Exposure-based therapy changes amygdala and hippocampus resting-state functional connectivity in patients with posttraumatic stress disorder

Structural covariance, topological organization, and volumetric features of amygdala subnuclei in posttraumatic stress disorder

The amygdala is divided into functional subnuclei which have been challenging to investigate due to functional magnetic resonance imaging (MRI) limitations in mapping small neural structures. Hence their role in the neurobiology of posttraumatic stress disorder (PTSD) remains poorly understood. Examination of covariance of structural MRI measures could be an alternate approach to circumvent this issue. T1-weighted anatomical scans from a 3 T scanner from non-trauma-exposed controls (NEC; n = 71, 75 % female) and PTSD participants (n = 67, 69 % female) were parcellated into 105 brain regions. Pearson's r partial correlations were computed for three and nine bilateral amygdala subnuclei and every other brain region, corrected for age, sex, and total brain volume. Pairwise correlation comparisons were performed to examine subnuclei covariance profiles between-groups. Graph theory was employed to investigate subnuclei network topology. Volumetric measures were compared to investigate structural changes. We found differences between amygdala subnuclei in covariance with the hippocampus for both groups, and additionally with temporal brain regions for the PTSD group. Network topology demonstrated the importance of the right basal nucleus in facilitating network communication only in PTSD. There were no between-group differences for any of the three structural metrics. These findings are in line with previous work that has failed to find structural differences for amygdala subnuclei between PTSD and controls. However, differences between amygdala subnuclei covariance profiles observed in our study highlight the need to investigate amygdala subnuclei functional connectivity in PTSD using higher field strength fMRI for better spatial resolution.

Clinical efficacy of deep transcranial magnetic stimulation (dTMS) in psychiatric and cognitive disorders: A systematic review

Deep transcranial magnetic stimulation (dTMS) has gained attention as an enhanced form of traditional TMS, targeting broader and deeper regions of the brain. However, a fulsome synthesis of dTMS efficacy across psychiatric and cognitive disorders using sham-controlled trials is lacking. We systematically reviewed 28 clinical trials comparing active dTMS to a sham/controlled condition to characterize dTMS efficacy across diverse psychiatric and cognitive disorders. A comprehensive search of APA PsycINFO, Cochrane, Embase, Medline, and PubMed databases was conducted. Predominant evidence supports dTMS efficacy in patients with obsessive-compulsive disorder (OCD; n = 2), substance use disorders (SUDs; n = 8), and in those experiencing depressive episodes with major depressive disorder (MDD) or bipolar disorder (BD; n = 6). However, the clinical efficacy of dTMS in psychiatric disorders characterized by hyperactivity or hyperarousal (i.e., attention-deficit/hyperactivity disorder, posttraumatic stress disorder, and schizophrenia) was heterogeneous. Common side effects included headaches and pain/discomfort, with rare but serious adverse events such as seizures and suicidal ideation/attempts. Risk of bias ratings indicated a collectively low risk according to the Grading of Recommendations, Assessment, Development, and Evaluations checklist (Meader et al., 2014). Literature suggests promise for dTMS as a beneficial alternative or add-on treatment for patients who do not respond well to traditional treatment, particularly for depressive episodes, OCD, and SUDs. Mixed evidence and limited clinical trials for other psychiatric and cognitive disorders suggest more extensive research is warranted. Future research should examine the durability of dTMS interventions and identify moderators of clinical efficacy.

Deep brain stimulation of the amygdala for treatment-resistant combat post-traumatic stress disorder: Long-term results

Deep brain stimulation (DBS) holds promise for neuropsychiatric conditions where imbalance in network activity contributes to symptoms. Treatment-resistant Combat post-traumatic stress disorder (TR-PTSD) is a highly morbid condition and 50% of PTSD sufferers fail to recover despite psychotherapy or pharmacotherapy. Reminder-triggered symptoms may arise from inadequate top-down ventromedial prefrontal cortex (vmPFC) control of amygdala reactivity. Here, we report long-term data on two TR-PTSD participants from an investigation utilizing high-frequency amygdala DBS. The two combat veterans were implanted bilaterally with quadripolar electrodes targeting the basolateral amygdala. Following a randomized staggered onset, patients received stimulation with adjustments based on PTSD symptom severity for four years while psychiatric and neuropsychiatric symptoms, neuropsychological performance, and electroencephalography were systematically monitored. Evaluation of vmPFC-Amygdala network engagement was assessed with 18FDG positron emission tomography (PET). CAPS-IV scores varied over time, but improved 55% from 119 at baseline to 53 at 4-year study endpoint in participant 1; and 44%, from 68 to 38 in participant 2. Thereafter, during 5 and 1.5 years of subsequent clinical care respectively, long-term bilateral amygdala DBS was associated with additional, clinically significant symptomatic and functional improvement. There were no serious stimulation-related adverse psychiatric, neuropsychiatric, neuropsychological, neurological, or neurosurgical effects. In one subject, symptomatic improvement was associated with an intensity-dependent reduction in amygdala theta frequency power. In our two participants, FDG-PET findings were inconclusive regarding the hypothesized mechanism of suppression of amygdala hyperactivity. Our findings encourage further research to confirm and extend our preliminary observations.

