Thirty-one publications met our inclusion criteria (k = 17 randomized controlled trials, k = 14 open label). Randomized controlled trial protocols were varied in terms of TMS protocols, cortical TMS targets, and memory activation protocols. There was no clear superiority of low-frequency (k = 5) versus high-frequency (k = 6) protocols or by stimulation location. Memory provocation or exposure protocols (k = 7) appear to enhance response. Overall, TMS appears to be effective in treating PTSD symptoms across a variety of TMS frequencies, hemispheric target differences, and exposure protocols. Disparate protocols may be conceptually harmonized when viewed as potentiating proposed anxiolytic networks or suppressing anxiogenic networks.

Unlocking NAC's potential ATF4 and m6A dynamics in rescuing cognitive impairments in PTSD

In this study, we investigated the therapeutic potential of N-acetylcysteine (NAC) in a mouse model of post-traumatic stress disorder (PTSD) induced by a single prolonged stress (SPS) protocol. Our findings demonstrate that NAC treatment significantly improved cognitive function and mitigated hippocampal neuronal apoptosis in PTSD model mice. These positive effects were accompanied by a reduction in m6A methylation levels and activating transcription factor 4 (ATF4) expression. Silencing ATF4 further attenuated hippocampal neuronal apoptosis and cognitive dysfunction, while ATF4 overexpression partially reversed the beneficial effects of NAC. It suggests that NAC's efficacy in PTSD may be mediated by its regulation of ATF4 expression and m6A methylation levels. Overall, our study provides valuable insights into the potential mechanism of action for NAC in PTSD treatment, offering promising avenues for future therapeutic strategies.

A review on hydroxyapatite fabrication: from powders to additive manufactured scaffolds

Hydroxyapatite (HA), the main inorganic bone component, is the most widely researched bioceramic for bone repair. This paper presents a comprehensive review of recent advancements in HA synthesis methods and their integration into additive manufacturing (AM) processes. Synthesis methodologies discussed include wet, dry, and biomimetic routes, emphasizing their impact on tailoring the physicochemical properties of HA for biomedical applications. The incorporation of dopants and additives during synthesis is explored for optimizing the mechanical, biological, and osteogenic characteristics of HA-based materials. Moreover, the evolution of AM technologies from conventional 3D printing to advanced 4D and 5D printing is detailed, covering material selection, process parameters, and post-processing strategies vital for fabricating intricate, patient-specific scaffolds, implants, and drug delivery systems utilizing HA. The review underscores the importance of achieving precise control over microstructure and porosity to mimic native tissue architectures accurately. Furthermore, emerging applications of HA-based constructs in tissue engineering, regenerative medicine, drug delivery, and orthopedic implants are discussed, highlighting their potential to address critical clinical needs. Despite the glimmer of hope provided by the advent and progress of such AM capabilities, several aspects need to be addressed to develop efficient HA-based bone substitutes, which are explored in detail in this review.

Golden Snub-Nosed Monkeys: Potential Primate Paradigm in Post-Traumatic Stress Disorder Research

Post-traumatic stress disorder (PTSD) is a severe psychiatric disorder, affecting approximately 25-35% of individuals exposed to significant psychological trauma. Despite extensive research, the underlying biological mechanisms of PTSD remain poorly understood, and the effectiveness of trauma-focused psychotherapeutic interventions is limited. To date, animal studies investigating trauma responses have primarily relied on rodent models, with the potential contributions of non-human primates relatively neglected. In this study, matched-control observations were employed to examine maternal caregiving behaviors, prosocial interactions, and responses to alarm calls in free-ranging golden snub-nosed monkeys (Rhinopithecus roxellana) before and after an infanticide event. Results indicated a significant decrease in prosocial behaviors among some mothers, accompanied by significant increases in caregiving behaviors, heightened responsiveness to alarm calls, and indications of low mood. These findings provide evidence of trauma-related behavioral changes in golden snub-nosed monkeys, underscoring their utility as a model for studying PTSD given the similarity to trauma responses observed in humans. Overall, this study provides a foundation for further investigation into the evolutionary and biological aspects of PTSD, as well as the interactions between species-specific trauma responses. Future research should explore the use of non-human primate models to deepen our understanding of PTSD mechanisms.

Decoding threat neurocircuitry representations during traumatic memory recall in PTSD

The neurocircuitry mechanisms underlying recall of traumatic memories remain unclear. This study investigated whether traumatic memory recall engages neurocircuitry representations that mirror activity patterns engaged during generalized threat stimulus processing in Post Traumatic Stress Disorder (PTSD). Multivariate pattern analysis was used to train 3 decoders. A "trauma" decoder was trained on fMRI patterns during idiographic trauma versus neutral narratives in a sample of 73 adult women with PTSD. A separate cohort of 125 adult participants completed a reward and threat learning task, from which "shock" and "reward loss" decoders were trained on neural patterns during threat or reward outcome delivery, respectively. These decoders were then cross-tested on the alternative datasets, allowing analyses of the degree to which traumatic memory recall engaged neurocircuitry representations that overlap with more general aversive stimuli. Decoders were trained and tested in four networks related to salience processing as well bilateral amygdala and hippocampal masks. The shock decoder trained in a midcingulate / posterior insula network demonstrated elevated predictions for shock during traumatic versus neutral memory recall. Similarly, the trauma decoder made elevated predictions about trauma recall during shock versus no shock delivery across multiple networks related to salience processing. There was no overlap between reward loss decoder predictions and trauma memory recall or vice versa. PTSD participants with elevated re-experiencing symptoms demonstrated the highest engagement of shock activity patterns during trauma memory recall. These results suggest that trauma memory recall engages neurocircuitry representations that overlap with threat, specifically painful, stimulus delivery.

Single-Nucleus RNA Sequencing Reveals That Gabra6+ Neurons in Prefrontal Cortex Promote the Progression of PTSD After Shockwave-Induced TBI

Shockwave-induced traumatic brain injury (TBI) results in the onset of post-traumatic stress disorder (PTSD), triggered either by the TBI itself or other stressors. However, the interplay and underlying mechanisms of how these factors synergistically induce PTSD remain inadequately elucidated. Here, mice in the TBI (induced by biological shock tube blast injury) and PTSD (induced by single prolonged stress method) groups both displayed symptoms of PTSD behaviors, with the TBI+PTSD (composite model) group exhibiting more severe manifestations. The result of snRNA-seq demonstrated a noticeable increase in the population of Gabra6+ neurons in the prefrontal cortex region of mice in the TBI+PTSD group. Knocking down cortical Gabra6 mitigated PTSD-related behavioral outcomes. Mechanistically, the Smad3/4 complex activation led to the upregulation of Gabra6 expression in cortical neurons. Interaction of Gabra6 with Homer1 activated downstream cAMP signaling pathways. Homer1KO-Nestin mice show reduced susceptibility to PTSD. Subsequently, the efficacy of monoclonal antibody intervention at the 218 site of Gabra6 in ameliorating PTSD development is verified. This study suggests that TBI and stressors act as independent components in PTSD development, with Gabra6+ neurons pivotal in synergistically facilitating PTSD formation. Strategies geared toward minimizing exposure to singular or combined stressors may effectively diminish the risk of developing PTSD.

