Smaller hippocampal CA1 subfield volume in posttraumatic stress disorder

Ketamine alleviates PTSD-like effect and improves hippocampal synaptic plasticity via regulation of GSK-3β/GR signaling of rats

BACKGROUND

Each year, 3-4% of the global population experiences post-traumatic stress disorder (PTSD), a chronic mental disorder with significant social and economic repercussions. Although it has been shown that ketamine can effectively alleviate PTSD symptoms in individuals, the specific mechanism of action underlying its anti-PTSD effects remains unclear. In this study, we investigated how a single, low dose of ketamine affected the glycogen synthase kinase 3β (GSK-3β)/glucocorticoid receptor (GR) signaling pathway in a single prolonged stress (SPS)-induced PTSD rat model.

METHODS

After establishing the model, stress-related behavioral alterations in the rats were assessed following intraperitoneal injections of ketamine (10 mg/kg) and GSK-3β antagonist SB216763 (5 mg/kg). In the hippocampus, alterations in the expression of specific proteins implicated in PTSD development, such as GR, brain-derived neurotrophic factor (BDNF), GSK-3β, and phosphorylated glycogen synthase kinase 3β (p-GSK-3β), were assessed. We also measured changes in the mRNA expression levels of GR, BDNF, GSK-3β, FK501 binding protein 51 (FKBP5), and corticotropin-releasing hormone (CRH), as well as synaptic ultrastructure, in the hippocampus, and measured changes in corticosterone levels in the blood.

RESULTS

SPS induced anxiety-like and depression-like behaviors in rats and induced morphological changes in synapse, which were accompanied by higher GSK-3β protein expression and conversely, decreased expression of GR, BDNF, p-GSK-3β, FKBP5 and CRH. Intraperitoneal administration of ketamine (10 mg/kg) after SPS prevented SPS-induced anxiety-like behaviors. Most importantly, ketamine attenuated SPS-induced dysfunctions in GSK-3β/GR signaling and synaptic deficits. Furthermore, treatment with a GSK-3β inhibitor played the same effect as ketamine on behavioral changes of SPS model rats.

CONCLUSION

Single doses of ketamine effectively ameliorate SPS-induced anxiety-like symptoms, potentially by improving synaptic plastic in the hippocampus by regulating GSK-3β/GR signaling.

GABAergic interneurons in the hippocampal CA1 mediate contextual fear generalization in PTSD rats

Fear overgeneralization is widely accepted as a pathogenic marker of post-traumatic stress disorder (PTSD). Recently, GABAergic interneurons have been regarded as key players in the regulation of fear memory. The role of hippocampal GABAergic interneurons in contextual fear generalization of PTSD remains incompletely understood. In the present study, we established a rat model of PTSD with inescapable foot shocks (IFS) and observed the loss of GABAergic interneuron phenotype in the hippocampal cornu ammonis-1 (CA1) subfield. To determine whether the loss of GABAergic interneuron phenotype was associated with fear generalization in PTSD rats, we used adeno-associated virus (AAV) to reduce the expression of GAD67 in CA1 and observed its effect on fear generalization. The results showed that the reduction of GAD67 in CA1 enhanced contextual fear generalization in rats. We investigated whether the PERK pathway was involved in the GABAergic interneuron injury. Increased expression of p-PERK, CHOP, and Caspase12 in GABAergic interneurons of PTSD rats was observed. Then, we used salubrinal, an endoplasmic reticulum stress inhibitor, to modulate the PERK pathway. The salubrinal treatment significantly protected the GABAergic interneurons and relieved fear generalization in PTSD rats. In addition, the results showed that salubrinal down-regulated the expression of CHOP and Caspase12 in GABAergic interneurons of PTSD rats. In conclusion, this study provided evidence that the loss of GABAergic interneuron phenotype in CA1 may contribute to contextual fear generalization in PTSD. The PERK pathway is involved in the GABAergic interneuron injury of PTSD rats and modulating it can protect GABAergic interneurons and constrain contextual fear generalization.

DCC, a potential target for controlling fear memory extinction and hippocampal LTP in male mice receiving single prolonged stress

Post-traumatic stress disorder (PTSD) is a severe stress-dependent psychiatric disorder characterized by impairment of fear memory extinction; however, biological markers to determine impaired fear memory extinction in PTSD remain unclear. In male mice with PTSD-like behaviors elicited by single prolonged stress (SPS), 19 differentially expressed proteins in the hippocampus were identified compared with controls. Among them, a biological macromolecular protein named deleted in colorectal cancer (DCC) was highly upregulated. Specific overexpression of DCC in the hippocampus induced similar impairment of long-term potentiation (LTP) and fear memory extinction as observed in SPS mice. The impairment of fear memory extinction in SPS mice was improved by inhibiting the function of hippocampal DCC using a neutralizing antibody. Mechanistic studies have shown that knocking down or inhibiting μ-calpain in hippocampal neurons increased DCC expression and induced impairment of fear memory extinction. Additionally, SPS-triggered impairment of hippocampal LTP and fear memory extinction could be rescued through activation of the Rac1-Pak1 signaling pathway. Our study provides evidence that calpain-mediated regulation of DCC controls hippocampal LTP and fear memory extinction in SPS mice, which likely through activation of the Rac1-Pak1 signaling pathway.

Central stress pathways in the development of cardiovascular disease

PURPOSE

Mental stress is of essential consideration when assessing cardiovascular pathophysiology in all patient populations. Substantial evidence indicates associations among stress, cardiovascular disease and aberrant brain-body communication. However, our understanding of the flow of stress information in humans, is limited, despite the crucial insights this area may offer into future therapeutic targets for clinical intervention.

METHODS

Key terms including mental stress, cardiovascular disease and central control, were searched in PubMed, ScienceDirect and Scopus databases. Articles indicative of heart rate and blood pressure regulation, or central control of cardiovascular disease through direct neural innervation of the cardiac, splanchnic and vascular regions were included. Focus on human neuroimaging research and the flow of stress information is described, before brain-body connectivity, via pre-motor brainstem intermediates is discussed. Lastly, we review current understandings of pathophysiological stress and cardiovascular disease aetiology.

RESULTS

Structural and functional changes to corticolimbic circuitry encode stress information, integrated by the hypothalamus and amygdala. Pre-autonomic brain-body relays to brainstem and spinal cord nuclei establish dysautonomia and lead to alterations in baroreflex functioning, firing of the sympathetic fibres, cellular reuptake of norepinephrine and withdrawal of the parasympathetic reflex. The combined result is profoundly adrenergic and increases the likelihood of cardiac myopathy, arrhythmogenesis, coronary ischaemia, hypertension and the overall risk of future sudden stress-induced heart failure.

CONCLUSIONS

There is undeniable support that mental stress contributes to the development of cardiovascular disease. The emerging accumulation of large-scale multimodal neuroimaging data analytics to assess this relationship promises exciting novel therapeutic targets for future cardiovascular disease detection and prevention.

The Genetic Architecture of Amygdala Nuclei

BACKGROUND

Whereas genetic variants influencing total amygdala volume have been identified, the genetic architecture of its distinct nuclei has yet to be explored. We aimed to investigate whether increased phenotypic specificity through nuclei segmentation aids genetic discoverability and elucidates the extent of shared genetic architecture and biological pathways with related disorders.

METHODS

T1-weighted brain magnetic resonance imaging scans (N = 36,352, 52% female) from the UK Biobank were segmented into 9 amygdala nuclei with FreeSurfer (version 6.1). Genome-wide association analyses were performed on the entire sample, a European-only subset (n = 31,690), and a generalization (transancestry) subset (n = 4662). We estimated single nucleotide polymorphism-based heritability; derived polygenicity, discoverability, and power estimates; and investigated genetic correlations and shared loci with psychiatric disorders.

RESULTS

The heritability of the nuclei ranged from 0.17 to 0.33. Across the whole amygdala and the nuclei volumes, we identified 28 novel genome-wide significant (padj < 5 × 10-9) loci in the European analysis, with significant en masse replication for the whole amygdala and central nucleus volumes in the generalization analysis, and we identified 10 additional candidate loci in the combined analysis. The central nucleus had the highest statistical power for discovery. The significantly associated genes and pathways showed unique and shared effects across the nuclei, including immune-related pathways. Shared variants were identified between specific nuclei and autism spectrum disorder, Alzheimer's disease, Parkinson's disease, bipolar disorder, and schizophrenia.

CONCLUSIONS

Through investigation of amygdala nuclei volumes, we have identified novel candidate loci in the neurobiology of amygdala volume. These nuclei volumes have unique associations with biological pathways and genetic overlap with psychiatric disorders.

Structural Neuroimaging of Hippocampus and Amygdala Subregions in Posttraumatic Stress Disorder: A Scoping Review

Numerous studies have explored the relationship between posttraumatic stress disorder (PTSD) and the hippocampus and the amygdala because both regions are implicated in the disorder's pathogenesis and pathophysiology. Nevertheless, those key limbic regions consist of functionally and cytoarchitecturally distinct substructures that may play different roles in the etiology of PTSD. Spurred by the availability of automatic segmentation software, structural neuroimaging studies of human hippocampal and amygdala subregions have proliferated in recent years. Here, we present a preregistered scoping review of the existing structural neuroimaging studies of the hippocampus and amygdala subregions in adults diagnosed with PTSD. A total of 3513 studies assessing subregion volumes were identified, 1689 of which were screened, and 21 studies were eligible for this review (total N = 2876 individuals). Most studies examined hippocampal subregions and reported decreased CA1, CA3, dentate gyrus, and subiculum volumes in PTSD. Fewer studies investigated amygdala subregions and reported altered lateral, basal, and central nuclei volumes in PTSD. This review further highlights the conceptual and methodological limitations of the current literature and identifies future directions to increase understanding of the distinct roles of hippocampal and amygdalar subregions in posttraumatic psychopathology.