A conceptual framework for a neurophysiological basis of art therapy for PTSD

Post-traumatic stress disorder (PTSD) is a heterogeneous condition that affects many civilians and military service members. Lack of engagement, high dropout rate, and variable response to psychotherapy necessitates more compelling and accessible treatment options that are based on sound neuroscientific evidence-informed decision-making. Art therapy incorporates elements proven to be effective in psychotherapy, such as exposure, making it a potentially valuable treatment option. This conceptual paper aims to inform the neurophysiological rationale for the use of art therapy as a therapeutic approach for individuals with PTSD. A narrative synthesis was conducted using literature review of empirical research on the neurophysiological effects of art therapy, with supporting literature on neuroaesthetics and psychotherapies to identify art therapy factors most pertinent for PTSD. Findings were synthesized through a proposed framework based on the triple network model considering the network-based dysfunctions due to PTSD. Art therapy's active components, such as concretization and metaphor, active art engagement, emotion processing and regulation, perspective taking and reframing, and therapeutic alliance, may improve symptoms of PTSD and prompt adaptive brain functioning. Given the scarcity of rigorous studies on art therapy's effectiveness and mechanisms of alleviating PTSD symptoms, the suggested framework offers a neurophysiological rationale and a future research agenda to investigate the impact of art therapy as a therapeutic approach for individuals with PTSD.

Neuroimaging of posttraumatic stress disorder in adults and youth: progress over the last decade on three leading questions of the field

Almost three decades have passed since the first posttraumatic stress disorder (PTSD) neuroimaging study was published. Since then, the field of clinical neuroscience has made advancements in understanding the neural correlates of PTSD to create more efficacious treatment strategies. While gold-standard psychotherapy options are available, many patients do not respond to them, prematurely drop out, or never initiate treatment. Therefore, elucidating the neurobiological mechanisms that define the disorder can help guide clinician decision-making and develop individualized mechanisms-based treatment options. To this end, this narrative review highlights progress made in the last decade in adult and youth samples on three outstanding questions in PTSD research: (1) Which neural alterations serve as predisposing (pre-exposure) risk factors for PTSD development, and which are acquired (post-exposure) alterations? (2) Which neural alterations can predict treatment outcomes and define clinical improvement? and (3) Can neuroimaging measures be used to define brain-based biotypes of PTSD? While the studies highlighted in this review have made progress in answering the three questions, the field still has much to do before implementing these findings into clinical practice. Overall, to better answer these questions, we suggest that future neuroimaging studies of PTSD should (A) utilize prospective longitudinal designs, collecting brain measures before experiencing trauma and at multiple follow-up time points post-trauma, taking advantage of multi-site collaborations/consortiums; (B) collect two scans to explore changes in brain alterations from pre-to-post treatment and compare changes in neural activation between treatment groups, including longitudinal follow up assessments; and (C) replicate brain-based biotypes of PTSD. By synthesizing recent findings, this narrative review will pave the way for personalized treatment approaches grounded in neurobiological evidence.

Resting-state cortico-limbic functional connectivity pattern in panic disorder: Relationships with emotion regulation strategy use and symptom severity

Cognitive reappraisal is an effective emotion regulation strategy involving prefrontal cortex (PFC) control of the amygdala. Its aberrant functioning is closely associated with panic disorder (PD). However, the resting-state functional connectivity (rsFC) between the PFC, implicated in cognitive reappraisal, and the amygdala in PD has not been studied. Thus, this study aims to investigate the rsFC patterns and their association with cognitive reappraisal and PD. This study involved 51 participants, including 26 untreated patients with PD and 25 healthy controls (HC). We evaluated the habit of cognitive reappraisal assessment and the severity of PD using neuropsychological and clinical measures. Resting-state fMRI was utilized to evaluate the rsFC pattern between the PFC, engaged in cognitive reappraisal, and the amygdala. Mediation analysis was performed to explore the role of this rsFC in the relationship between cognitive reappraisal and PD severity. PD patients showed reduced rsFC between the PFC and the amygdala compared to HC. This weakened rsFC was associated with the severity of PD symptoms. Moreover, cognitive reappraisal was negatively correlated with PD severity, and mediation analysis indicated that the rsFC of the PFC-amygdala played a mediating role in this association. Abnormal PFC-amygdala rsFC may play a pivotal role in PD development and/or manifestation and mediate the association between cognitive reappraisal and PD severity, potentially serving as a clinical indicator for monitoring and intervention.

Intrusive Traumatic Re-Experiencing Domain: Functional Connectivity Feature Classification by the ENIGMA PTSD Consortium

Background

Intrusive traumatic re-experiencing domain (ITRED) was recently introduced as a novel perspective on posttraumatic psychopathology, proposing to focus research of posttraumatic stress disorder (PTSD) on the unique symptoms of intrusive and involuntary re-experiencing of the trauma, namely, intrusive memories, nightmares, and flashbacks. The aim of the present study was to explore ITRED from a neural network connectivity perspective.

Methods

Data were collected from 9 sites taking part in the ENIGMA (Enhancing Neuro Imaging Genetics through Meta Analysis) PTSD Consortium (n= 584) and included itemized PTSD symptom scores and resting-state functional connectivity (rsFC) data. We assessed the utility of rsFC in classifying PTSD, ITRED-only (no PTSD diagnosis), and trauma-exposed (TE)-only (no PTSD or ITRED) groups using a machine learning approach, examining well-known networks implicated in PTSD. A random forest classification model was built on a training set using cross-validation, and the averaged cross-validation model performance for classification was evaluated using the area under the curve. The model was tested using a fully independent portion of the data (test dataset), and the test area under the curve was evaluated.

Results

rsFC signatures differentiated TE-only participants from PTSD and ITRED-only participants at about 60% accuracy. Conversely, rsFC signatures did not differentiate PTSD from ITRED-only individuals (45% accuracy). Common features differentiating TE-only participants from PTSD and ITRED-only participants mainly involved default mode network-related pathways. Some unique features, such as connectivity within the frontoparietal network, differentiated TE-only participants from one group (PTSD or ITRED-only) but to a lesser extent from the other group.