Post-traumatic stress disorder: evolving conceptualization and evidence, and future research directions

The understanding of responses to traumatic events has been greatly influenced by the introduction of the diagnosis of post-traumatic stress disorder (PTSD). In this paper we review the initial versions of the diagnostic criteria for this condition and the associated epidemiological findings, including sociocultural differences. We consider evidence for post-traumatic reactions occurring in multiple contexts not previously defined as traumatic, and the implications that these observations have for the diagnosis. More recent developments such as the DSM-5 dissociative subtype and the ICD-11 diagnosis of complex PTSD are reviewed, adding to evidence that there are several distinct PTSD phenotypes. We describe the psychological foundations of PTSD, involving disturbances to memory as well as to identity. A broader focus on identity may be able to accommodate group and communal influences on the experience of trauma and PTSD, as well as the impact of resource loss. We then summarize current evidence concerning the biological foundations of PTSD, with a particular focus on genetic and neuroimaging studies. Whereas progress in prevention has been disappointing, there is now an extensive evidence supporting the efficacy of a variety of psychological treatments for established PTSD, including trauma-focused interventions - such as trauma-focused cognitive behavior therapy (TF-CBT) and eye movement desensitization and reprocessing (EMDR) - and non-trauma-focused therapies, which also include some emerging identity-based approaches such as present-centered and compassion-focused therapies. Additionally, there are promising interventions that are neither psychological nor pharmacological, or that combine a pharmacological and a psychological approach, such as 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy. We review advances in the priority areas of adapting interventions in resource-limited settings and across cultural contexts, and of community-based approaches. We conclude by identifying future directions for work on trauma and mental health.

Multimodal associations between posterior hippocampus glutamate metabolism, visual cortex connectivity, and intrusive trauma reexperiencing symptoms

Objective

Hippocampal dysfunction is implicated in posttraumatic stress disorder (PTSD), particularly intrusive reexperiencing symptoms, and may be mediated by glutamatergic excitotoxicity. Markers of glutamate dysfunction (higher glutamate to N-acetyl aspartate levels; Glu/NAA) in the hippocampus (HPC) have been linked to reexperiencing symptoms. However, the HPC demonstrates heterogeneity along its anterior-posterior axis, with different functional connectivity patterns and PTSD symptom associations, motivating investigations into glutamate metabolism in anterior and posterior HPC subregions (a/pHPC).

Methods

121 symptomatic trauma-exposed adults (93 female) with current trauma reexperiencing symptoms completed magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging to examine the regional specificity of HPC Glu/NAA associations with reexperiencing, and the link to a/pHPC functional connectivity. PTSD symptoms were assessed with the Clinician-Administered PTSD Scale for DSM-5.

Results

Reexperiencing symptom severity was associated with greater Glu/NAA in the pHPC, but not aHPC. pHPC Glu/NAA was further linked to stronger functional connectivity between the pHPC and visual cortex (VC), which in turn correlated with more severe reexperiencing symptoms. This strengthened pHPC-VC connectivity explained the shared variance between pHPC Glu/NAA and reexperiencing severity, suggesting dysregulated glutamate metabolism in the pHPC may contribute to reexperiencing symptoms through functional connectivity with the VC.

Conclusions

These findings replicate prior work linking HPC Glu/NAA to trauma reexperiencing symptoms and provide novel evidence this association may be specific to the pHPC and mediated by its functional connectivity with the VC. This multimodal investigation supports translational models of glutamatergic dysfunction in trauma-related disorders and highlights new targets for pharmacological and neuromodulatory interventions.

Physiology mechanisms of exercise for PTSD: a narrative review

In at-risk societies, the population of post-traumatic stress disorder (PTSD) incidence is gradually expanding from veterans to the general public. In the face of the high incidence of PTSD, exercise therapy, as an economical and maneuverable treatment, has not received the attention it deserves. In this paper, the literature on PTSD symptom improvement through comb-climbing exercise interventions found that performing long-term exercise can achieve significant improvement in PTSD symptoms by modulating the central nervous system, autonomic nervous system, and immune system at the physiological level. Aerobic exercise (running, walking) is beneficial to the central nervous system and immune system; anaerobic exercise positively affects the autonomic nervous system, including resistance or strength endurance training; yoga, which focuses on flexibility and balance training, has a positive effect on the immune system. Future research should explore the neutral and negative effects and mechanisms of exercise on PTSD interventions. Expand more empirical studies in special occupational populations. And implement longitudinal intervention studies with PTSD patients to gain an in-depth understanding of PTSD intervention effects.

Transauricular vagus nerve stimulation in preventing post-traumatic stress disorder in emergency trauma surgery patients in China: a study protocol for a multicenter, double-blind, randomised, controlled trial

INTRODUCTION

The incidence of post-traumatic stress disorder (PTSD) in emergency trauma surgery patients is 24%, emphasising the urgent need for effective early interventions and treatments. Transauricular vagus nerve stimulation (ta-VNS) modulates the autonomic nervous system by stimulating the nucleus tractus solitarius while affecting PTSD-related neural networks, including the prefrontal cortex, hippocampus and amygdala, potentially offering new options for PTSD prevention and treatment. This study aims to evaluate the efficacy and safety of ta-VNS in preventing PTSD in emergency trauma surgery patients.

METHODS AND ANALYSIS

This multicentre, double-blind, randomised controlled study aims to evaluate the incidence of PTSD in emergency trauma surgery patients receiving either ta-VNS or sham stimulation. A total of 350 participants will be randomly assigned to receive either active or sham stimulation. The active group will undergo electrical stimulation of the left cymba conchae at 30 Hz with a pulse width of 250 µs, using a 30 s on/30 s off cycle. The intensity will start at 0.4 V, increasing in 0.4 V increments until a tingling sensation is detected, and will be adjusted to the highest tolerable level without causing pain. The initial intervention will begin once informed consent is obtained and randomisation is completed in the preoperative preparation room, continuing until the surgery is finished. For the four postoperative days, the intervention will be administered two times per day in 2-h sessions each morning and evening. The sham stimulation group will follow a similar procedure without actual stimulation. The primary outcome is the incidence of PTSD evaluated on postoperative day 30, with secondary outcomes including recovery quality, sleep quality, and adverse events.

ETHICS AND DISSEMINATION

The protocol received approval from Sir Run Run Shaw Hospital, affiliated with Zhejiang University School of Medicine, on 15 October 2024 (approval number: 20240562). The study will adhere to the Declaration of Helsinki guidelines, and written informed consent will be obtained from all participants. Results will be submitted to a peer-reviewed journal for publication.

TRIAL REGISTRATION NUMBER

China Clinical Trial Registration Center (ChiCTR2400080342). Trial details: https://www.chictr.org.cn/showproj.html?proj=217809.

4-Methoxycinnamic acid ameliorates post-traumatic stress disorder-like behavior in mice by antagonizing the CRF type 1 receptor

AIMS

Posttraumatic stress disorder (PTSD) is a debilitating neuropsychiatric illness caused by traumatic or life-threatening events and manifesting as various symptoms, including intrusive re-experiences of trauma, avoidance behaviors, hyperarousal, and negative changes in perception and mood.

MAIN METHODS

Current monoamine-based medications commonly exhibit limited efficacy and significant side effects, which hamper their clinical utility. To address this unmet need, we explored 4-methoxycinnamic acid (4-MCA) as a potential novel treatment for PTSD in a single prolonged stress (SPS)-induced animal model.