Occupational stress is associated with sex and subregion specific modifications of the amygdala volumes

Background: Despite the rapid increase in reports of exhaustion syndrome (ES) due to daily occupational stress, the mechanisms underlying ES are unknown. In the present study, we investigated whether occupational ES is associated with specific modifications of the subfields of the amygdala and hippocampus resembling those described in other chronic stress conditions. Special focus was paid to possible sex differences.Methods: As a follow up to our previous studies of occupational ES, we carried out MRI-based subfield segmentation of the hippocampus and amygdala volumes in 58 patients with occupational ES (22 males) and 65 age-matched controls (27 males) (age range 30-46 years).Results: There was a significant and bilateral enlargement of the lateral, basal and central nucleus of the amygdala in patients with ES (corrected for the total intracranial volume (ICV)). These differences were detected only in females. Higher values in the right central and right basal amygdala remained when the whole amygdala volume was used as reference, instead of the ICV. Notably, in female patients the volumes of these specific nuclei were positively correlated with the degree of perceived stress. No changes in the hippocampus subfields were detected in female or male patients.Conclusions: The findings underline that ES is a chronic stress condition, suggesting that not only extreme forms of stress, but also the everyday stress is associated with localized differences from controls in the amygdala. The absence of significant alterations among men with ES despite a similar degree of perceived stress supports the notion that women seem more susceptible to stress-related cerebral changes, and may explain the higher prevalence of ES among women.

Cross-sectional field study comparing hippocampal subfields in patients with post-traumatic stress disorder, major depressive disorder, post-traumatic stress disorder with comorbid major depressive disorder, and adjustment disorder using routine clinical data

Background

The hippocampus is a central brain structure involved in stress processing. Previous studies have linked stress-related mental disorders, such as post-traumatic stress disorder (PTSD) and major depressive disorder (MDD), with changes in hippocampus volume. As PTSD and MDD have similar symptoms, clinical diagnosis relies solely on patients reporting their cognitive and emotional experiences, leading to an interest in utilizing imaging-based data to improve accuracy. Our field study aimed to determine whether there are hippocampal subfield volume differences between stress-related mental disorders (PTSD, MDD, adjustment disorders, and AdjD) using routine clinical data from a military hospital.

Methods

Participants comprised soldiers (N = 185) with PTSD (n = 50), MDD (n = 70), PTSD with comorbid MDD (n = 38), and AdjD (n = 27). The hippocampus was segmented and volumetrized into subfields automatically using FreeSurfer. We used ANCOVA models with estimated total intracranial volume as a covariate to determine whether there were volume differences in the hippocampal subfields cornu ammonis 1 (CA1), cornu ammonis 2/3 (CA2/3), and dentate gyrus (DG) among patients with PTSD, MDD, PTSD with comorbid MDD, and AdjD. Furthermore, we added self-reported symptom duration and previous psychopharmacological and psychotherapy treatment as further covariates to examine whether there were associations with CA1, CA2/3, and DG.

Results

No significant volume differences in hippocampal subfields between stress-related mental disorders were found. No significant associations were detected between symptom duration, psychopharmacological treatment, psychotherapy, and the hippocampal subfields.

Conclusion

Hippocampal subfields may distinguish stress-related mental disorders; however, we did not observe any subfield differences. We provide several explanations for the non-results and thereby inform future field studies.

Neurobiological and genetic correlates of the dissociative subtype of posttraumatic stress disorder

Approximately 10%-30% of individuals with posttraumatic stress disorder (PTSD) exhibit a dissociative subtype of the condition defined by symptoms of depersonalization and derealization. This study examined the psychometric evidence for the dissociative subtype of PTSD in a sample of young, primarily male post-9/11-era Veterans (n = 374 at baseline and n = 163 at follow-up) and evaluated its biological correlates with respect to resting state functional connectivity (default mode network [DMN]; n = 275), brain morphology (hippocampal subfield volume and cortical thickness; n = 280), neurocognitive functioning (n = 337), and genetic variation (n = 193). Multivariate analyses of PTSD and dissociation items suggested a class structure was superior to dimensional and hybrid ones, with 7.5% of the sample comprising the dissociative class; this group showed stability over 1.5 years. Covarying for age, sex, and PTSD severity, linear regression models revealed that derealization/depersonalization severity was associated with: decreased DMN connectivity between bilateral posterior cingulate cortex and right isthmus (p = .015; adjusted-p [padj] = .097); increased bilateral whole hippocampal, hippocampal head, and molecular layer head volume (p = .010-.034; padj = .032-.053); worse self-monitoring (p = .018; padj = .079); and a candidate genetic variant (rs263232) in the adenylyl cyclase 8 gene (p = .026), previously associated with dissociation. Results converged on biological structures and systems implicated in sensory integration, the neural representation of spatial awareness, and stress-related spatial learning and memory, suggesting possible mechanisms underlying the dissociative subtype of PTSD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Expanding the canon: An inclusive neurobiology of thalamic and subthalamic fear circuits

Appropriate expression of fear in the face of threats in the environment is essential for survival. The sustained expression of fear in the absence of threat signals is a central pathological feature of trauma- and anxiety-related disorders. Our understanding of the neural circuitry that controls fear inhibition coalesces around the amygdala, hippocampus, and prefrontal cortex. By discussing thalamic and sub-thalamic influences on fear-related learning and expression in this review, we suggest a more inclusive neurobiological framework that expands our canonical view of fear. First, we visit how fear-related learning and expression is influenced by the aforementioned canonical brain regions. Next, we review emerging data that shed light on new roles for thalamic and subthalamic nuclei in fear-related learning and expression. Then, we highlight how these neuroanatomical hubs can modulate fear via integration of sensory and salient stimuli, gating information flow and calibrating behavioral responses, as well as maintaining and updating memory representations. Finally, we propose that the presence of this thalamic and sub-thalamic neuroanatomy in parallel with the tripartite prefrontal cortex-amygdala-hippocampus circuit allows for dynamic modulation of information based on interoceptive and exteroceptive signals. This article is part of the Special Issue on "Fear, Anxiety and PTSD".

A neurostructural biomarker of dissociative amnesia: a hippocampal study in dissociative identity disorder

BACKGROUND

Little is known about the neural correlates of dissociative amnesia, a transdiagnostic symptom mostly present in the dissociative disorders and core characteristic of dissociative identity disorder (DID). Given the vital role of the hippocampus in memory, a prime candidate for investigation is whether total and/or subfield hippocampal volume can serve as biological markers of dissociative amnesia.

METHODS

A total of 75 women, 32 with DID and 43 matched healthy controls (HC), underwent structural magnetic resonance imaging (MRI). Using Freesurfer (version 6.0), volumes were extracted for bilateral global hippocampus, cornu ammonis (CA) 1-4, the granule cell molecular layer of the dentate gyrus (GC-ML-DG), fimbria, hippocampal-amygdaloid transition area (HATA), parasubiculum, presubiculum and subiculum. Analyses of covariance showed volumetric differences between DID and HC. Partial correlations exhibited relationships between the three factors of the dissociative experience scale scores (dissociative amnesia, absorption, depersonalisation/derealisation) and traumatisation measures with hippocampal global and subfield volumes.

RESULTS

Hippocampal volumes were found to be smaller in DID as compared with HC in bilateral global hippocampus and bilateral CA1, right CA4, right GC-ML-DG, and left presubiculum. Dissociative amnesia was the only dissociative symptom that correlated uniquely and significantly with reduced bilateral hippocampal CA1 subfield volumes. Regarding traumatisation, only emotional neglect correlated negatively with bilateral global hippocampus, bilateral CA1, CA4 and GC-ML-DG, and right CA3.

CONCLUSION

We propose decreased CA1 volume as a biomarker for dissociative amnesia. We also propose that traumatisation, specifically emotional neglect, is interlinked with dissociative amnesia in having a detrimental effect on hippocampal volume.

Longitudinal volumetric evaluation of hippocampus and amygdala subregions in recent trauma survivors

The hippocampus and the amygdala play a central role in post-traumatic stress disorder (PTSD) pathogenesis. While alternations in volumes of both regions have been consistently observed in individuals with PTSD, it remains unknown whether these reflect pre-trauma vulnerability traits or acquired post-trauma consequences of the disorder. Here, we conducted a longitudinal panel study of adult civilian trauma survivors admitted to a general hospital emergency department (ED). One hundred eligible participants (mean age = 32.97 ± 10.97, n = 56 females) completed both clinical interviews and structural MRI scans at 1-, 6-, and 14-months after ED admission (alias T1, T2, and T3). While all participants met PTSD diagnosis at T1, only n = 29 still met PTSD diagnosis at T3 (a "non-Remission" Group), while n = 71 did not (a "Remission" Group). Bayesian multilevel modeling analysis showed robust evidence for smaller right hippocampus volume (P+ of ~0.014) and moderate evidence for larger left amygdala volume (P+ of ~0.870) at T1 in the "non-Remission" group, compared to the "Remission" group. Subregion analysis further demonstrated robust evidence for smaller volume in the subiculum and right CA1 hippocampal subregions (P+ of ~0.021-0.046) in the "non-Remission" group. No time-dependent volumetric changes (T1 to T2 to T3) were observed across all participants or between groups. Results support the "vulnerability trait" hypothesis, suggesting that lower initial volumes of specific hippocampus subregions are associated with non-remitting PTSD. The stable volume of all hippocampal and amygdala subregions does not support the idea of consequential, progressive, stress-related atrophy during the first critical year following trauma exposure.

