Trauma, PTSD, and the Developing Brain

The Persian Language Version of the Obsession With the COVID-19 Scale for Adolescents

Objective: The worldwide pandemic of coronavirus disease (COVID-19) has caused significant public health burdens and psychological dysfunctions. In this challenging time, adolescents require special care. The Persian version of the Obsession with COVID-19 Scale (OCS) for adolescents was developed to screen for dysfunctional obsession associated with the coronavirus during the global pandemic. The structure and internal consistency of the OCS were established. Design and Measures: Although there are different language versions of the OCS, this is the first study to validate the psychometric properties of the OCS in Iranian adolescents. Seven hundred and nine students (369 girls) participated in the study. Demographic questions and the OCS were administered. Results: The findings provided support for the existence of a unidimensional structure that met the criteria for configural, metric, and full scalar invariance across gender (girls and boys), inhabitancy (urban and rural), and infection experience (infected and non-infected). The OCS is short and highly reliable measurement. However, further research is necessary to establish the validity of the scale in Iranian population. Conclusions: The development of such valid scales is an essential part of both research and practice during times of crisis, like a global pandemic. Diagnosis of pandemic related to obsessive thoughts in adolescents is needed as the COVID-19 pandemic is still ongoing and as experts point out, it can be expected that the effects of the pandemic will be observed in the coming years. The Persian version makes it possible to conduct international comparative research on the anxiety related to the COVID-19 pandemic.

Early life stress causes sex-specific changes in adult fronto-limbic connectivity that differentially drive learning

It is currently unclear whether early life stress (ELS) affects males and females differently. However, a growing body of work has shown that sex moderates responses to stress and injury, with important insights into sex-specific mechanisms provided by work in rodents. Unfortunately, most of the ELS studies in rodents were conducted only in males, a bias that is particularly notable in translational work that has used human imaging. Here we examine the effects of unpredictable postnatal stress (UPS), a mouse model of complex ELS, using high resolution diffusion magnetic resonance imaging. We show that UPS induces several neuroanatomical alterations that were seen in both sexes and resemble those reported in humans. In contrast, exposure to UPS induced fronto-limbic hyper-connectivity in males, but either no change or hypoconnectivity in females. Moderated-mediation analysis found that these sex-specific changes are likely to alter contextual freezing behavior in males but not in females.

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.

Adolescent psychiatric disorders during the COVID-19 pandemic and lockdown

The aim of this paper was to review the literature on adolescent psychiatric disorders related to the COVID-19 pandemic and lockdown. Stressful life events, extended home confinement, brutal grief, intrafamilial violence, overuse of the Internet and social media are factors that could influence the mental health of adolescents during this period. The COVID-19 pandemic could result in increased psychiatric disorders such as Post-Traumatic Stress, Depressive, and Anxiety Disorders, as well as grief-related symptoms. Adolescents with psychiatric disorders are at risk of a break or change in their care and management; they may experience increased symptoms. The COVID-19 pandemic and lockdown may have a negative impact on the mental health of adolescents, although there is still no data on the long term impact of this crisis. Adolescents' individual, familial, and social vulnerability, as well as individual and familial coping abilities, are factors related to adolescent mental health in times of crisis. Adolescents are often vulnerable and require careful consideration by caregivers and healthcare system adaptations to allow for mental health support despite the lockdown. Research on adolescent psychiatric disorders in times of pandemics is necessary, as such a global situation could be prolonged or repeated.

Impact of ADCYAP1R1 genotype on longitudinal fear conditioning in children: interaction with trauma and sex

