MRI-based measurement of hippocampal volume in patients with combat-related posttraumatic stress disorder

Effects of traumatic brain injury and posttraumatic stress disorder on development of Alzheimer's disease in Vietnam Veterans using the Alzheimer's Disease Neuroimaging Initiative: Preliminary Report

INTRODUCTION

Traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) have previously been reported to be associated with increased risk of Alzheimer's disease (AD). We are using biomarkers to study Vietnam Veterans with/without mild cognitive impairment with a history of at least one TBI and/or ongoing PTSD to determine whether these contribute to the development of AD.

METHODS

Potential subjects identified by Veterans Administration records underwent an initial telephone screen. Consented subjects underwent clinical evaluation, lumbar puncture, structural MRI and amyloid PET scans.

RESULTS

We observed worse cognitive functioning in PTSD and TBI + PTSD groups, worse global cognitive functioning in the PTSD group, lower superior parietal volume in the TBI + PTSD group, and lower amyloid positivity in the PTSD group, but not the TBI group compared to controls without TBI/PTSD. Medial temporal lobe atrophy was not increased in the PTSD and/or TBI groups.

DISCUSSION

Preliminary results do not indicate that TBI or PTSD increase the risk for AD measured by amyloid PET. Additional recruitment, longitudinal follow-up, and tau PET scans will provide more information in the future.

Does pediatric post-traumatic stress disorder alter the brain? Systematic review and meta-analysis of structural and functional magnetic resonance imaging studies

Several studies have recently demonstrated that the volumes of specific brain regions are reduced in children and adolescents with post-traumatic stress disorder (PTSD) compared with those of healthy controls. Our study investigated the potential association between early traumatic experiences and altered brain regions and functions. We conducted a systematic review of the scientific literature regarding functional magnetic resonance imaging and a meta-analysis of structural magnetic resonance imaging studies that investigated cerebral region volumes in pediatric patients with PTSD. We searched for articles from 2000 to 2014 in the PsycINFO, PubMed, Medline, Lilacs, and ISI (Web of Knowledge) databases. All data regarding the amygdala, hippocampus, corpus callosum, brain, and intracranial volumes that fit the inclusion criteria were extracted and combined in a meta-analysis that assessed differences between groups. The meta-analysis found reduced total corpus callosum areas and reduced total cerebral and intracranial volumes in the patients with PTSD. The total hippocampus (left and right hippocampus) and gray matter volumes of the amygdala and frontal lobe were also reduced, but these differences were not significant. The functional studies revealed differences in brain region activation in response to stimuli in the post-traumatic stress symptoms/PTSD group. Our results confirmed that the pediatric patients with PTSD exhibited structural and functional brain abnormalities and that some of the abnormalities occurred in different brain regions than those observed in adults.

Evidence for the changes of pituitary volumes in patients with post-traumatic stress disorder

In pubertal and postpubertal patients with post-traumatic stress disorder (PTSD), significantly greater pituitary gland volumes have been reported. Moving from this point, in the present study, we aimed to investigate pituitary gland volumes in patients with PTSD and hypothesized that volumes of the gland would be structurally changed. Volumetric magnetic resonance imaging of the pituitary gland was performed among sixteen patients with PTSD and fifteen healthy control subjects. We found that the mean volume of the pituitary gland was statistically significant and smaller than that of healthy subjects (0.69±0.08cm³ for patient group and 0.83±0.21 for control subjects). Consequently, in the present study, we found that patients with PTSD had smaller pituitary gland volumes than those of healthy controls like other anxiety disorders. It is important to provide support for this finding in future longitudinal investigations.

Trauma-related Structural Dissociation of the Personality

Many traumatized individuals alternate between re-experiencing their trauma and being detached from, or even relatively unaware of the trauma and its effects. At first sight one may be inclined to conceptualize detachment from trauma and re-experiencing of trauma as mental states. However, on closer scrutiny it becomes apparent that in both cases a range or cluster of states rather than a singular state is involved. For example, being detached from trauma does not itself exclude being joyful, ashamed, sexually aroused, or curious at times, and re-experiencing trauma can encompass states such as fleeing, freezing, and being in pain or being analgesic. In this paper we relate detachment from trauma and re-experiencing trauma to emotional operating systems (Panksepp, 1998) and functional systems (Fanselow & Lester, 1988), briefly addressed as action systems. Action systems control a range of functions, but some are more complex than others. Reexperiencing trauma will be associated with the inborn and evolutionary derived defensive system that is evoked by severe threat, in particular threat to the integrity of the body. As a complex system, it encompasses various subsystems, such as flight, freeze, and fight. Detachment from trauma, in our view, is associated with several action systems (Panksepp, 1998), i.e., the ones that control functions in daily life (e.g., exploration of the environment, energy control), and the ones that are dedicated to survival of the species (e.g., reproduction, attachment to and care for offspring). In this context we will maintain that severe threat may provoke a structural dissociation of the premorbid personality (Van der Hart, 2000). In its primary form this dissociation is between the defensive system on one hand, and the systems that involve managing daily life and survival of the species on the other hand. To summarize the essence of the theory of structural dissociation of the personality, we argue (1) that traumatic experiences, especially when they occur early in life and involve severe threat to the integrity of the body, may activate psychobiological action systems that have been developed by evolution, and (2) that due to extreme stress levels and classical as well as evaluative conditioning to traumatic memories these systems may remain unintegrated to varying degrees.

Dissociation, Epileptiform Discharges and Chaos in the Brain: Toward a Neuroscientific Theory of Dissociation

Dissociated states represent pathological conditions when psychological trauma may emerge in a variety of forms such as psychic dissociative symptoms or, on the contrary, as paroxysms or other somatoform symptoms. There is evidence that epileptic activity plays an important role in the generation of dissociative states and it is able to generate various psychopathological processes as well as a wide spectrum of somatic symptoms or seizures. For the explanation of these connections between dissociative states and epileptic discharges the author proposes a neuroscientific model of dissociation based on the theory of competitive neural assemblies which can lead to chaotic self-organization in brain neural networks. This model is suggested as an integrative view interconnecting the various psychopathological and somatoform manifestations of dissociative states and suggests further possibilities for future research regarding common pathogenic mechanisms among epilepsy and mental disorders.

Altered Microstructural Caudate Integrity in Posttraumatic Stress Disorder but Not Traumatic Brain Injury

OBJECTIVE

Given the high prevalence and comorbidity of combat-related PTSD and TBI in Veterans, it is often difficult to disentangle the contributions of each disorder. Examining these pathologies separately may help to understand the neurobiological basis of memory impairment in PTSD and TBI independently of each other. Thus, we investigated whether a) PTSD and TBI are characterized by subcortical structural abnormalities by examining diffusion tensor imaging (DTI) metrics and volume and b) if these abnormalities were specific to PTSD versus TBI.

METHOD

We investigated whether individuals with PTSD or TBI display subcortical structural abnormalities in memory regions by examining DTI metrics and volume of the hippocampus and caudate in three groups of Veterans: Veterans with PTSD, Veterans with TBI, and Veterans with neither PTSD nor TBI (Veteran controls).