Psychosocial factors and hippocampal subfields: The Medea-7T study

Specific subfields within the hippocampus have shown vulnerability to chronic stress, highlighting the importance of looking regionally within the hippocampus to understand the role of psychosocial factors in the development of neurodegenerative diseases. A systematic review on psychosocial factors and hippocampal subfield volumes was performed and showed inconsistent results, highlighting the need for future studies to explore this relationship. The current study aimed to explore the association of psychosocial factors with hippocampal (subfield) volumes, using high-field 7T MRI. Data were from the Memory Depression and Aging (Medea)-7T study, which included 333 participants without dementia. Hippocampal subfields were automatically segmented from T2-weighted images using ASHS software. Generalized linear models accounting for correlated outcomes were used to assess the association between subfields (i.e., entorhinal cortex, subiculum, Cornu Ammonis [CA]1, CA2, CA3, dentate gyrus, and tail) and each psychosocial factor (i.e., depressive symptoms, anxiety symptoms, childhood maltreatment, recent stressful life events, and social support), adjusted for age, sex, and intracranial volume. Neither depression nor anxiety was associated with specific hippocampal (subfield) volumes. A trend for lower total hippocampal volume was found in those reporting childhood maltreatment, and a trend for higher total hippocampal volume was found in those who experienced a recent stressful life event. Among subfields, low social support was associated with lower volume in the CA3 (B = -0.43, 95% CI: -0.72; -0.15). This study suggests possible differential effects among hippocampal (subfield) volumes and psychosocial factors.

The DRD2 Taq1A polymorphism moderates the effect of PTSD symptom severity on the left hippocampal CA3 volume: a pilot study

RATIONALE AND OBJECTIVES

The hippocampus, especially the CA1, CA3, and dentate gyrus (DG) subfields, is reported to be associated with post-traumatic stress disorder (PTSD) after trauma. However, neuroimaging studies of the associations between PTSD and hippocampal subfield volumes have failed to yield consistent findings. The aim of this study is to examine whether the dopamine D2 receptor (DRD2) Taq1A polymorphism, which is associated with both hippocampal function and PTSD, moderated the association between PTSD severity and hippocampal CA1, CA3 and DG volumes.

METHODS

T1-weighted images were acquired from 142 trauma survivors from the 2008 Wenchuan earthquake using a 3.0-T magnetic resonance imaging system. Hippocampal subfield segmentations were performed with FreeSurfer v6.0. We used the simple moderation model from the PROCESS v3.4 tool for SPSS 23.0 to examine the association between the rs1800497 polymorphism, PTSD severity, and hippocampal CA3 and DG volumes.

RESULTS

A significant genotype × PTSD symptom severity interaction was found for the left CA3 volume (ΔF = 5.01, p = 0.008, ΔR2 = 0.05). Post hoc, exploratory analyses deconstructing the interaction revealed that severe PTSD symptomatology were associated with reduced left CA3 volume among TC heterozygotes (t =  - 2.86, p = 0.005).

CONCLUSIONS

This study suggests that DRD2 Taq1A polymorphism moderates the association between PTSD symptomatology and left CA3 volume, which promotes an etiological understanding of the hippocampal atrophy at the subfield level. This highlights the complex effect of environmental stress, and provides possible mechanism for the relationship between the dopaminergic system and hippocampal function in PTSD.

Intergenerational transmission of psychological trauma: A structural neuroimaging study

Traumatic events have an important effect in human life and may lead to psychopathological disturbances by affecting the personal and social lives of individuals. Recently, various studies have been reported in the literature showing that the traumatic experiences may be associated with intergenerational psychopathologies. However, there is limited data regarding the neuroimaging studies investigating changes in brain structures in children of traumatized mothers. In this study, we aimed to investigate the potential changes in the hippocampus and amygdala volumes in the children of mothers exposed to mass trauma. The traumatic event experienced by the mothers was the two devastating earthquakes they experienced when they were teenagers. Hippocampus and amygdala volumes were evaluated in magnetic resonance imaging of 40 children whose mothers were exposed to earthquakes and 27 children in control group. Bilateral amygdala volumes were significantly smaller in the children of mothers exposed to earthquake compared to the control group. In addition, right amygdala and hippocampus volumes were smaller in children of mothers exposed to earthquakes than left. This is one of the pioneering neuroimaging studies on the intergenerational transmission of trauma. Our study shows that there may be a potential relationship between intergenerational trauma and various brain structures.

Elastic shape analysis of brain structures for predictive modeling of PTSD

It is well-known that morphological features in the brain undergo changes due to traumatic events and associated disorders such as post-traumatic stress disorder (PTSD). However, existing approaches typically offer group-level comparisons, and there are limited predictive approaches for modeling behavioral outcomes based on brain shape features that can account for heterogeneity in PTSD, which is of paramount interest. We propose a comprehensive shape analysis framework representing brain sub-structures, such as the hippocampus, amygdala, and putamen, as parameterized surfaces and quantifying their shape differences using an elastic shape metric. Under this metric, we compute shape summaries (mean, covariance, PCA) of brain sub-structures and represent individual brain shapes by their principal scores under a shape-PCA basis. These representations are rich enough to allow visualizations of full 3D structures and help understand localized changes. In order to validate the elastic shape analysis, we use the principal components (PCs) to reconstruct the brain structures and perform further evaluation by performing a regression analysis to model PTSD and trauma severity using the brain shapes represented via PCs and in conjunction with auxiliary exposure variables. We apply our method to data from the Grady Trauma Project (GTP), where the goal is to predict clinical measures of PTSD. The framework seamlessly integrates accurate morphological features and other clinical covariates to yield superior predictive performance when modeling PTSD outcomes. Compared to vertex-wise analysis and other widely applied shape analysis methods, the elastic shape analysis approach results in considerably higher reconstruction accuracy for the brain shape and reveals significantly greater predictive power. It also helps identify local deformations in brain shapes associated with PTSD severity.

Cingulate and hippocampal subregion abnormalities in combat-exposed veterans with PTSD

BACKGROUND

The hippocampus and cingulate gyrus are strongly interconnected brain regions that have been implicated in the neurobiology of post-traumatic stress disorder (PTSD). These brain structures are comprised of functionally distinct subregions that may contribute to the expression of PTSD symptoms or associated cardio-metabolic markers, but have not been well investigated in prior studies.

METHODS

Two divisions of the cingulate cortex (i.e., rostral and caudal) and 11 hippocampal subregions were investigated in 22 male combat-exposed veterans with PTSD and 22 male trauma-exposed veteran controls (TC). Cardio-metabolic measures included cholesterol, body mass index, and mean arterial pressure.

RESULTS

Individuals with PTSD had less caudal cingulate area compared to TC even after controlling for caudal cingulate thickness. Total hippocampus volume was lower in PTSD compared to TC, accounted for by differences in CA1-CA4, granule cell layer of the dentate gyrus, molecular layer, and subiculum. Individuals with PTSD had higher mean arterial pressure compared to TC, which correlated with hippocampus volume only in the PTSD group.

LIMITATIONS

Sample size, cross-sectional analysis, no control for medications and findings limited to males.

CONCLUSIONS

These data demonstrate preferential involvement of caudal cingulate area (vs. thickness) and hippocampus subregions in PTSD. The inverse association between hippocampus volume and mean arterial pressure may contribute to accelerated aging known to be associated with PTSD.

Anshen Dingzhi prescription in the treatment of PTSD in mice: Investigation of the underlying mechanism from the perspective of hippocampal synaptic function

BACKGROUND

Anshen Dingzhi prescription (ADP) is an important prescription for the treatment of mental diseases in traditional Chinese medicine and is widely used to treat neuropsychiatric disorders.

PURPOSE

To explore the ameliorative effect of ADP on post-traumatic stress disorder (PTSD)-like behaviors in mice and determine the underlying mechanism.

METHODS

The constituents of ADP were analyzed by UPLC-Q-TOF/MS. The PTSD-like behaviors of mice subjected to single prolonged stress (SPS) were evaluated using behavioral tests. Potential pathological changes in the hippocampus were assessed by hematoxylin and eosin (H&E) staining. Western blotting and immunohistochemistry (IHC) were employed to detect the expression of proteins involved in relevant signaling pathways.

RESULTS

Five quality control markers (ginsenoside Rg1, ginsenoside Rb1, tenuifolin, poricoic acid B, and α-asarone) were detected in the ADP solution. The ginsenoside Rg1 content in ADP was found to be 0.114 mg/g. Mice subjected to SPS showed obvious fear generalization and anxiety-like behaviors. ADP treatment prevented the behavioral changes caused by exposure to SPS. Compared with control animals, the number of normal pyramidal cells in the hippocampal CA1 region of mice exposed to SPS was decreased and the number of degenerating pyramidal cells was increased; however, ADP administration could counteract these effects. Furthermore, the protein expression of BDNF, p-TrkB, μ-calpain, PSD95, GluN2A, GluA1, p-AKT, p-mTOR, and ARC was decreased, while that of PTEN and GluN2B was increased in the hippocampus of mice subjected to SPS compared with that in control animals; however, these changes in protein expression were reversed following ADP treatment. Importantly, the ameliorative effect of ADP on PTSD-like behaviors and synaptic protein expression were inhibited by rapamycin administration.

CONCLUSIONS

ADP administration improves PTSD-like behaviors in mice and this effect may be mediated through an mTOR-dependent improvement in synaptic function in the hippocampus.