KEY FINDINGS

Administration of 4-MCA (3 and 10 mg/kg, p.o.) significantly mitigated anxiety-like behaviors, alleviated depression-like behaviors, and improved cognitive function in an SPS-treated PTSD mouse model. Further, 4-MCA treatment effectively rectified the fear extinction deficits in the fear conditioning test. Molecular analyses revealed that 4-MCA normalized the elevated corticotropin-releasing hormone (CRH) levels as well as the phosphorylation of protein kinase A (PKA) and cAMP response element-binding protein (CREB) in the amygdala, a pivotal region for fear memory formation. Co-administration of 4-MCA and the CRFR1 antagonist antalarmin at subeffective doses facilitated fear memory extinction.

SIGNIFICANCE

These findings suggest that 4-MCA alleviates SPS-induced PTSD-like behaviors by regulating the CRH-CRFR1-PKA-CREB signaling pathway in the amygdala, and that 4-MCA may be a potential candidate for future PTSD treatment.

Transcranial magnetic stimulation for obsessive-compulsive disorder and post-traumatic stress disorder: A comprehensive systematic review and analysis of therapeutic benefits, cortical targets, and psychopathophysiological mechanisms

Transcranial magnetic stimulation (TMS) is a safe non-invasive treatment technique. We systematically reviewed randomised controlled trials (RCTs) applying TMS in obsessive compulsive disorder (OCD) and post-traumatic stress disorder (PTSD) to analyse its therapeutic benefits and explore the relationship between cortical target and psychopathophysiology. We included 47 randomised controlled trials (35 for OCD) and found a 22.7 % symptom improvement for OCD and 29.4 % for PTSD. Eight cortical targets were investigated for OCD and four for PTSD, yielding similar results. Bilateral dlPFC-TMS exhibited the greatest symptom change (32.3 % for OCD, N = 4 studies; 35.7 % for PTSD, N = 1 studies), followed by right dlPFC-TMS (24.4 % for OCD, N = 8; 26.7 % for PTSD, N = 10), and left dlPFC-TMS (22.9 % for OCD, N = 6; 23.1 % for PTSD, N = 1). mPFC-TMS showed promising results, although evidence is limited (N = 2 studies each for OCD and PTSD) and findings for PTSD were conflicting. Despite clinical improvement, reviewed reports lacked a consistent and solid rationale for cortical target selection, revealing a gap in TMS research that complicates the interpretation of findings and hinders TMS development and optimisation. Future research should adopt a hypothesis-driven approach rather than relying solely on correlations from imaging studies, integrating neurobiological processes with affective, behavioural, and cognitive states, thereby doing justice to the complexity of human experience and mental illness.

Aberrant neural event segmentation during a continuous social narrative in trauma-exposed older adolescents and young adults

Post-traumatic stress and major depressive disorders are associated with "overgeneral" autobiographical memory, or impaired recall of specific life events. Interpersonal trauma exposure, a risk factor for both conditions, may influence how symptomatic trauma-exposed (TE) individuals segment everyday events. The ability to parse experience into units (event segmentation) supports memory. Neural state transitions occur within a cortical hierarchy and play a key role in event segmentation, with regions like the occipital cortex, angular gyrus, and striatum involved in parsing event structure. We examined whether interpersonal trauma exposure was associated with alterations in the cortical hierarchy and striatal activity at neural state transitions in symptomatic TE versus healthy control (HC) individuals. Fifty older adolescents and young adults (29 TE, 21 HC) viewed the film "Partly Cloudy" during functional magnetic resonance imaging. A greedy-state boundary search algorithm assessed the optimal number of events, quality, and segmentation agreement of neural state transitions in the occipital cortex and angular gyrus. Striatal (nucleus accumbens, caudate, and putamen) activity was assessed at occipital and angular gyrus-evoked state transitions. Compared to HCs, TE participants displayed less occipital and greater angular gyrus-evoked optimal number of neural state transitions. TE participants also displayed lower quality of neural state segmentation solutions in occipital and angular cortices compared to HCs. Additionally, TE participants had less putamen activity at angular gyrus-evoked state transitions than HCs. This investigation provides neurobiological insights into aberrant event segmentation in symptomatic TE individuals, shedding light on mechanisms influencing overgeneral memory in trauma-related disorders.

Offline ensemble co-reactivation links memories across days

Memories are encoded in neural ensembles during learning1-6 and are stabilized by post-learning reactivation7-17. Integrating recent experiences into existing memories ensures that memories contain the most recently available information, but how the brain accomplishes this critical process remains unclear. Here we show that in mice, a strong aversive experience drives offline ensemble reactivation of not only the recent aversive memory but also a neutral memory formed 2 days before, linking fear of the recent aversive memory to the previous neutral memory. Fear specifically links retrospectively, but not prospectively, to neutral memories across days. Consistent with previous studies, we find that the recent aversive memory ensemble is reactivated during the offline period after learning. However, a strong aversive experience also increases co-reactivation of the aversive and neutral memory ensembles during the offline period. Ensemble co-reactivation occurs more during wake than during sleep. Finally, the expression of fear in the neutral context is associated with reactivation of the shared ensemble between the aversive and neutral memories. Collectively, these results demonstrate that offline ensemble co-reactivation is a neural mechanism by which memories are integrated across days.

Post-traumatic stress disorder-induced behavioral modulation by the medial septum-medial habenula neural pathway

Post-traumatic stress disorder (PTSD) is characterized by anxiety, excessive fear, distress, and weakness as symptoms of a psychiatric disorder. However, the mechanism associated with its symptoms such as anxiety-like behaviors is not well understood. It is aimed to investigate the underlying mechanisms of the medial septum (MS)-medial habenula (MHb) neural circuit modulating the anxiety-like behaviors of PTSD mice through in vivo fiber photometry recording, optogenetics, behavioral testing by open-field and elevated plus maze, fluorescent gold retrograde tracer technology, and viral tracer technology. In the mouse PTSD model induced by compound stress consisting of single-prolonged stress combined with electrical foot shock, the average peak value of the Ca2 + signals in both the MHb and MS glutamatergic neurons significantly increased. The anterograde and retrograde tracer markers were used to indicate the possible connection between MS and MHb via glutamatergic neural pathway. After the optogenetic manipulation of the MS-MHb pathway in mice with PTSD, if the MS-MHb glutamatergic pathway was inhibited, anxiety was relieved based on changes in the various indices of behavioral experiments in mice with PTSD. Moreover, the heart rate of mice decreased. In conclusion, both glutamatergic neurons located in MS and MHb can be engaged in the development of PTSD anxiety-like behavior, and the MS-MHb can be related to the regulation of PTSD anxiety-like behavior and cardiac function through the glutamatergic neural pathway.

Uncovering the dynamics and causality of PTSD symptoms in firefighters: Insights from cross-lagged panel network analyses

Firefighters have a greater prevalence of posttraumatic stress disorder (PTSD) because of their greater risk of exposure to traumatic events. Network analysis offers novel perspectives for understanding PTSD. However, most previous network analysis studies were cross-sectional and failed to reveal the dynamics and causality of PTSD symptoms. Therefore, this study aimed to elucidate the longitudinal development of and causal relationships among PTSD symptoms in firefighters. Two survey waves were conducted among 637 Chinese male firefighters: in April 2021 (baseline) and March 2023 (follow-up). We constructed two cross-sectional networks and one longitudinal cross-lagged panel network (CLPN) of PTSD symptoms. By comparing the two cross-sectional networks, we found that the central symptoms of PTSD changed over time, with central symptoms scattered across different dimensions at baseline and focused on the avoidance dimension at follow-up. The CLPN revealed causal relationships among PTSD symptoms and showed that irritability and nightmares significantly predicted other PTSD symptoms from baseline to follow-up. In summary, our study fills a gap in the longitudinal development of and causal relationships among PTSD symptoms in firefighters and provides potential targets for subsequent prevention and intervention.

