Long-term treatment with paroxetine increases verbal declarative memory and hippocampal volume in posttraumatic stress disorder

Inwardly Rectifying Potassium Channel Kir4.1 as a Novel Modulator of BDNF Expression in Astrocytes

Brain-derived neurotrophic factor (BDNF) is a key molecule essential for neural plasticity and development, and is implicated in the pathophysiology of various central nervous system (CNS) disorders. It is now documented that BDNF is synthesized not only in neurons, but also in astrocytes which actively regulate neuronal activities by forming tripartite synapses. Inwardly rectifying potassium (Kir) channel subunit Kir4.1, which is specifically expressed in astrocytes, constructs Kir4.1 and Kir4.1/5.1 channels, and mediates the spatial potassium (K⁺) buffering action of astrocytes. Recent evidence illustrates that Kir4.1 channels play important roles in bringing about the actions of antidepressant drugs and modulating BDNF expression in astrocytes. Although the precise mechanisms remain to be clarified, it seems likely that inhibition (down-regulation or blockade) of astrocytic Kir4.1 channels attenuates K⁺ buffering, increases neuronal excitability by elevating extracellular K⁺ and glutamate, and facilitates BDNF expression. Conversely, activation (up-regulation or opening) of Kir4.1 channels reduces neuronal excitability by lowering extracellular K⁺ and glutamate, and attenuates BDNF expression. Particularly, the former pathophysiological alterations seem to be important in epileptogenesis and pain sensitization, and the latter in the pathogenesis of depressive disorders. In this article, we review the functions of Kir4.1 channels, with a focus on their regulation of spatial K⁺ buffering and BDNF expression in astrocytes, and discuss the role of the astrocytic Kir4.1-BDNF system in modulating CNS disorders.

A shared effect of paroxetine treatment on gray matter volume in depressive patients with and without childhood maltreatment: A voxel-based morphometry study

AIMS

This study assessed whether antidepressant drug treatment has a common effect on gray matter (GM) volume in MDD patients with and without childhood maltreatment (CM).

METHODS

T1-weighted structural magnetic resonance imaging data were collected from 168 participants, including 51 MDD patients with CM, 31 MDD patients without CM, 48 normal controls with CM, and 38 normal controls without CM. MDD patients received 6 months of treatment with paroxetine, and 24 patients with CM, and 16 patients without CM received a second MRI scan. A whole-brain voxel-based morphometry approach was used to estimate GM volume in each participant at two time points. Two-way analysis of variance (ANOVA) was used to determine the effects of MDD and CM on GM volume at baseline. Repeated measures two-way ANOVA was used to determine the treatment-by-CM interactive effect and main effect of treatment during paroxetine treatment. We further investigated the relationship between GM volume and clinical variables.

RESULTS

At baseline, significant MDD-by-CM interactive effects on GM volume were mainly observed in the left parahippocampal gyrus, left entorhinal cortex, and left cuneus. GM volume was significantly lower mainly in the right middle temporal gyrus in patients with MDD than in normal controls. We did not find any significant treatment-by-CM interactive effects. However, a treatment-related increase in GM was found in the right middle temporal gyrus in both MDD groups.

CONCLUSIONS

These results suggest that paroxetine treatment operates via a shared neurobiological mechanism in MDD patients with and without CM.

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.

Adult Hippocampal Neurogenesis: Regulation and Possible Functional and Clinical Correlates

The formation of new neurons in the adult central nervous system (CNS) has been recognized as one of the major findings in neuroanatomical research. The hippocampal formation (HF), one of the main targets of these investigations, holds a neurogenic niche widely recognized among several mammalian species and whose existence in the human brain has sparked controversy and extensive debate. Many cellular features from this region emphasize that hippocampal neurogenesis suffers changes with normal aging and, among regulatory factors, physical exercise and chronic stress provoke opposite effects on cell proliferation, maturation and survival. Considering the numerous functions attributable to the HF, increasing or decreasing the integration of new neurons in the delicate neuronal network might be significant for modulation of cognition and emotion. The role that immature and mature adult-born neurons play in this circuitry is still mostly unknown but it could prove fundamental to understand hippocampal-dependent cognitive processes, the pathophysiology of depression, and the therapeutic effects of antidepressant medication in modulating behavior and mental health.

Neurotrophic factors and hippocampal activity in PTSD

Although numerous studies have investigated the neurotrophic factors and hippocampal activity in posttraumatic stress disorder (PTSD) separately each other, it is unclear whether an association between neurotrophic factors and hippocampal activity is present. The aim of this study was to evaluate the functional changes in hippocampus before and after treatment with escitalopram and to associate these changes with peptides related to neuronal growth in patients with chronic PTSD and trauma survivors without PTSD. Fifteen earthquake survivors with chronic PTSD and thirteen drug naïve trauma exposed individuals without PTSD underwent fMRI scans in a block design. Serum levels of Nerve Growth Factor (NGF) and Brain Derived Neurotrophic Factor (BDNF) were measured before and after 12 weeks treatment with escitalopram. Baseline median serum level of NGF was significantly lower in patients with chronic PTSD than trauma survivors; however, 12 weeks of treatment with escitalopram significantly increased it. Higher activation was found both in left and right hippocampus for chronic PTSD group than trauma survivors. Treatment with escitalopram was significantly associated with suppression of the hyperactivation in left hippocampus in patients with chronic PTSD. Bilateral hyperactivation in hippocampus and lowered NGF may associate with neurobiological disarrangements in chronic PTSD. Treatment with escitalopram was significantly associated with both improvement in the severity of PTSD symptoms and biological alterations. Patients diagnosed with PTSD may have further and complicated deteriorations in hippocampal networks and neurotransmitter systems than individuals who had not been diagnosed with PTSD following the same traumatic experience.

Neurocognitive functioning over the course of trauma-focused psychotherapy for PTSD: Changes in verbal memory and executive functioning

OBJECTIVES

Individuals with post-traumatic stress disorder (PTSD) have neurocognitive deficits in verbal memory and executive functioning. In this study, we examined whether memory and executive functioning changed over the course of treatment and which clinical variables were associated with change.

DESIGN

Neuropsychological assessments were administered at baseline and endpoint of a randomized controlled trial as secondary outcome.