Volumetric differences in hippocampal subfields and associations with clinical measures in myalgic encephalomyelitis/chronic fatigue syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients suffer from a cognitive and memory dysfunction. Because the hippocampus plays a key role in both cognition and memory, we tested for volumetric differences in the subfields of the hippocampus in ME/CFS. We estimated hippocampal subfield volumes for 25 ME/CFS patients who met Fukuda criteria only (ME/CFS_Fukuda), 18 ME/CFS patients who met the stricter ICC criteria (ME/CFS_ICC), and 25 healthy controls (HC). Group comparisons with HC detected extensive differences in subfield volumes in ME/CFS_ICC but not in ME/CFS_Fukuda. ME/CFS_ICC patients had significantly larger volume in the left subiculum head (p < 0.001), left presubiculum head (p = 0.0020), and left fimbria (p = 0.004). Correlations of hippocampus subfield volumes with clinical measures were stronger in ME/CFS_ICC than in ME/CFS_Fukuda patients. In ME/CFS_Fukuda patients, we detected positive correlations between fatigue and hippocampus subfield volumes and a negative correlation between sleep disturbance score and the right CA1 body volume. In ME/CFS_ICC patients, we detected a strong negative relationship between fatigue and left hippocampus tail volume. Strong negative relationships were also detected between pain and SF36 physical scores and two hippocampal subfield volumes (left: GC‐ML‐DG head and CA4 head). Our study demonstrated that volumetric differences in hippocampal subfields have strong statistical inference for patients meeting the ME/CFS_ICC case definition and confirms hippocampal involvement in the cognitive and memory problems of ME/CFS_ICC patients.

MRI volumetric changes in hippocampal subfields in psychosis: a protocol for a systematic review and meta-analysis

BACKGROUND

The hippocampus has for long been known for its ability to form new, declarative memory. However, emerging findings across conditions in the psychosis spectrum also implicate its role in emotional regulation. Systematic reviews have demonstrated consistent volume atrophic changes in the hippocampus. The aim of the systematic review and metanalysis which will follow from this protocol will be to investigate the volume-based neuroimaging findings across each of the subfields of the hippocampus in psychosis independent of diagnosis.

METHODS

Volume changes across subfields of the hippocampus in psychotic illnesses will be assessed by systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). MRI neuroimaging studies of patients with a definitive diagnosis of psychosis (including brief pre-diagnostic states) will be included. Studies lacking adequate controls, illicit drug use, medical psychosis, history of other significant psychiatric comorbidities, or emphasis on age groups above 65 or below 16 will be excluded. Subfields investigated will include the CA1, CA2/3, CA4, subiculum, presubiculum, parasubiculum, dentate gyrus, stratum, molecular layer, granular cell layer, entorhinal cortex, and fimbria. Two people will independently screen abstracts from the output of the search to select suitable studies. This will be followed by the two reviewers performing a full-text review of the studies which were selected based on suitable abstracts. One reviewer will independently perform all the data extraction, and another reviewer will then systemically check all the extracted information using the original articles to ensure accuracy. Statistical analysis will be performed using the metafor and meta-packages in R Studio with the application of the random-effects model.

DISCUSSION

This study will provide insight into the volumetric changes in psychosis of the subfields of the hippocampus, independent of diagnosis. This may shed light on the intricate neural pathology which encompasses psychosis and will open avenues for further exploration of the structures identified as potential drivers of volume change.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020199558.

Structural correlates of trauma-induced hyperarousal in mice

Post-traumatic stress disorder (PTSD) is a chronic disease caused by traumatic incidents. Numerous studies have revealed grey matter volume differences in affected individuals. The nature of the disease renders it difficult to distinguish between a priori versus a posteriori changes. To overcome this difficulty, we studied the consequences of a traumatic event on brain morphology in mice before and 4 weeks after exposure to brief foot shocks (or sham treatment), and correlated morphology with symptoms of hyperarousal. In the latter context, we assessed hyperarousal upon confrontation with acoustic, visual, or composite (acoustic/visual/tactile) threats and integrated the individual readouts into a single Hyperarousal Score using logistic regression analysis. MRI scans with subsequent whole-brain deformation-based morphometry (DBM) analysis revealed a volume decrease of the dorsal hippocampus and an increase of the reticular nucleus in shocked mice when compared to non-shocked controls. Using the Hyperarousal Score as regressor for the post-exposure MRI measurement, we observed negative correlations with several brain structures including the dorsal hippocampus. If the development of changes with respect to the basal MRI was considered, reduction in globus pallidus volume reflected hyperarousal severity. Our findings demonstrate that a brief traumatic incident can cause volume changes in defined brain structures and suggest the globus pallidus as an important hub for the control of fear responses to threatening stimuli of different sensory modalities.

Trauma and posttraumatic stress disorder modulate polygenic predictors of hippocampal and amygdala volume

The volume of subcortical structures represents a reliable, quantitative, and objective phenotype that captures genetic effects, environmental effects such as trauma, and disease effects such as posttraumatic stress disorder (PTSD). Trauma and PTSD represent potent exposures that may interact with genetic markers to influence brain structure and function. Genetic variants, associated with subcortical volumes in two large normative discovery samples, were used to compute polygenic scores (PGS) for the volume of seven subcortical structures. These were applied to a target sample enriched for childhood trauma and PTSD. Subcortical volume PGS from the discovery sample were strongly associated in our trauma/PTSD enriched sample (n = 7580) with respective subcortical volumes of the hippocampus (p = 1.10 × 10-20), thalamus (p = 7.46 × 10-10), caudate (p = 1.97 × 10-18), putamen (p = 1.7 × 10-12), and nucleus accumbens (p = 1.99 × 10-7). We found a significant association between the hippocampal volume PGS and hippocampal volume in control subjects from our sample, but was absent in individuals with PTSD (GxE; (beta = -0.10, p = 0.027)). This significant GxE (PGS × PTSD) relationship persisted (p < 1 × 10-19) in four out of five threshold peaks (0.024, 0.133, 0.487, 0.730, and 0.889) used to calculate hippocampal volume PGSs. We detected similar GxE (G × ChildTrauma) relationships in the amygdala for exposure to childhood trauma (rs4702973; p = 2.16 × 10-7) or PTSD (rs10861272; p = 1.78 × 10-6) in the CHST11 gene. The hippocampus and amygdala are pivotal brain structures in mediating PTSD symptomatology. Trauma exposure and PTSD modulate the effect of polygenic markers on hippocampal volume (GxE) and the amygdala volume PGS is associated with PTSD risk, which supports the role of amygdala volume as a risk factor for PTSD.

Morphometry Difference of the Hippocampal Formation Between Blind and Sighted Individuals

The detailed morphometry alterations of the human hippocampal formation (HF) for blind individuals are still understudied. 50 subjects were recruited from Yantai Affiliated Hospital of Binzhou Medical University, including 16 congenital blindness, 14 late blindness, and 20 sighted controls. Volume and shape analysis were conducted between the blind (congenital or late) and sighted groups to observe the (sub)regional alterations of the HF. No significant difference of the hippocampal volume was observed between the blind and sighted subjects. Rightward asymmetry of the hippocampal volume was found for both congenital and late blind individuals, while no significant hemispheric difference was observed for the sighted controls. Shape analysis showed that the superior and inferior parts of both the hippocampal head and tail expanded, while the medial and lateral parts constrained for the blind individuals as compared to the sighted controls. The morphometry alterations for the congenital blind and late blind individuals are nearly the same. Significant expansion of the superior part of the hippocampal tail for both congenital and late blind groups were observed for the left hippocampi after FDR correction. Current results suggest that the cross-model plastic may occur in both hemispheres of the HF to improve the navigation ability without the stimuli of visual cues, and the alteration is more prominent for the left hemisphere.

Stability of hippocampal subfield volumes after trauma and relationship to development of PTSD symptoms

BACKGROUND

The hippocampus plays a central role in post-traumatic stress disorder (PTSD) pathogenesis, and the majority of neuroimaging research on PTSD has studied the hippocampus in its entirety. Although extensive literature demonstrates changes in hippocampal volume are associated with PTSD, fewer studies have probed the relationship between symptoms and the hippocampus' functionally and structurally distinct subfields. We utilized data from a longitudinal study examining post-trauma outcomes to determine whether hippocampal subfield volumes change post-trauma and whether specific subfields are significantly associated with, or prospectively related to, PTSD symptom severity. As a secondary aim, we leveraged our unique study design sample to also investigate reliability of hippocampal subfield volumes using both cross-sectional and longitudinal pipelines available in FreeSurfer v6.0.

METHODS

Two-hundred and fifteen traumatically injured individuals were recruited from an urban Emergency Department. Two-weeks post-injury, participants underwent two consecutive days of neuroimaging (time 1: T1, and time 2: T2) with magnetic resonance imaging (MRI) and completed self-report assessments. Six-months later (time 3: T3), participants underwent an additional scan and were administered a structured interview assessing PTSD symptoms. First, we calculated reliability of hippocampal measurements at T1 and T2 (automatically segmented with FreeSurfer v6.0). We then examined the prospective (T1 subfields) and cross-sectional (T3 subfields) relationship between volumes and PTSD. Finally, we tested whether change in subfield volumes between T1 and T3 explained PTSD symptom variability.

RESULTS

After controlling for sex, age, and total brain volume, none of the subfield volumes (T1) were prospectively related to T3 PTSD symptoms nor were subfield volumes (T3) associated with current PTSD symptoms (T3). Tl - T2 reliability of all hippocampal subfields ranged from good to excellent (intraclass correlation coefficient (ICC) values > 0.83), with poorer reliability in the hippocampal fissure.