The Implementation of the Biopsychosocial Model: Individuals With Alcohol Use Disorder and Post-Traumatic Stress Disorder

INTRODUCTION

This extensive literature review investigates the relationship between post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD), focusing on the neurobiological changes associated with their co-occurrence. Given that these disorders frequently coexist, we analyze mechanisms through which alcohol serves as a coping strategy for PTSD symptoms, particularly highlighting the drinking-to-cope self-medication model, which suggests that alcohol use exacerbates PTSD symptoms and complicates recovery.

METHODS

A systematic literature search was conducted across multiple databases, including PubMed and Google Scholar, to identify studies examining the intersection of the biopsychosocial model with PTSD, AUD, and associated neural alterations.

RESULTS

Findings demonstrate that chronic PTSD is associated with progressive dysfunction in the amygdala, hippocampus, prefrontal cortex, hypothalamic-pituitary-adrenal axis, and white matter pathways. Also, our findings underscore alterations within the reward system, prefrontal cortex, hippocampus, amygdala, basal ganglia, and hypothalamic-pituitary-adrenal axis that contribute to the pathophysiology of AUD. Our results support the notion that a biopsychosocial framework is essential for contemporary addiction treatment, particularly in the context of alcohol addiction and PTSD.

CONCLUSION

PTSD frequently leads individuals to use alcohol as a maladaptive coping strategy, ultimately resulting in neuroadaptive alterations across critical brain regions. These neurobiological changes contribute to the development and maintenance of AUD. The findings reiterate the necessity of employing a biopsychosocial model in treating individuals grappling with both PTSD and AUD. This model allows for a comprehensive understanding of the unique challenges faced by this population, integrating biological, psychological, and social factors that influence recovery.

The clinically relevant MEK inhibitor mirdametinib combined with D-cycloserine and prediction error disrupts fear memory in PTSD models

This study establishes mirdametinib as the first MEK inhibitor that can undergo clinical development for psychiatric indications such as post-traumatic stress disorder (PTSD). PTSD is characterized by persistent traumatic memories with limited effective treatment options. A body of evidence suggests that memory storage is dynamic and constantly updated through post-retrieval modification a process termed reconsolidation. Although ERK/MAPK signaling plays a central role in fear memory consolidation, no clinically translatable MEK inhibitor has been tested in experimental models or in clinical trials to disrupt this process. Furthermore, there is need to develop pharmacological and behavioral strategies to labilize the memory to make it susceptible for disruption. Here, we disrupted fear memory reconsolidation with the clinically relevant MEK inhibitor mirdametinib in C57BL/6 mice and tested memory destabilization strategies using an auditory fear conditioning paradigm, with drugs administered following reactivation of memory. We found prediction error effective in labilizing weak fear memory and combined D-cycloserine (DCS) and predication error effective in labilizing strong fear memory. Mirdametinib disrupted the weak fear memory and reduced ERK phosphorylation in lateral amygdala when coupled with prediction error at the time of memory reactivation but required coordinated combination of DCS, prediction error and mirdametinib to disrupt strong fear memory. Barnes maze spatial memory test and open field test revealed that mirdametinib did not affect retrieval of other forms (spatial) of long-term memory and locomotor activity. Furthermore, the effect of mirdametinib was specific to reconsolidation as it had no effect on fear memory when given without reactivation. These translational findings identify a new drug that can be adapted for the treatment of PTSD.

Memantine Alleviates PTSD-like Symptoms and Improves Dendritic Arborization through Modulation of the HPA Axis and Neuroinflammation in Rats

Post-traumatic stress disorder (PTSD) poses significant neurological and psychiatric challenges. Investigations into the glutamatergic system, particularly the N-methyl-D-aspartate (NMDA) receptor, are crucial for understanding PTSD mechanisms. This study aimed to evaluate the therapeutic potential of the non-competitive NMDA receptor antagonist memantine in mitigating PTSD symptoms and to explore its underlying cellular and molecular impacts. Male Sprague Dawley rats were subjected to inescapable foot shock stress (FS-stress) to model PTSD. Following stress exposure, memantine was administered at doses of 5 mg/kg and 10 mg/kg six hours post-stress. Behavioural assessments, including fear conditioning and sucrose preference tests, were conducted. Golgi-Cox staining was used to assess neuroanatomical changes related to synaptic plasticity. Western blotting was used to analyse molecular markers associated with synaptic plasticity, while immunoassays measured proinflammatory cytokines and cortisol levels. Memantine treatment improved behavioral outcomes, restoring sucrose preference and reducing freezing behavior. Morphological analysis demonstrated that memantine enhanced dendritic spine structure, particularly increasing the proportion of mature mushroom spines, which are critical for synaptic stability. Additionally, memantine normalized cortisol levels, suggesting a regulatory effect on the hypothalamic-pituitary-adrenal (HPA) axis. Additionally, memantine treatment improved the inflammatory cytokine profile, reducing IL-6 and TNF-α levels. These results suggest that memantine has potential as a therapeutic intervention for PTSD by targeting critical pathways involved in stress responses.The findings indicate that memantine, an NMDA receptor antagonist, can counteract behavioral and functional disturbances induced by FS-stress.

The Neuronal Hypofunction of Subdivisions of the Prefrontal Cortex Shows Differential Effects on Contingency Judgment Learning to Gauge Fear Responses

Previous studies have indicated that the infralimbic (IL) and prelimbic (PL) subdivisions of the medial prefrontal cortex (mPFC) serve as critical modulators of fear suppression and expression. Although significant research has been conducted on the extinction of conditioned fear, the mechanisms underlying contextual fear discrimination learning, a form of contingency judgment learning, remain inadequately understood. Our investigation aimed to explore the influence of epigenetic regulation associated with cyclic AMP-response element binding protein (CREB)-dependent long-term memory encoding within the IL and PL on contextual fear discrimination. Our prior and current findings illustrate that epigenetic hypofunction induced by a CREB-Binding Protein (CBP) mutant, which is deficient in histone acetyltransferase activity (CBPΔHAT), within the mPFC leads to compromised contextual fear discrimination while not affecting contextual fear conditioning in these mutants. Unexpectedly, the effect was not noticeable when the hypofunction was constrained to the infralimbic (IL) area; however, the hypofunction of the prelimbic (PL) network led to considerable impairment in fear discrimination. The findings indicate that learning fear discrimination involves differential encoding across the specialized networks of the mPFC. These data suggest that the IL network is not essential for encoding during the acquisition and discrimination of fear or that the PL network may compensate for the IL's inability to encode new information. Furthermore, these results emphasize the importance of histone acetylation in the mPFC as a crucial physiological mechanism for learning contingency judgment.

Fear generalization modulated by shock intensity and protein synthesis inhibitor

RATIONALE

Maladaptive fear responses, including sensitized threat reactions and overgeneralization, contribute to anxiety disorders such as generalized anxiety disorder and post-traumatic stress disorder. Although stress intensity influences the generation and extent of these maladaptive fears, the underlying mechanisms remain unclear.