Dysregulated fear conditioned responses have been associated with PTSD in adults, with increased fear-potentiated startle (FPS) serving as a potential intermediate phenotype for PTSD risk. This phenotype has also been associated with stress-related ADCYAP1R1 gene variants in adult women. However, FPS and genotype have not yet been examined during development. The aim of this study was to examine developmental changes in fear conditioning, and to see whether these changes were impacted by genotype and trauma. Differential fear conditioning using FPS was tested in n = 63 children ages 8-13 at two visits (V1, V2) 1 year apart. Startle response was measured using electromyograph recordings of the eyeblink muscle. The rs2267735 SNP of the ADCYAP1R1 gene was extracted from genome-wide (GWAS) analyses. Trauma exposure was assessed using the Violence Exposure Scale-Revised (VEX-R). We found significant Visit by Genotype interactions, with CC genotype increasing FPS from V1 to V2. At V2 there was a Genotype by Violence interaction, with higher FPS in the CC vs G allele groups among those with higher violence exposure (F = 17.46, p = 0.0002). Females with the CC genotype had higher FPS compared to G allele females (F = 12.09, p = 0.002); there were no effects of genotype in males. This study showed Gene × Environment × Development and Gene × Sex effects of ADCYAP1R1 in a high-risk pediatric population. Those with the CC genotype and high levels of violence exposure, as well as females with the CC genotype, showed the greatest conditioned fear responses in adolescence.

Inequity and the disproportionate impact of COVID-19 on communities of color in the United States: The need for a trauma-informed social justice response

COVID-19 has had disproportionate contagion and fatality in Black, Latino, and Native American communities and among the poor in the United States. Toxic stress resulting from racial and social inequities have been magnified during the pandemic, with implications for poor physical and mental health and socioeconomic outcomes. It is imperative that our country focus and invest in addressing health inequities and work across sectors to build self-efficacy and long-term capacity within communities and systems of care serving the most disenfranchised, now and in the aftermath of the COVID-19 epidemic. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Inequity and the disproportionate impact of COVID-19 on communities of color in the United States: The need for a trauma-informed social justice response

COVID-19 has had disproportionate contagion and fatality in Black, Latino, and Native American communities and among the poor in the United States. Toxic stress resulting from racial and social inequities have been magnified during the pandemic, with implications for poor physical and mental health and socioeconomic outcomes. It is imperative that our country focus and invest in addressing health inequities and work across sectors to build self-efficacy and long-term capacity within communities and systems of care serving the most disenfranchised, now and in the aftermath of the COVID-19 epidemic. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Social supports moderate the effects of child adversity on neural correlates of threat processing

BACKGROUND

Child abuse and other forms of adversity are associated with alterations in threat processing and emotion regulation brain circuits.

OBJECTIVE

The goal of the current investigation is to determine if the availability of positive social support can ameliorate the negative impact of adversity on these brain systems.

PARTICIPANTS AND SETTING

Subjects included 55 children ages 7-16 (X = 11.8, SD = 2.0). Approximately one-third of the cohort had no significant history of adversity, one-third had a history of moderate adversity, and one-third had a history of severe adversity. Brain imaging was conducted at the University of Vermont using a 3.0 T Philips scanner.

METHODS

The Emotional Go-NoGo task with fearful and calm facial stimuli was used to assess the neural correlates of threat processing and emotion regulation in children during functional magnetic resonance imaging (fMRI). Dimensional measures of anxiety, social supports, and children's adverse experiences were also obtained.

RESULTS

A conjunction analysis was used to test if trauma-related brain activation in responding to fearful vs. calm targets was impacted by social support. This approach identified multiple activation foci, including a cluster extending from the left amygdala to several other key brain regions involved in emotion regulation, including the orbitofrontal cortex, anterior cingulate cortex (ACC), anterior insula, nucleus accumbens, and frontal pole (Family Wise Error (FWE) correction, p < 0.05).

CONCLUSIONS

Greater social support may reduce the effect that adversity has on neural processing of threat stimuli, consistent with the protective role of positive supports in promoting resilience and recovery demonstrated in the literature.

Interactions between childhood maltreatment and combat exposure trauma on stress-related activity within the cingulate cortex: a pilot study