METHODS

Trauma survivors (n = 88) diagnosed with PTSD received trauma-focused psychotherapy within a 17-week randomized controlled trial. Neuropsychological tests were the California Verbal Learning Test, Rivermead Behavioural Memory Test, Stroop Color Word Test, and Trail Making Test.

RESULTS

Significant, small- to medium-sized improvements in verbal memory, information processing speed, and executive functioning were found after trauma-focused psychotherapy (Cohen's d 0.16-0.68). Greater PTSD symptom decrease was significantly related to better post-treatment neurocognitive performance (all p < .005). Patients with comorbid depression improved more than patients with PTSD alone on interference tasks (p < .01). No differences emerged between treatment conditions and between patients on serotonergic antidepressants and those who were not.

CONCLUSIONS

This study suggests that neurocognitive deficits in PTSD can improve over the course of trauma-focused psychotherapy and are therefore at least partly reversible. Improvements over treatment are in line with previous neuropsychological and neuroimaging studies and effect sizes exceed those of practice effects. Future research should determine whether these changes translate into improved functioning in the daily lives of the patients.

PRACTITIONER POINTS

Patients with PTSD have difficulties performing verbal memory tasks (e.g., remembering a grocery list, recall of a story) and executive functioning tasks (e.g., shifting attention between two tasks, ignoring irrelevant information to complete a task). Verbal memory, information processing speed, and executive functioning significantly improved in patients with post-traumatic stress disorder over the course of trauma-focused psychotherapy. Improvements were equal in size for two different trauma-focused psychotherapies (Eye movement desensitization and reprocessing therapy and brief eclectic psychotherapy for PTSD). Medium-sized effects were found for recall of a story, whereas effects in other aspects of verbal memory, information processing speed, and executive functioning were small-sized. No causal attributions can be made because we could not include a control group without treatment for ethical reasons. Findings may be more reflective of patients who completed treatment than patients who prematurely dropped out as completers were overrepresented in our sample.

Hippocampal gray matter increases following multimodal psychological treatment for combat-related post-traumatic stress disorder

INTRODUCTION

Smaller hippocampal volumes are one of the most consistent findings in neuroimaging studies of post-traumatic stress disorder (PTSD). However, very few prospective studies have assessed changes in hippocampal gray matter prior to and following therapy for PTSD, and no neuroimaging studies to date have longitudinally assessed military populations.

METHODS

A pilot study was conducted, assessing patients with combat-related PTSD with structural MRI. Participants were then assigned either to a treatment group or waiting-list control group. After the treatment group received multimodal psychological therapy for approximately 6 weeks, both groups completed a second neuroimaging assessment.

RESULTS

Region-of-interest analysis was used to measure gray matter volume in the hippocampus and amygdala. There was a group by time interaction; the therapy group (n = 6) showed a significant increase in hippocampal volume and a nonsignificant trend toward an increase in amygdala volume following therapy, while no change was observed in the waiting-list group (n = 9).

CONCLUSIONS

This study provides initial evidence for increases in gray matter volume in the hippocampus in response to therapy for combat-related PTSD.

How Does Exercise Reduce the Rate of Age-Associated Cognitive Decline? A Review of Potential Mechanisms

The rate of age-associated cognitive decline varies considerably between individuals. It is important, both on a societal and individual level, to investigate factors that underlie these differences in order to identify those which might realistically slow cognitive decline. Physical activity is one such factor with substantial support in the literature. Regular exercise can positively influence cognitive ability, reduce the rate of cognitive aging, and even reduce the risk of Alzheimer's disease (AD) and other dementias. However, while there is substantial evidence in the extant literature for the effect of exercise on cognition, the processes that mediate this relationship are less clear. This review examines cardiovascular health, production of brain derived neurotrophic factor (BDNF), insulin sensitivity, stress, and inflammation as potential pathways, via which exercise may maintain or improve cognitive functioning, and may be particularly pertinent in the context of the aging brain. A greater understanding of these mechanisms and their potential relationships with exercise and cognition will be invaluable in providing biomarkers for investigating the efficacy of differing exercise regimes on cognitive outcomes.

Effect of cyclooxygenase‑2 inhibition on the development of post‑traumatic stress disorder in rats

Post‑traumatic stress disorder (PTSD) is characterized by re‑experiencing of a traumatic event, avoidance of trauma‑associated stimulation, general changes in mood and cognition, and hyper arousal symptoms. Cyclooxygenase is involved in the production of prostaglandins and thromboxanes, and its inducible form cyclooxygenase‑2(COX‑2), an important mediator of cell injury in inflammation, is primarily expressed in leukocytes and brain cells. The present study investigated the expression of COX‑2 in the hippocampi of rats with PTSD and evaluated the effect of COX‑2 inhibition on PTSD. Adult male Wistar rats were randomly divided into three groups: Control (n=20), PTSD (n=20) and intervention group (PTSD+COX‑2 inhibitor treatment, n=20). The expression of COX‑2 was detected by immunohistochemistry, reverse transcription‑quantitative polymerase chain reaction and western blotting. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling staining was used to observe the apoptosis of rat hippocampal neurons. Tumor necrosis factor α (TNF‑α), interleukin (IL)‑6 and prostaglandin E2 (PGE2) levels were analyzed by ELISA. Nitric oxide (NO) was detected using the Griess test. The behavioral and cognitive function of rats in the PTSD group was significantly decreased compared with the control group, while the behavioral and cognitive function of rats in the intervention group were improved. The COX‑2 mRNA and protein expression levels in hippocampi of rats in the PTSD group were higher than in the control and intervention group. The apoptosis of hippocampus in rats with PTSD was significantly increased compared with the control group and following treatment with COX‑2 inhibitor, apoptosis was decreased. In addition, compared with the control group and intervention group, the levels of TNF‑α, IL‑6, PGE2 and NO in hippocampi of rats were increased in the PTSD group. The present study indicated that COX‑2 may be involved in the pathogenesis of PTSD, and inhibition of its expression serves a neuroprotective role in hippocampi of PTSD rats.