Conclusions

Neural network connectivity supports ITRED as a novel neurobiologically based approach to classifying posttrauma psychopathology.

Impaired learning, memory, and extinction in posttraumatic stress disorder: translational meta-analysis of clinical and preclinical studies

Current evidence-based treatments for post-traumatic stress disorder (PTSD) are efficacious in only part of PTSD patients. Therefore, novel neurobiologically informed approaches are urgently needed. Clinical and translational neuroscience point to altered learning and memory processes as key in (models of) PTSD psychopathology. We extended this notion by clarifying at a meta-level (i) the role of information valence, i.e. neutral versus emotional/fearful, and (ii) comparability, as far as applicable, between clinical and preclinical phenotypes. We hypothesized that cross-species, neutral versus emotional/fearful information processing is, respectively, impaired and enhanced in PTSD. This preregistered meta-analysis involved a literature search on PTSD+Learning/Memory+Behavior, performed in PubMed. First, the effect of information valence was estimated with a random-effects meta-regression. The sources of variation were explored with a random forest-based analysis. The analyses included 92 clinical (N = 6732 humans) and 182 preclinical (N = 6834 animals) studies. A general impairment of learning, memory and extinction processes was observed in PTSD patients, regardless of information valence. Impaired neutral learning/memory and fear extinction were also present in animal models of PTSD. Yet, PTSD models enhanced fear/trauma memory in preclinical studies and PTSD impaired emotional memory in patients. Clinical data on fear/trauma memory was limited. Mnemonic phase and valence explained most variation in rodents but not humans. Impaired neutral learning/memory and fear extinction show stable cross-species PTSD phenotypes. These could be targeted for novel PTSD treatments, using information gained from neurobiological animal studies. We argue that apparent cross-species discrepancies in emotional/fearful memory deserve further in-depth study; until then, animal models targeting this phenotype should be applied with utmost care.

Neural correlates of PTSD in women with childhood sexual abuse with and without PTSD and response to paroxetine treatment: A placebo-controlled, double-blind trial

Objective

Childhood sexual abuse is the leading cause of posttraumatic stress disorder (PTSD) in women, and is a prominent cause of morbidity and loss of function for which limited treatments are available. Understanding the neurobiology of treatment response is important for developing new treatments. The purpose of this study was to assess neural correlates of personalized traumatic memories in women with childhood sexual abuse with and without PTSD, and to assess response to treatment.

Methods

Women with childhood sexual abuse with (N = 28) and without (N = 17) PTSD underwent brain imaging with High-Resolution Positron Emission Tomography scanning with radiolabeled water for brain blood flow measurements during exposure to personalized traumatic scripts and memory encoding tasks. Women with PTSD were randomized to paroxetine or placebo followed by three months of double-blind treatment and repeat imaging with the same protocol.

Results

Women with PTSD showed decreases in areas involved in the Default Mode Network (DMN), a network of brain areas usually active when the brain is at rest, hippocampus and visual processing areas with exposure to traumatic scripts at baseline while women without PTSD showed increased activation in superior frontal gyrus and other areas (p < 0.005). Treatment of women with PTSD with paroxetine resulted in increased anterior cingulate activation and brain areas involved in the DMN and visual processing with scripts compared to placebo (p < 0.005).

Conclusion

PTSD related to childhood sexual abuse in women is associated with alterations in brain areas involved in memory and the stress response and treatment with paroxetine results in modulation of these areas.

Exploring the association between early exposure to material hardship and psychopathology through indirect effects of fronto-limbic functional connectivity during fear learning

Experiencing family material hardship has been shown to be associated with disruptions in physical and psychological development. However, the association between material hardship and functional connectivity in the fronto-limbic circuit during fear learning is unclear. A total of 161 healthy young adults aged 17-28 were recruited in our brain imaging study, using the Fear Conditioning Task to test the associations between material hardship and connectivity in fronto-limbic circuit and psychopathology. The results showed that family material hardship was linked to higher positive connectivity between the left amygdala and bilateral dorsal anterior cingulate cortex, as well as higher negative connectivity between the left hippocampus and right ventromedial prefrontal cortex. A mediation analysis showed that material hardship was associated with depression via amygdala functional connectivity (indirect effect = 0.228, P = 0.016), and also indirectly associated with aggression and anger-hostility symptoms through hippocampal connections (aggression: indirect effect = 0.057, P = 0.001; anger-hostility: indirect effect = 0.169, P = 0.048). That is, family material hardship appears to affect fronto-limbic circuits through changes in specific connectivity, and these specific changes, in turn, could lead to specific psychological symptoms. The findings have implications for designing developmentally sensitive interventions to mitigate the emergence of psychopathological symptoms.

Hippocampal Connectivity with the Default Mode Network is Linked to Hippocampal Volume in the Clinical High Risk for Psychosis Syndrome and Healthy Individuals

Reduced hippocampal volume (HV) is an established brain morphological feature of psychiatric conditions. HV is associated with brain connectivity in humans and non-human animals and altered connectivity is associated with risk for psychiatric illness. Associations between HV and connectivity remain poorly characterized in humans, and especially in phases of psychiatric illness that precede disease onset. This study examined associations between HV and hippocampal functional connectivity (FC) during rest in 141 healthy controls and 248 individuals at-risk for psychosis. Significant inverse associations between HV and hippocampal FC with the inferior parietal lobe (IPL) and thalamus were observed. Select associations between hippocampal FC and HV were moderated by diagnostic group. Significant moderation results shifted from implicating the IPL to the temporal pole after excluding participants on antipsychotic medication. Considered together, this work implicates hippocampal FC with the temporoparietal junction, within a specialized subsystem of the default mode network, as sensitive to HV.