Childhood trauma may sensitize the brain, increasing vulnerability to maladaptive stress responses following adulthood trauma exposure. Previous work has identified the cingulum as a white matter pathway that may be sensitized to adulthood trauma by childhood maltreatment. In this pilot study of young adult male military veterans (N = 28), we examined a priori regions of interest (ROIs) connected by the cingulum, including regions involved in cognitive processes and stress responses. Our goal was to examine the interaction between childhood maltreatment and combat exposure on stress-related activity within cingulum-associated ROIs. As such we utilized a mild cognitive stress task, a performance-titrated multi-source interference task (MSIT). We found that childhood maltreatment moderated the effect of combat exposure on stress-related, interference-evoked activity within the dorsal anterior cingulate cortex (dACC, activation), subgenual ACC (sgACC, deactivation) and posterior midcingulate cortex (pMCC, deactivation). Greater combat exposure was associated with greater interference-evoked activation within the dACC, and less sgACC and pMCC deactivation among individuals with more severe childhood maltreatment. Our findings suggest that child maltreatment sensitizes these anterior and mid-cingulate regions to later life trauma. These findings may have implications for cognitive control, autonomic regulation/stress reactivity, and responses to noxious/aversive stimuli, which may contribute to increased psychiatric vulnerability.

Meta-analysis of Structural Magnetic Resonance Imaging Studies in Pediatric Posttraumatic Stress Disorder and Comparison With Related Conditions

BACKGROUND

Findings on structural brain volume associated with pediatric posttraumatic stress disorder (PTSD) have been variable, and it is unclear whether any structural differences are specific to pediatric PTSD in comparison with adult PTSD or other co-occurring pediatric psychiatric conditions.

METHODS

We tested volumetric brain differences between pediatric groups with and without PTSD in a region-of-interest meta-analysis. We conducted meta-regressions to test the effects of age and sex on heterogeneous study findings. To assess specificity, we compared pediatric PTSD with the following: adult PTSD, pediatric trauma exposure without PTSD, pediatric depression, and pediatric anxiety.

RESULTS

In 15 studies examined, pediatric PTSD was associated with smaller total gray matter and cerebral, temporal lobe (total, right, and left), total cerebellar vermis, and hippocampal (total, right, and left) volumes, compared to peers without PTSD. In the pediatric PTSD group, but not the comparison group, we found a trend toward smaller total, right, and left amygdalar volumes. In an external comparison, smaller hippocampal volume was not significantly different between adult and pediatric PTSD groups. Qualitative comparisons with a pediatric trauma exposure without PTSD group, a pediatric depression group, and a pediatric anxiety group revealed differences that may be unique to pediatric PTSD, and others that may be convergent with these related clinical conditions in youth.

CONCLUSIONS

Pediatric PTSD is associated with structural differences that parallel those associated with adult PTSD. Furthermore, pediatric PTSD appears to be distinct from other related pediatric conditions at the structural level. Future studies employing longitudinal, dimensional, and multimodal neuroimaging approaches will further elucidate the nature of neurobiological differences in pediatric PTSD.

Improved prediction of brain age using multimodal neuroimaging data

Brain age prediction based on imaging data and machine learning (ML) methods has great potential to provide insights into the development of cognition and mental disorders. Though different ML models have been proposed, a systematic comparison of ML models in combination with imaging features derived from different modalities is still needed. In this study, we evaluate the prediction performance of 36 combinations of imaging features and ML models including deep learning. We utilize single and multimodal brain imaging data including MRI, DTI, and rs‐fMRI from a large data set with 839 subjects. Our study is a follow‐up to the initial work (Liang et al., 2019. Human Brain Mapping) to investigate different analytic strategies to combine data from MRI, DTI, and rs‐fMRI with the goal to improve brain age prediction accuracy. Additionally, the traditional approach to predicting the brain age gap has been shown to have a systematic bias. The potential nonlinear relationship between the brain age gap and chronological age has not been thoroughly tested. Here we propose a new method to correct the systematic bias of brain age gap by taking gender, chronological age, and their interactions into consideration. As the true brain age is unknown and may deviate from chronological age, we further examine whether various levels of behavioral performance across subjects predict their brain age estimated from neuroimaging data. This is an important step to quantify the practical implication of brain age prediction. Our findings are helpful to advance the practice of optimizing different analytic methodologies in brain age prediction.

Longitudinal cortical markers of persistence and remission of pediatric PTSD

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Neural correlates of clinical outcomes in pediatric PTSD are poorly understood.

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Remission and persistence show unique patterns of cortical development over time.

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Nonremitters exhibit atypical decreases in prefrontal, parietal, and occipital CSA.