Test-retest reliability and longitudinal analysis of automated hippocampal subregion volumes in healthy ageing and Alzheimer's disease populations

The hippocampal formation is a complex brain structure that is important in cognitive processes such as memory, mood, reward processing and other executive functions. Histological and neuroimaging studies have implicated the hippocampal region in neuropsychiatric disorders as well as in neurodegenerative diseases. This highly plastic limbic region is made up of several subregions that are believed to have different functional roles. Therefore, there is a growing interest in imaging the subregions of the hippocampal formation rather than modelling the hippocampus as a homogenous structure, driving the development of new automated analysis tools. Consequently, there is a pressing need to understand the stability of the measures derived from these new techniques. In this study, an automated hippocampal subregion segmentation pipeline, released as a developmental version of Freesurfer (v6.0), was applied to T1-weighted magnetic resonance imaging (MRI) scans of 22 healthy older participants, scanned on 3 separate occasions and a separate longitudinal dataset of 40 Alzheimer's disease (AD) patients. Test-retest reliability of hippocampal subregion volumes was assessed using the intra-class correlation coefficient (ICC), percentage volume difference and percentage volume overlap (Dice). Sensitivity of the regional estimates to longitudinal change was estimated using linear mixed effects (LME) modelling. The results show that out of the 24 hippocampal subregions, 20 had ICC scores of 0.9 or higher in both samples; these regions include the molecular layer, granule cell layer of the dentate gyrus, CA1, CA3 and the subiculum (ICC > 0.9), whilst the hippocampal fissure and fimbria had lower ICC scores (0.73-0.88). Furthermore, LME analysis of the independent AD dataset demonstrated sensitivity to group and individual differences in the rate of volume change over time in several hippocampal subregions (CA1, molecular layer, CA3, hippocampal tail, fissure and presubiculum). These results indicate that this automated segmentation method provides a robust method with which to measure hippocampal subregions, and may be useful in tracking disease progression and measuring the effects of pharmacological intervention.

Preliminary Evidence for the Impact of Combat Experiences on Gray Matter Volume of the Posterior Insula

Background: Combat-exposed veteran populations are at an increased risk for developing cardiovascular disease. The anterior cingulate cortex (ACC) and insula have been implicated in both autonomic arousal to emotional stressors and homeostatic processes, which may contribute to cardiovascular dysfunction in combat veteran populations. The aim of the present study was to explore the intersecting relationships of combat experiences, rostral ACC and posterior insula volume, and cardiovascular health in a sample of combat veterans.

Method: Twenty-four male combat veterans completed clinical assessment of combat experiences and posttraumatic stress symptoms. Subjects completed a magnetic resonance imaging scan and autosegmentation using FreeSurfer was used to estimate regional gray matter volume (controlling for total gray matter volume) of the rostral ACC and posterior insula. Flow-mediated dilation (FMD) was conducted to assess cardiovascular health. Theil-sen robust regressions and Welch's analysis of variance were used to examine relationships of combat experiences and PTSD symptomology with (1) FMD and (2) regional gray matter volume.

Results: Increased combat experiences, deployment duration, and multiple deployments were related to smaller posterior insula volume. Combat experiences were marginally associated with poorer cardiovascular health. However, cardiovascular health was not related to rostral ACC or posterior insula volume.

Conclusion: The present study provides initial evidence for the relationships of combat experiences, deployment duration, and multiple deployments with smaller posterior insula volume. Results may suggest that veterans with increased combat experiences may exhibit more dysfunction regulating the autonomic nervous system, a key function of the posterior insula. However, the relationship between combat and cardiovascular health was not mediated by regional brain volume. Future research is warranted to further clarify the cardiovascular or functional impact of smaller posterior insula volume in combat veterans.

Enhancing Plasticity of the Central Nervous System: Drugs, Stem Cell Therapy, and Neuro-Implants

Stroke represents the first cause of adult acquired disability. Spontaneous recovery, dependent on endogenous neurogenesis, allows for limited recovery in 50% of patients who remain functionally dependent despite physiotherapy. Here, we propose a review of novel drug therapies with strong potential in the clinic. We will also discuss new avenues of stem cell therapy in patients with a cerebral lesion. A promising future for the development of efficient drugs to enhance functional recovery after stroke seems evident. These drugs will have to prove their efficacy also in severely affected patients. The efficacy of stem cell engraftment has been demonstrated but will have to prove its potential in restoring tissue function for the massive brain lesions that are most debilitating. New answers may lay in biomaterials, a steadily growing field. Biomaterials should ideally resemble lesioned brain structures in architecture and must be proven to increase functional reconnections within host tissue before clinical testing.

Relationship of Hippocampal Volumes and Posttraumatic Stress Disorder Symptoms Over Early Posttrauma Periods

BACKGROUND

Smaller hippocampal volume is associated with more severe posttraumatic stress disorder (PTSD) symptoms years after traumatic experiences. Posttraumatic stress symptoms appear early following trauma, but the relationship between hippocampal volume and PTSD symptom severity during early posttrauma periods is not well understood. It is possible that the inverse relationship between hippocampal volume and PTSD symptom severity is already present soon after trauma. To test this possibility, we prospectively examined the association between hippocampal volumes and severity of PTSD symptoms within weeks to months after trauma due to a motor vehicle collision.

METHODS

Structural magnetic resonance imaging scans of 44 survivors were collected about 2 weeks and again at 3 months after a motor vehicle collision to measure hippocampal volumes. The PTSD Checklist was used to evaluate PTSD symptoms at each scan time. Full (n = 5) or partial (n = 6) PTSD was evaluated using the Clinician-Administered PTSD Scale at 3 months.

RESULTS

Left hippocampal volumes at both time points negatively correlated with PTSD Checklist scores, and with subscores for re-experiencing symptoms at 3 months. Left hippocampal volumes at 3 months also negatively correlated with hyperarousal symptoms at 3 months. Finally, neither left nor right hippocampal volumes significantly changed between 2 weeks and 3 months posttrauma.

CONCLUSIONS

The results suggest that small hippocampal volume at early posttrauma weeks is associated with increased risk for PTSD development. Furthermore, the inverse relationship between hippocampal volume and PTSD symptoms at 3 months did not arise from posttrauma shifts in hippocampal volume between 2 weeks and 3 months after trauma.

