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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

A guided single session intervention to reduce intrusive memories of work-related trauma: a randomised controlled trial with healthcare workers in the COVID-19 pandemic

BACKGROUND

Intrusive memories of psychologically traumatic events bring distress both sub-clinically and clinically. This parallel-group, two-arm randomised controlled trial evaluated the effect of a brief behavioural intervention on reducing intrusive memories in frontline healthcare workers exposed to traumatic events during the COVID-19 pandemic.

METHODS

Participants with at least two intrusive memories of work-related trauma in the week before recruitment were randomised 1:1 to an imagery-competing task intervention (n = 73) or attention-based control task (n = 71). The number of intrusive memories was assessed at baseline and 5 weeks after the guided session (primary endpoint).

RESULTS

The intervention significantly reduced intrusive memory frequency compared with control [intervention Mdn = 1.0 (IQR = 0-3), control Mdn = 5.0 (IQR = 1-17); p < 0.0001, IRR = 0.30; 95% CI = 0.17-0.53] and led to fewer post-traumatic stress-related symptoms at 1, 3 and 6 month follow-ups (secondary endpoints). Participants and statisticians were blinded to allocation. Adverse events data were acquired throughout the trial, demonstrating safety. There was high adherence and low attrition.

CONCLUSIONS

This brief, single-symptom, repeatable digital intervention for subclinical-to-clinical samples after trauma allows scalability, taking a preventing-to-treating approach after trauma.

TRIAL REGISTRATION

2020-07-06, ClinicalTrials.gov identifier: NCT04460014.

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.

A dopamine-dependent mechanism for Reward-induced modification of Fear memories

A positive mental state has been shown to modulate fear-related emotions associated with the recall of fear memories. These, and other observations suggest the presence of central brain mechanisms for affective states to interact. The neurotransmitter dopamine is important for both Reward- and fear-related processes, but it is unclear whether dopamine contributes to such affective interactions. Here, we show that precisely timed Reward-induced activation of dopamine neurons in mice potently modifies fear memories and enhances their extinction. This Reward-based switch in fear states is associated with changes in dopamine release and dopamine-dependent regulation of fear encoding in the central amygdala (CeA). These data provide a central mechanism for Reward-induced modification of fear states that have broad implications for treating generalized fear disorders.

The psychometric properties of the Swahili version of the Primary Care Post Traumatic Stress Disorder screen for DSM-5 among adults in Kenya

Background

The psychometric properties of the Primary Care PTSD Screen for DSM-5 (PC-PTSD-5) are undocumented in Kenya and sub-Saharan Africa (SSA) at large. This study aimed to evaluate the psychometric properties of the Swahili version of the tool, S-PC-PTSD-5, in a community sample of adults 18 years and older drawn from Nairobi, Mombasa and Kwale counties in Kenya.

Methods

Analysis of cross-sectional data from 1431 adults from the community was conducted, examining the reliability, factorial structure, measurement invariance, and convergent and divergent validity of the interviewer-administered S-PC-PTSD-5.

Results

Out of 1431 adults who completed the S-PC-PTSD-5, 666 (46.5%) reported experiencing at least one traumatic event. Internal consistency of the S-PC-PTSD-5 was good overall, with alpha and omega values above 0.7. Confirmatory factor analysis (CFA) results indicated a one-factor structure of the S-PC-PTSD-5 for the overall sample. Multigroup CFA also demonstrated factorial invariance for sex for the one-factor structure of S-PC-PTSD-5. Scores for S-PC-PTSD-5 significantly correlated (positively) with those of generalized anxiety disorder (GAD7) and depressive symptoms (PHQ9), indicating convergent validity. S-PC-PTSD-5 scores also significantly correlated (negatively) with the WHO-5 wellbeing index, supporting divergent validity.

Conclusions

The S-PC-PTSD-5 is a reliable and valid unidimensional measure. It appears to be a valuable screening measure for probable PTSD in both urban and rural community settings in Kenya. Nonetheless, to confidently identify those who may need treatment/additional support, further research on the reliability and validity of S-PC-PTSD-5 is required, especially its diagnostic accuracy at different cutoff scores.