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PTSD remission was associated with cortical expansion in the prefrontal cortex.

Background

Previous studies have identified structural brain abnormalities in pediatric PTSD. However, little is known about what structural brain substrates may confer recovery versus persistence of PTSD in the context of the developing brain.

Methods

This naturalistic longitudinal study used T1-weighted MRI to evaluate cortical thickness and surface area in youth with a PTSD diagnosis (n = 28) and typically developing healthy youth (TD; n = 27) at baseline and one-year follow-up. Of the PTSD group, 10 youth were remitters at one-year follow up while 18 had persistent PTSD. Whole-brain estimates of cortical thickness and surface area were extracted to identify differences in cortical architecture associated with PTSD remission and persistence as compared to typical development.

Results

Youth who achieved PTSD remission entered the study with significantly lower trauma exposure and reduced symptom severity as compared to nonremitters. PTSD persistence was associated with decreased surface area over time in the ventrolateral prefrontal cortex (vlPFC) as compared to both remitters and TD youth. In contrast, PTSD remission was associated with expansion of frontal pole surface area and ventromedial PFC (vmPFC) thickness over time. Across clinical groups, vmPFC thickness was further inversely associated with symptom severity.

Conclusions

To our knowledge, these findings represent the first report of cortical substrates underlying persistence versus remission in pediatric PTSD. Together, these findings suggest active structural developmental processes unique to both remission and nonremission in youth with PTSD. In particular, expansion of prefrontal regions implicated in emotion regulation may facilitate recovery from PTSD in youth and would warrant further study.

The Moderating Effects of Sex on Consequences of Childhood Maltreatment: From Clinical Studies to Animal Models

Stress has pronounced effects on the brain, and thus behavioral outputs. This is particularly true when the stress occurs during vulnerable points in development. A review of the clinical literature regarding the moderating effects of sex on psychopathology in individuals exposed to childhood maltreatment (CM) is complicated by a host of variables that are difficult to quantify and control in clinical settings. As a result, the precise role of sex in moderating the consequences of CM remains elusive. In this review, we explore the rationale for studying this important question and their implications for treatment. We examine this issue using the threat/deprivation conceptual framework and highlight a growing body of work demonstrating important sex differences in human studies and in animal models of early life stress (ELS). The challenges and obstacles for effectively studying this question are reviewed and are followed by recommendations on how to move forward at the clinical and preclinical settings. We hope that this review will help inspire additional studies on this important topic.

Prefrontal glutamate levels predict altered amygdala-prefrontal connectivity in traumatized youths

BACKGROUND

Neurobiological models of stress and stress-related mental illness, including post-traumatic stress disorder, converge on the amygdala and the prefrontal cortex (PFC). While a surge of research has reported altered structural and functional connectivity between amygdala and the medial PFC following severe stress, few have addressed the underlying neurochemistry.

METHODS

We combined resting-state functional magnetic resonance imaging measures of amygdala connectivity with in vivo MR-spectroscopy (1H-MRS) measurements of glutamate in 26 survivors from the 2011 Norwegian terror attack and 34 control subjects.

RESULTS

Traumatized youths showed altered amygdala-anterior midcingulate cortex (aMCC) and amygdala-ventromedial prefrontal cortex (vmPFC) connectivity. Moreover, the trauma survivors exhibited reduced levels of glutamate in the vmPFC which fits with the previous findings of reduced levels of Glx (glutamate + glutamine) in the aMCC (Ousdal et al., 2017) and together suggest long-term impact of a traumatic experience on glutamatergic pathways. Importantly, local glutamatergic metabolite levels predicted the individual amygdala-aMCC and amygdala-vmPFC functional connectivity, and also mediated the observed group difference in amygdala-aMCC connectivity.

CONCLUSIONS

Our findings suggest that traumatic stress may influence amygdala-prefrontal neuronal connectivity through an effect on prefrontal glutamate and its compounds. Understanding the neurochemical underpinning of altered amygdala connectivity after trauma may ultimately lead to the discovery of new pharmacological agents which can prevent or treat stress-related mental illness.