Differential Effects of the Factor Structure of the Wechsler Memory Scale-Revised on the Cortical Thickness and Complexity of Patients Aged Over 75 Years in a Memory Clinic Setting

The Wechsler Memory Scale-Revised (WMS-R) is one of the internationally well-known batteries for memory assessment in a general memory clinic setting. Several factor structures of the WMS-R for patients aged under 74 have been proposed. However, little is known about the factor structure of the WMS-R for patients aged over 75 years and its neurological significance. Thus, we conducted exploratory factor analysis to determine the factor structure of the WMS-R for patients aged over 75 years in a memory clinic setting. Regional cerebral blood flow (rCBF) was calculated from single-photon emission computed tomography data. Cortical thickness and cortical fractal dimension, as the marker of cortical complexity, were calculated from high resolution magnetic resonance imaging data. We found that the four factors appeared to be the most appropriate solution to the model, including recognition memory, paired associate memory, visual-and-working memory, and attention as factors. Patients with mild cognitive impairments showed significantly higher factor scores for paired associate memory, visual-and-working memory, and attention than patients with Alzheimer's disease. Regarding the neuroimaging data, the factor scores for paired associate memory positively correlated with rCBF in the left pericallosal and hippocampal regions. Moreover, the factor score for paired associate memory showed most robust correlations with the cortical thickness in the limbic system, whereas the factor score for attention correlated with the cortical thickness in the bilateral precuneus. Furthermore, each factor score correlated with the cortical fractal dimension in the bilateral frontotemporal regions. Interestingly, the factor scores for the visual-and-working memory and attention selectively correlated with the cortical fractal dimension in the right posterior cingulate cortex and right precuneus cortex, respectively. These findings demonstrate that recognition memory, paired associate memory, visual-and-working memory, and attention can be crucial factors for interpreting the WMS-R results of elderly patients aged over 75 years in a memory clinic setting. Considering these findings, the results of WMS-R in elderly patients aged over 75 years in a memory clinic setting should be cautiously interpreted.

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.

Better Sleep in a Strange Bed? Sleep Quality in South African Women with Posttraumatic Stress Disorder

Although individuals diagnosed with posttraumatic stress disorder (PTSD) regularly report subjective sleep disruption, many studies using objective measures (e.g., polysomnography) report no PTSD-related sleep disruption. To account for these inconsistencies, some authors hypothesize that PTSD-diagnosed individuals have sleep-state misperception; that is, they self-report experiencing poor sleep quality, but objectively sleep relatively normally. We tested this sleep-state misperception hypothesis, collecting data on subjectively-reported sleep quality (in the home, and in the laboratory) and on objectively-measured, laboratory-based, sleep quality in PTSD-diagnosed participants from low socioeconomic status South African communities. Women with PTSD (n = 21), with trauma exposure but no PTSD (TE; n = 19), and healthy controls (HC; n = 20) completed questionnaires on their average sleep quality in the past 30 days, and on their sleep quality after a night (8 h) of polysomnographic-monitored sleep in the laboratory. PTSD-diagnosed individuals reported poorer everyday subjective sleep quality than TE and HC individuals. In the laboratory, however, there were no between-group differences in subjective sleep quality, and few between-group differences in objective sleep quality (PTSD-diagnosed individuals only had decreased sleep depth). Furthermore, whereas measures of laboratory-based objective and subjective sleep quality correlated significantly, especially in PTSD-diagnosed individuals, there were few significant associations between objective sleep measures and everyday subjective sleep quality. Taken together, these findings suggest that PTSD-diagnosed individuals likely experienced better sleep quality in the laboratory than at home. Descriptive observations corroborated this interpretation, with almost half the sample rating their laboratory sleep (which they described as “safe” and “quiet”) as better than their home sleep (which was experienced in an atmosphere marked by high levels of violence and nighttime noise). These findings disconfirm the sleep-state misperception hypothesis as related to PTSD, and suggest that the laboratory environment may influence sleep quality positively in these individuals. Many investigations of sleep in PTSD do not consider the influence of the laboratory environment. Our findings suggest that future studies in this field should consider that sleep-state misperception may be an artifact of the laboratory setting, especially when samples are drawn from communities where violence and crime are an everyday reality.

Grey matter density changes of structures involved in Posttraumatic Stress Disorder (PTSD) after recovery following Eye Movement Desensitization and Reprocessing (EMDR) therapy

Recovery of stress-induced structural alterations in Posttraumatic Stress Disorder (PTSD) remains largely unexplored. This study aimed to determine whether symptoms improvement is associated with grey matter (GM) density changes of brain structures involved in PTSD. Two groups of PTSD patients were involved in this study. The first group was treated with Eye Movement Desensitization and Reprocessing (EMDR) therapy and recovered from their symptoms (recovery group) (n = 11); Patients were scanned prior to therapy (T1), one week (T2) and five months after the end of therapy (T3). The second group included patients which followed a supportive therapy and remained symptomatic (wait-list group) (n = 7). They were scanned at three time-steps mimicking the same inter-scan intervals. Voxel-based morphometry (VBM) was used to characterize GM density evolution. GM density values showed a significant group-by-time interaction effect between T1 and T3 in prefrontal cortex areas. These interaction effects were driven by a GM density increase in the recovery group with respect to the wait-list group. Symptoms removal goes hand-in-hand with GM density enhancement of structures involved in emotional regulation.

Synaptic Loss and the Pathophysiology of PTSD: Implications for Ketamine as a Prototype Novel Therapeutic

PURPOSE OF REVIEW

Studies of the neurobiology and treatment of PTSD have highlighted many aspects of the pathophysiology of this disorder that might be relevant to treatment. The purpose of this review is to highlight the potential clinical importance of an often-neglected consequence of stress models in animals that may be relevant to PTSD: the stress-related loss of synaptic connectivity.

RECENT FINDINGS

Here, we will briefly review evidence that PTSD might be a "synaptic disconnection syndrome" and highlight the importance of this perspective for the emerging therapeutic application of ketamine as a potential rapid-acting treatment for this disorder that may work, in part, by restoring synaptic connectivity. Synaptic disconnection may contribute to the profile of PTSD symptoms that may be targeted by novel pharmacotherapeutics.