Coping Mechanisms and Posttraumatic Stress Exhibited by Children in Areas of Yemen's Armed Conflict in Southern Saudi Arabia

This study is an attempt to explore war-related trauma, its stressful effects, and the coping strategies of Saudi schoolchildren. The authors hypothesized that children exposed to war-related trauma will show higher levels of PTSD, and that those with higher levels of PTSD symptoms use more maladaptive coping strategies. The study describes the correlation between traumatic events and posttraumatic stress disorder (PTSD) as well as coping strategies. Five hundred twenty-seven intermediate and high school students, 12 to 18 years old, living in the conflict zone in southern Saudi Arabia completed three standardized self-reported scales: the War Zone Traumatic Events Checklist, the Child PTSD Symptom Scale, and the Children's Coping Strategies Checklist. Each participating student was randomly chosen. Analysis was based on two groups: the high-PTSD symptoms group (182 children) and the low-PTSD symptoms group (345 children). The study was conducted between September 2020 and April 2022 while the war was ongoing as part of an ongoing larger study. Children exposed to war-related traumatic events exhibited greater prevalence rates for PTSD. The children reported high levels of PTSD symptoms and applied a variety of coping strategies to manage related stress. Participants rarely reported that psychological or educational interventions had been used to manage the war-related traumatic experiences and PTSD or to improve related coping styles. The results are discussed in the context of mental health services needed for children in the conflict zone. To bridge the gap between health care services and the needs of children with PTSD, and for better understanding and interventions, health professionals are invited to develop a biopsychosocial model that identifies the risks of PTSD related to exposure to war-related traumatic events in school-aged children and, hence, provide a multidisciplinary intervention program that educates, encourages, and supports teachers and parents in following medical recommendations and goals.

Uncovering the determinants of brain functioning, behavior and their interplay in the light of context

Notwithstanding the huge progress in molecular and cellular neuroscience, our ability to understand the brain and develop effective treatments promoting mental health is still limited. This can be partially ascribed to the reductionist, deterministic and mechanistic approaches in neuroscience that struggle with the complexity of the central nervous system. Here, I introduce the Context theory of constrained systems proposing a novel role of contextual factors and genetic, molecular and neural substrates in determining brain functioning and behavior. This theory entails key conceptual implications. First, context is the main driver of behavior and mental states. Second, substrates, from genes to brain areas, have no direct causal link to complex behavioral responses as they can be combined in multiple ways to produce the same response and different responses can impinge on the same substrates. Third, context and biological substrates play distinct roles in determining behavior: context drives behavior, substrates constrain the behavioral repertoire that can be implemented. Fourth, since behavior is the interface between the central nervous system and the environment, it is a privileged level of control and orchestration of brain functioning. Such implications are illustrated through the Kitchen metaphor of the brain. This theoretical framework calls for the revision of key concepts in neuroscience and psychiatry, including causality, specificity and individuality. Moreover, at the clinical level, it proposes treatments inducing behavioral changes through contextual interventions as having the highest impact to reorganize the complexity of the human mind and to achieve a long-lasting improvement in mental health.

The efficacy and safety of MDMA-assisted psychotherapy for treatment of posttraumatic stress disorder: A systematic review and meta-analysis from randomized controlled trials