RESULTS

While our results demonstrated no macrostructural differences among the groups in these regions, there were significant alterations in microstructural DTI indices in the caudate for the PTSD group but not the TBI group compared to Veteran controls.

CONCLUSIONS

The result of increased mean, radial, and axial diffusivity, and decreased fractional anisotropy in the caudate in absence of significant volume atrophy in the PTSD group suggests the presence of subtle abnormalities evident only at a microstructural level. The caudate is thought to play a role in the physiopathology of PTSD, and the habit-like behavioral features of the disorder could be due to striatal-dependent habit learning mechanisms. Thus, DTI appears to be a vital tool to investigate subcortical pathology, greatly enhancing the ability to detect subtle brain changes in complex disorders.

Treatment of OSA with CPAP Is Associated with Improvement in PTSD Symptoms among Veterans

STUDY OBJECTIVES

Posttraumatic stress disorder (PTSD) is common among veterans of the military, with sleep disturbance as a hallmark manifestation. A growing body of research has suggested a link between obstructive sleep apnea and PTSD, potentially due to obstructive sleep apnea (OSA) related sleep disruption, or via other mechanisms. We examined the hypothesis that treatment of OSA with positive airway pressure would reduce PTSD symptoms over 6 months.

METHODS

A prospective study of Veterans with confirmed PTSD and new diagnosis of OSA not yet using PAP therapy were recruited from a Veteran's Affairs sleep medicine clinic. All subjects were instructed to use PAP each night. Assessments were performed at 3 and 6 months. The primary outcome was a reduction in PTSD symptoms at 6 months.

RESULTS

Fifty-nine subjects were enrolled; 32 remained in the study at 6 months. A significant reduction in PTSD symptoms, measured by PCL-S score was observed over the course of the study (60.6 ± 2.7 versus 52.3 ± 3.2 points; p < 0.001). Improvement was also seen in measures of sleepiness, sleep quality, and daytime functioning, as well as depression and quality of life. Percentage of nights in which PAP was used, but not mean hours used per night, was predictive of improvement.

CONCLUSIONS

Treatment of OSA with PAP therapy is associated with improvement in PTSD symptoms, although the mechanism is unclear. Nonetheless, PAP should be considered an important component of PTSD treatment for those with concurrent OSA. Improving PAP compliance is a challenge in this patient population warranting further investigation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02019914.

COMMENTARY

A commentary on this article appears in this issue on page 5.

A Pilot Study of the Effects of Mindfulness-Based Stress Reduction on Post-traumatic Stress Disorder Symptoms and Brain Response to Traumatic Reminders of Combat in Operation Enduring Freedom/Operation Iraqi Freedom Combat Veterans with Post-traumatic Stress Disorder

OBJECTIVE

Brain imaging studies in patients with post-traumatic stress disorder (PTSD) have implicated a circuitry of brain regions including the medial prefrontal cortex, amygdala, hippocampus, parietal cortex, and insula. Pharmacological treatment studies have shown a reversal of medial prefrontal deficits in response to traumatic reminders. Mindfulness-based stress reduction (MBSR) is a promising non-pharmacologic approach to the treatment of anxiety and pain disorders. The purpose of this study was to assess the effects of MBSR on PTSD symptoms and brain response to traumatic reminders measured with positron-emission tomography (PET) in Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) combat veterans with PTSD. We hypothesized that MBSR would show increased prefrontal response to stress and improved PTSD symptoms in veterans with PTSD.

METHOD

Twenty-six OEF/OIF combat veterans with PTSD who had recently returned from a combat zone were block randomized to receive eight sessions of MBSR or present-centered group therapy (PCGT). PTSD patients underwent assessment of PTSD symptoms with the Clinician-Administered PTSD Scale (CAPS), mindfulness with the Five Factor Mindfulness Questionnaire (FFMQ) and brain imaging using PET in conjunction with exposure to neutral and Iraq combat-related slides and sound before and after treatment. Nine patients in the MBSR group and 8 in the PCGT group completed all study procedures.

RESULTS

Post-traumatic stress disorder patients treated with MBSR (but not PCGT) had an improvement in PTSD symptoms measured with the CAPS that persisted for 6 months after treatment. MBSR also resulted in an increase in mindfulness measured with the FFMQ. MBSR-treated patients had increased anterior cingulate and inferior parietal lobule and decreased insula and precuneus function in response to traumatic reminders compared to the PCGT group.

CONCLUSION

This study shows that MBSR is a safe and effective treatment for PTSD. Furthermore, MBSR treatment is associated with changes in brain regions that have been implicated in PTSD and are involved in extinction of fear responses to traumatic memories as well as regulation of the stress response.

Genome to Phenome: A Systems Biology Approach to PTSD Using an Animal Model

Post-traumatic stress disorder (PTSD) is a debilitating illness that imposes significant emotional and financial burdens on military families. The understanding of PTSD etiology remains elusive; nonetheless, it is clear that PTSD is manifested by a cluster of symptoms including hyperarousal, reexperiencing of traumatic events, and avoidance of trauma reminders. With these characteristics in mind, several rodent models have been developed eliciting PTSD-like features. Animal models with social dimensions are of particular interest, since the social context plays a major role in the development and manifestation of PTSD.For civilians, a core trauma that elicits PTSD might be characterized by a singular life-threatening event such as a car accident. In contrast, among war veterans, PTSD might be triggered by repeated threats and a cumulative psychological burden that coalesced in the combat zone. In capturing this fundamental difference, the aggressor-exposed social stress (Agg-E SS) model imposes highly threatening conspecific trauma on naïve mice repeatedly and randomly.There is abundant evidence that suggests the potential role of genetic contributions to risk factors for PTSD. Specific observations include putatively heritable attributes of the disorder, the cited cases of atypical brain morphology, and the observed neuroendocrine shifts away from normative. Taken together, these features underscore the importance of multi-omics investigations to develop a comprehensive picture. More daunting will be the task of downstream analysis with integration of these heterogeneous genotypic and phenotypic data types to deliver putative clinical biomarkers. Researchers are advocating for a systems biology approach, which has demonstrated an increasingly robust potential for integrating multidisciplinary data. By applying a systems biology approach here, we have connected the tissue-specific molecular perturbations to the behaviors displayed by mice subjected to Agg-E SS. A molecular pattern that links the atypical fear plasticity to energy deficiency was thereby identified to be causally associated with many behavioral shifts and transformations.PTSD is a multifactorial illness sensitive to environmental influence. Accordingly, it is essential to employ the optimal animal model approximating the environmental condition that elicits PTSD-like symptoms. Integration of an optimal animal model with a systems biology approach can contribute to a more knowledge-driven and efficient next-generation care management system and, potentially, prevention of PTSD.

Neural Correlates of Psychotherapeutic Treatment of Post-traumatic Stress Disorder: A Systematic Literature Review

OBJECTIVES

Post-traumatic stress disorder (PTSD) is a common psychiatric disease with changes in neural circuitries. Neurobiological models conceptualize the symptoms of PTSD as correlates of a dysfunctional stress reaction to traumatic events. Functional imaging studies showed an increased amygdala and a decreased prefrontal cortex response in PTSD patients. As psychotherapeutic approaches represent the gold standard for PTSD treatment, it is important to examine its underlying neurobiological correlates.