Oxidative stress and brain morphology in individuals with depression, anxiety and healthy controls

Oxidative stress is a biological process, caused by an imbalance between reactive oxygen species (ROS) and antioxidants, in favour of the ROS. This imbalance leads to oxidative damage to lipids, proteins and DNA and ultimately cell death. Studies in rodents have shown that the brain, particularly the amygdala and hippocampus, is sensitive to oxidative stress, although studies on the association between oxidative stress and brain morphology in humans are lacking. Oxidative stress has also been associated with major depressive disorder (MDD) and may be related to volumetric abnormalities in the amygdala and hippocampus in MDD and anxiety disorders. In this study we aimed to examine the association between two robust measures of oxidative damage in plasma (8-OHdG and F2-isoprostanes) and volume of the hippocampus and amygdala in a large sample of individuals with and without MDD and/or anxiety (N=297). In secondary analyses, we examine whether this association is similar in patients and controls. 8-OHdG and F2-isoprostanes plasma levels were determined using liquid chromatography tandem mass spectrometry and volume of the hippocampus and amygdala and hippocampal subfields was determined using Freesurfer. We found no association between plasma markers (or interaction with MDD and/or anxiety disorder diagnosis) and subcortical volume, suggesting that peripheral oxidative stress damage is not associated with subcortical brain volume.

Serotonin and neuroplasticity - Links between molecular, functional and structural pathophysiology in depression

Serotonin modulates neuroplasticity, especially during early life, and dysfunctions in both systems likewise contribute to pathophysiology of depression. Recent findings demonstrate that serotonin reuptake inhibitors trigger reactivation of juvenile-like neuroplasticity. How these findings translate to clinical antidepressant treatment in major depressive disorder remains unclear. With this review, we link preclinical with clinical work on serotonin and neuroplasticity to bring two pathophysiologic models in clinical depression closer together. Dysfunctional developmental plasticity impacts on later-life cognitive and emotional functions, changes of synaptic serotonin levels and receptor levels are coupled with altered synaptic plasticity and neurogenesis. Structural magnetic resonance imaging in patients reveals disease-state-specific reductions of gray matter, a marker of neuroplasticity, and reversibility upon selective serotonin reuptake inhibitor treatment. Translational evidence from magnetic resonance imaging in animals support that reduced densities and sizes of neurons and reduced hippocampal volumes in depressive patients could be attributable to changes of serotonergic neuroplasticity. Since ketamine, physical exercise or learning enhance neuroplasticity, combinatory paradigms with selective serotonin reuptake inhibitors could enhance clinical treatment of depression.

Is Trauma Memory Special? Trauma Narrative Fragmentation in PTSD: Effects of Treatment and Response

Seminal theories posit that fragmented trauma memories are critical to posttraumatic stress disorder (PTSD; van der Kolk & Fisler, 1995; Brewin, 2014) and that elaboration of the trauma narrative is necessary for recovery (e.g., Foa, Huppert, & Cahill, 2006). According to fragmentation theories, trauma narrative changes, particularly for those receiving trauma-focused treatment, should accompany symptom reduction. Trauma and control narratives in 77 men and women with chronic PTSD were examined pre- and post-treatment, comparing prolonged exposure (PE) and sertraline. Utilizing self-report, rater coding, and objective coding of narrative content, fragmentation was compared across narrative types (trauma, negative, positive) by treatment modality and response, controlling for potential confounds. Although sensory components increased with PE (d = 0.23 - 0.44), there were no consistent differences in fragmentation from pre- to post-treatment between PE and sertraline or treatment responders and non-responders. Contrary to theories, changes in fragmentation may not be a crucial mechanism underlying PTSD therapeutic recovery.

Childhood adversity impacts on brain subcortical structures relevant to depression

Childhood adversity plays an important role for development of major depressive disorder (MDD). There are differences in subcortical brain structures between patients with MDD and healthy controls, but the specific impact of childhood adversity on such structures in MDD remains unclear. Thus, aim of the present study was to investigate whether childhood adversity is associated with subcortical volumes and how it interacts with a diagnosis of MDD and sex. Within the ENIGMA-MDD network, nine university partner sites, which assessed childhood adversity and magnetic resonance imaging in patients with MDD and controls, took part in the current joint mega-analysis. In this largest effort world-wide to identify subcortical brain structure differences related to childhood adversity, 3036 participants were analyzed for subcortical brain volumes using FreeSurfer. A significant interaction was evident between childhood adversity, MDD diagnosis, sex, and region. Increased exposure to childhood adversity was associated with smaller caudate volumes in females independent of MDD. All subcategories of childhood adversity were negatively associated with caudate volumes in females - in particular emotional neglect and physical neglect (independently from age, ICV, imaging site and MDD diagnosis). There was no interaction effect between childhood adversity and MDD diagnosis on subcortical brain volumes. Childhood adversity is one of the contributors to brain structural abnormalities. It is associated with subcortical brain abnormalities that are relevant to psychiatric disorders such as depression.

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.

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.

Dentate gyrus-cornu ammonis (CA) 4 volume is decreased and associated with depressive episodes and lipid peroxidation in bipolar II disorder: Longitudinal and cross-sectional analyses

OBJECTIVES

Reduced dentate gyrus volume and increased oxidative stress have emerged as potential pathophysiological mechanisms in bipolar disorder. However, the relationship between dentate gyrus volume and peripheral oxidative stress markers remains unknown. Here, we examined dentate gyrus-cornu ammonis (CA) 4 volume longitudinally in patients with bipolar II disorder (BD-II) and healthy controls and investigated whether BD-II is associated with elevated peripheral levels of oxidative stress.

METHODS

We acquired high-resolution structural 3T-magnetic resonance imaging (MRI) images and quantified hippocampal subfield volumes using an automated segmentation algorithm in individuals with BD-II (n=29) and controls (n=33). The participants were scanned twice, at study inclusion and on average 2.4 years later. In addition, we measured peripheral levels of two lipid peroxidation markers (4-hydroxy-2-nonenal [4-HNE] and lipid hydroperoxides [LPH]).