3,4-methylenedioxymethamphetamine (MDMA), commonly known as ecstasy, is one of the most widely used illicit substances worldwide. MDMA-assisted psychotherapy has become a novel treatment for posttraumatic stress disorder (PTSD), and many randomized controlled trials (RCTs) have been performed over the past decade. Therefore, this study aimed to systematically review and demonstrate the efficacy and safety of MDMA-assisted psychotherapy for the treatment of PTSD. We conducted a systematic search of PubMed, Embase, and Web of Science databases up to October 27, 2023, selected RCTs assessing the efficacy and safety of MDMA-assisted psychotherapy for the treatment of PTSD, and evaluated their quality using the Cochrane risk of bias tool. Seven RCTs were selected from the retrieved references. The results revealed that MDMA-assisted psychotherapy effectively reduced the change from baseline score in the Clinician-Administered PTSD Scale in patients with PTSD compared with either placebo or active controls. However, MDMA causes a series of adverse events, including muscle tightness, nausea, and decreased appetite. To a certain extent, MDMA-assisted psychotherapy may improve symptoms in patients with PTSD. However, side effects and abuse issues still seriously hinder clinical application of MDMA.

Individual Differences in Volitional Social Self-Administration and Motivation in Male and Female Mice Following Social Stress

BACKGROUND

A key challenge in developing treatments for neuropsychiatric illness is the disconnect between preclinical models and the complexity of human social behavior. We integrate voluntary social self-administration into a rodent model of social stress as a platform for the identification of fundamental brain and behavior mechanisms underlying stress-induced individual differences in social motivation.

METHODS

Here, we introduced an operant social stress procedure in male and female mice composed of 3 phases: 1) social self-administration training, 2) social stress exposure concurrent with reinforced self-administration testing, and 3) poststress operant testing under nonreinforced and reinforced conditions. We used social-defeat and witness-defeat stress in male and female mice.

RESULTS

Social defeat attenuated social reward seeking in males but not females, whereas witness defeat had no effect in males but promoted seeking behavior in females. We resolved social stress-induced changes to social motivation by aggregating z-scored operant metrics into a cumulative social index score to describe the spectrum of individual differences exhibited during operant social stress. Clustering does not adequately describe the relative distributions of social motivation following stress and is better described as a nonbinary behavioral distribution defined by the social index score, capturing a dynamic range of stress-related alterations in social motivation inclusive of sex as a biological variable.

CONCLUSIONS

We demonstrated that operant social stress can detect stable individual differences in stress-induced changes to social motivation. The inclusion of volitional behavior in social procedures may enhance the understanding of behavioral adaptations that promote stress resiliency and their mechanisms under more naturalistic conditions.

Neuromodulation treatments for post-traumatic stress disorder: A systematic review and network meta-analysis covering efficacy, acceptability, and follow-up effects

Neuromodulation treatments are novel interventions for post-traumatic stress disorder (PTSD), but their comparative effects at treatment endpoint and follow-up and the influence of moderators remain unclear. We included randomized controlled trials (RCTs) that explored neuromodulation, both as monotherapy and in combination, for treating patients with PTSD. 21 RCTs with 981 PTSD patients were included. The neuromodulation treatment was classified into nine protocols, including subtypes of transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), cervical vagal nerve stimulation (VNS), and trigeminal nerve stimulation (TNS). This Bayesian network meta-analysis demonstrated that (1) dual-tDCS (SMD = -1.30), high-frequency repetitive TMS (HF-rTMS) (SMD = -0.97), intermittent theta burst stimulation (iTBS) (SMD = -0.93), and low-frequency repetitive TMS (LF-rTMS) (SMD = -0.76) were associated with significant reductions in PTSD symptoms at the treatment endpoint, but these effects were not significant at follow-up; (2) no difference was found between any active treatment with sham controls; (3) regarding co-morbid additions, synchronized TMS (sTMS) was significantly associated with reductions of depression symptoms at treatment endpoint (SMD = -1.80) and dual-tDCS was associated with reductions in anxiety symptoms at follow-up (SMD = -1.70). Findings suggested dual-tDCS, HF-rTMS, iTBS, and LF-rTMS were effective for reducing PTSD symptoms, while their sustained efficacy was limited.

Cardiovascular impact of post-traumatic stress disorder: A systematic review and meta-analysis

BACKGROUND

Post-traumatic stress disorder (PTSD) is increasingly recognized for its effects beyond mental health, with emerging evidence suggesting a significant association with cardiovascular diseases (CVD). This systematic review and meta-analysis aimed to synthesize available evidence on the association between PTSD and various cardiovascular outcomes.