METHODS

Studies published until August 2016 were selected through systematic literature research in the databases PubMed, PsychInfo, and Cochrane Library's Central Register of Controlled Trials or were identified manually by searching reference lists of selected articles. Search terms were "neural correlates" OR "fMRI" OR "SPECT," AND "therapy" AND "PTSD." A total of 19 articles were included in the present review whereof 15 studies compared pre-to-post-therapy signal changes, six studies related pre-treatment activity to pre-to-post-symptom improvement, and four studies compared neural correlates of responders versus non-responders. The disposed therapy forms were cognitive behavioral therapy (CBT), eye movement desensitization and reprocessing, cognitive therapy, exposure therapy, mindfulness-based intervention, brief eclectic psychotherapy, and unspecified therapy.

RESULTS

Successful psychotherapy of PTSD was repeatedly shown to be accompanied by decreased activity in the amygdala and the insula as well as increased activity in the dorsal anterior cingulate cortex (dACC) and hippocampus. Elevated dACC activity prior to treatment was related to subsequent treatment success and a positive predictor for treatment response. Elevated amygdala and insula pre-treatment activities were related to treatment failure.

DISCUSSION

Decreased activity in limbic brain regions and increased activity in frontal brain areas in PTSD patients after successful psychotherapeutic treatment might reflect regained top-down control over previously impaired bottom-up processes.

Salivary Cortisol and Regional Brain Volumes Among Veterans With and Without Posttraumatic Stress Disorder

BACKGROUND

Human studies have often found that brain regions rich in glucocorticoid receptors exhibit smaller volume in samples with past trauma and ongoing stress; however, relatively little research has addressed the hypothesis that such smaller volumes can be traced to elevated circulating glucocorticoid hormones (GCs). This issue takes on renewed interest in light of recent proposals to treat symptoms of stress disorders such as posttraumatic stress disorder (PTSD) with exogenous synthetic GCs. We sought to examine the relation of circulating GCs to brain macrostructure among veterans with and without PTSD.

METHODS

Participants (n = 90) included combat veterans with and without PTSD. Veterans completed self-report surveys, home-based cortisol samples, reactive cortisol samples over the course of two serial Trier Social Stress Tests, a low-dose dexamethasone suppression test, and structural magnetic resonance brain imaging over the course of 3 to 5 days.

RESULTS

No associations were observed between any salivary cortisol index and the volumes of the hippocampus or amygdala. A negative association was observed between evening basal cortisol and both FreeSurfer global volume and BrainImage supratentorial tissue volume. This effect was moderated by PTSD. Also observed was a positive association between reactive cortisol and these same brain volumes.

CONCLUSIONS

Estimates of cortical but not hippocampal or amygdala volume were moderately associated with evening basal salivary cortisol and cortisol reactivity to a social stressor. Existing models relating GC receptor density, circulating cortisol levels, and regional brain volumes received little support.

Neurobiology of comorbid post-traumatic stress disorder and alcohol-use disorder

Post-traumatic stress disorder (PTSD) and alcohol-use disorder (AUD) are highly comorbid in humans. Although we have some understanding of the structural and functional brain changes that define each of these disorders, and how those changes contribute to the behavioral symptoms that define them, little is known about the neurobiology of comorbid PTSD and AUD, which may be due in part to a scarcity of adequate animal models for examining this research question. The goal of this review is to summarize the current state-of-the-science on comorbid PTSD and AUD. We summarize epidemiological data documenting the prevalence of this comorbidity, review what is known about the potential neurobiological basis for the frequent co-occurrence of PTSD and AUD and discuss successes and failures of past and current treatment strategies. We also review animal models that aim to examine comorbid PTSD and AUD, highlighting where the models parallel the human condition, and we discuss the strengths and weaknesses of each model. We conclude by discussing key gaps in our knowledge and strategies for addressing them: in particular, we (1) highlight the need for better animal models of the comorbid condition and better clinical trial design, (2) emphasize the need for examination of subpopulation effects and individual differences and (3) urge cross-talk between basic and clinical researchers that is reflected in collaborative work with forward and reverse translational impact.

Risk for developing dementia among patients with posttraumatic stress disorder: A nationwide longitudinal study

OBJECTIVES

Previous studies suggested a relationship between posttraumatic stress disorder (PTSD) in the specific population (i.e., war survivors and veterans) and subsequent dementia risk. However, whether patients with PTSD in the general population were at an increased risk for developing dementia in later life remained unclear.

METHODS

The Cox regression analysis was performed using data from the Taiwan National Health Insurance Research Database. The study sample comprised 1750 patients diagnosed with PTSD between 2001 and 2009 and 7000 age-/sex-matched individuals without PTSD. Those who developed dementia during follow-up to the end of 2011 were identified.

RESULTS

After adjusting for demographic data and medical and psychiatric comorbidities, PTSD was an independent risk factor for the risk for subsequent dementia (hazard ratio [HR]=4.37; 95% confidence interval [CI]: 2.53-7.55). There was a dose-dependent relationship between PTSD severity indicated by the frequency of psychiatric clinics visiting of PTSD (times per year) and the risk of subsequent dementia (<5: HR: 2.81, 95% CI: 1.50-5.29; 5-10: 6.90, 95% CI: 3.09-15.40;>10: HR: 18.13, 95% CI: 9.13-36.00). Furthermore, patients with depressive disorder and medical comorbidities, such as cerebrovascular diseases, diabetes mellitus, and head injuries, exhibited a higher risk for developing dementia.

DISCUSSIONS

Our study suggested a significant dose-dependent association between PTSD and its severity and an increased risk of developing dementia later in life. The importance of mental care for trauma victims would increase in the coming century, and our findings broadened another era for the end result of a widely prevalent psychiatric disorder.

Early childhood trauma and hippocampal volumes in patients with epileptic and psychogenic seizures

OBJECTIVE

Exposure to early life childhood trauma has been implicated as resulting in a vulnerability to epileptic and psychogenic nonepileptic seizures (PNES), hippocampal atrophy, and psychiatric disorders. This study aimed to explore the relationships between childhood trauma, epilepsy, PNES, and hippocampal volume in patients admitted to a video-electroencephalogram monitoring (VEM) unit.

METHODS

One hundred thirty-one patients were recruited from the Royal Melbourne Hospital VEM unit. The diagnostic breakdown of this group was: temporal lobe epilepsy (TLE) (32), other epilepsy syndromes (35), PNES (47), other nonepileptic syndromes (5), both epilepsy and PNES (6), and uncertain diagnosis (6). All patients completed a questionnaire assessing exposure to childhood trauma, the Childhood Trauma Questionnaire (CTQ), as well as questionnaires assessing psychiatric symptomatology (SCL-90-R), Anxiety and Depression (HADS), quality of life (QOLIE-98) and cognition (NUCOG). Volumetric coronal T1 MRI scans were available for 84 patients. Hippocampal volumes were manually traced by a blinded operator.