RESULTS

First, we demonstrated that the automated hippocampal subfield segmentation technique employed in this work reliably measured dentate gyrus-CA4 volume. Second, we found a decreased left dentate gyrus-CA4 volume in patients and that a larger number of depressive episodes between T1 and T2 predicted greater volume decline. Finally, we showed that 4-HNE was elevated in BD-II and that 4-HNE was negatively associated with left and right dentate gyrus-CA4 volumes in patients.

CONCLUSIONS

These results are consistent with a role for the dentate gyrus in the pathophysiology of bipolar disorder and suggest that depressive episodes and elevated oxidative stress might contribute to hippocampal volume decreases. In addition, these findings provide further support for the hypothesis that peripheral lipid peroxidation markers may reflect brain alterations in bipolar disorders.

High frequency stimulation of the infralimbic cortex induces morphological changes in rat hippocampal neurons

BACKGROUND

Although a significant subset of patients with major depressive disorder (MDD) fail to respond to medical or behavioural therapy, deep brain stimulation (DBS) applied to the subgenual cingulate cortex (SCC; sg25) has been shown to reduce depressive symptoms in a subset of patients. This area receives projections from neurons in the CA1 region and subiculum of the hippocampus (HC), a brain region implicated in the pathobiology and treatment of MDD.

OBJECTIVE

To assess whether high frequency stimulation (HFS) of the infralimbic cortex is associated with changes in cellular morphology in the HC.

METHODS

Rats were subjected to either infralimbic HFS or sham-stimulation. Measures of cellular morphology, including dendritic length and complexity, were assessed in pyramidal neurons in the CA1 region of the HC by means of the Golgi-Cox histological stain.

RESULTS

Dendritic length (p = 0.013) and number of branch points (p = 0.004) were significantly increased across the entire dendritic tree in animals subjected to HFS. Subsequent Scholl analysis revealed that for dendritic length these effects were localized to the region between 80 and 160 μm from the soma (p < 0.001 for either 40 μm interval) in the basal dendritic tree, while branch point number was predominantly increased between 120 and 160 μm from the soma (p < 0.001) in the apical dendritic tree.

CONCLUSIONS

High-frequency stimulation of the infralimbic cortex increases the complexity of apical dendrites and the length of basal dendritic trees of pyramidal neurons located in the CA1 hippocampal subfield relative to sham-stimulated animals.

Posttraumatic Stress Disorder: Overview of Evidence-Based Assessment and Treatment

Posttraumatic stress disorder (PTSD) is a chronic psychological disorder that can develop after exposure to a traumatic event. This review summarizes the literature on the epidemiology, assessment, and treatment of PTSD. We provide a review of the characteristics of PTSD along with associated risk factors, and describe brief, evidence-based measures that can be used to screen for PTSD and monitor symptom changes over time. In regard to treatment, we highlight commonly used, evidence-based psychotherapies and pharmacotherapies for PTSD. Among psychotherapeutic approaches, evidence-based approaches include cognitive-behavioral therapies (e.g., Prolonged Exposure and Cognitive Processing Therapy) and Eye Movement Desensitization and Reprocessing. A wide variety of pharmacotherapies have received some level of research support for PTSD symptom alleviation, although selective serotonin reuptake inhibitors have the largest evidence base to date. However, relapse may occur after the discontinuation of pharmacotherapy, whereas PTSD symptoms typically remain stable or continue to improve after completion of evidence-based psychotherapy. After reviewing treatment recommendations, we conclude by describing critical areas for future research.

Deficient fear extinction memory in posttraumatic stress disorder

BACKGROUND

Posttraumatic stress disorder (PTSD) might be maintained by deficient extinction memory. We used a cued fear conditioning design with extinction and a post-extinction phase to provoke the return of fear and examined the role of the interplay of amygdala, hippocampus and prefrontal regions.

METHODS

We compared 18 PTSD patients with two healthy control groups: 18 trauma-exposed subjects without PTSD (nonPTSD) and 18 healthy controls (HC) without trauma experience. They underwent a three-day ABC-conditioning procedure in a functional magnetic resonance imaging scanner. Two geometric shapes that served as conditioned stimuli (CS) were presented in the context of virtual reality scenes. Electric painful stimuli were delivered after one of the two shapes (CS+) during acquisition (in context A), while the other (CS-) was never paired with pain. Extinction was performed in context B and extinction memory was tested in a novel context C.

RESULTS

The PTSD patients showed significantly higher differential skin conductance responses than the non-PTSD and HC and higher differential amygdala and hippocampus activity than the HC in context C. In addition, elevated arousal to the CS+ during extinction and to the CS- throughout the experiment was present in the PTSD patients but self-reported differential valence or contingency were not different. During extinction recall, differential amygdala activity correlated positively with the intensity of numbing and ventromedial prefrontal cortex activity correlated positively with behavioral avoidance.

CONCLUSIONS

PTSD patients show heightened return of fear in neural and peripheral measures. In addition, self-reported arousal was high to both danger (CS+) and safety (CS-) cues. These results suggest that a deficient maintenance of extinction and a failure to identify safety signals might contribute to PTSD symptoms, whereas non-PTSD subjects seem to show normal responses.

Greater hippocampal volume is associated with PTSD treatment response

Previous research associates smaller hippocampal volume with posttraumatic stress disorder (PTSD). It is unclear, however, whether treatment affects hippocampal volume or vice versa. Seventy-six subjects, 40 PTSD patients and 36 matched trauma-exposed healthy resilient controls, underwent clinical assessments and magnetic resonance imaging (MRI) at baseline, and 10 weeks later, during which PTSD patients completed ten weeks of Prolonged Exposure (PE) treatment. The resilient controls and treatment responders (n=23) had greater baseline hippocampal volume than treatment non-responders (n=17) (p=0.012 and p=0.050, respectively), perhaps due to more robust fear-extinction capacity in both the initial phase after exposure to trauma and during treatment.