OBJECTIVES

The present study examined whether varying footshock stress intensity and inhibition of protein synthesis have differential effect on fear sensitization and generalization in mice.

METHODS

Mice were subjected to a classic fear conditioning protocol involving five different levels of footshock intensities. Prior to fear acquisition, the protein synthesis inhibitor cycloheximide (CHX) was administered intraperitoneally. Fear sensitization to white noise and fear generalization to tones with frequencies differing from the conditioned tone were assessed at either 2 or 4 days after fear acquisition.

RESULTS

The results showed that, although varying shock intensities (except the lowest) led to a similar pattern of increased freezing during auditory cues in fear acquisition, the extent of both fear sensitization and generalization increased with the intensity of the footshock in the following days. As shock intensities increased, there was a proportional rise in sensitized fear to white noise and generalized freezing to tones with frequencies progressively closer to the conditioned stimulus. Mildest shocks did not induce discriminative conditioned fear memory, whereas the most intense shocks led to pronounced fear generalization. Administration of CHX before fear acquisition did not affect sensitized fear but reduced generalization of freezing to tones dissimilar from the conditioned stimulus in the group exposed to the most intense shock.

CONCLUSIONS

Our results suggest that maladaptive fear responses elicited by varying stress intensities exhibit distinct characteristics. The effect of CHX to prevent overgeneralization without affecting discriminative fear memory points to potential therapeutic approaches for fear-related disorders, suggesting the possibility of mitigating overgeneralization while preserving necessary fear discrimination.

Acute sleep disruption reduces fear memories in male and female mice

Sleep problems are a prominent feature of mental health conditions including post-traumatic stress disorder (PTSD). Despite its potential importance, the role of sleep in the development of and/or recovery from trauma-related illnesses is not understood. Interestingly, there are reports that sleep disruption immediately after a traumatic experience can reduce fear memories, an effect that could be utilized therapeutically in humans. While the mechanisms of this effect are not completely understood, one possible explanation for these findings is that immediate sleep disruption interferes with consolidation of fear memories, rendering them weaker and more sensitive to intervention. Here, we allowed fear-conditioned mice to sleep immediately after fear conditioning during a time frame (18 h) that includes and extends beyond periods typically associated with memory consolidation before subjecting them to 6-h of sleep disruption. Mice exposed to this delayed regimen showed dramatic reductions in fear during tests conducted immediately after sleep disruption, as well as 24 h later. This sleep disruption regimen also increased levels of mRNA encoding brain-derived neurotrophic factor (BDNF), a molecule implicated in neuroplasticity, in the basolateral amygdala (BLA), a brain area implicated in fear and its extinction. These findings raise the possibility that the effects of our delayed sleep disruption regimen are not due to disruption of memory consolidation, but instead are caused by BDNF-mediated neuroadaptations within the BLA that actively suppress expression of fear. Treatments that safely reduce expression of fear memories would have considerable therapeutic potential in the treatment of conditions triggered by trauma.

Psychedelics: A review of their effects on recalled aversive memories and fear/anxiety expression in rodents

Threatening events and stressful experiences can lead to maladaptive memories and related behaviors. Existing treatments often fail to address these issues linked to anxiety/stress-related disorders effectively. This review identifies dose ranges associated with specific actions across various psychedelics. We examined psilocybin/psilocin, lysergic acid diethylamide (LSD), N,N-dimethyltryptamine (DMT), mescaline, 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), serotonin 2 A/2 C agonists (e.g., DOI) and 3,4-methylenedioxymethamphetamine (MDMA) on aversive memory extinction and reconsolidation, learned fear, anxiety, and locomotion in rodents. Nearly 400 studies published since 1957 were reviewed. Psychedelics often show biphasic effects on locomotion at doses that enhance extinction learning/retention, impair memory reconsolidation, or reduce learned fear and anxiety. Emerging evidence suggests a dissociation between their prospective benefits and locomotor effects. Under-explored aspects include sex differences, susceptibility to interference as memories age and generalize, repeated treatments, and immediate vs. delayed changes. Validating findings in traumatic-like memory and maladaptive fear/anxiety models is essential. Understanding how psychedelics modulate threat responses and post-retrieval memory processes in rodents may inform drug development and human studies, improving therapeutic approaches for related psychiatric conditions.

Intolerance of uncertainty enhances adolescent fear generalization in both perceptual-based and category-based tasks: fNIRS studies

Fear generalization undergoes marked changes during adolescence, which may relate to the high prevalence of anxiety disorders. While intolerance of uncertainty (IU) is a key factor that amplifies fear generalization, its impact and neural basis in adolescence remain unclear. Here, we investigated the effects of IU on perceptual-based (n = 72) and category-based (n = 68) fear generalization in adolescents aged 12-15 years. Specifically, Experiment 1 utilized two different size rings as conditioned stimuli, with middle-sized rings serving as the generalized stimuli; Experiment 2 employed pictures of sparrows and refrigerators as conditioned stimuli, with other animals categorically related to the sparrow as generalized stimuli. We collected self-reported threat expectancy, response times, and fear ratings in both experiments, and conducted functional near-infrared spectroscopy in Experiment 2. Results showed that high IU adolescents had higher threat expectancy in both experiments compare to low IU. Moreover, in category-based generalization, high IU adolescents had higher fear ratings, shorter response times and reduced engagement of the left dorsolateral prefrontal cortex (DLPFC). Results indicated that IU may enhance fear generalization by deficient left DLPFC recruitment. Together the present findings point to a behavioral and neural mechanism that can render adolescents vulnerable for mental disorders.

The Functional Connectome and Long-Term Symptom Presentation Associated With Mild Traumatic Brain Injury and Blast Exposure in Combat Veterans

Mild traumatic brain injury (TBI) sustained in a deployment environment (deployment TBI) can be associated with increased severity of long-term symptom presentation, despite the general expectation of full recovery from a single mild TBI. The heterogeneity in the effects of deployment TBI on the brain can be difficult for a case-control design to capture. The functional connectome of the brain is an approach robust to heterogeneity that allows global measurement of effects using a common set of outcomes. The present study evaluates how differences in the functional connectome relate to remote symptom presentation following combat deployment and determines if deployment TBI, blast exposure, or post-traumatic stress disorder (PTSD) are associated with these neurological differences. Participants included 181 Iraq and Afghanistan combat-exposed Veterans, approximately 9.4 years since deployment. Structured clinical interviews provided diagnoses and characterizations of TBI, blast exposure, and PTSD. Self-report measures provided characterization of long-term symptoms (psychiatric, behavioral health, and quality of life). Resting-state magnetoencephalography was used to characterize the functional connectome of the brain individually for each participant. Linear regression identified factors contributing to symptom presentation including relevant covariates, connectome metrics, deployment TBI, blast exposure PTSD, and conditional relationships. Results identified unique contributions of aspects of the connectome to symptom presentation. Furthermore, several conditional relationships were identified, demonstrating that the connectome was related to outcomes in the presence of only deployment-related TBI (including blast-related TBI, primary blast TBI, and blast exposure). No conditional relationships were identified for PTSD; however, the main effect of PTSD on symptom presentation was significant for all models. These results demonstrate that the connectome captures aspects of brain function relevant to long-term symptom presentation, highlighting that deployment-related TBI influences symptom outcomes through a neurological pathway. These findings demonstrate that changes in the functional connectome associated with deployment-related TBI are relevant to symptom presentation over a decade past the injury event, providing a clear demonstration of a brain-based mechanism of influence.