Commentary: Paediatric post-traumatic stress disorder from a neurodevelopmental network perspective: reflections on Weems et al. (2019)

Paediatric post-traumatic stress disorder (PTSD) is an incredibly heterogeneous and syndromic disorder that likely has a myriad of underlying neurobiological mechanisms at play. The disorder is even more complicated in youth, given that the expression of illness interacts with ongoing developmental processes. In their review in this issue, Weems and colleagues call for broader network-based approaches for studying the development and expression of PTSD in youth. In this commentary, I highlight some of the important knowledge gaps raised by Weems et al. and propose ways in which future studies may leverage network-based approaches for eventual translation into clinical care. Key concepts include the use of network-based approaches for understanding the emergence and maintenance of PTSD symptom architecture over development, identification of resilient and vulnerable patterns of symptom and brain network architecture following trauma, and consideration of how divergence between biological (e.g. brain) and chronological may inform our understanding of resilient and vulnerable patterns over development. Importantly, advancing and translating this work to clinical care will require larger, prospective studies assessing youth as early in development as possible, and integrating information across multiple research groups and sites.

Annual Research Review: Pediatric posttraumatic stress disorder from a neurodevelopmental network perspective

BACKGROUND

Experiencing traumatic stress is common and may lead to posttraumatic stress disorder (PTSD) in a number of children and adolescents. Research using advanced imaging techniques is beginning to elucidate some of the neurobiological correlates of the traumatic stress response in youth.

METHODS

This paper summarizes the emerging network perspective of PTSD symptoms and reviews brain imaging research emphasizing structural and functional connectivity studies that employ magnetic resonance imaging techniques in pediatric samples.

RESULTS

Differences in structural connections and distributed functional networks such as the salience, default mode, and central executive networks are associated with traumatic and severe early life stress. The role of development has been relatively underappreciated in extant studies though there is evidence that critical brain regions as well as the structural and functional networks implicated undergo significant change in childhood and these typical developmental differences may be affected by traumatic stress.

CONCLUSIONS

Future research will benefit from adopting a truly developmental approach that considers children's growth as a meaningful effect (rather than simply a covariate) interacting with traumatic stress to predict disruptions in the anatomical, functional, and connective aspects of brain systems thought to underlie the network of PTSD symptoms. Linking symptom networks with neurodevelopmental network models may be a promising avenue for future work.

Post-Traumatic Stress Symptoms after Pediatric Injury: Relation to Pre-Frontal Limbic Circuitry

Pre-frontal limbic circuitry is vulnerable to effects of stress and injury. We examined microstructure of pre-frontal limbic circuitry after traumatic brain injury (TBI) or extracranial injury (EI) and its relation to post-traumatic stress symptoms (PTSS). Participants aged 8 to 15 years who sustained mild to severe TBI (n = 53) or EI (n = 26) in motor vehicle incidents were compared with healthy children (n = 38) in a prospective longitudinal study. At the seven-week follow-up, diffusion tensor imaging was obtained in all groups; injured children completed PTSS ratings using a validated scale. Using probabilistic diffusion tensor tractography, pathways were seeded from bilateral amygdalae and hippocampi to estimate the trajectory of white matter connecting them to each other and to targeted pre-frontal cortical (PFC) regions. Microstructure was estimated using fractional anisotropy (FA) in white matter and mean diffusivity (MD) in gray matter. Pre-frontal limbic microstructure was similar across groups, except for reduced FA in the right hippocampus to orbital PFC pathway in the injured versus healthy group. We examined microstructure of components of pre-frontal limbic circuitry with concurrently obtained PTSS cluster scores in the injured children. Neither microstructure nor PTSS scores differed significantly in the TBI and EI groups. Across PTSS factors, specific symptom clusters were related positively to higher FA and MD. Higher hyperarousal, avoidance, and re-experiencing symptoms were associated with higher FA in amygdala to pre-frontal and hippocampus to amygdala pathways. Higher hippocampal MD had a central role in hyperarousal and emotional numbing symptoms. Age moderated the relation of white and gray matter microstructure with hyperarousal scores. Our findings are consistent with models of traumatic stress that implicate disrupted top-down PFC and hippocampal moderation of overreactive subcortical threat arousal systems. Alterations in limbic pre-frontal circuitry and PTSS place children with either brain or body injuries at elevated risk for both current and future psychological health problems.