RESULTS

The prevalence of childhood trauma in patients with PNES was higher than in patients with other diagnoses (p=0.005), and the group with PNES overall scored significantly higher on the CTQ (p=0.002). No association was found between CTQ scores and hippocampal volumes; however, patients with a history of sexual abuse were found to have smaller left hippocampal volumes than patients who had not (p=0.043). Patients reporting having experienced childhood trauma scored lower on measures of quality of life and higher on measures of psychiatric symptomatology.

SIGNIFICANCE

Patients with PNES report having experienced significantly more childhood trauma than those with epileptic seizures, and in both groups there was a relationship between a history of having experienced sexual abuse and reduced left hippocampal volume. Patients with PNES and those with epilepsy who have a history of childhood trauma have overall worse quality of life and more psychiatric symptomatology.

Hippocampal and amygdala volumes in adults with posttraumatic stress disorder secondary to childhood abuse or maltreatment: A systematic review

We systematically reviewed differences in hippocampal and amygdala volumes between adults with childhood maltreatment-related posttraumatic stress disorder (PTSD) and healthy controls. Using the terms "adults", "MRI", "magnetic resonance imaging", with "posttraumatic stress disorder" "PTSD", "child abuse", and "child maltreatment", we conducted searches on several electronic databases. We identified 10 studies that met our inclusion criteria; 7 of which were included in a meta-analysis of hippocampal volume and 4 that were included in a meta-analysis of amygdala volume. Mean hippocampal and amygdala volumes were used to determine effect sizes. We found bilateral reduction of both the hippocampus and amygdala in the PTSD group compared to healthy controls, with effect sizes of -0.66 and -0.67 for the left and right hippocampus (p<0.00001 and p=0.002) and -1.08 and -1.15 for the left and right amygdala, (p=0.013 and p=0.003), respectively. Confidence intervals were -0.93,-0.39 and -1.26,-0.29 for the left and right hippocampus, respectively. For the amygdala, confidence intervals were -1.92,-0.23 and -1.19, -0.39 for the left and right amygdala. The relatively few studies available for analysis is a limitation. Additionally, sex diverse MRI studies in PTSD are needed to determine whether sex plays a significant role in the hippocampal effects associated with childhood-onset trauma.

The Atypical Antipsychotic Paliperidone Regulates Endogenous Antioxidant/Anti-Inflammatory Pathways in Rat Models of Acute and Chronic Restraint Stress

Alterations in the innate inflammatory response may underlie the pathophysiology of psychiatric diseases. Current antipsychotics modulate pro-/anti-inflammatory pathways, but their specific actions on these pathways remain only partly explored. This study was conducted to elucidate the regulatory role of paliperidone (1 mg/kg i.p.) on acute (6 h) and chronic (6 h/day for 21 consecutive days) restraint stress-induced alterations in 2 emerging endogenous anti-inflammatory/antioxidant mechanisms: nuclear factor erythroid-related factor 2 (NRF2)/antioxidant enzymes pathway, and the cytokine milieu regulating M1/M2 polarization in microglia, analyzed at the mRNA and protein levels in prefrontal cortex samples. In acute stress conditions, paliperidone enhanced NRF2 levels, possibly related to phosphoinositide 3-kinase upregulation and reduced kelch-Like ECH-associated protein 1 expression. In chronic conditions, paliperidone tended to normalize NRF2 levels through a phosphoinositide 3-kinase related-mechanism, with no effects on kelch-Like ECH-associated protein 1. Antioxidant response element-dependent antioxidant enzymes were upregulated by paliperidone in acute stress, while in chronic stress, paliperidone tended to prevent stress-induced downregulation of the endogenous antioxidant machinery. However, paliperidone increased transforming growth factor-β and interleukin-10 in favor of an M2 microglia profile in acute stress conditions, which was also corroborated by paliperidone-induced increased levels of the M2 cellular markers arginase I and folate receptor 2. This latter effect was also produced in chronic conditions. Immunofluorescence studies suggested an increase in the number of microglial cells expressing arginase I and folate receptor 2 in the stressed animals pretreated with paliperidone. In conclusion, the enhancement of endogenous antioxidant/anti-inflammatory pathways by current and new antipsychotics could represent an interesting therapeutic strategy for the future.

Reasons and Causes for Post-Traumatic Stress Disorder

PTSD's most distinctive feature is its etiological event. With out this event, PTSD symptoms are indistinguishable from symptoms associated with combinations of other psychiatric diagnoses. The DSM definition of PTSD assumes that the relation between the etiological event and its symptoms is equivalent to a cause and effect. In reality, these events are often reasons rather than causes of the syndrome. Where this is true, the syndrome loses its specificity. This paper explains why it is often impossible to distinguish between the reasons and causes of PTSD, and why this difficulty is generally ignored.

Vietnam Service, Combat, and Lifetime Educational Attainment

Combat experiences early in adulthood may have lifelong ramifications. In the Vietnam Era Twin Study of Aging (VETSA), the authors studied lifetime educational attainment (LEA) in 236 male twins from the Vietnam Era Twin Registry. Twins who served in Vietnam had completed significantly fewer years of education by their 50s. Level of combat exposure was negatively correlated with LEA. To control for variables that might confound the relationship between combat and LEA, the authors compared twin pairs discordant for Vietnam service ( n = 44 pairs); the twins who served in Vietnam had significantly lower LEA than their cotwins. Greater cognitive ability at military induction and older age at induction both predicted higher LEA, but after statistically controlling for these variables, the relationship between combat exposure and LEA remained significant. The VETSA results demonstrate that combat experience and entering military service at a younger age may reduce lifelong educational prospects, even after cognitive ability is controlled.

Biological markers for anxiety disorders, OCD and PTSD - a consensus statement. Part I: Neuroimaging and genetics

OBJECTIVES

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part I) summarises findings on potential biomarkers in neuroimaging studies, including structural brain morphology, functional magnetic resonance imaging and techniques for measuring metabolic changes, including positron emission tomography and others. Furthermore, this review reports on the clinical and molecular genetic findings of family, twin, linkage, association and genome-wide association studies. Part II of the review focuses on neurochemistry, neurophysiology and neurocognition.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high-quality research has accumulated that will improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Posttraumatic Relationship Syndrome

This case study describes the treatment of an individual with Posttraumatic Relationship Syndrome (PTRS), a newly proposed mental health syndrome that occurs subsequent to the experience of trauma in an intimate relationship. It includes the intrusive and arousal symptoms of Posttraumatic Stress Disorder (PTSD) but lacks the avoidance symptoms required for a diagnosis of PTSD due to a very different mode of coping with the traumatized state from that which is characteristic of individuals with PTSD. It also includes a category of relational symptoms that, of course, are not part of PTSD because the trauma it addresses does not have to occur in the context of an emotionally intimate relationship, as in PTRS. The treatment model developed and successfully implemented by the authors is described along with the posttraumatic growth the client achieved.