Prefrontal multistimulus integration within a dedicated disambiguation circuit guides interleaving contingency judgment learning

Understanding how cortical network dynamics support learning is a challenge. This study investigates the role of local neural mechanisms in the prefrontal cortex during contingency judgment learning (CJL). To better understand brain network mechanisms underlying CJL, we introduce ambiguity into associative learning after fear acquisition, inducing a generalized fear response to an ambiguous stimulus sharing nontrivial similarities with the conditioned stimulus. Real-time recordings at single-neuron resolution from the prelimbic (PL) cortex show distinct PL network dynamics across CJL phases. Fear acquisition triggers PL network reorganization, led by a disambiguation circuit managing spurious and predictive relationships during cue-danger, cue-safety, and cue-neutrality contingencies. Mice with PL-targeted memory deficiency show malfunctioning disambiguation circuit function, while naive mice lacking unconditioned stimulus exposure lack the disambiguation circuit. This study shows that fear conditioning induces prefrontal cortex cognitive map reorganization and that subsequent CJL relies on the disambiguation circuit's ability to learn predictive relationships.

Dopamine release and dopamine-related gene expression in the amygdala are modulated by the gastrin-releasing peptide in opposite directions during stress-enhanced fear learning and extinction

Fear extinction leads to a decrease of originally acquired fear responses after the threat is no longer present. Fear extinction is adaptive and critical for organism's survival, but deficits in extinction may lead to exaggerated fear in animals or post-traumatic stress disorder (PTSD) in humans. Dopamine has recently emerged as essential for fear extinction and PTSD, however the neural circuits serving this dopamine function are only beginning to be investigated, and the dopamine intracellular signaling pathways are unknown. We generated gastrin-releasing peptide gene knockout (Grp-/-) mice and found that they exhibit enhanced fear memory in a stress-enhanced fear learning (SEFL) paradigm, which combines stress exposure and fear extinction, two features critical for developing PTSD. Using in vivo fiber photometry to record dopamine signals, we found that the susceptibility of Grp-/- mice to SEFL is paralleled by an increase in basolateral amygdala (BLA) dopaminergic binding during fear conditioning and early extinction. Combined optogenetics and ex vivo electrophysiology showed an increase in presynaptic ventral tegmental area (VTA)-BLA connectivity in Grp-/- mice, demonstrating a role of dysregulated input from the VTA on BLA function in the absence of the GRP. When examining gene transcription using RNA-seq and qPCR, we discovered concerted down-regulation in dopamine-related genes in the BLA of Grp-/- mice following long-term SEFL memory recall that was not observed in naïve conditions. These experiments demonstrate that the GRP regulates dopamine function in stress-enhanced fear processing and identify the Grp as the first gene known to regulate dopaminergic control of fear extinction.

Corticosteroid-Induced Psychiatric Disorders: Mechanisms, Outcomes, and Clinical Implications

Corticosteroids are extensively used in medicine for their powerful anti-inflammatory and immunosuppressive effects. However, their psychiatric side effects-such as mood disturbances, anxiety, and psychosis-are significant yet often underappreciated. This review provides a comprehensive exploration of corticosteroid-induced psychiatric disorders, with a focus on their underlying mechanisms and clinical implications. We examine how corticosteroids influence the hypothalamic-pituitary-adrenal (HPA) axis, leading to the dysregulation of stress responses and alterations in neurotransmitter levels, particularly dopamine, serotonin, and glutamate. These changes are linked to structural abnormalities in key brain areas such as the hippocampus and amygdala, which are implicated in mood and anxiety disorders, psychosis, and conditions like post-traumatic stress disorder (PTSD) and eating disorders. This review highlights the need for healthcare providers to be vigilant in recognizing and managing corticosteroid-induced psychiatric symptoms, especially in vulnerable populations with pre-existing mental health conditions. The complex relationship between corticosteroid type, dose, duration, and mental health outcomes is explored, emphasizing the importance of personalized treatment approaches to mitigate psychiatric risks. Given the widespread use of corticosteroids, there is an urgent need for more focused research on their psychiatric side effects. This review underscores the importance of patient education and careful monitoring to ensure optimal therapeutic outcomes while minimizing mental health risks associated with corticosteroid therapy.

Hypothalamic Regulation of Cardiorespiratory Functions: Insights into the Dorsomedial and Perifornical Pathways

The dorsomedial hypothalamus nucleus (DMH) plays a pivotal role in the orchestration of sympathetic nervous system activities. Through its projections to the brainstem and pontomedullary nuclei, it controls heart rate, contractility, blood pressure, and respiratory activity, such as timing and volumes. The DMH integrates inputs from higher brain centers and processes these signals in order to modulate autonomic outflow accordingly. It has been demonstrated to be of particular significance in the context of stress responses, where it orchestrates the physiological adaptations that are necessary for all adaptative responses. The perifornical region (PeF), which is closely associated with the DMH, also makes a contribution to autonomic regulation. The involvement of the PeF region in autonomic control is evidenced by its function in coordinating the autonomic and endocrine responses to stress, frequently in conjunction with the DMH. The DMH and the PeF do not function in an isolated manner; rather, they are components of a comprehensive hypothalamic network that integrates several autonomic responses. This neural network could serve as a target for developing therapeutic strategies in cardiovascular diseases.

A brainstem circuit amplifies aversion

Dynamic gain control of aversive signals enables adaptive behavioral responses. Although the role of amygdalar circuits in aversive processing is well established, the neural pathway for amplifying aversion remains elusive. Here, we show that the brainstem circuit linking the interpeduncular nucleus (IPN) with the nucleus incertus (NI) amplifies aversion and promotes avoidant behaviors. IPN GABA neurons are activated by aversive stimuli and their predicting cues, with their response intensity closely tracking aversive values. Activating these neurons does not trigger aversive behavior on its own but rather amplifies responses to aversive stimuli, whereas their ablation or inhibition suppresses such responses. Detailed circuit dissection revealed anatomically distinct subgroups within the IPN GABA neuron population, highlighting the NI-projecting subgroup as the modulator of aversiveness related to fear and opioid withdrawal. These findings unveil the IPN-NI circuit as an aversion amplifier and suggest potential targets for interventions against affective disorders and opioid relapse.

Differences and similarities between children and adolescent exposed to interpersonal traumas with and without Intellectual Disability: An explorative study

BACKGROUND

Individuals with intellectual disability (ID) are more vulnerable to traumatic and stressful events, increasing their risk of developing post-traumatic stress disorder (PTSD).

AIMS

This study aimed to investigate differences in psychopathology, post-traumatic symptoms, and adaptive functioning in a sample of Italian children and adolescents with and without ID. It also sought to determine whether the type of interpersonal trauma was associated with distinct psychopathological outcomes.

METHODS AND PROCEDURES

Sixty-six children and adolescents exposed to interpersonal trauma (physical/sexual abuse, domestic violence, and neglect), were selected and divided into two groups based on the presence or absence of ID. Assessment consisted of structured parent interviews and parent-reported questionnaires. For each scale, comparisons between subtests were performed.