UCLA PTSD reaction index for DSM-5 (PTSD-RI-5): a psychometric study of adolescents sampled from communities in eleven countries

Background: Children and adolescents are often exposed to traumatic events, which may lead to the development of posttraumatic stress disorder (PTSD). It is therefore important for clinicians to screen for potential symptoms that can be signs of PTSD onset. PTSD in youth is a worldwide problem, thus congruent screening tools in various languages are needed. Objective: The aim of this study was to test the general psychometric properties of the Traumatic Stress Disorder Reaction Index for children and adolescents (UCLA PTSD) Reaction Index for DSM-5 (PTSD-RI-5) in adolescents, a self-report instrument intended to screen for trauma exposure and assess PTSD symptoms. Method: Data was collected from 4201 adolescents in communities within eleven countries worldwide (i.e. Brazil, Bulgaria, Croatia, Indonesia, Montenegro, Nigeria, Palestine-Gaza, Philippines, Portugal, Romania, and Serbia). Internal consistency, discriminant validity, and a confirmatory factor analysis of a four-factor model representing the main DSM-5 symptoms of the PTSD-RI-5 were evaluated. Results: The PTSD-RI-5 total score for the entire sample shows very good reliability (α = .92) as well as across all countries included (α ranged from .90 to .94). The correlations between anxiety/depressive symptoms and the PTSD-RI-5 scores were below .70 indicating on good discriminant validity. The four-factor structure of the scale was confirmed for the total sample and data from six countries. The standardized regression weights for all items varied markedly across the countries. The lack of a common acceptable model across all countries prevented us from direct testing of cross-cultural measurement invariance. Conclusions: The four-factor structure of the PTSD-RI-5 likely represents the core PTSD symptoms as proposed by the DSM-5 criteria, but there could be items interpreted in a conceptually different manner by adolescents from different cultural/regional backgrounds and future cross-cultural evaluations need to consider this finding.

Differential Roles of the Salience Network During Prediction Error Encoding and Facial Emotion Processing Among Female Adolescent Assault Victims

BACKGROUND

Early-life assaultive violence exposure is a potent risk factor for posttraumatic stress disorder (PTSD) and other mood and anxiety disorders. Neurocircuitry models posit that increased risk is mediated by heightened emotion processing in a salience network including the dorsal anterior cingulate cortex, anterior insula, and amygdala. However, the processes of reinforcement learning (RL) also engage the salience network and are implicated in responses to early-life trauma and PTSD. To define their relative roles in response to early-life trauma and PTSD symptoms, the current study compared engagement of the salience network during emotion processing and RL as a function of early-life assault exposure.

METHODS

Adolescent girls (n = 30 girls who had previously been physically or sexually assaulted; n = 30 healthy girls for comparison) 11 to 17 years of age completed two types of tasks during functional magnetic resonance imaging: a facial emotion processing task and an RL task using either social or nonsocial stimuli. Independent component analysis was used to identify a salience network and characterize its engagement in response to emotion processing and prediction error encoding during the RL tasks.

RESULTS

Assault was related to greater reactivity of the salience network during emotion processing. By contrast, we found lesser encoding of negative prediction errors in the salience network, particularly during the social RL task, in girls who had been assaulted. The dysfunction of salience network activity during emotion processing and prediction error encoding was not associated with PTSD symptoms.

CONCLUSIONS

These results suggest that hyper- versus hypoactivity of the salience network among trauma-exposed youths depends on the cognitive-affective domain.

Abnormal Prefrontal Development in Pediatric Posttraumatic Stress Disorder: A Longitudinal Structural and Functional Magnetic Resonance Imaging Study

BACKGROUND

Prior studies of pediatric posttraumatic stress disorder (PTSD) have reported cross-sectional and age-related structural and functional brain abnormalities in networks associated with cognitive, affective, and self-referential processing. However, no reported studies have comprehensively examined longitudinal gray matter development and its intrinsic functional correlates in pediatric PTSD.