Early hippocampal volume loss as a marker of eventual memory deficits caused by repeated stress

Exposure to severe and prolonged stress has detrimental effects on the hippocampus. However, relatively little is known about the gradual changes in hippocampal structure, and its behavioral consequences, over the course of repeated stress. Behavioral analyses during 10 days of chronic stress pointed to a delayed decline in spatial memory, the full impact of which is evident only after the end of stress. In contrast, concurrent volumetric measurements in the same animals revealed significant reduction in hippocampal volumes in stressed animals relative to their unstressed counterparts, as early as the third day of stress. Notably, animals that were behaviorally the worst affected at the end of chronic stress suffered the most pronounced early loss in hippocampal volume. Together, these findings support the view that not only is smaller hippocampal volume linked to stress-induced memory deficits, but it may also act as an early risk factor for the eventual development of cognitive impairments seen in stress-related psychiatric disorders.

Attachment and Contained Splitting: A Combined Approach of Group and Individual Therapy to the Treatment of Patients Suffering from Borderline Personality Disorder

In this article the authors describe the three-year combined group and individual therapy project for patients suffering from severe borderline personality disorder. The project attempted through careful supervision and regular whole-team meetings to integrate the research findings of attachment theory into the practice of both group and individual therapy. Material from the group sessions follows a description of the project's organization and the relevant attachment theory.

Review : The Neurobiological Basis of Anxiety and Fear: Circuits, Mechanisms, and Neurochemical Interactions (Part I

There have been tremendous advances in our knowledge of the neurobiological basis of human anxiety and fear. This review seeks to highlight how specific neuronal circuits, neural mechanisms, and neuromod ulators may play a critical role in anxiety and fear states. It focuses on several brain structures, including the amygdala, locus coeruleus, hippocampus, and various cortical regions and the functional interactions among brain noradrenergic (NE), corticotropin releasing hormone (CRH), and the hypothalamic pituitary adrenal axis (HPA). Particular attention is directed toward results that can lead to a better understanding of the constellation of the symptoms associated with two of the more severe anxiety disorders, panic disorder and posttraumatic stress disorder (PTSD), the persistence of traumatic memories, and the effects of stress, particularly early life adverse experiences, on brain function and clinical outcome. NEUROSCIENTIST 4: 35-44, 1998

Review : Stress, Antidepressant Treatments, and Neurotrophic Factors: Molecular and Cellular Mechanisms

Repeated stress or an excess of glucocorticoids can exacerbate neuronal damage in response to insults and, in severe cases, can lead to neuronal atrophy and death. These effects are thought to be related to the actions of stress and glucocorticoids on glutamate function, neuronal metabolism, and the generation of cytotoxic free radicals. Recent studies demonstrate that the regulation of neurotrophic factors may contribute to the actions of stress on neuronal function. Acute or chronic stress decreases the expression of brain derived neurotrophic factor, the most abundant neurotrophin in the brain, in specific regions of the hippocampus, and other forebrain regions. In addition, chronic stress increases the expression of neurotrophin-3 in certain regions of the hippocampus and may, thereby, help to protect these regions from the neurotoxic effects of chronic stress. The deleterious effects of stress may contribute to psy chiatric illnesses, such as depression, that can be precipitated or worsened by stress and that are often characterized by hypercortisolism. Electroconvulsive seizure therapy, as well as antidepressant drugs, increase the expression of brain derived neurotrophic factor and its receptor, trkB, in the brain, demon strating that neurotrophins are a target of antidepressant treatments. These findings outline a role of neurotrophic factors in the etiology and treatment of certain psychiatric illnesses. The Neuroscientist 1:351-360, 1995

Posttraumatic Stress Disorder: Structural Characterization with 3-T MR Imaging

Purpose To explore cerebral alterations related to the emergence of posttraumatic stress disorder (PTSD) by using three-dimensional T1-weighted imaging and also to explore the relationship of gray and white matter abnormalities and the anatomic changes with clinical severity and duration of time since the trauma. Materials and Methods Informed consent was provided, and the prospective study was approved by the ethics committee of the West China Hospital. Recruited were 67 patients with PTSD and 78 adult survivors without PTSD 7-15 months after a devastating earthquake in western China. All participants underwent magnetic resonance (MR) imaging with a 3-T imager to obtain anatomic images. Cortical thickness and volumes of 14 subcortical gray matter structures and five subregions of the corpus callosum were analyzed with software. Statistical differences between patients with PTSD and healthy survivors were evaluated with a general linear model. Averaged data from the regions with volumetric or cortical thickness differences between groups were extracted in each individual to examine correlations between morphometric measures and clinical profiles. Results Patients with PTSD showed greater cortical thickness in the right superior temporal gyrus, inferior parietal lobule, and left precuneus (P < .05; Monte Carlo null-z simulation corrected) and showed reduced volume in the posterior portion of the corpus callosum (F = 6.167; P = .014) compared with healthy survivors of the earthquake. PTSD severity was positively correlated with cortical thickness in the left precuneus (r = 0.332; P = .008). The volumes of posterior corpus callosum were negatively correlated with PTSD ratings in all survivors (r = -0.210; P = .013) and with cortical thickness of the left precuneus in patients with PTSD (r = -0.302; P = .017). Conclusion Results indicate that patients with PTSD had alterations in both cerebral gray matter and white matter compared with individuals who experienced similar psychologic trauma from the same stressor. Importantly, early in the course of PTSD, gray matter changes were in the form of increased, not decreased, cortical thickness, which may have resulted from neuroinflammatory or other trophic process related to endocrine changes or functional compensation. (©) RSNA, 2016.

Posttraumatic stress disorder

PURPOSE OF REVIEW

The objectives of this article are to update the reader on the current definition and diagnostic assessment of posttraumatic stress disorder (PTSD) and to describe its clinical characteristics, discuss its epidemiology and pathophysiologic aspects, as well as to summarize the current therapeutic options for PTSD.

RECENT FINDINGS

The new nomenclature of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) includes 20 PTSD symptoms clustered into four symptomatic domains: intrusive symptoms, active avoidance, disturbed emotional states, and alterations of arousal and reactivity. Diagnostic structured interviews and severity scales have been updated in order to address this recent revision. It is also recognized that the neural circuits whose disruption might explain the genesis of PTSD symptoms, although overlapping, may be different between these four domains, a fact that may inform new biologically based phenotypes with prognostic and therapeutic implications.During the past years, there has been active research into the different factors influencing vulnerability and resilience to stress, including the effect of genetic and epigenetic variations. The neural circuits involved in the processing of threatening stimuli have been studied in patients with PTSD through paradigms inspired in animal research. These studies suggest that patients with PTSD have difficulty discriminating danger from safety cues and have problems suppressing fear in the presence of safety cues. Functional MRI (fMRI) studies suggest that the increased amygdala activation observed in these patients results from abnormal modulatory input from the ventromedial prefrontal cortex. Structural brain abnormalities, on the other hand, have been more consistently identified in the hippocampus.Prolonged exposure therapy and cognitive reprocessing are the interventions that have the more extensive validation of their psychotherapeutic efficacy. Medications are modestly more effective than placebo to treat PTSD symptoms, and selective serotonin reuptake inhibitors (SSRIs) are considered a safe initial choice. Use of combined strategies including pharmacologic modulation of fear processing is an area of active research.

SUMMARY

PTSD is a frequent psychopathologic condition with a lifetime prevalence that is close to 10%. In the past few years, there have been significant advances in the definition of the disorder, in elucidating the neurobiology of vulnerability and resilience, and in developing new treatment alternatives.