The brain on stress: Insight from studies using the Visible Burrow System

The discovery of adrenal steroid receptors outside of the hypothalamus in the hippocampus and other forebrain regions catalyzed research on the effects of stress upon cognitive function, emotions and self-regulatory behaviors as well as the molecular, cellular and neuroanatomical mechanisms underlying acute and chronic stress effects on the brain. Indeed, this work has shown that the brain is a plastic and vulnerable organ in the face of acute and chronic stress. The insight that Bob and Caroline Blanchard had in developing and interpreting findings using the Visible Burrow System model made an enormous contribution to the current view that the human brain is very sensitive to the social environment and to agonistic interactions between individuals. Their collaboration with Sakai and McEwen at The Rockefeller University extended application of the Visible Burrow System model to demonstrate that it also was a unique and highly relevant neuroethological model with which to study stress and adaptation to stressors. Those studies focused on the brain and systemic organ responses to stress and, in turn, described that the brain is also very responsive to changes in systemic physiology.

Genetic and environmental modulation of neurodevelopmental disorders: Translational insights from labs to beds

Neurodevelopmental disorders (NDDs) are a heterogeneous group of prevalent neuropsychiatric illnesses with various degrees of social, cognitive, motor, language and affective deficits. NDDs are caused by aberrant brain development due to genetic and environmental perturbations. Common NDDs include autism spectrum disorder (ASD), intellectual disability, communication/speech disorders, motor/tic disorders and attention deficit hyperactivity disorder. Genetic and epigenetic/environmental factors play a key role in these NDDs with significant societal impact. Given the lack of their efficient therapies, it is important to gain further translational insights into the pathobiology of NDDs. To address these challenges, the International Stress and Behavior Society (ISBS) has established the Strategic Task Force on NDDs. Summarizing the Panel's findings, here we discuss the neurobiological mechanisms of selected common NDDs and a wider NDD+ spectrum of associated neuropsychiatric disorders with developmental trajectories. We also outline the utility of existing preclinical (animal) models for building translational and cross-diagnostic bridges to improve our understanding of various NDDs.

Antidepressant Use in the Elderly Is Associated With an Increased Risk of Dementia

A retrospective cohort study was conducted including 3688 patients age 60 years or older without dementia enrolled in a depression screening study in primary care clinics. Information on antidepressant use and incident dementia during follow-up was retrieved from electronic medical records. The Cox proportional hazard models were used to compare the risk for incident dementia among 5 participant groups: selective serotonin re-uptake inhibitors (SSRI) only, non-SSRI only (non-SSRI), mixed group of SSRI and non-SSRI, not on antidepressants but depressed, and not on antidepressants and not depressed. SSRI and non-SSRI users had significantly higher dementia risk than the nondepressed nonusers (hazard ratio [HR]=1.83, P=0.0025 for SSRI users and HR=1.50, P=0.004 for non-SSRI users). In addition, SSRIs users had significantly higher dementia risk than non-users with severe depression (HR=2.26, P=0.0005). Future research is needed to confirm our results in other populations and to explore potential mechanism underlying the observed association.

Propranolol's impact on cognitive performance in post-traumatic stress disorder

BACKGROUND

Propranolol has effectively diminished fear-based emotional memories in posttraumatic stress disorder (PTSD) and this effect has been attributed to traumatic memory reconsolidation blockade. However, propranolol may also exert cognitive effects by modulating stress and arousal.

METHOD

Within a randomized double-blind placebo controlled trial, propranolol's impact on cognitive functioning was examined in individuals who were diagnosed with chronic PTSD. Participants received a single dose of 1mg/kg of propranolol (n=20) or placebo (n=21), and completed subtests of the Wechsler Adult Intelligence Scale third edition (WAIS-III). PTSD symptoms were assessed 1 week before and after treatment by the Impact of Event Scale Revised (IES-R).

RESULTS

The propranolol group performed significantly better on the Processing Speed composite measure compared to the placebo group. Furthermore, greater heart rate decreases were associated with higher Perceptual Organization performance, within the propranolol group.

LIMITATIONS

The generalizability of results may have been reduced as participants were treatment seeking; the sample size was small and included a greater proportion of females.This study could not assess whether pre-existing psychological function influenced cognitive performance, post-trauma. Future studies might consider including a non-PTSD control group to determine if our findings are specific to propranolol's effect on PTSD associated cognitive impairment.

CONCLUSIONS

Our preliminary results demonstrated that cognitive functioning improved following propranolol administration in PTSD patients. The implications are discussed with regards to the processing of traumatic events.

Changes in temporal attention inhibition following prolonged exposure and sertraline in the treatment of PTSD

OBJECTIVE

Attentional inhibitory deficits expressed as difficulty ignoring irrelevant stimuli in the pursuit of goal-directed behavior may serve as a fundamental mechanism of posttraumatic stress disorder (PTSD). Evidence of inhibitory processes as central to extinction suggests that exposure-based treatments may act more directly on the inhibitory deficits implicated in PTSD, whereas, in facilitating serotonergic neurotransmission, selective serotonin reuptake inhibitors (SSRIs) may be less direct and bring about general neurochemical changes in the fear circuitry. If these inhibitory deficits underlie PTSD, then inhibition should improve with successful treatment, with those treated with prolonged exposure (PE) potentially resulting in greater changes in inhibition than those treated with sertraline.

METHOD

Changes in temporal attentional inhibition, using an attentional blink (AB) paradigm, were examined at pre- and posttreatment in 49 individuals (74.5% female, 66.7% Caucasian, age M = 37.69, SD = 12.8 years) with chronic PTSD. Participants completed 10 weeks of either PE or sertraline.

RESULTS

Individuals who made greater improvements with PE showed faster improvements in temporal inhibition on the critical inhibitory lag of AB than those who made greater improvements with sertraline (d = 0.94). These changes could not be accounted for by basic attention.

CONCLUSIONS

Greater improvement in fundamental attentional inhibitory processes with better treatment response to PE, compared with sertraline, suggests potential specificity in how PTSD treatments normalize inhibitory processes, such that exposure-based treatments like PE may target inhibitory processes and improve basic inhibitory functioning.