OUTCOMES AND RESULTS

Children and adolescents with ID were more likely to exhibit more severe post-traumatic symptoms, anxiety issues, social problems, and poorer adaptive functioning, with the exception of the practical domain, which appeared to be equally impaired in both groups. In terms of interpersonal trauma typology, exposure to physical/sexual abuse and domestic violence led to greater post-traumatic symptoms compared to neglect.

CONCLUSION AND IMPLICATIONS

Interpersonal trauma significantly affects children and adolescents, with or without ID, highlighting the need for tailored treatments for both groups.

The hippocampal CA2 region discriminates social threat from social safety

The dorsal cornu ammonis 2 (dCA2) region of the hippocampus enables the discrimination of novel from familiar conspecifics. However, the neural bases for more complex social-spatial episodic memories are unknown. Here we report that the spatial and social contents of an aversive social experience require distinct hippocampal regions. While dorsal CA1 (dCA1) pyramidal neurons mediate the memory of an aversive location, dCA2 pyramidal neurons enable the discrimination of threat-associated (CS+) from safety-associated (CS-) conspecifics in both female and male mice. Silencing dCA2 during encoding or recall trials disrupted social fear discrimination memory, resulting in fear responses toward both the CS+ and CS- mice. Calcium imaging revealed that the aversive experience strengthened and stabilized dCA2 representations of both the CS+ and CS- mice, with the incorporation of an abstract representation of social valence into representations of social identity. Thus, dCA2 contributes to both social novelty detection and the adaptive discrimination of threat-associated from safety-associated individuals during an aversive social episodic experience.

The persistent effects of predator odor stressor enhance interoceptive sensitivity to alcohol through GABAA receptor adaptations in the prelimbic cortex in male, but not female rats

Background

Traumatic stress is associated with high rates of problematic alcohol use, but how the persistent effects of trauma impact sensitivity to alcohol remain unknown. This study examined the persistent effects of traumatic stress exposure on sensitivity to alcohol and underlying neurobiological mechanisms in rats.

Methods

Male (N=98) and female (N=98) Long-Evans rats were exposed to the predator odor TMT, and two weeks later, molecular, neuronal, and behavioral sensitivity to alcohol were assessed. Next, rats were trained to discriminate alcohol from water (male N=70; female N=56), and the impact of TMT on interoceptive sensitivity to alcohol and the alcohol-like effects of systemic GABAA receptor activation were evaluated. Lastly, functional involvement of GABAA and NMDA receptors in the prelimbic cortex (PrL) and the anterior insular cortex (aIC) was investigated.

Results

TMT exposure sex-dependently altered PrL Gabra1, and elevated aIC Grin2b and Grin2c in males. TMT increased PrL c-Fos in males, which was attenuated by alcohol administration. Alcohol-induced locomotor and startle response effects were attenuated in the TMT group in both sexes. TMT exposure potentiated interoceptive sensitivity to alcohol in males but not in females, and this effect was driven by GABAA receptors in the PrL. Greater stress reactivity during TMT exposure was associated with higher interoceptive sensitivity to alcohol, and alcohol exposure history was linked to a heightened stress response to TMT in males.

Conclusions

Traumatic stress increased interoceptive sensitivity to alcohol in males, but not females, through PrL GABAA receptor adaptations, potentially enhancing the stimulatory, and by extension the rewarding, effects of alcohol.

Divergent input patterns to the central lateral amygdala play a duet in fear memory formation

Somatostatin (SOM)-expressing neurons in the central lateral amygdala (CeL) are responsible for fear memory learning, but the circuit and molecular mechanisms underlying this biology remain elusive. Here, we found that glutamatergic neurons in the lateral parabrachial nucleus (LPB) directly dominated the activity of CeLSOM neurons, and that selectively inhibiting the LPBGlu→CeLSOM pathway suppressed fear memory acquisition. By contrast, inhibiting CeL-projecting glutamatergic neurons in the paraventricular thalamic nucleus (PVT) interfered with consolidation-related processes. Notably, CeLSOM-innervating neurons in the LPB were modulated by presynaptic cannabinoid receptor 1 (CB1R), and knock down of CB1Rs in LPB glutamatergic neurons enhanced excitatory transmission to the CeL and partially rescued the impairment in fear memory induced by CB1R activation in the CeL. Overall, our study reveals the mechanisms by which CeLSOM neurons mediate the formation of fear memories during fear conditioning in mice, which may provide a new direction for the clinical research of fear-related disorders.

Cortical morphological changes and associated transcriptional signatures in post-traumatic stress disorder and psychological resilience

BACKGROUND

Individuals who have experienced severe traumatic events are estimated to have a post-traumatic stress disorder (PTSD) prevalence rate ranging from 10 to 50%, while those not affected by trauma exposure are often considered to possess psychological resilience. However, the neural mechanisms underlying the development of PTSD, especially resilience after trauma, remain unclear. This study aims to investigate changes of cortical morphometric similarity network (MSN) in PTSD and trauma-exposed healthy individuals (TEHI), as well as the associated molecular alterations in gene expression, providing potential targets for the prevention and intervention of PTSD.

METHODS

We recruited PTSD patients and TEHI who had experienced severe earthquakes, and healthy controls who had not experienced earthquakes. We identified alterations in the whole-brain MSN changes in PTSD and TEHI, and established associations between these changes and brain-wide gene expression patterns from the Allen Human Brain Atlas microarray dataset using partial least squares regression.

RESULTS

At the neuroimaging level, we found not only trauma-susceptible changes in TEHI same as those in PTSD, but also unique neurobiological alterations to counteract the deleterious impact of severe trauma. We identified 1444 and 2214 genes transcriptionally related to MSN changes in PTSD and TEHI, respectively. Functional enrichment analysis of weighted gene expression for PTSD and TEHI revealed distinct enrichments in Gene Ontology biological processes and Kyoto Encyclopedia of Genes and Genomes pathways. Furthermore, gene expression profiles of astrocytes, excitatory neurons, and microglial cells are highly related to MSN abnormalities in PTSD.

CONCLUSIONS

The formation of resilience may be by an active compensatory process of the brain. The combination of macroscopic neuroimaging changes and microscopic human brain transcriptomics could offer a more direct and in-depth understanding of the pathogenesis of PTSD and psychological resilience, shedding light on new targets for the prevention and treatment of PTSD.

Impacts of linseed oil diet on anxiety and memory extinction after early life stress: A sex-specific analysis of mitochondrial dysfunction, astrocytic markers, and inflammation in the amygdala