The role of adult neurogenesis in psychiatric and cognitive disorders

Neurogenesis in mammals occurs throughout life in two brain regions: the ventricular-subventricular zone (V-SVZ) and the subgranular zone (SGZ) of the hippocampal dentate gyrus. Development and regulation of the V-SVZ and SGZ is unique to each brain region, but with several similar characteristics. Alterations to the production of new neurons in neurogenic regions have been linked to psychiatric and neurodegenerative disorders. Decline in neurogenesis in the SGZ correlates with affective and psychiatric disorders, and can be reversed by antidepressant and antipsychotic drugs. Likewise, neurogenesis in the V-SVZ can also be enhanced by antidepressant drugs. The regulation of neurogenesis by neurotransmitters, particularly monoamines, in both regions suggests that aberrant neurotransmitter signaling observed in psychiatric disease may play a role in the pathology of these mental health disorders. Similarly, the cognitive deficits that accompany neurodegenerative disease may also be exacerbated by decreased neurogenesis. This review explores the regulation and function of neural stem cells in rodents and humans, and the involvement of factors that contribute to psychiatric and cognitive deficits. This article is part of a Special Issue entitled SI:StemsCellsinPsychiatry.

White matter abnormalities are associated with chronic postconcussion symptoms in blast-related mild traumatic brain injury

Blast-related mild traumatic brain injury (mTBI) is a common injury among Iraq and Afghanistan military veterans due to the frequent use of improvised explosive devices. A significant minority of individuals with mTBI report chronic postconcussion symptoms (PCS), which include physical, emotional, and cognitive complaints. However, chronic PCS are nonspecific and are also associated with mental health disorders such as posttraumatic stress disorder (PTSD). Identifying the mechanisms that contribute to chronic PCS is particularly challenging in blast-related mTBI, where the incidence of comorbid PTSD is high. In this study, we examined whether blast-related mTBI is associated with diffuse white matter changes, and whether these neural changes are associated with chronic PCS. Ninety Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans were assigned to one of three groups including a blast-exposed no--TBI group, a blast-related mTBI without loss of consciousness (LOC) group (mTBI--LOC), and a blast-related mTBI with LOC group (mTBI + LOC). PCS were measured with the Rivermead Postconcussion Questionnaire. Results showed that participants in the mTBI + LOC group had more spatially heterogeneous white matter abnormalities than those in the no--TBI group. These white matter abnormalities were significantly associated with physical PCS severity even after accounting for PTSD symptoms, but not with cognitive or emotional PCS severity. A mediation analysis revealed that mTBI + LOC significantly influenced physical PCS severity through its effect on white matter integrity. These results suggest that white matter abnormalities are associated with chronic PCS independent of PTSD symptom severity and that these abnormalities are an important mechanism explaining the relationship between mTBI and chronic physical PCS.

Neighborhood matters: divergent patterns of stress-induced plasticity across the brain

The fact that exposure to severe stress leads to the development of psychiatric disorders serves as the basic rationale for animal models of stress disorders. Clinical and neuroimaging studies have shown that three brain areas involved in learning and memory--the hippocampus, amygdala and prefrontal cortex--undergo distinct structural and functional changes in individuals with stress disorders. These findings from patient studies pose several challenges for animal models of stress disorders. For instance, why does stress impair cognitive function, yet enhance fear and anxiety? Can the same stressful experience elicit contrasting patterns of plasticity in the hippocampus, amygdala and prefrontal cortex? How does even a brief exposure to traumatic stress lead to long-lasting behavioral abnormalities? Thus, animal models of stress disorders must not only capture the unique spatio-temporal features of structural and functional alterations in these brain areas, but must also provide insights into the underlying neuronal plasticity mechanisms. This Review will address some of these key questions by describing findings from animal models on how stress-induced plasticity varies across different brain regions and thereby gives rise to the debilitating emotional and cognitive symptoms of stress-related psychiatric disorders.

Animal models for posttraumatic stress disorder: An overview of what is used in research

Posttraumatic stress disorder (PTSD) is a common anxiety disorder characterised by its persistence of symptoms after a traumatic experience. Although some patients can be cured, many do not benefit enough from the psychological therapies or medication strategies used. Many researchers use animal models to learn more about the disorder and several models are available. The most-used physical stressor models are single-prolonged stress, restraint stress, foot shock, stress-enhanced fear learning, and underwater trauma. Common social stressors are housing instability, social instability, early-life stress, and social defeat. Psychological models are not as diverse and rely on controlled exposure to the test animal’s natural predator. While validation of these models has been resolved with replicated symptoms using analogous stressors, translating new findings to human patients remains essential for their impact on the field. Choosing a model to experiment with can be challenging; this overview of what is possible with individual models may aid in making a decision.

Subliminal trauma reminders impact neural processing of cognitive control in adults with developmental earthquake trauma: a preliminary report

Little is known about the effects of developmental trauma on the neural basis of cognitive control among adults who do not have posttraumatic stress disorder. To examine this question, we used functional magnetic resonance imaging to compare the effect of subliminal priming with earthquake-related images on attentional control during a Stroop task in survivors of the 2008 Wenchuan earthquake in China (survivor group, survivors were adolescents at the time of the earthquake) and in matched controls (control group). We found that the survivor group showed greater activation in the left ventral anterior cingulate cortex (vACC) and the bilateral parahippocampal gyrus during the congruent versus incongruent condition, as compared to the control group. Depressive symptoms were positively correlated with left vACC activation during the congruent condition. Moreover, psychophysiological interaction results showed that the survivor group had stronger functional connectivity between the left parahippocampal gyrus and the left vACC than the control group under the congruent-incongruent condition. These results suggested that trauma-related information was linked to abnormal activity in brain networks associated with cognitive control (e.g., vACC-parahippocampal gyrus). This may be a potential biomarker for depression following developmental trauma, and it may also provide a mechanism linking trauma reminders with depression.

Sleep-disordered breathing in patients with post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) and sleep-disordered breathing (SDB) are shared by many patients. They both affect sleep and the quality of life of affected subjects. A critical review of the literature supports an association between the two disorders in both combat-related and non-combat-related PTSD. The exact mechanism linking PTSD and SDB is not fully understood. A complex interplay between sleep fragmentation and neuroendocrine pathways is suggested. The overlap of symptoms between PTSD and SDB raises diagnostic challenges that may require a novel approach in the methods used to diagnose the coexisting disorders. Similar therapeutic challenges face patients and providers when treating concomitant PTSD and SDB. Although continuous positive airway pressure therapy imparts a mitigating effect on PTSD symptomatology, lack of both acceptance and adherence are common. Future research should focus on ways to improve adherence to continuous positive airway pressure therapy and on the use of alternative therapeutic methods for treating SDB in patients with PTSD.