Functional connectivity of amygdala subnuclei in PTSD: a narrative review

While the amygdala is often implicated in the neurobiology of posttraumatic stress disorder (PTSD), the pattern of results remains mixed. One reason for this may be the heterogeneity of amygdala subnuclei and their functional connections. This review used PRISMA guidelines to synthesize research exploring the functional connectivity of three primary amygdala subnuclei, basolateral (BLA), centromedial (CMA), and superficial nuclei (SFA), in PTSD (N = 331) relative to trauma-exposed (N = 155) and non-trauma-exposed controls (N = 210). Although studies were limited (N = 11), preliminary evidence suggests that in PTSD compared to trauma-exposed controls, the BLA shows greater connectivity with the dorsal anterior cingulate, an area involved in salience detection. In PTSD compared to non-trauma-exposed controls, the BLA shows greater connectivity with the middle frontal gyrus, an area involved in attention. No other connections were replicated across studies. A secondary aim of this review was to outline the limitations of this field to better shape future research. Importantly, the results from this review indicate the need to consider potential mediators of amygdala subnuclei connectivity, such as trauma type and sex, when conducting such studies. They also highlight the need to be aware of the limited inferences we can make with such small samples that investigate small subcortical structures on low field strength magnetic resonance imaging scanners. Collectively, this review demonstrates the importance of exploring the differential connectivity of amygdala subnuclei to understand the pathophysiology of PTSD and stresses the need for future research to harness the strength of ultra-high field imaging to gain a more sensitive picture of the neural connectivity underlying PTSD.

Pre-treatment amygdala activation and habituation predict symptom change in post-traumatic stress disorder

Trauma-focused psychotherapy approaches are the first-line treatment option for post-traumatic stress disorder (PTSD); however, up to a third of patients remain symptomatic even after completion of the treatment. Predicting which patients will respond to a given treatment option would support personalized treatments and improve the efficiency of healthcare systems. Although previous neuroimaging studies have examined possible pre-treatment predictors of response to treatment, the findings have been somewhat inconsistent, and no other study has examined habituation to stimuli as a predictor. In this study, 16 treatment-seeking adults (MAge = 43.63, n = 10 women) with a primary diagnosis of PTSD passively viewed pictures of emotional facial expressions during functional magnetic resonance imaging (fMRI). After scanning, participants rated facial expressions on both valence and arousal. Participants then completed eight weekly sessions of prolonged exposure (PE) therapy. PTSD symptom severity was measured before and after treatment. Overall, participants showed symptomatic improvement with PE. Consistent with hypotheses, lesser activation in the amygdala and greater activation in the ventromedial prefrontal cortex during the presentation of fearful vs. happy facial expressions, as well as a greater decline in amygdala activation across blocks of fearful facial expressions at baseline, were associated with greater reduction of PTSD symptoms. Given that the repeated presentation of emotional material underlies PE, changes in brain responses with repeated stimulus presentations warrant further studies as potential predictors of response to exposure therapies.

How past trauma impacts emotional intelligence: Examining the connection

Backed by both research and practice, the organizational psychology field has come to value emotional intelligence (EI) as being vital for leader and employee effectiveness. While this field values EI, it has paid little attention to the antecedents of emotional intelligence, leaving the EI domain without clarity on (1) why EI might vary across individuals, and (2) how to best develop EI. In this article, we rely on neuroscience and psychology research to make the case that past psychological trauma impacts later EI capabilities. Specifically, we present evidence that psychological trauma impairs the brain areas and functions that support EI. Establishing psychological trauma has valuable theoretical and practical implications that include providing an explanation of why EI might vary across individuals and providing a focus for improving EI: healing from past trauma. Further theoretical and practical implications for the field of organizational psychology are provided.

Structural equation modeling of treatment-related changes in neural connectivity for youth with PTSD

BACKGROUND

Previous studies suggest that improvement in symptoms of posttraumatic stress disorder (PTSD) is accompanied by changes in neural connectivity, however, few studies have investigated directional (effective) connectivity. The current study assesses treatment-related changes in effective connectivity in youth with PTSD undergoing Trauma-Focused Cognitive Behavioral Therapy (TF-CBT).

METHODS

Functional MRI scans before and after 16 weeks of TF-CBT for 20 youth with PTSD, or the same time interval for 20 healthy controls (HC) were included in the analysis. Structural equation modeling was used to model group differences in directional connectivity at baseline, and changes in connectivity from pre- to post-treatment.

RESULTS

At baseline, the PTSD group, relative to the HC group, had significantly greater connectivity in the path from dorsal cingulate to anterior cingulate and from dorsal cingulate to posterior cingulate corticies. From pre- to post-treatment, connectivity in these paths decreased significantly in the PTSD group, as did connectivity from right hippocampus to left superior temporal gyrus. Connectivity from the left amygdala to the lateral orbital frontal cortex was significantly lower in PTSD vs HC at baseline, but did not change from pre- to post-treatment.

CONCLUSION

Although based on a small sample, these results converge with previous studies in suggesting a central role for the dorsal cingulate cortex in PTSD symptoms. The direction of this connectivity suggests that the dorsal cingulate is the source of modulation of anterior and posterior cingulate cortex during trauma-focused cognitive behavioral therapy.