METHODS

We conducted a comprehensive literature search in databases until March 15, 2024. Studies were included if they were observational in design and assessed the association between PTSD and cardiovascular outcomes. Data were extracted on study characteristics, participant demographics, PTSD assessment, cardiovascular outcomes, and effect estimates. Meta-analyses were performed using random-effects models, and heterogeneity was assessed using the I² statistic. All statistical analyses were conducted using R software version 4.3.

RESULTS

Twenty studies met the inclusion criteria, encompassing a total of over 335,000 participants. The pooled analyses demonstrated a statistically significant increased risk of any CVD (HR = 1.417, 95 % CI: 1.313-1.522), MI (HR = 1.415, 95 % CI: 1.331-1.500), and stroke (HR = 2.074, 95 % CI: 1.165-2.982) associated with PTSD. Substantial heterogeneity was observed across the studies for stroke and MACE, and evidence of publication bias was noted.

CONCLUSION

This meta-analysis confirms a significant association between PTSD and an increased risk of several cardiovascular outcomes, indicating the importance of integrating cardiovascular risk management with psychiatric care for PTSD patients to mitigate the heightened risk of CVDs. Future research should focus on exploring the underlying mechanisms and potential interventions to manage both PTSD and its associated cardiovascular risks effectively.

Psychiatric Disease as a Potential Risk Factor for Dementia: A Narrative Review

Neurodegenerative disease is a major global health problem with 150 million people predicted to have dementia by 2050. Genetic factors, environmental factors, demographics, and some diseases have been associated with dementia. In addition to associations between diseases such as hypertension and cerebrovascular disease and dementia, emerging findings associate some psychiatric disorders with incident dementia. Because of the high and increasing global prevalence of dementia and the high worldwide prevalence of psychiatric disorders, the primary objective of this narrative review was to evaluate published findings that evaluate the association between bipolar disorder, depression, anxiety, post-traumatic stress disorder, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorder, schizophrenia and other psychosis syndromes, and personality disorders and personality traits and incident dementia. Here, we highlight findings indicating possible associations between these psychiatric disorders and subsequent dementia and suggest that some psychiatric disorders may be risk factors for incident dementia. Further research, including more large longitudinal studies and additional meta-analyses, however, is needed to better characterize the associations between psychiatric disorders and incident dementia, to identify possible mechanisms for these putative associations, and to identify risk factors within psychiatric disorders that predispose some people with a psychiatric disorder but not others to subsequent dementia. Additional important questions concern how the treatment of psychiatric disorders might affect the risk of incident dementia.

Functional lateralization in the medial prefrontal cortex control of contextual conditioned emotional responses in rats

A functional lateralization has been reported in control of emotional responses by the medial prefrontal cortex (mPFC). However, a hemisphere asymmetry in involvement of the mPFC in expression of fear conditioning responses has never been reported. Therefore, we investigated whether control by mPFC of freezing and cardiovascular responses during re-exposure to an aversively conditioned context is lateralized. For this, rats had guide cannulas directed to the mPFC implanted bilaterally or unilaterally in the right or left hemispheres. Vehicle or the non-selective synaptic inhibitor CoCl2 was microinjected into the mPFC 10 min before re-exposure to a chamber where the animals had previously received footshocks. A catheter was implanted into the femoral artery before the fear retrieval test for cardiovascular recordings. We observed that bilateral microinjection of CoCl2 into the mPFC reduced both the freezing behavior (enhancing locomotion and rearing) and arterial pressure and heart rate increases during re-exposure to the aversively conditioned context. Unilateral microinjection of CoCl2 into the right hemisphere of the mPFC also decreased the freezing behavior (enhancing locomotion and rearing), but without affecting the cardiovascular changes. Conversely, unilateral synaptic inhibition in the left mPFC did not affect either behavioral or cardiovascular responses during fear retrieval test. Taken together, these results suggest that the right hemisphere of the mPFC is necessary and sufficient for expression of freezing behavior to contextual fear conditioning. However, the control of cardiovascular responses and freezing behavior during fear retrieval test is somehow dissociated in the mPFC, being the former bilaterally processed.