Burning odor-elicited anxiety in OEF/OIF combat veterans: Inverse relationship to gray matter volume in olfactory cortex

Despite the anatomical overlap between the brain's fear/threat and olfactory systems, a very limited number of investigations have considered the role of odors and the central olfactory system in the pathophysiology of PTSD. The goal of the present study was to assess structural differences in primary and secondary olfactory cortex between combat veterans with and without PTSD (CV + PTSD, CV-PTSD, respectively). An additional goal was to determine the relationship between gray matter volume (GMV) in olfactory cortex and the distressing properties of burning-related odors. A region of interest voxel-based morphometric (VBM) approach was used to measure GMV in olfactory cortex in a well-characterized group of CV + PTSD (n = 20) and CV-PTSD (n = 25). Prior to the MRI exam, combat-related (i.e., burning rubber) and control odors were systematically sampled and rated according to their potential for eliciting PTSD symptoms. Results showed that CV + PTSD exhibited significantly reduced GMV in anterior piriform (primary olfactory) and orbitofrontal (secondary olfactory) cortices compared to CV-PTSD (both p < .01). For the entire group, GMV in bilateral anterior piriform cortex was inversely related to burning rubber odor-elicited memories of trauma (p < .05). GMV in orbitofrontal cortex was inversely related to both clinical and laboratory measures of PTSD symptoms (all p < .05). In addition to replicating an established inverse relationship between GMV in anxiety-associated brain structures and PTSD symptomatology, the present study extends those findings by being the first report of volumetric decreases in olfactory cortex that are inversely related to odor-elicited PTSD symptoms. Potential mechanisms underlying these findings are discussed.

Functional neuroanatomy on the working memory under emotional distraction in patients with generalized anxiety disorder

AIMS

Patients with generalized anxiety disorder (GAD) suffer the symptoms of psychological distress, including excessive and uncontrollable anxiety. Until now, the functional neuroanatomy for working memory (WM) in conjunction with the major anxiety symptoms in GAD patients has not yet been clearly identified. This study investigated the neural activation patterns associated with the effect of neutral and anxiety-inducing distractors during the delayed-response WM task in GAD patients.

METHODS

Eighteen patients with GAD and 18 age-matched healthy controls participated in this study. The functional magnetic resonance images were obtained while the subjects performed a delayed-response WM task with neutral and anxiety-inducing distractors.

RESULTS

During the neutral distractor, GAD patients compared to controls showed significantly lower activities in the fusiform gyrus, superior parietal gyrus, precuneus, superior occipital gyrus, lingual gyrus, cuneus, calcarine gyrus, parahippocampal gyrus and cerebellar cortex. During the anxiety-inducing distractor, GAD patients showed significantly higher activity in the hippocampus, whereas they showed lower activities in the dorsolateral prefrontal cortex, fusiform gyrus, superior parietal gyrus, precuneus, superior occipital gyrus and cerebellar cortex. The blood-oxygen-level dependent signal changes in the dorsolateral prefrontal cortex in GAD patients during the anxiety-inducing distractor were negatively correlated with Anxiety Sensitivity Index-Revised scores.

CONCLUSIONS

This study identified the specific brain areas associated with the interaction between emotional regulation and cognitive function associated with neutral and anxiety-inducing distractors during WM maintenance in GAD patients. These findings will be helpful for understanding the neural mechanism on the WM-related cognitive deficits and emotional dysfunction with typical anxiety symptoms in GAD.

Plasma brain-derived neurotrophic factor levels in patients suffering from post-traumatic stress disorder

A number of studies have been done to investigate the role of brain-derived neurotrophic factor (BDNF) in patients with post-traumatic stress disorder (PTSD). In this study we aimed to test the relationship between plasma BDNF levels and PTSD. We solicited 65 subjects having recently experienced road traffic accidents (RTA) conforming to screening criteria. They were given follow-up examinations after one month, three months, and six months. PTSD was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-R-TR, American Psychiatric Association, 2000) using the Mini International Neuropsychiatric Interview (MINI). All participants were divided into two groups: a group with PTSD and a group without PTSD. There were no significant differences in plasma BDNF levels between the two groups at either the 48h or six-month examination. Within the PTSD group, no significant differences were found in plasma BDNF levels between the two examinations. BDNF levels in those without PTSD showed a higher trend over time after trauma. Higher BDNF levels may be an important protective factor for the prevention of traumatized subjects from developing PTSD.

Stress effects on the hippocampus: a critical review

Uncontrollable stress has been recognized to influence the hippocampus at various levels of analysis. Behaviorally, human and animal studies have found that stress generally impairs various hippocampal-dependent memory tasks. Neurally, animal studies have revealed that stress alters ensuing synaptic plasticity and firing properties of hippocampal neurons. Structurally, human and animal studies have shown that stress changes neuronal morphology, suppresses neuronal proliferation, and reduces hippocampal volume. Since the inception of stress research nearly 80 years ago, much focus has been on the varying levels of hypothalamic-pituitary-adrenal (HPA) axis neuroendocrine hormones, namely glucocorticoids, as mediators of the myriad stress effects on the hippocampus and as contributing factors to stress-associated psychopathologies such as post-traumatic stress disorder (PTSD). However, reports of glucocorticoid-produced alterations in hippocampal functioning vary widely across studies. This review provides a brief history of stress research, examines how the glucocorticoid hypothesis emerged and guides contemporary stress research, and considers alternative approaches to understanding the mechanisms underlying stress effects on hippocampal functioning.

The case for neuropsychoanalysis: Why a dialogue with neuroscience is necessary but not sufficient for psychoanalysis

Recent advances in the cognitive, affective and social neurosciences have enabled these fields to study aspects of the mind that are central to psychoanalysis. These developments raise a number of possibilities for psychoanalysis. Can it engage the neurosciences in a productive and mutually enriching dialogue without compromising its own integrity and unique perspective? While many analysts welcome interdisciplinary exchanges with the neurosciences, termed neuropsychoanalysis, some have voiced concerns about their potentially deleterious effects on psychoanalytic theory and practice. In this paper we outline the development and aims of neuropsychoanalysis, and consider its reception in psychoanalysis and in the neurosciences. We then discuss some of the concerns raised within psychoanalysis, with particular emphasis on the epistemological foundations of neuropsychoanalysis. While this paper does not attempt to fully address the clinical applications of neuropsychoanalysis, we offer and discuss a brief case illustration in order to demonstrate that neuroscientific research findings can be used to enrich our models of the mind in ways that, in turn, may influence how analysts work with their patients. We will conclude that neuropsychoanalysis is grounded in the history of psychoanalysis, that it is part of the psychoanalytic worldview, and that it is necessary, albeit not sufficient, for the future viability of psychoanalysis.

Medial prefrontal pathways for the contextual regulation of extinguished fear in humans

The maintenance of anxiety disorders is thought to depend, in part, on deficits in extinction memory, possibly due to reduced contextual control of extinction that leads to fear renewal. Animal studies suggest that the neural circuitry responsible fear renewal includes the hippocampus, amygdala, and dorsomedial (dmPFC) and ventromedial (vmPFC) prefrontal cortex. However, the neural mechanisms of context-dependent fear renewal in humans remain poorly understood. We used functional magnetic resonance imaging (fMRI), combined with psychophysiology and immersive virtual reality, to elucidate how the hippocampus, amygdala, and dmPFC and vmPFC interact to drive the context-dependent renewal of extinguished fear. Healthy human participants encountered dynamic fear-relevant conditioned stimuli (CSs) while navigating through 3-D virtual reality environments in the MRI scanner. Conditioning and extinction were performed in two different virtual contexts. Twenty-four hours later, participants were exposed to the CSs without reinforcement while navigating through both contexts in the MRI scanner. Participants showed enhanced skin conductance responses (SCRs) to the previously-reinforced CS+ in the acquisition context on Day 2, consistent with fear renewal, and sustained responses in the dmPFC. In contrast, participants showed low SCRs to the CSs in the extinction context on Day 2, consistent with extinction recall, and enhanced vmPFC activation to the non-reinforced CS-. Structural equation modeling revealed that the dmPFC fully mediated the effect of the hippocampus on right amygdala activity during fear renewal, whereas the vmPFC partially mediated the effect of the hippocampus on right amygdala activity during extinction recall. These results indicate dissociable contextual influences of the hippocampus on prefrontal pathways, which, in turn, determine the level of reactivation of fear associations.