Altered Resting-State functional connectivity in the anterior and posterior hippocampus in Post-traumatic stress disorder: The central role of the anterior hippocampus

BACKGROUND

Post-traumatic stress disorder can be viewed as a memory disorder, with trauma-related flashbacks being a core symptom. Given the central role of the hippocampus in autobiographical memory, surprisingly, there is mixed evidence concerning altered hippocampal functional connectivity in PTSD. We shed light on this discrepancy by considering the distinct roles of the anterior versus posterior hippocampus and examine how this distinction may map onto whole-brain resting-state functional connectivity patterns among those with and without PTSD.

METHODS

We first assessed whole-brain between-group differences in the functional connectivity profiles of the anterior and posterior hippocampus within a publicly available data set of resting-state fMRI data from 31 male Vietnam war veterans diagnosed with PTSD (mean age = 67.6 years, sd = 2.3) and 29 age-matched combat-exposed male controls (age = 69.1 years, sd = 3.5). Next, the connectivity patterns of each subject within the PTSD group were correlated with their PTSD symptom scores. Finally, the between-group differences in whole-brain functional connectivity profiles discovered for the anterior and posterior hippocampal seeds were used to prescribe post-hoc ROIs, which were then used to perform ROI-to-ROI functional connectivity and graph-theoretic analyses.

RESULTS

The PTSD group showed increased functional connectivity of the anterior hippocampus with affective brain regions (anterior/posterior insula, orbitofrontal cortex, temporal pole) and decreased functional connectivity of the anterior/posterior hippocampus with regions involved in processing bodily self-consciousness (supramarginal gyrus). Notably, decreased anterior hippocampus connectivity with the posterior cingulate cortex/precuneus was associated with increased PTSD symptom severity. The left anterior hippocampus also emerged as a central locus of abnormal functional connectivity, with graph-theoretic measures suggestive of a more central hub-like role for this region in those with PTSD compared to trauma-exposed controls.

CONCLUSIONS

Our results highlight that the anterior hippocampus plays a critical role in the neurocircuitry underlying PTSD and underscore the importance of the differential roles of hippocampal sub-regions in serving as biomarkers of PTSD. Future studies should investigate whether the differential patterns of functional connectivity stemming from hippocampal sub-regions is observed in PTSD populations other than older war veterans.

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

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

Therapeutic interventions impact brain function and promote post-traumatic growth in adults living with post-traumatic stress disorder: A systematic review and meta-analysis of functional magnetic resonance imaging studies

Introduction

The present systematic review and meta-analysis explores the impacts of cognitive processing therapy (CPT), eye movement desensitization and reprocessing (EMDR), and prolonged exposure (PE) therapy on neural activity underlying the phenomenon of post-traumatic growth for adult trauma survivors.

Methods

We utilized the following databases to conduct our systematic search: Boston College Libraries, PubMed, MEDLINE, and PsycINFO. Our initial search yielded 834 studies for initial screening. We implemented seven eligibility criteria to vet articles for full-text review. Twenty-nine studies remained for full-text review after our systematic review process was completed. Studies were subjected to several levels of analysis. First, pre-and post- test post-traumatic growth inventory (PTGI) scores were collected from all studies and analyzed through a forest plot using Hedges' g. Next, Montreal Neurological Institute (MNI) coordinates and t-scores were collected and analyzed using an Activation Likelihood Estimation (ALE) to measure brain function. T-scores and Hedges' g values were then analyzed using Pearson correlations to determine if there were any relationships between brain function and post-traumatic growth for each modality. Lastly, all studies were subjected to a bubble plot and Egger's test to assess risk of publication bias across the review sample.

Results

Forest plot results indicated that all three interventions had a robust effect on PTGI scores. ALE meta-analysis results indicated that EMDR exhibited the largest effect on brain function, with the R thalamus (t = 4.23, p < 0.001) showing robust activation, followed closely by the R precuneus (t = 4.19, p < 0.001). Pearson correlation results showed that EMDR demonstrated the strongest correlation between increased brain function and PTGI scores (r = 0.910, p < 0.001). Qualitative review of the bubble plot indicated no obvious traces of publication bias, which was corroborated by the results of the Egger's test (p = 0.127).

Discussion

Our systematic review and meta-analysis showed that CPT, EMDR, and PE each exhibited a robust effect on PTG impacts across the course of treatment. However, when looking closer at comparative analyses of neural activity (ALE) and PTGI scores (Pearson correlation), EMDR exhibited a more robust effect on PTG impacts and brain function than CPT and PE.

Neural correlates of psychodynamic and non-psychodynamic therapies in different clinical populations through fMRI: A meta-analysis and systematic review

Background

The COVID-19 pandemic has exacerbated the ongoing crisis in psychiatric and psychological care, contributing to what we have identified as a new psychological and psychiatric pandemic. Psychotherapy is an effective method for easing the psychological suffering experienced also by the various impacts of COVID-19. This treatment can be examined from a neurological perspective, through the application of brain imaging techniques. Specifically, the meta-analysis of imaging studies can aid in expanding researchers' understanding of the many beneficial applications of psychotherapy.

Objectives

We examined the functional brain changes accompanying different mental disorders with functional Magnetic Resonance Imaging (fMRI), through a meta-analysis, and systematic review in order to better understand the general neural mechanism involved in psychotherapy and the potential neural difference between psychodynamic and non-psychodynamic approaches.

Data sources

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were employed for our systematic review and meta-analysis. We conducted a computer-based literature search, following the Population, Intervention, Comparison and Outcomes (PICO) approach, to retrieve all published articles in English regarding the above-described topics from PubMed (MEDLINE), Scopus, and Web of Science.