Cannabidiol effects on fear processing and implications for PTSD: Evidence from rodent and human studies

Cannabidiol (CBD) modulates aversive memory and its extinction, with potential implications for treating anxiety- and stress-related disorders. Here, we summarize and discuss scientific evidence showing that CBD administered after the acquisition (consolidation) and retrieval (reconsolidation) of fear memory attenuates it persistently in rats and mice. CBD also reduces fear expression and enhances fear extinction. These effects involve the activation of cannabinoid type-1 (CB1) receptors in the dorsal hippocampus, bed nucleus of stria terminalis, and medial prefrontal cortex, comprising the anterior cingulate, prelimbic, and infralimbic subregions. Serotonin type-1A (5-HT1A) receptors also mediate some CBD effects on fear memory. CBD effects on fear memory acquisition vary, depending on the aversiveness of the conditioning procedure. While rodent findings are relatively consistent and encouraging, human studies investigating CBD's efficacy in modulating aversive/traumatic memories are still limited. More studies are needed to investigate CBD's effects on maladaptive, traumatic memories, particularly in post-traumatic stress disorder patients.

Spatiotemporal dynamics of hippocampal-cortical networks underlying the unique phenomenological properties of trauma-related intrusive memories

Trauma-related intrusive memories (TR-IMs) possess unique phenomenological properties that contribute to adverse post-traumatic outcomes, positioning them as critical intervention targets. However, transdiagnostic treatments for TR-IMs are scarce, as their underlying mechanisms have been investigated separate from their unique phenomenological properties. Extant models of more general episodic memory highlight dynamic hippocampal-cortical interactions that vary along the anterior-posterior axis of the hippocampus (HPC) to support different cognitive-affective and sensory-perceptual features of memory. Extending this work into the unique properties of TR-IMs, we conducted a study of eighty-four trauma-exposed adults who completed daily ecological momentary assessments of TR-IM properties followed by resting-state functional magnetic resonance imaging (rs-fMRI). Spatiotemporal dynamics of anterior and posterior hippocampal (a/pHPC)-cortical networks were assessed using co-activation pattern analysis to investigate their associations with different properties of TR-IMs. Emotional intensity of TR-IMs was inversely associated with the frequency and persistence of an aHPC-default mode network co-activation pattern. Conversely, sensory features of TR-IMs were associated with more frequent co-activation of the HPC with sensory cortices and the ventral attention network, and the reliving of TR-IMs in the "here-and-now" was associated with more persistent co-activation of the pHPC and the visual cortex. Notably, no associations were found between HPC-cortical network dynamics and conventional symptom measures, including TR-IM frequency or retrospective recall, underscoring the utility of ecological assessments of memory properties in identifying their neural substrates. These findings provide novel insights into the neural correlates of the unique features of TR-IMs that are critical for the development of individualized, transdiagnostic treatments for this pervasive, difficult-to-treat symptom.

Temporalities of emergency: the experiences of Indigenous women with traumatic brain injury from violence waiting for healthcare and service support in Australia

Globally, traumatic brain injury (TBI) has been recognised as a serious health issue not only because of the immediate impacts at the time the injury occurs but even more so due to the longstanding impacts. Even though TBI is a globally recognised condition, the research is disproportionately focused on its incidence in, and immediate and long-term effects on men. A growing body of research suggests that generally, women who experience family violence are at high risk of TBI and suffer its impacts in ways that reflect gendered differences in the patterns and frequency of violence. In Australia, the social and physical costs of TBI are multiplied for Indigenous women, whose experience of disability and access to healthcare lies at the intersection of gender and race in the historical context of settler colonialism. The present study addresses the need for research into the sociodemographic inequalities that affect access to culturally appropriate hospital care, timely response systems, and flexible, safe and engaged social services. This paper draws on data from interviews and focus groups with Indigenous women, hospital staff and community-based service providers and suggests potential pathways for further research in settler-colonial settings elsewhere in the world.