Post-traumatic stress influences the brain even in the absence of symptoms: A systematic, quantitative meta-analysis of neuroimaging studies

Stress affects brain function, and may lead to post-traumatic stress disorder (PTSD). Considerable empirical data for the neurobiology of PTSD has been derived from neuroimaging studies, although findings have proven inconsistent. We used an activation likelihood estimation analysis to explore differences in brain activity between adults with and without PTSD in response to affective stimuli. We separated studies by type of control group: trauma-exposed and trauma-naïve. This revealed distinct patterns of differences in functional activity. Compared to trauma-exposed controls, regions of the basal ganglia were differentially active in PTSD; whereas the comparison with trauma-naïve controls revealed differential involvement in the right anterior insula, precuneus, cingulate and orbitofrontal cortices known to be involved in emotional regulation. Changes in activity in the amygdala and parahippocampal cortex distinguished PTSD from both control groups. Results suggest that trauma has a measurable, enduring effect upon the functional dynamics of the brain, even in individuals who experience trauma but do not develop PTSD. These findings contribute to the understanding of whole-brain network activity following trauma, and its transition to clinical PTSD.

An event-related potentials study on the attention function of posttraumatic stress disorder

OBJECTIVE

In order to examine the functional defects and attentional bias in post-traumatic stress disorder (PTSD) patients, event-related potentials (ERP) of attention was investigated.

METHODS

Three groups of emotion pictures, positive, negative (or violent) and neutral, were viewed by 19 PTSD patients and 15 normal controls. Each picture had a frame, and participants reacted to the color of the frame by clicking buttons. Electroencephalogram (EEG) and behavior data were recorded. Peak latencies and amplitudes of P2 were measured.

RESULTS

For the three groups of pictures, PTSD patients had longer reaction time than the controls. Significant difference was found between PTSD patients and controls in response to violent, positive and neutral pictures.

The dynamic opponent relativity model: an integration and extension of capacity theory and existing theoretical perspectives on the neuropsychology of arousal and emotion

Arousal theory as discussed within the present paper refers to those mechanisms and neural systems involved in central nervous system activation and more specifically the systems involved in cortical activation. Historical progress in the evolution of arousal theory has led to a better understanding of the functional neural systems involved in arousal or activation processes and ultimately contributed much to our current theories of emotion. Despite evidence for the dynamic interplay between the left and right cerebral hemispheres, the concepts of cerebral balance and dynamic activation have been emphasized in the neuropsychological literature. A conceptual model is proposed herein that incorporates the unique contributions from multiple neuropsychological theories of arousal and emotion. It is argued that the cerebral hemispheres may play oppositional roles in emotion partially due to the differences in their functional specializations and in their persistence upon activation. In the presence of a threat or provocation, the right hemisphere may activate survival relevant responses partially derived from hemispheric specializations in arousal and emotional processing, including the mobilization of sympathetic drive to promote heightened blood pressure, heart rate, glucose mobilization and respiratory support necessary for the challenge. Oppositional processes and mechanisms are discussed, which may be relevant to the regulatory control over the survival response; however, the capacity of these systems is necessarily limited. A limited capacity mechanism is proposed, which is familiar within other physiological systems, including that providing for the prevention of muscular damage under exceptional demand. This capacity theory is proposed, wherein a link may be expected between exceptional stress within a neural system and damage to the neural system. These mechanisms are proposed to be relevant to emotion and emotional disorders. Discussion is provided on the possible role of currently applied therapeutic interventions for emotional disorders.

Behavioral inhibition in childhood predicts smaller hippocampal volume in adolescent offspring of parents with panic disorder

Behavioral inhibition (BI) is a genetically influenced behavioral profile seen in 15-20% of 2-year-old children. Children with BI are timid with people, objects and situations that are novel or unfamiliar, and are more reactive physiologically to these challenges as evidenced by higher heart rate, pupillary dilation, vocal cord tension and higher levels of cortisol. BI predisposes to the later development of anxiety, depression and substance abuse. Reduced hippocampal volumes have been observed in anxiety disorders, depression and posttraumatic stress disorder. Animal models have demonstrated that chronic stress can damage the hippocampal formation and implicated cortisol in these effects. We, therefore, hypothesized that the hippocampi of late adolescents who had been behaviorally inhibited as children would be smaller compared with those who had not been inhibited. Hippocampal volume was measured with high-resolution structural magnetic resonance imaging in 43 females and 40 males at 17 years of age who were determined to be BI+ or BI- based on behaviors observed in the laboratory as young children. BI in childhood predicted reduced hippocampal volumes in the adolescents who were offspring of parents with panic disorder, or panic disorder with comorbid major depression. We discuss genetic and environmental factors emanating from both child and parent that may explain these findings. To the best of our knowledge, this is the first study to demonstrate a relationship between the most extensively studied form of temperamentally based human trait anxiety, BI, and hippocampal structure. The reduction in hippocampal volume, as reported by us, suggests a role for the hippocampus in human trait anxiety and anxiety disorder that warrants further investigation.

Stress, trauma and PTSD: translational insights into the core synaptic circuitry and its modulation

Evidence is considered as to whether behavioral criteria for diagnosis of post-traumatic stress disorder (PTSD) are applicable to that of traumatized animals and whether the phenomena of acquisition, extinction and reactivation of fear behavior in animals are also successfully applicable to humans. This evidence suggests an affirmative answer in both cases. Furthermore, the deficits in gray matter found in PTSD, determined with magnetic resonance imaging, are also observed in traumatized animals, lending neuropsychological support to the use of animals to probe what has gone awry in PTSD. Such animal experiments indicate that the core synaptic circuitry mediating behavior following trauma consists of the amygdala, ventral-medial prefrontal cortex and hippocampus, all of which are modulated by the basal ganglia. It is not clear if this is the case in PTSD as the observations using fMRI are equivocal and open to technical objections. Nevertheless, the effects of the basal ganglia in controlling glutamatergic synaptic transmission through dopaminergic and serotonergic synaptic mechanisms in the core synaptic circuitry provides a ready explanation for why modifying these mechanisms delays extinction in animal models and predisposes towards PTSD. In addition, changes of brain-derived neurotrophic factor (BDNF) in the core synaptic circuitry have significant effects on acquisition and extinction in animal experiments with single nucleotide polymorphisms in the BDNF gene predisposing to PTSD.