Study eligibility criteria participants and interventions

We combined terms related to psychotherapy and fMRI: ("psychotherapy" [All Fields] OR "psychotherapy" [MeSH Terms] OR "psychotherapy" [All Fields] OR "psychotherapies" [All Fields] OR "psychotherapy s" [All Fields]) AND ("magnetic resonance imaging" [MeSH Terms]) OR ("magnetic"[All Fields] AND "resonance"[All Fields] AND "imaging"[All Fields]) OR ("magnetic resonance imaging"[All Fields] OR "fmri"[All Fields]). We considered (1) whole brain fMRI studies; (2) studies in which participants have been involved in a clinical trial with psychotherapy sessions, with pre/post fMRI; (3) fMRI results presented in coordinate-based (x, y, and z) in MNI or Talairach space; (4) presence of neuropsychiatric patients. The exclusion criteria were: (1) systematic review or meta-analysis; (2) behavioral study; (3) single-case MRI or fMRI study; and (4) other imaging techniques (i.e., PET, SPECT) or EEG.

Results

After duplicates removal and assessment of the content of each published study, we included 38 sources. The map including all studies that assessed longitudinal differences in brain activity showed two homogeneous clusters in the left inferior frontal gyrus, and caudally involving the anterior insular cortex (p < 0.0001, corr.). Similarly, studies that assessed psychotherapy-related longitudinal changes using emotional or cognitive tasks (TASK map) showed a left-sided homogeneity in the anterior insula (p < 0.000) extending to Broca's area of the inferior frontal gyrus (p < 0.0001) and the superior frontal gyrus (p < 0.0001). Studies that applied psychodynamic psychotherapy showed Family-Wise Error (FWE) cluster-corrected (p < 0.05) homogeneity values in the right superior and inferior frontal gyri, with a small cluster in the putamen. No FWE-corrected homogeneity foci were observed for Mindful- based and cognitive behavioral therapy psychotherapy. In both pre- and post-therapy results, studies showed two bilateral clusters in the dorsal anterior insulae (p = 0.00001 and p = 0.00003, respectively) and involvement of the medial superior frontal gyrus (p = 0.0002).

Limitations

Subjective experiences, such as an individual's response to therapy, are intrinsically challenging to quantify as objective, factual realities. Brain changes observed both pre- and post-therapy could be related to other factors, not necessary to the specific treatment received. Therapeutic modalities and study designs are generally heterogeneous. Differences exist in sample characteristics, such as the specificity of the disorder and number and duration of sessions. Moreover, the sample size is relatively small, particularly due to the paucity of studies in this field and the little contribution of PDT.

Conclusions and implications of key findings

All psychological interventions seem to influence the brain from a functional point of view, showing their efficacy from a neurological perspective. Frontal, prefrontal regions, insular cortex, superior and inferior frontal gyrus, and putamen seem involved in these neural changes, with the psychodynamic more linked to the latter three regions.

Effective psychological therapy for PTSD changes the dynamics of specific large-scale brain networks

In posttraumatic stress disorder (PTSD), re-experiencing of the trauma is a hallmark symptom proposed to emerge from a de-contextualised trauma memory. Cognitive therapy for PTSD (CT-PTSD) addresses this de-contextualisation through different strategies. At the brain level, recent research suggests that the dynamics of specific large-scale brain networks play an essential role in both the healthy response to a threatening situation and the development of PTSD. However, very little is known about how these dynamics are altered in the disorder and rebalanced after treatment and successful recovery. Using a data-driven approach and fMRI, we detected recurring large-scale brain functional states with high temporal precision in a population of healthy trauma-exposed and PTSD participants before and after successful CT-PTSD. We estimated the total amount of time that each participant spent on each of the states while being exposed to trauma-related and neutral pictures. We found that PTSD participants spent less time on two default mode subnetworks involved in different forms of self-referential processing in contrast to PTSD participants after CT-PTSD (mtDMN+ and dmDMN+ ) and healthy trauma-exposed controls (only mtDMN+ ). Furthermore, re-experiencing severity was related to decreased time spent on the default mode subnetwork involved in contextualised retrieval of autobiographical memories, and increased time spent on the salience and visual networks. Overall, our results support the hypothesis that PTSD involves an imbalance in the dynamics of specific large-scale brain network states involved in self-referential processes and threat detection, and suggest that successful CT-PTSD might rebalance this dynamic aspect of brain function.

Intrusive experiences in posttraumatic stress disorder: Treatment response induces changes in the directed functional connectivity of the anterior insula

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Many causal paths were less influenced by the AI after effective therapy for PTSD.

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Insular influences over the rest of the brain were found to be positively correlated with re-experiencing.

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Re-experiencing was linked with changes in intrinsic networks’ spatial stability after treatment.

Background

One of the core features of posttraumatic stress disorder (PTSD) is re-experiencing trauma. The anterior insula (AI) has been proposed to play a crucial role in these intrusive experiences. However, the dynamic function of the AI in re-experiencing trauma and its putative modulation by effective therapy need to be specified.

Methods

Thirty PTSD patients were enrolled and exposed to traumatic memory reactivation therapy. Resting-state functional magnetic resonance imaging (fMRI) scans were acquired before and after treatment. To explore AI-directed influences over the rest of the brain, we referred to a mixed model using pre-/posttreatment Granger causality analysis seeded on the AI as a within-subject factor and treatment response as a between-subject factor. To further identify correlates of re-experiencing trauma, we investigated how intrusive severity affected (i) causality maps and (ii) the spatial stability of other intrinsic brain networks.

Results

We observed changes in AI-directed functional connectivity patterns in PTSD patients. Many within- and between-network causal paths were found to be less influenced by the AI after effective therapy. Insular influences were found to be positively correlated with re-experiencing symptoms, while they were linked with a stronger default mode network (DMN) and more unstable central executive network (CEN) connectivity.