CONCLUSION

Our study was a novel examination of the prospective relationship between hippocampal subfield volumes in relation to PTSD in a large trauma-exposed urban sample. There was no significant relationship between subfield volumes and PTSD symptoms, however, we confirmed FreeSurfer v6.0 hippocampal subfield segmentation is reliable when applied to a traumatically-injured sample, using both cross-sectional and longitudinal analysis pipelines. Although hippocampal subfield volumes may be an important marker of individual variability in PTSD, findings are likely conditional on the timing of the measurements (e.g. acute or chronic post-trauma periods) and analysis strategy (e.g. cross-sectional or prospective).

Association of Tau Pathology With Clinical Symptoms in the Subfields of Hippocampal Formation

Objective: To delineate the relationship between clinical symptoms and tauopathy of the hippocampal subfields under different amyloid statuses. Methods: One hundred and forty-three subjects were obtained from the ADNI project, including 87 individuals with normal cognition, 46 with mild cognitive impairment, and 10 with Alzheimer's disease (AD). All subjects underwent the tau PET, amyloid PET, T1W, and high-resolution T2W scans. Clinical symptoms were assessed by the Neuropsychiatric Inventory (NPI) total score and Alzheimer's Disease Assessment Scale cognition 13 (ADAS-cog-13) total score, comprising memory and executive function scores. The hippocampal subfields including Cornu Ammonis (CA1-3), subiculum (Sub), and dentate gyrus (DG), as well as the adjacent para-hippocampus (PHC) and entorhinal cortex (ERC), were segmented automatically using the Automatic Segmentation of Hippocampal Subfields (ASHS) software. The relationship between tauopathy/volume of the hippocampal subfields and assessment scores was calculated using partial correlation analysis under different amyloid status, by controlling age, gender, education, apolipoprotein E (APOE) allele ɛ4 carrier status, and, time interval between the acquisition time of tau PET and amyloid PET scans. Results: Compared with amyloid negative (A-) group, individuals from amyloid positive (A+) group are more impaired based on the Mini-mental State Examination (MMSE; p = 3.82e-05), memory (p = 6.30e-04), executive function (p = 0.0016), and ADAS-cog-13 scores (p = 5.11e-04). Significant decrease of volume (CA1, DG, and Sub) and increase of tau deposition (CA1, Sub, ERC, and PHC) of the hippocampal subfields of both hemispheres were observed for the A+ group compared to the A- group. Tauopathy of ERC is significantly associated with memory score for the A- group, and the associated regions spread into Sub and PHC for the A+ group. The relationship between the impairment of behavior or executive function and tauopathy of the hippocampal subfield was discovered within the A+ group. Leftward asymmetry was observed with the association between assessment scores and tauopathy of the hippocampal subfield, which is more prominent for the NPI score for the A+ group. Conclusion: The associations of tauopathy/volume of the hippocampal subfields with clinical symptoms provide additional insight into the understanding of local changes of the human HF during the AD continuum and can be used as a reference for future studies.

Larger dentate gyrus volume as predisposing resilience factor for the development of trauma-related symptoms

Early interventions to improve resilience require the identification of objective risk biomarkers for PTSD symptom development. Although altered hippocampal and amygdala volumes are consistently observed in PTSD, it remains currently unknown whether they represent a predisposing vulnerability factor for PTSD symptom development or an acquired consequence of trauma exposure and/or the disorder. We conducted a longitudinal, prospective study in 210 police recruits at high risk for trauma exposure (56 females(26.7%); mean[SD] age = 24.02[5.19]). Structural MRI scans and trauma-related symptom severity were assessed at pre-trauma baseline and at 16-month follow-up. Between assessments, police recruits were exposed to various potentially traumatic events during their police training. Police recruits reported a significant increase in police-related trauma exposure and stress-related symptoms between assessments. Smaller hippocampal left dentate gyrus (DG) volumes at baseline predicted increase in self-reported PTSD symptoms (B[SE] = -0.21[0.08], p = 0.011), stress symptoms (B[SE] = -0.16[0.07], p = 0.024) and negative affect (B[SE] = -0.21[0.07], p = 0.005) upon trauma exposure. Amount of police-related trauma exposure between assessments was positively associated with an increase in left basal amygdala nucleus volume (B[SE] = 0.11[0.05], p = 0.026). Taken together, smaller DG-volumes pre-trauma may represent a predisposing neurobiological vulnerability factor for development of trauma-related symptoms. On the other hand, amount of trauma exposure between assessments was positively associated with increased amygdala basal nucleus volume, suggesting acquired neural effects. These findings suggest that preventive interventions for PTSD aimed at improving resilience could be targeted at increasing DG-volume and potentially its functioning.

Variations in response to trauma and hippocampal subfield changes

Models of posttraumatic stress disorder (PTSD) suggest that the hippocampus is key to the persistence of traumatic memory. Yet very little is known about the precise changes that take place in this structure, nor their relation with PTSD symptoms. Previous studies have mostly used magnetic resonance imaging (MRI) at low resolutions, making it impossible to identify sensitive anatomical landmarks, or compared groups often unequally matched in terms of traumatic exposure. The present cross-sectional study included 92 individuals who had all been exposed to the terrorist attacks in Paris on November 13, 2015 (53 of whom subsequently developed PTSD) and 56 individuals who had not been exposed. Hippocampal subfield volumes were estimated using cross-validated automatic segmentation of high-resolution MRI images. Results revealed changes in CA1 and CA2-3/dentate gyrus (DG) volumes in individuals with PTSD, but not in resilient (i.e., exposed but without PTSD) individuals, after controlling for potential nuisance variables such as previous traumatic exposure and substance abuse. In line with current models of hippocampal subfield functions, CA1 changes were linked to the uncontrollable re-experiencing of intrusive memories, while CA2-3/DG changes, potentially exacerbated by comorbid depression, fostered the overgeneralization of fear linked to avoidance and hypervigilance behaviors. Additional analyses revealed that CA1 integrity was linked to optimum functioning of the memory control network in resilient individuals. These findings shed new light on potential pathophysiological mechanisms in the hippocampus subtending the development of PTSD and the failure to recover from trauma.

Selective hippocampal subfield volume reductions in World Trade Center responders with cognitive impairment

INTRODUCTION

The objective of this study was to investigate associations between dementia in World Trade Center (WTC) responders and in vivo volumetric measures of hippocampal subfield volumes in WTC responders at midlife.

METHODS

A sample of 99 WTC responders was divided into dementia and unimpaired groups. Participants underwent structural T1-weighted magnetic resonance imaging. Volumetric measures included the overall hippocampus and eight subfields. Regression models examined volumetric measure of interest adjusting for confounders including intracranial volume.

RESULTS

Dementia was associated with smaller hippocampal volume and with reductions across hippocampal subfields. Smaller hippocampal subfield volumes were associated with longer cumulative time worked at the WTC. Domain-specific cognitive performance was associated with lower volumetric measures across hippocampal subregions.

CONCLUSIONS

This is the first study to investigate hippocampal subfield volumes in a sample of WTC responders at midlife. Selective hippocampal subfield volume reductions suggested abnormal cognition that were associated with WTC exposure duration.

Hippocampal subfield alterations in pediatric patients with post-traumatic stress disorder

The hippocampus, a key structure with distinct subfield functions, is strongly implicated in the pathophysiology of post-traumatic stress disorder (PTSD); however, few studies of hippocampus subfields in PTSD have focused on pediatric patients. We therefore investigated the hippocampal subfield volume using an automated segmentation method and explored the subfield-centered functional connectivity aberrations related to the anatomical changes, in a homogenous population of traumatized children with and without PTSD. To investigate the potential diagnostic value in individual patients, we used a machine learning approach to identify features with significant discriminative power for diagnosis of PTSD using random forest classifiers. Compared to controls, we found significant mean volume reductions of 8.4% and 9.7% in the right presubiculum and hippocampal tail in patients, respectively. These two subfields' volumes were the most significant contributors to group discrimination, with a mean classification accuracy of 69% and a specificity of 81%. These anatomical alterations, along with the altered functional connectivity between (pre)subiculum and inferior frontal gyrus, may underlie deficits in fear circuitry leading to dysfunction of fear extinction and episodic memory, causally important in post-traumatic symptoms such as hypervigilance and re-experience. For the first time, we suggest that hippocampal subfield volumes might be useful in discriminating traumatized children with and without PTSD.