White Matter Hyperintensity Accumulation During Treatment of Late-Life Depression

White matter hyperintensities (WMHs) have been shown to be associated with the development of late-life depression (LLD) and eventual treatment outcomes. This study sought to investigate longitudinal WMH changes in patients with LLD during a 12-week antidepressant treatment course. Forty-seven depressed elderly patients were included in this analysis. All depressed subjects started pharmacological treatment for depression shortly after a baseline magnetic resonance imaging (MRI) scan. At 12 weeks, patients underwent a follow-up MRI scan, and were categorized as either treatment remitters (n=23) or non-remitters (n=24). Among all patients, there was as a significant increase in WMHs over 12 weeks (t(46)=2.36, P=0.02). When patients were stratified by remission status, non-remitters demonstrated a significant increase in WMHs (t(23)=2.17, P=0.04), but this was not observed in remitters (t(22)=1.09, P=0.29). Other markers of brain integrity were also investigated including whole brain gray matter volume, hippocampal volume, and fractional anisotropy. No significant differences were observed in any of these markers during treatment, including when patients were stratified based on remission status. These results add to existing literature showing the association between WMH accumulation and LLD treatment outcomes. Moreover, this is the first study to demonstrate similar findings over a short interval (ie 12 weeks), which corresponds to the typical length of an antidepressant trial. These findings serve to highlight the acute interplay of cerebrovascular ischemic disease and LLD.

Smaller hippocampal volume as a vulnerability factor for the persistence of post-traumatic stress disorder

BACKGROUND

Smaller hippocampal volume has often been observed in patients with post-traumatic stress disorder (PTSD). However, there is no consensus whether this is a result of stress/trauma exposure, or constitutes a vulnerability factor for the development of PTSD. Second, it is unclear whether hippocampal volume normalizes with successful treatment of PTSD, or whether a smaller hippocampus is a risk factor for the persistence of PTSD.

METHOD

Magnetic resonance imaging (MRI) scans and clinical interviews were collected from 47 war veterans with PTSD, 25 healthy war veterans (combat controls) and 25 healthy non-military controls. All veterans were scanned a second time with a 6- to 8-month interval, during which PTSD patients received trauma-focused therapy. Based on post-treatment PTSD symptoms, patients were divided into a PTSD group who was in remission (n = 22) and a group in whom PTSD symptoms persisted (n = 22). MRI data were analysed with Freesurfer.

RESULTS

Smaller left hippocampal volume was observed in PTSD patients compared with both control groups. Hippocampal volume of the combat controls did not differ from healthy controls. Second, pre- and post-treatment analyses of the PTSD patients and combat controls revealed reduced (left) hippocampal volume only in the persistent patients at both time points. Importantly, hippocampal volume did not change with treatment.

CONCLUSIONS

Our findings suggest that a smaller (left) hippocampus is not the result of stress/trauma exposure. Furthermore, hippocampal volume does not increase with successful treatment. Instead, we demonstrate for the first time that a smaller (left) hippocampus constitutes a risk factor for the persistence of PTSD.

Epigenetic mechanisms underlying the role of brain-derived neurotrophic factor in depression and response to antidepressants

Major depressive disorder (MDD) is a devastating neuropsychiatric disorder encompassing a wide range of cognitive and emotional dysfunctions. The prevalence of MDD is expected to continue its growth to become the second leading cause of disease burden (after HIV) by 2030. Despite an extensive research effort, the exact etiology of MDD remains elusive and the diagnostics uncertain. Moreover, a marked inter-individual variability is observed in the vulnerability to develop depression, as well as in response to antidepressant treatment, for nearly 50% of patients. Although a genetic component accounts for some cases of MDD, it is now clearly established that MDD results from strong gene and environment interactions. Such interactions could be mediated by epigenetic mechanisms, defined as chromatin and DNA modifications that alter gene expression without changing the DNA structure itself. Some epigenetic mechanisms have recently emerged as particularly relevant molecular substrates, promoting vulnerability or resilience to the development of depressive-like symptoms. Although the role of brain-derived neurotrophic factor (BDNF) in the pathophysiology of MDD remains unclear, its modulation of the efficacy of antidepressants is clearly established. Therefore, in this review, we focus on the epigenetic mechanisms regulating the expression of BDNF in humans and in animal models of depression, and discuss their role in individual differences in vulnerability to depression and response to antidepressant drugs.

Fluoxetine-induced regulation of heat shock protein 90 and 14-3-3ε in human embryonic carcinoma cells

Fluoxetine, a serotonin-selective reuptake inhibitor, exerts antidepressant and antianxiety effects on major depressive and anxiety disorders. Previous studies suggest that treatment with fluoxetine influences the expression of various proteins that are involved in proliferation, differentiation, and apoptosis in the neuronal cells of the brain. However, many aspects of the molecular pathways that modulate antidepressant action are not well understood. Here, with the aim of identifying proteins involved in antidepressant action, we examined the protein expression profile of human embryonic carcinoma (NCCIT) cells in response to fluoxetine treatment using proteomic techniques such as two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). We found several upregulated and downregulated proteins in fluoxetine-treated NCCIT cells, and then biochemically confirmed the increased expression of heat shock protein 90 and 14-3-3ε, which play an essential role in many cellular mechanisms including cell cycle control and other signaling pathways. Our data suggest that the regulated expression of heat shock protein 90, 14-3-3ε, and other identified proteins may be associated with the therapeutic action of fluoxetine.

Resting-State Functional Connectivity in Patients with Long-Term Remission of Cushing's Disease

Glucocorticoid disturbance can be a cause of psychiatric symptoms. Cushing's disease represents a unique model for examining the effects of prolonged exposure to high levels of endogenous cortisol on the human brain as well as for examining the relation between these effects and psychiatric symptomatology. This study aimed to investigate resting-state functional connectivity (RSFC) of the limbic network, the default mode network (DMN), and the executive control network in patients with long-term remission of Cushing's disease. RSFC of these three networks of interest was compared between patients in remission of Cushing's disease (n=24; 4 male, mean age=44.96 years) and matched healthy controls (n=24; 4 male, mean age=46.5 years), using probabilistic independent component analysis to extract the networks and a dual regression method to compare both groups. Psychological and cognitive functioning was assessed with validated questionnaires and interviews. In comparison with controls, patients with remission of Cushing's disease showed an increased RSFC between the limbic network and the subgenual subregion of the anterior cingulate cortex (ACC) as well as an increased RSFC of the DMN in the left lateral occipital cortex. However, these findings were not associated with psychiatric symptoms in the patient group. Our data indicate that previous exposure to hypercortisolism is related to persisting changes in brain function.