Conclusion

We showed that directed changes in AI signaling to the DMN and CEN at rest may underlie the degree of re-experiencing symptoms in PTSD. A positive response to treatment further induced changes in network-to-network anticorrelated patterns. Such findings may guide targeted neuromodulation strategies in PTSD patients not suitably improved by conventional treatment.

Learning to forget: Hippocampal-amygdala connectivity partially mediates the effect of sexual trauma severity on verbal recall in older women undiagnosed with posttraumatic stress disorder

Verbal learning deficits are common among sexually traumatized women who have not been formally diagnosed with posttraumatic stress disorder (PTSD). Aberrant resting-state functional connectivity (rsFC) of the amygdala and hippocampus are implicated in PTSD and verbal memory impairment. We tested rsFC between bilateral dentate gyrus (DG) and both centromedial (CM) and basolateral (BL) nuclei of the amygdala as statistical mediators for the effect of sexual trauma-related symptom severity on delayed verbal recall performance in 63 older women (age: 60-85 years) undiagnosed with PTSD. Participant data were drawn from the NKI-Rockland Study. Individuals completed a 10-min resting-state scan, Rey Auditory Verbal Learning Test (RAVLT), and the Sexual Abuse Trauma Index (SATI) from the Trauma Symptom Checklist. Z-scores indicating rsFC of DG with BL and CM amygdala seeds were evaluated in two separate mediation models. Higher SATI scores were associated with lower RAVLT after controlling for age, β = -.23, 95% CI [.48, .03], p = .039. This effect was negated upon adding a negative path from SATI to rsFC of left DG and right CM, β = -.29, 95% CI [-.52, -.02], p = .022, and a positive path from that seed pair to RAVLT List A recall, β = .28, 95% CI [.03, 0.48], p = .015. Chi-square fit indices supported partial mediation by this seed pair, p = .762. In the absence of PTSD sexual trauma symptoms partially relate to verbal learning deficits as a function of aberrant rsFC between left hippocampus DG and right amygdala CM nuclei.

Exposure in Vivo as a Treatment Approach to Target Pain-Related Fear: Theory and New Insights From Research and Clinical Practice

Pain-related fear (PRF) can be a significant factor contributing to the development and maintenance of pain-related disability in individuals with persistent pain. One treatment approach to target PRF and related avoidance behavior is exposure in vivo (EXP). EXP has a long history in the field of anxiety, a field that is constantly evolving. This Perspective outlines recent theoretical advancements and how they apply to EXP for PRF, including suggestions for how to optimize inhibitory learning during EXP; reviews mechanistic work from neuroimaging supporting the targeting of PRF in people with chronic pain; and focuses on clinical applications of EXP for PRF, as EXP is moving into new directions regarding who is receiving EXP (eg, EXP in chronic secondary pain) and how treatment is provided (EXP in primary care with a crucial role for physical therapists). Considerations are provided regarding challenges, remaining questions, and promising future perspectives.

IMPACT

For patients with chronic pain who have elevated pain-related fear (PRF), exposure is the treatment of choice. This Perspective highlights the inhibitory learning approach, summarizes mechanistic work from experimental psychology and neuroimaging regarding PRF in chronic pain, and describes possible clinical applications of EXP in chronic secondary pain as well as in primary care.

Hippocampal Resting-State Functional Connectivity Forecasts Individual Posttraumatic Stress Disorder Symptoms: A Data-Driven Approach

BACKGROUND

Posttraumatic stress disorder (PTSD) is a debilitating disorder, and there is no current accurate prediction of who develops it after trauma. Neurobiologically, individuals with chronic PTSD exhibit aberrant resting-state functional connectivity (rsFC) between the hippocampus and other brain regions (e.g., amygdala, prefrontal cortex, posterior cingulate), and these aberrations correlate with severity of illness. Previous small-scale research (n < 25) has also shown that hippocampal rsFC measured acutely after trauma is predictive of future severity using a region-of-interest-based approach. While this is a promising biomarker, to date, no study has used a data-driven approach to test whole-brain hippocampal FC patterns in forecasting the development of PTSD symptoms.

METHODS

A total of 98 adults at risk of PTSD were recruited from the emergency department after traumatic injury and completed resting-state functional magnetic resonance imaging (8 min) within 1 month; 6 months later, they completed the Clinician-Administered PTSD Scale for DSM-5 for assessment of PTSD symptom severity. Whole-brain rsFC values with bilateral hippocampi were extracted (using CONN) and used in a machine learning kernel ridge regression analysis (PRoNTo); a k-folds (k = 10) and 70/30 testing versus training split approach were used for cross-validation (1000 iterations to bootstrap confidence intervals for significance values).

RESULTS

Acute hippocampal rsFC significantly predicted Clinician-Administered PTSD Scale for DSM-5 scores at 6 months (r = 0.30, p = .006; mean squared error = 120.58, p = .006; R² = 0.09, p = .025). In post hoc analyses, hippocampal rsFC remained significant after controlling for demographics, PTSD symptoms at baseline, and depression, anxiety, and stress severity at 6 months (B = 0.59, SE = 0.20, p = .003).

CONCLUSIONS

Findings suggest that functional connectivity of the hippocampus across the brain acutely after traumatic injury is associated with prospective PTSD symptom severity.

The relationship between recent PTSD secondary to sexual assault, hippocampal volume and resting state functional connectivity in adolescent girls

Objective

Improved understanding of the time course of neural changes associated with adolescent PTSD would elucidate the development of the disorder and could inform approaches to treatment. We compared hippocampal volumes and resting state functional connectivity (RSFC) in adolescent girls with post-traumatic stress disorder (PTSD) secondary to sexual assault, within six months of onset and age- and gender-matched, non-trauma exposed healthy controls (HCs) in São Paulo, Brazil. We also examined the relationship between pre- and post-treatment PTSD symptoms and RSFC.