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.

An ultra-short-acting benzodiazepine in thalamic nucleus reuniens undermines fear extinction via intermediation of hippocamposeptal circuits

Benzodiazepines, commonly used for anxiolytics, hinder conditioned fear extinction, and the underlying circuit mechanisms are unclear. Utilizing remimazolam, an ultra-short-acting benzodiazepine, here we reveal its impact on the thalamic nucleus reuniens (RE) and interconnected hippocamposeptal circuits during fear extinction. Systemic or RE-specific administration of remimazolam impedes fear extinction by reducing RE activation through A type GABA receptors. Remimazolam enhances long-range GABAergic inhibition from lateral septum (LS) to RE, underlying the compromised fear extinction. RE projects to ventral hippocampus (vHPC), which in turn sends projections characterized by feed-forward inhibition to the GABAergic neurons of the LS. This is coupled with long-range GABAergic projections from the LS to RE, collectively constituting an overall positive feedback circuit construct that promotes fear extinction. RE-specific remimazolam negates the facilitation of fear extinction by disrupting this circuit. Thus, remimazolam in RE disrupts fear extinction caused by hippocamposeptal intermediation, offering mechanistic insights for the dilemma of combining anxiolytics with extinction-based exposure therapy.

Medicinal cannabis oil improves anxiety-like and depressive-like behaviors in CCS mice via the BDNF/TRPC6 signaling pathway

BACKGROUND

Post-traumatic stress disorder (PTSD) refers to a chronic impairing psychiatric disorder occurring after exposure to the severe traumatic event. Studies have demonstrated that medicinal cannabis oil plays an important role in neuroprotection, but the mechanism by which it exerts anti-PTSD effects remains unclear.

METHODS

The chronic complex stress (CCS) simulating the conditions of long voyage stress for 4 weeks was used to establish the PTSD mice model. After that, behavioral tests were used to evaluate PTSD-like behaviors in mice. Mouse brain tissue index was detected and hematoxylin-eosin staining was used to assess pathological changes in the hippocampus. The indicators of cell apoptosis and the BDNF/TRPC6 signaling activation in the mice hippocampus were detected by western blotting or real-time quantitative reverse transcription PCR experiments.

RESULTS

We established the PTSD mice model induced by CCS, which exhibited significant PTSD-like phenotypes, including increased anxiety-like and depression-like behaviors. Medicinal cannabis oil treatment significantly ameliorated PTSD-like behaviors and improved brain histomorphological abnormalities in CCS mice. Mechanistically, medicinal cannabis oil reduced CCS-induced cell apoptosis and enhanced the activation of BDNF/TRPC6 signaling pathway.

CONCLUSIONS

We constructed a PTSD model with CCS and medicinal cannabis oil that significantly improved anxiety-like and depressive-like behaviors in CCS mice, which may play an anti-PTSD role by stimulating the BDNF/TRPC6 signaling pathway.

Memory Trace for Fear Extinction: Fragile yet Reinforceable

Fear extinction is a biological process in which learned fear behavior diminishes without anticipated reinforcement, allowing the organism to re-adapt to ever-changing situations. Based on the behavioral hypothesis that extinction is new learning and forms an extinction memory, this new memory is more readily forgettable than the original fear memory. The brain's cellular and synaptic traces underpinning this inherently fragile yet reinforceable extinction memory remain unclear. Intriguing questions are about the whereabouts of the engram neurons that emerged during extinction learning and how they constitute a dynamically evolving functional construct that works in concert to store and express the extinction memory. In this review, we discuss recent advances in the engram circuits and their neural connectivity plasticity for fear extinction, aiming to establish a conceptual framework for understanding the dynamic competition between fear and extinction memories in adaptive control of conditioned fear responses.