METHODS

Twenty-seven youths with PTSD and 21 nontraumatized typically developing (TD) youths were assessed at baseline and 1-year follow-up. At each visit, youths underwent structural magnetic resonance imaging and resting-state functional magnetic resonance imaging. Regions with volumetric abnormalities in whole-brain structural analyses were identified and used as seeds in exploratory intrinsic connectivity analyses.

RESULTS

Youths with PTSD exhibited sustained reductions in gray matter volume (GMV) in right ventromedial prefrontal cortex (PFC) and bilateral ventrolateral PFC. Group-by-time analyses revealed aberrant longitudinal development in dorsolateral PFC, where typically developing youths exhibited normative decreases in GMV between baseline and follow-up, and youths with PTSD showed increases in GMV. Using these regions as seeds, patients with PTSD exhibited atypical longitudinal decreases in intrinsic PFC-amygdala and PFC-hippocampus connectivity, in contrast to increases in typically developing youths. Specifically, youths with PTSD showed decreasing ventromedial PFC-amygdala connectivity as well as decreasing ventrolateral PFC-hippocampus connectivity over time. Notably, volumetric abnormalities in ventromedial PFC and ventrolateral PFC were predictive of symptom severity.

CONCLUSIONS

These findings represent novel longitudinal volumetric and connectivity changes in pediatric PTSD. Atypical prefrontal GMV and prefrontal-amygdala/hippocampus development may underlie persistence of PTSD in youths and could serve as future therapeutic targets.

Childhood Emotional Abuse Moderates Associations Among Corticomotor White Matter Structure and Stress Neuromodulators in Women With and Without Depression

Adverse caregiving during development can produce long-lasting changes to neural, endocrine, and behavioral responses to stress, and is strongly related to elevated risk of adult psychopathology. While prior experience of adversity is associated with altered sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis activity, the underlying neural pathways are not completely understood. In a double-blind crossover study, we used diffusion tensor imaging (DTI) to examine whether variation in white matter structure predicts differences in HPA-SNS interactions as a function of early adversity. Participants included 74 women who exhibited a wide range of depression severity and/or childhood emotional abuse (EA). Participants attended two experimental sessions during which they were administered 20 mg cortisol (CORT) or placebo and after 90 min, viewed emotionally laden pictures while undergoing MRI scanning. Immediately after emotional picture-viewing, we collected salivary alpha-amylase (sAA) to index SNS activation. We tested whether EA moderated the relation between fractional anisotropy (FA), a measure of white matter fiber structure, and sAA. In the placebo condition, for participants with minimal history of EA, higher FA in corticomotor projections was negatively correlated with sAA, whereas in participants with severe EA, the correlation was trending in the opposite direction. Following CORT administration, FA and sAA were not related, suggesting that SNS tone during acute cortisol elevation may depend on neural pathways other than corticomotor projections. The results suggest that at baseline—though not during cortisol elevation—increased FA in these tracts is associated with lower levels of SNS activity in women with minimal EA, but not in women with severe EA. These findings provide evidence that corticomotor projections may be a key component of altered neural circuitry in adults with history of maltreatment, and may be related to alterations in stress neuromodulators in psychopathology.

A Network-Based Neurobiological Model of PTSD: Evidence From Structural and Functional Neuroimaging Studies

PURPOSE OF REVIEW

Although a fine-grained understanding of the neurobiology of posttraumatic stress disorder (PTSD) is yet to be elucidated, the last two decades have seen a rapid growth in the study of PTSD using neuroimaging techniques. The current review summarizes important findings from functional and structural neuroimaging studies of PTSD, by primarily focusing on their relevance towards an emerging network-based neurobiological model of the disorder.

RECENT FINDINGS

PTSD may be characterized by a weakly connected and hypoactive default mode network (DMN) and central executive network (CEN) that are putatively destabilized by an overactive and hyperconnected salience network (SN), which appears to have a low threshold for perceived saliency, and inefficient DMN-CEN modulation. There is considerable evidence for large-scale functional and structural network dysfunction in PTSD. Nevertheless, several limitations and gaps in the literature need to be addressed in future research.