Volumetric trajectories of hippocampal subfields and amygdala nuclei influenced by adolescent alcohol use and lifetime trauma

Alcohol use and exposure to psychological trauma frequently co-occur in adolescence and share many risk factors. Both exposures have deleterious effects on the brain during this sensitive developmental period, particularly on the hippocampus and amygdala. However, very little is known about the individual and interactive effects of trauma and alcohol exposure and their specific effects on functionally distinct substructures within the adolescent hippocampus and amygdala. Adolescents from a large longitudinal sample (N = 803, 2684 scans, 51% female, and 75% White/Caucasian) ranging in age from 12 to 21 years were interviewed about exposure to traumatic events at their baseline evaluation. Assessments for alcohol use and structural magnetic resonance imaging scans were completed at baseline and repeated annually to examine neurodevelopmental trajectories. Hippocampal and amygdala subregions were segmented using Freesurfer v6.0 tools, followed by volumetric analysis with generalized additive mixed models. Longitudinal statistical models examined the effects of cumulative lifetime trauma measured at baseline and alcohol use measured annually on trajectories of hippocampal and amygdala subregions, while controlling for covariates known to impact brain development. Greater alcohol use, quantified using the Cahalan scale and measured annually, was associated with smaller whole hippocampus (β = -12.0, p_FDR = 0.009) and left hippocampus tail volumes (β = -1.2, p_FDR = 0.048), and larger right CA3 head (β = 0.4, p_FDR = 0.027) and left subiculum (β = 0.7, p_FDR = 0.046) volumes of the hippocampus. In the amygdala, greater alcohol use was associated with larger right basal nucleus volume (β = 1.3, p_FDR = 0.040). The effect of traumatic life events measured at baseline was associated with larger right CA3 head volume (β = 1.3, p_FDR = 0.041) in the hippocampus. We observed an interaction between baseline trauma and within-person age change where younger adolescents with greater trauma exposure at baseline had smaller left hippocampal subfield volumes in the subiculum (β = 0.3, p_FDR = 0.029) and molecular layer HP head (β = 0.3, p_FDR = 0.041). The interaction also revealed that older adolescents with greater trauma exposure at baseline had larger right amygdala nucleus volume in the paralaminar nucleus (β = 0.1, p_FDR = 0.045), yet smaller whole amygdala volume overall (β = -3.7, p_FDR = 0.003). Lastly, we observed an interaction between alcohol use and baseline trauma such that adolescents who reported greater alcohol use with greater baseline trauma showed smaller right hippocampal subfield volumes in the CA1 head (β = -1.1, p_FDR = 0.011) and hippocampal head (β = -2.6, p_FDR = 0.025), yet larger whole hippocampus volume overall (β = 10.0, p_FDR = 0.032). Cumulative lifetime trauma measured at baseline and alcohol use measured annually interact to affect the volume and trajectory of hippocampal and amygdala substructures (measured via structural MRI annually), regions that are essential for emotion regulation and memory. Our findings demonstrate the value of examining these substructures and support the hypothesis that the amygdala and hippocampus are not homogeneous brain regions.

Smaller Regional Brain Volumes Predict Posttraumatic Stress Disorder at 3 Months After Mild Traumatic Brain Injury

BACKGROUND

Brain volumes in regions such as the hippocampus and amygdala have been associated with risk for the development of posttraumatic stress disorder (PTSD). The objective of this study was to determine whether a set of regional brain volumes, measured by magnetic resonance imaging at 2 weeks following mild traumatic brain injury, were predictive of PTSD at 3 and 6 months after injury.

METHODS

Using data from TRACK-TBI (Transforming Research and Clinical Knowledge in TBI), we included patients (N = 421) with Glasgow Coma Scale scores 13-15 assessed after evaluation in the emergency department and at 2 weeks, 3 months, and 6 months after injury. Probable PTSD diagnosis (PTSD Checklist for DSM-5 score, ≥33) was the outcome. FreeSurfer 6.0 was used to perform volumetric analysis of three-dimensional T1-weighted magnetic resonance images at 3T obtained 2 weeks post injury. Brain regions selected a priori for volumetric analyses were insula, hippocampus, amygdala, superior frontal cortex, rostral and caudal anterior cingulate, and lateral and medial orbitofrontal cortices.

RESULTS

Overall, 77 (18.3%) and 70 (16.6%) patients had probable PTSD at 3 and 6 months. A composite volume derived as the first principal component incorporating 73.8% of the variance in insula, superior frontal cortex, and rostral and caudal cingulate contributed to the prediction of 3-month (but not 6-month) PTSD in multivariable models incorporating other established risk factors.

CONCLUSIONS

Results, while needing replication, provide support for a brain reserve hypothesis of PTSD and proof of principle for how prediction of at-risk individuals might be accomplished to enhance prognostic accuracy and enrich clinical prevention trials for individuals at the highest risk of PTSD following mild traumatic brain injury.

Alterations in hippocampal subfield and amygdala subregion volumes in posttraumatic subjects with and without posttraumatic stress disorder

The hippocampus and amygdala are important structures in the posttraumatic stress disorder (PTSD); however, the exact relationship between these structures and stress or PTSD remains unclear. Moreover, they consist of several functionally distinct subfields/subregions that may serve different roles in the neuropathophysiology of PTSD. Here we present a subregional profile of the hippocampus and amygdala in 145 survivors of a major earthquake and 56 non‐traumatized healthy controls (HCs). We found that the bilateral hippocampus and left amygdala were significantly smaller in survivors than in HCs, and there was no difference between survivors with (n = 69) and without PTSD (trauma‐exposed controls [TCs], n = 76). Analyses revealed similar results in most subfields/subregions, except that the right hippocampal body (in a head‐body‐tail segmentation scheme), right presubiculum, and left amygdala medial nuclei (Me) were significantly larger in PTSD patients than in TCs but smaller than in HCs. Larger hippocampal body were associated with the time since trauma in PTSD patients. The volume of the right cortical nucleus (Co) was negatively correlated with the severity of symptoms in the PTSD group but positively correlated with the same measurement in the TC group. This correlation between symptom severity and Co volume was significantly different between the PTSD and TCs. Together, we demonstrated that generalized smaller volumes in the hippocampus and amygdala were more likely to be trauma‐related than PTSD‐specific, and their subfields/subregions were distinctively affected. Notably, larger left Me, right hippocampal body and presubiculum were PTSD‐specific; these could be preexisting factors for PTSD or reflect rapid posttraumatic reshaping.

Knock-Down of Hippocampal DISC1 in Immune-Challenged Mice Impairs the Prefrontal-Hippocampal Coupling and the Cognitive Performance Throughout Development

Disrupted-in-schizophrenia 1 (DISC1) gene represents an intracellular hub of developmental processes. When combined with early environmental stressors, such as maternal immune activation, but not in the absence of thereof, whole-brain DISC1 knock-down leads to memory and executive deficits as result of impaired prefrontal–hippocampal communication throughout development. While synaptic dysfunction in neonatal prefrontal cortex (PFC) has been recently identified as one source of abnormal long-range coupling, the contribution of hippocampus (HP) is still unknown. Here, we aim to fill this knowledge gap by combining in vivo electrophysiology and optogenetics with morphological and behavioral assessment of immune-challenged mice with DISC1 knock-down either in the whole brain (GE) or restricted to pyramidal neurons in hippocampal CA1 area (G_HPE). We found abnormal network activity, sharp-waves, and neuronal firing in CA1 that complement the deficits in upper layer of PFC. Moreover, optogenetic activating CA1 pyramidal neurons fails to activate the prefrontal local circuits. These deficits that persist till prejuvenile age relate to dendrite sparsification and loss of spines of CA1 pyramidal neurons. As a long-term consequence, DISC1 knock-down in HP leads to poorer recognition memory at prejuvenile age. Thus, DISC1-controlled developmental processes in HP in immune-challenged mice are critical for circuit function and cognitive behavior.

Reduced Hippocampal Subfield Volume in Schizophrenia and Clinical High-Risk State for Psychosis

Magnetic resonance imaging (MRI) studies in schizophrenia demonstrated volume reduction in hippocampal subfields divided on the basis of specific cytoarchitecture and function. However, it remains unclear whether this abnormality exists prior to the onset of psychosis and differs across illness stages. MRI (3 T) scans were obtained from 77 patients with schizophrenia, including 24 recent-onset and 40 chronic patients, 51 individuals with an at-risk mental state (ARMS) (of whom 5 subsequently developed psychosis within the follow-up period), and 87 healthy controls. Using FreeSurfer software, hippocampal subfield volumes were measured and compared across the groups. Both schizophrenia and ARMS groups exhibited significantly smaller volumes for the bilateral Cornu Ammonis 1 area, left hippocampal tail, and right molecular layer of the hippocampus than the healthy control group. Within the schizophrenia group, chronic patients exhibited a significantly smaller volume for the left hippocampal tail than recent-onset patients. The left hippocampal tail volume was positively correlated with onset age, and negatively correlated with duration of psychosis and duration of medication in the schizophrenia group. Reduced hippocampal subfield volumes observed in both schizophrenia and ARMS groups may represent a common biotype associated with psychosis vulnerability. Volumetric changes of the left hippocampal tail may also suggest ongoing atrophy after the onset of schizophrenia.

A novel arousal-based individual screening reveals susceptibility and resilience to PTSD-like phenotypes in mice

Translational animal models for studying post-traumatic stress disorder (PTSD) are valuable for elucidating the poorly understood neurobiology of this neuropsychiatric disorder. These models should encompass crucial features, including persistence of PTSD-like phenotypes triggered after exposure to a single traumatic event, trauma susceptibility/resilience and predictive validity. Here we propose a novel arousal-based individual screening (AIS) model that recapitulates all these features. The AIS model was designed by coupling the traumatization (24 h restraint) of C57BL/6 J mice with a novel individual screening. This screening consists of z-normalization of post-trauma changes in startle reactivity, which is a measure of arousal depending on neural circuits conserved across mammals. Through the AIS model, we identified susceptible mice showing long-lasting hyperarousal (up to 56 days post-trauma), and resilient mice showing normal arousal. Susceptible mice further showed persistent PTSD-like phenotypes including exaggerated fear reactivity and avoidance of trauma-related cue (up to 75 days post-trauma), increased avoidance-like behavior and social/cognitive impairment. Conversely, resilient mice adopted active coping strategies, behaving like control mice. We further uncovered novel transcriptional signatures driven by PTSD-related genes as well as dysfunction of hypothalamic–pituitary–adrenal axis, which corroborated the segregation in susceptible/resilient subpopulations obtained through the AIS model and correlated with trauma susceptibility/resilience. Impaired hippocampal synaptic plasticity was also observed in susceptible mice. Finally, chronic treatment with paroxetine ameliorated the PTSD-like phenotypes of susceptible mice. These findings indicate that the AIS model might be a new translational animal model for the study of crucial features of PTSD. It might shed light on the unclear PTSD neurobiology and identify new pharmacological targets for this difficult-to-treat disorder.