Early exposure to stressors affects how the organism reacts to stimuli, its emotional state throughout life, and how it deals with emotional memories. Consequently, it may affect susceptibility to psychopathology later in life. We used an animal model of early stress by maternal separation to study its potential impact on the extinction of aversive memories and anxiety-like behavior in adulthood, as well as its effects on mitochondrial functionality, inflammatory and astrocytic markers in the amygdala. We also assessed whether a diet enriched with linseed oil, known for its high content in omega-3 fats, could be used to attenuate the behavioral and neurochemical effects of early stress. Litters of Wistar rats were divided into controls (intact) or subjected to maternal separation (MS). They were subdivided into two groups receiving isocaloric diets enriched in soy or linseed oils at weaning. In adulthood, the animals were exposed to the open field and the elevated plus maze, to evaluate exploratory activity and anxiety-like behavior. They were also trained in a context of fear conditioning, and afterward subjected to an extinction session, followed by a test session to evaluate the extinction memory. Amygdalae were evaluated for inflammatory cytokines (interleukin (IL)-1beta, IL-6, and tumor-necrose factor (TNF)-alpha), mitochondrial functionality, and astrocyte markers (glial fibrillary acidic protein - GFAP, S100B, and glutamine synthetase activity). MS induced anxiety-like behavior in the elevated plus-maze, which was reversed by a diet enriched in linseed oil offered from weaning. When testing the memory of an extinction session of fear conditioning, MS animals showed more freezing behavior. MS males receiving a linseed oil-enriched diet had lower functional mitochondria in the amygdala. In addition, MS led to increased inflammatory cytokines, particularly IL-1beta, and the diet enriched in linseed oil further increased these levels in MS animals. MS also increased S100B levels. These results point to a higher emotionality presented by MS animals, with higher levels of inflammatory cytokines and S100B. While a diet enriched in linseed oil attenuated anxiety-like behavior, it further altered amygdala IL-1beta and reduced mitochondria functionality, particularly in males. MS also increased glutamine synthetase activity in the amygdala, and this effect was higher when the animals received a diet enriched in linseed oil, particularly in females. In conclusion, these results point to MS effects on emotional behavior, and neurochemical alterations in the amygdala, with sex-specific effects. Although a diet enriched in linseed oil appears to be able to reverse some of MS behavioral effects, these results must be considered with caution, since biochemical parameters could be worsened in MS animals receiving a linseed oil-enriched diet. This knowledge is important for the understanding of mechanisms of action of strategies aiming to reverse early stress effects, and future studies are warranted to determine possible interventions to promote resilience.

The impact of trauma core dimensions on anxiety and depression: a latent regression model through the Post-Traumatic Symptom Questionnaire (PTSQ)

Adverse life events (e.g., severe accidents, violence/abuse, organic disorders) can elicit traumatic responses characterized by intrusive thoughts, hyperarousal, and avoidance-highlighting the need for sound assessment tools. Also, these traumatic components could heighten anxiety and depression symptoms. This study aims included to: (1) assessing the psychometric properties of the Post-Traumatic Symptom Questionnaire (PTSQ) and delineating clinical cut-offs; (2) investigating how distinct trauma components contribute to anxiety and depression symptoms. Involving 761 participants who experienced a traumatic event, Part I tested the PTSQ psychometric properties, defining clinical cut-offs. Part II tested the impact of traumatic components on anxiety and depression symptoms, using a multiple multivariate latent regression model. PTSQ exhibited exemplary fit indices and robust psychometric properties. Clinically relevant cut-offs were identified. The differential contributions of intrusion, avoidance, and hyperarousal to anxiety and depression symptoms were evaluated, elucidating the strength and nature of these relationships. This study reaffirms the PTSQ as a psychometrically sound and reliable instrument. It underscores the effects of intrusion, avoidance, and hyperarousal on anxiety and depression symptoms in individuals with traumatic experiences. These insights advocate for evidence-based interventions aimed at alleviating the psychological suffering associated with trauma components, fostering adaptation and supporting psychological health.

Mechanisms of psilocybin on the treatment of posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a condition that can develop after a traumatic event, causing distressing symptoms, including intrusive re-experiencing symptoms, alterations in mood and cognition, and changes in arousal and reactivity. Few treatment options exist for patients who find conventional psychotherapy and pharmacotherapy to be inaccessible, ineffective, or intolerable. We explore psilocybin as a potential treatment option for PTSD by examining the neurobiology of PTSD as well as psilocybin's mechanism of action. Based on both pharmacodynamic and psychoanalytic principles, psilocybin may be an underexplored treatment option for patients with PTSD, though further research is required.

Neural underpinnings of a two-phase memory suppression process in the neural response to self-related and observed perspective views

Individuals often actively suppress intrusive memories to alleviate the distress they cause and maintain mental well-being. However, those with post-traumatic stress disorder (PTSD) often exhibit difficulties particularly in inhibiting or suppressing negative memories compared to individuals without PTSD. These memories can involve a physical threat either to the individual themselves or to others. Unfortunately, there is still limited understanding of the cognitive and neural mechanisms that underlie how suppression differs for self-related versus other-related memories. Here we capitalized on multivariate pattern analyses in combination with fMRI data acquired during a two-phase memory suppression paradigm where participants volitionally suppressed and subsequently recognized self-related and other-related stimuli. The results suggested that the recognition process following memory suppression demands more cognitive engagement for self-related stimuli than other-related stimuli, manifesting in increased activity in the dorsal anterior cingulate cortex (dACC). Furthermore, after memory suppression, we observed a stronger functional coupling between dACC identified during memory suppression, and both the middle frontal gyrus and the insula during self-related recognition compared to other-related recognition. An advanced multivariate pattern analysis substantiated that the limbic system and empathy network particularly contributed to accurately distinguishing between self-related and other-related recognition following memory suppression. Our findings demonstrated distinct neural representations of memory suppression related to self and others, suggesting that different strategies may be employed for suppressing intrusive memories originating from different sources.

An information-theoretic approach to build hypergraphs in psychometrics

Psychological network approaches propose to see symptoms or questionnaire items as interconnected nodes, with links between them reflecting pairwise statistical dependencies evaluated on cross-sectional, time-series, or panel data. These networks constitute an established methodology to visualise and conceptualise the interactions and relative importance of nodes/indicators, providing an important complement to other approaches such as factor analysis. However, limiting the representation to pairwise relationships can neglect potentially critical information shared by groups of three or more variables (higher-order statistical interdependencies). To overcome this important limitation, here we propose an information-theoretic framework to assess these interdependencies and consequently to use hypergraphs as representations in psychometrics. As edges in hypergraphs are capable of encompassing several nodes together, this extension can thus provide a richer account on the interactions that may exist among sets of psychological variables. Our results show how psychometric hypergraphs can highlight meaningful redundant and synergistic interactions on either simulated or state-of-the-art, re-analysed psychometric datasets. Overall, our framework extends current network approaches while leading to new ways of assessing the data that differ at their core from other methods, enriching the psychometrics toolbox, and opening promising avenues for future investigation.

Stimulation of an entorhinal-hippocampal extinction circuit facilitates fear extinction in a post-traumatic stress disorder model

Effective psychotherapy of post-traumatic stress disorder (PTSD) remains challenging owing to the fragile nature of fear extinction, for which the ventral hippocampal CA1 (vCA1) region is considered as a central hub. However, neither the core pathway nor the cellular mechanisms involved in implementing extinction are known. Here, we unveil a direct pathway, where layer 2a fan cells in the lateral entorhinal cortex (LEC) target parvalbumin-expressing interneurons (PV-INs) in the vCA1 region to propel low-gamma-band synchronization of the LEC-vCA1 activity during extinction learning. Bidirectional manipulations of either hippocampal PV-INs or LEC fan cells sufficed for fear extinction. Gamma entrainment of vCA1 by deep brain stimulation (DBS) or noninvasive transcranial alternating current stimulation (tACS) of LEC persistently enhanced the PV-IN activity in vCA1, thereby promoting fear extinction. These results demonstrate that the LEC-vCA1 pathway forms a top-down motif to empower low-gamma-band oscillations that facilitate fear extinction. Finally, application of low-gamma DBS and tACS to a mouse model with persistent PTSD showed potent efficacy, suggesting that the dedicated LEC-vCA1 pathway can be stimulated for therapy to remove traumatic memory trace.