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The AIS model includes highly requested features necessary to shape a translational PTSD animal model.

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Susceptible mice identified through the AIS model exhibited persistent PTSD-like phenotypes.

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Resilient mice identified through the AIS model adopted active coping strategies.

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The AIS model revealed molecular adaptations underlying trauma susceptibility/resilience.

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The AIS model meets the criterion of predictive validity by exclusively using susceptible mice.

Vasopressin and post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a debilitating psychiatric condition with a wide range of behavioral disturbances and serious consequences for both patient and society. One of the main reasons for unsuccessful therapies is insufficient knowledge about its underlying pathomechanism. In the search for centrally signaling molecules that might be relevant to the development of PTSD we focus here on arginine vasopressin (AVP). So far AVP has not been strongly implicated in PTSD, but different lines of evidence suggest a possible impact of its signaling in all clusters of PTSD symptomatology. More specifically, in laboratory rodents, AVP agonists affect behavior in a PTSD-like manner, while significant reduction of AVP signaling in the brain e.g. in AVP-deficient Brattleboro rats, ameliorated defined behavioral parameters that can be linked to PTSD symptoms. Different animal models of PTSD also show alterations in the AVP signaling in distinct brain areas. However, pharmacological treatment targeting central AVP receptors via systemic routes is hampered by possible side effects that are linked to the peripheral action of AVP as a hormone. Indeed, the V1a receptor, the most common receptor subtype in the brain, is implicated in vasoconstriction. Thus, systemic treatment with V1a receptor antagonists would be implicated in hypotonia. This implies that novel treatment concepts are needed to target AVP receptors not only at brain level but also in distinct brain areas, to offer alternative treatments for PTSD.

Hyper-Activation of mPFC Underlies Specific Traumatic Stress-Induced Sleep-Wake EEG Disturbances

Sleep disturbances have been recognized as a core symptom of post-traumatic stress disorders (PTSD). However, the neural basis of PTSD-related sleep disturbances remains unclear. It has been challenging to establish the causality link between a specific brain region and traumatic stress-induced sleep abnormalities. Here, we found that single prolonged stress (SPS) could induce acute changes in sleep/wake duration as well as short- and long-term electroencephalogram (EEG) alterations in the isogenic mouse model. Moreover, the medial prefrontal cortex (mPFC) showed persistent high number of c-fos expressing neurons, of which more than 95% are excitatory neurons, during and immediately after SPS. Chemogenetic inhibition of the prelimbic region of mPFC during SPS could specifically reverse the SPS-induced acute suppression of delta power (1–4 Hz EEG) of non-rapid-eye-movement sleep (NREMS) as well as most of long-term EEG abnormalities. These findings suggest a causality link between hyper-activation of mPFC neurons and traumatic stress-induced specific sleep–wake EEG disturbances.

Long-Term Effect of Post-traumatic Stress in Adolescence on Dendrite Development and H3K9me2/BDNF Expression in Male Rat Hippocampus and Prefrontal Cortex

Exposure to a harsh environment in early life increases in the risk of post-traumatic stress disorder (PTSD) of an individual. Brain derived neurotrophic factor (BDNF) plays an important role in neurodevelopment in developmental stages. Both chronic and traumatic stresses induce a decrease in the level of BDNF and reduce neural plasticity, which is linked to the pathogenesis of PTSD. Also, studies have shown that stress alters the epigenetic marker H3K9me2, which can bind to the promoter region of the Bdnf gene and reduce BDNF protein level. However, the long-term effects of traumatic stress during adolescence on H3K9me2, BDNF expression and dendrite development are not well-known. The present study established a model of PTSD in adolescent rats using an inescapable foot shock (IFS) procedure. Anxiety-like behaviors, social interaction behavior and memory function were assessed by the open field test, elevated plus maze test, three-chamber sociability test and Morris water maze test. In addition, neuronal development and H3K9me2/BDNF expression in hippocampus (HIP) and prefrontal cortex (PFC) were evaluated by Golgi staining, western blotting, qRT-PCR analysis and CHIP-qPCR analysis. Additionally, the Unc0642, a small molecule inhibitor of histone methyltransferase (EHMT2) was used for intervention. The results showed that the IFS procedure induced the PTSD-like behaviors in rats, resulted in fewer dendrite branches and shorter dendrite length in CA1 of HIP and PFC, increased H3K9me2 level and decreased BDNF expression in HIP and PFC. Also, although all the changes can persist to adulthood, Unc0642 administration relieved most of alterations. Our study suggests that traumatic stress in adolescence leads to immediate and long-term mental disorders, neuronal morphological changes, lower BDNF level and increased H3K9me2 level in the HIP and PFC, indicating that H3K9me2/BDNF dysfunction plays a key role in pathogenesis of PTSD.

Genetic predictors of hippocampal subfield volume in PTSD cases and trauma-exposed controls

Behavioural, structural, and functional neuroimaging have implicated the hippocampus as a critical brain region in posttraumatic stress disorder (PTSD) pathogenesis. Recent work in a normative, primarily European, sample identified 15 unique genetic loci contributing to structural variability in six hippocampal subfield volumes. We explored the relevance of these loci in two samples (Mental Illness Research Education and Clinical Centre [MIRECC] and Grady; n = 290) of trauma-exposed individuals enriched for PTSD and of diverse ancestry. Four of the previous loci demonstrated nominal evidence of replication in the MIRECC dataset, primarily within non-Hispanic whites (NHW). One locus replicated in the Grady cohort, which was composed exclusively of non-Hispanic blacks (NHB). Our data supported genetic interactions with diagnosis of lifetime PTSD and genetic interactions with childhood trauma in the MIRECC sample, but not the Grady sample. Given the racial, diagnostic, and trauma-exposure differences with the original genome-wide association study (GWAS) report, we conducted a full GWAS in the MIRECC and Grady datasets. Interactions between genetic variants and lifetime PTSD or childhood trauma were interrogated for single nucleotide polymorphisms (SNPs) with evidence of main effects. Genetic associations surpassed false discovery rate (FDR)-correction within hippocampal subfields in fimbria, subiculum, cornu ammonis-1 (CA1), and hippocampal amygdala transition area (HATA). One association was replicated in the Grady cohort (rs12880795 in TUNAR with left (L)-HATA volume). The most significant association in the MIRECC dataset was between rs6906714 in LINC02571 and right (R)-fimbria volume (p = 5.99×10-8, q = 0.0056). Interestingly, the effect of rs6906714 on R-fimbria volume increased with exposure to childhood trauma (gene*environment [G*E] interaction p = 0.022). These preliminary results argue for G*E interactions between genetic loci with PTSD and childhood trauma on hippocampal phenotypes. Our results underscore the need for larger neuroimaging-genetic studies in PTSD, trauma, and ancestrally diverse populations.

A new simple brain segmentation method for extracerebral intracranial tumors

Normal brain segmentation is available via FreeSurfer, Vbm, and Ibaspm software. However, these software packages cannot perform segmentation of the brain for patients with brain tumors. As we know, damage from extracerebral tumors to the brain occurs mainly by way of pushing and compressing while leaving the structure of the brain intact. Three-dimensional (3D) imaging, augmented reality (AR), and virtual reality (VR) technology have begun to be applied in clinical practice. The free medical open-source software 3D Slicer allows us to perform 3D simulations on a computer and requires little user interaction. Moreover, 3D Slicer can integrate with the third-party software mentioned above. The relationship between the tumor and surrounding brain tissue can be judged, but accurate brain segmentation cannot be performed using 3D Slicer. In this study, we combine 3D Slicer and FreeSurfer to provide a novel brain segmentation method for extracerebral tumors. This method can help surgeons identify the “real” relationship between the lesion and adjacent brain tissue before surgery and improve preoperative planning.

Approach-oriented coping strategy level may be related to volume of the whole hippocampus in the elderly

AIM

Stress-related disorders and severe stress exposure can cause atrophy of the whole hippocampus and its subfields. However, the impact of stress coping strategies on the hippocampus remains unclear. Therefore, we aimed to examine the relation between approach- and avoidance-oriented coping strategies and hippocampal volume in elderly persons.

METHODS

A total of 1045 elderly persons living in Arakawa-ward, Tokyo (mean ± SD age: 72.8 ± 5.2 years; 569 females [54.4%]) were included in the study and completed several questionnaires and face-to-face interviews and underwent magnetic resonance imaging. Approach- or avoidance-oriented coping strategies were assessed with the Stress and Coping Inventory, while cognitive function and depressive symptoms were assessed with the Mini-Mental State Examination and Geriatric Depression Scale, respectively. The volume of the whole hippocampus on T1-weighted images was delineated and calculated using FreeSurfer 6.0. Multiple regression analyses were performed to examine the relation between Stress and Coping Inventory scores and whole hippocampal volume.

RESULTS

Approach-oriented coping strategy scores were positively correlated with whole hippocampal volume. Furthermore, these relations remained significant after controlling for the influence of cognitive function and depressive symptoms on these volumetric variables. In contrast, avoidance-oriented coping strategy scores were not correlated with whole hippocampal volume.

CONCLUSION

This study demonstrated that hippocampal volume may be associated with the approach-oriented coping strategy; therefore, this strategy may preserve hippocampal volume in the elderly.

Threat-induced anxiety during goal pursuit disrupts amygdala-prefrontal cortex connectivity in posttraumatic stress disorder

To investigate how unpredictable threat during goal pursuit impacts fronto-limbic activity and functional connectivity in posttraumatic stress disorder (PTSD), we compared military veterans with PTSD (n = 25) vs. trauma-exposed control (n = 25). Participants underwent functional magnetic resonance imaging (fMRI) while engaged in a computerized chase-and-capture game task that involved optimizing monetary rewards obtained from capturing virtual prey while simultaneously avoiding capture by virtual predators. The game was played under two alternating contexts-one involving exposure to unpredictable task-irrelevant threat from randomly occurring electrical shocks, and a nonthreat control condition. Activation in and functional connectivity between the amygdala and ventromedial prefrontal cortex (vmPFC) was tested across threat and nonthreat task contexts with generalized psychophysiological interaction (gPPI) analyses. PTSD patients reported higher anxiety than controls across contexts. Better task performance represented by successfully avoiding capture by predators under threat compared with nonthreat contexts was associated with stronger left amygdala-vmPFC functional connectivity in controls and greater vmPFC activation in PTSD patients. PTSD symptom severity was negatively correlated with vmPFC activation in trauma-exposed controls and with right amygdala-vmPFC functional connectivity across all participants in the threat relative to nonthreat contexts. The findings showed that veterans with PTSD have disrupted amygdala-vmPFC functional connectivity and greater localized vmPFC processing under threat modulation of goal-directed behavior, specifically related to successfully avoiding loss of monetary rewards. In contrast, trauma survivors without PTSD relied on stronger threat-modulated left amygdala-vmPFC functional connectivity during goal-directed behavior, which may represent a resilience-related functional adaptation.

Amygdala Nuclei Volume and Shape in Military Veterans With Posttraumatic Stress Disorder

BACKGROUND

The amygdala is a subcortical structure involved in socioemotional and associative fear learning processes relevant for understanding the mechanisms of posttraumatic stress disorder (PTSD). Research in animals indicates that the amygdala is a heterogeneous structure in which the basolateral and centromedial divisions are susceptible to stress. While the amygdala complex is implicated in the pathophysiology of PTSD, little is known about the specific contributions of the individual nuclei that constitute the amygdala complex.

METHODS

Military veterans (n = 355), including military veterans with PTSD (n = 149) and trauma-exposed control subjects without PTSD (n = 206), underwent high-resolution T1-weighted anatomical scans. Automated FreeSurfer segmentation of the amygdala yielded 9 structures: basal, lateral, accessory basal, anterior amygdaloid, and central, medial, cortical, and paralaminar nuclei, along with the corticoamygdaloid transition zone. Subregional volumes were compared between groups using ordinary-least-squares regression with relevant demographic and clinical regressors followed by 3-dimensional shape analysis of whole amygdala.

RESULTS

PTSD was associated with smaller left and right lateral and paralaminar nuclei, but with larger left and right central, medial, and cortical nuclei (p < .05, false discovery rate corrected). Shape analyses revealed lower radial distance in anterior bilateral amygdala and lower Jacobian determinant in posterior bilateral amygdala in PTSD compared with control subjects.

CONCLUSIONS

Alterations in select amygdala subnuclear volumes and regional shape distortions are associated with PTSD in military veterans. Volume differences of the lateral nucleus and the centromedial complex associated with PTSD demonstrate a subregion-specific pattern that is consistent with their functional roles in fear learning and fear expression behaviors.

Normative hippocampal volumetric measurements using magnetic resonance imaging

Background/aim

A wide variety of neurological and psychiatric disorders have been shown to be closely related to changes in hippocampal volume (HV). It appears that hippocampal volumetry will be an indispensable part of clinical practice for a number of neuropsychiatric disorders in the near future. The aim of this study was to establish a normative data set for HV according to age and sex in the general population.

Materials and methods

Hippocampal magnetic resonance imaging scans of 302 healthy volunteers were obtained using a 1.5 T unit with a 20-channel head coil. The hippocampal volumetric assessment was conducted using the volBrain fully automated segmentation algorithm on coronal oblique T1-weighted magnetization prepared rapid gradient-echo (MP-RAGE) images obtained perpendicular to the long axis of the hippocampus. The mean values of HV of groups according to age and sex were calculated. The associations between HV and age and sex were analyzed.

Results

The mean HV of the study group was found to be 3.81 ± 0.46 cm3. We found that the mean HV of males (3.94 ± 0.49 cm3) was significantly higher than that of females (3.74 ± 0.42 cm3), and the mean right HV (3.86 ± 0.48 cm3) was significantly higher than that of the left HV (3.78 ± 0.49 cm3) (P = 0.001). Among both females and males, there were statistically significant but poor negative correlations between age and volumetric measurements of both the right and the left hippocampi (P < 0.05).

Conclusion

The normative hippocampal volumetric data obtained in this study may be beneficial in clinical applications for many neuropsychiatric diseases, especially for mesial temporal sclerosis and cognitive disorders.

Involvement of calcineurin/NFATc4 pathway in a single-prolonged stress-based rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a mental disease associated with the exposure of traumatic stress, and results in the structural and functional changes of hippocampus. Calcineurin (CaN), a calcium/calmodulin-regulated protein phosphatase ubiquitously expressed in brain, has a very important role in the fear extinction, neuronal structure and neuronal excitability. With CaN activation, its down target nuclear factor of activated T cells (NFATs) dephosphorylated and then translocated from the cytoplasm to the nucleus to affect neuronal function, resulting in the function changes of brain structure such as hippocampus. Increasing evidence has suggested that CaN/NFATs signaling are involved in the regulation of mental disorders like Alzheimer's disease, depression, while little is known about its effects on the molecular mechanisms on PTSD. This study seek to know the relationship between PTSD and CaN/NFATc4 pathway, and to detect whether CaN/NFATc4 pathway are involved in the hippocampus dysfunctions in a single-prolonged stress (SPS)-based rat model of PTSD. Our results have showed that after 4 days exposed to SPS, the protein expression of CaN up-regulated and the NFATc4 dephosphorylated and imported into the nucleus; while at the 7 and 14 day exposed to SPS, with the down-regulation of CaN, the expression of phosphorylate-NFATc4 increased. Our results show that CaN/NFATc4 pathway were involved in the development of PTSD model, which suggested that the changes of CaN/NFATc4 pathway may be one of the pathological molecular mechanism in the dysfunction of hippocampus in PTSD.

Reduced hippocampal subfield volumes and memory function in school-aged children born preterm with very low birthweight (VLBW)

BACKGROUND

The hippocampus, an essential structure for learning and memory, has a reduced volume in preterm born (gestational age < 37 weeks) individuals with very low birth weight (VLBW: birth weight < 1500 g), which may affect memory function. However, the hippocampus is a complex structure with distinct subfields related to specific memory functions. These subfields are differentially affected by a variety of neuropathological conditions, but it remains unclear how these subfields may be affected by medical complications following preterm birth which may cause aberrant brain development, and the consequences of this on learning and memory function in children with VLBW.

METHODS

Children born preterm with VLBW (n = 34) and term-born controls from the Norwegian Mother and Child Cohort Study (MoBa) (n = 104) underwent structural MRI and a neuropsychological assessment of memory function at primary school age. FreeSurfer 6.0 was used to analyze the volumes of hippocampal subfields which were compared between groups, as was memory performance. Correlations between abnormal hippocampal subfields and memory performance were explored in the VLBW group.

RESULTS

All absolute hippocampal subfield volumes were lower in the children with VLBW compared to MoBa term-born controls, and the volumes of the left and right dentate gyrus and the right subiculum remained significantly lower after correcting for total intracranial volume. The VLBW group had inferior working memory performance and the score on the subtest Spatial Span backwards was positively correlated to the volume of the right dentate gyrus.

CONCLUSIONS

Hippocampal subfield volumes seem to be differently affected by early brain development related to preterm birth. The dentate gyrus appears particularly susceptible to adverse effects of preterm birth. Reduced working memory function among children with VLBW was associated with smaller volume of right dentate gyrus. This finding demonstrates alterations in hippocampal structure-function relationships associated with early brain development related to preterm birth.

Posttraumatic stress disorder, social anxiety disorder and childhood trauma: Differences in hippocampal subfield volume

Volume-based hippocampal findings in Social Anxiety Disorder (SAD) and Posttraumatic Stress Disorder (PTSD) have been inconsistent, with very little investigation of hippocampal subfields. We assessed the effects of early childhood trauma on hippocampal subfields in participants with SAD with and without early childhood trauma and PTSD, compared to healthy controls. The sample comprised 26 participants SAD with early childhood trauma, 22 participants with SAD without early childhood trauma, 17 with PTSD secondary to early childhood trauma and 25 control participants. We used Freesurfer version 6 to determine hippocampal subfield volumes. Findings included significant reduction in right parasubiculum volume between the PTSD group secondary to early childhood trauma and the SAD group without early childhood trauma, as well as a significant reduction in left HATA (Hippocampal Amygdala Transition Area) volume between PTSD with early childhood trauma compared to controls, as well as compared to SAD with early childhood trauma. These findings did withstand correction for multiple resting using the false discovery rate. Our findings of an association of reduced volumes in the parasubiculum and HATA regions with PTSD secondary to childhood trauma are interesting. Further work should investigate whether parasubiculum and HATA regional volume reductions in PTSD are a specific effect of early childhood trauma or a specific manifestation of PTSD pathology. Further work should also be undertaken to determine if hippocampal subfield atrophy is associated with SAD in the setting of early childhood maltreatment.