Method

We collected brain structure, RSFC, and PTSD symptoms in 30 adolescents with PTSD (mean age: 15.7 ± 1.04 years) and 21 HCs (mean age: 16.2 ± 1.21 years) at baseline. We collected repeated measures in 21 participants with PTSD following treatment; 9 participants dropped out. Hippocampal volume and RSFC from hippocampal and default mode network (DMN) seeds were compared between participants with PTSD and HCs. We examined associations between within-subject changes in RSFC and PTSD symptoms following treatment.

Results

No hippocampal volumetric differences between groups were found. Compared to HCs, adolescents with recent PTSD had reduced RSFC between hippocampus and the lateral parietal node of the DMN, encompassing the angular gyrus, peak coordinates: −38, −54, 16; 116 voxels; peak F_1,47 = 31.76; FDR corrected p = 0.038. Improvements in PTSD symptoms were associated with increased RSFC between hippocampus and part of the lateral parietal node of the DMN, peak coordinates: −38, −84, 38; 316 voxels; peak F_1,47 = 40.28; FDR corrected p < 0.001.

Conclusion

Adolescents with recent PTSD had reduced hippocampal-DMN RSFC, while no group differences in hippocampal volume were found, suggesting that hippocampal function, but not structure, is altered early in the course of PSTD. Following treatment, hippocampal-DMN RSFC increased with symptom improvement and may indicate an important neural mechanism related to successful PTSD treatment.

Functional connectivity changes in the delta frequency band following trauma treatment in complex trauma and dissociative disorder patients

OBJECTIVE

Phase-oriented trauma treatment is efficacious in the treatment of complex trauma and dissociative disorder patients. However, the neural correlates of this therapeutic effect are not yet well-understood. In the current study we investigated whether patients show a strengthening in functional network connectivity in the delta frequency band (1-3.5 Hz) over the course of phase-oriented inpatient trauma treatment while they performed an emotion regulation task. Further, we examined whether neural changes were associated with symptom reduction and improvement in emotion regulation skills.

METHODS

Before and after 8 weeks of treatment, electroencephalography (EEG) was acquired in patients (n = 28) with a complex posttraumatic stress disorder (cPTSD) or complex dissociative disorder (CDD). They also completed clinical and emotion regulation questionnaires. To delimit data variability, patients participated as one dissociative part that is referred to as Apparently Normal Part (ANP). Patients' data were compared to a matched healthy control croup (n = 38), also measured twice.

RESULTS

Prior to treatment, functional connectivity was significantly lower in patients compared to controls during cognitive reappraisal of unpleasant pictures and passive viewing of unpleasant and neutral pictures. These hypoconnected networks largely overlapped with networks typically activated during the recall of (emotional) autobiographical memories. Functional connectivity strength within these networks significantly increased following treatment and was comparable to controls. Patients showed symptom reduction across various clinical domains and improvement in the use of cognitive reappraisal as emotion regulation strategy. Treatment-related network normalizations were not related to changes in questionnaire data.

CONCLUSION

Phase-oriented treatment may strengthen connections between regions that are activated during autobiographical recall. These findings encourage further investigation of this circuitry as a therapeutic target in cPTSD and CDD patients.

CLINIAL TRIAL REGISTRATION

www.ClinicalTrials.gov, identifier: NCT02459340, https://www.kofam.ch/de/studienportal/suche/149284/studie/26681.

Lateralized Contributions of Medial Prefrontal Cortex Network to Episodic Memory Deficits in Subjects With Amnestic Mild Cognitive Impairment

Both episodic memory and executive function are impaired in amnestic mild cognitive impairment (aMCI) subjects, but it is unclear if these impairments are independent or interactive. The present study aimed to explore the relationship between episodic memory deficits and executive function deficits, and the underlying functional mechanisms in aMCI subjects. Thirty-one aMCI subjects and 27 healthy subjects underwent neuropsychological tests and multimodal magnetic resonance imaging (MRI) scans. Hippocampal networks and medial prefrontal cortex (MPFC) networks were identified based on resting-sate functional MRI (fMRI) data. AMCI subjects displayed lower episodic memory scores and executive function scores than control subjects, and the episodic memory scores were positively correlated with the executive function scores in aMCI subjects. Brain network analyses showed an interaction between the hippocampal networks and the MPFC networks, and the interaction was significantly associated with the episodic memory scores and the executive function scores. Notably, aMCI subjects displayed higher functional connectivity (FC) of the right hippocampal network with the right prefrontal cortex than did control subjects, but this difference disappeared when controlling for the MPFC networks. Furthermore, the effects of the MPFC networks on the hippocampal networks were significantly associated with the episodic memory scores in aMCI subjects. The present findings suggested that the episodic memory deficits in aMCI subjects could be partially underpinned by the modulation of the MPFC networks on the hippocampal networks.

Neuroimaging correlates and predictors of response to repeated-dose intravenous ketamine in PTSD: preliminary evidence

Promising initial data indicate that the glutamate N-methyl-D-aspartate (NMDA) receptor antagonist ketamine may be beneficial in post-traumatic stress disorder (PTSD). Here, we explore the neural correlates of ketamine-related changes in PTSD symptoms, using a rich battery of functional imaging data (two emotion-processing tasks and one task-free scan), collected from a subset of participants of a randomized clinical trial of repeated-dose intravenous ketamine vs midazolam (total N = 21). In a pre-registered analysis, we tested whether changes in an a priori set of imaging measures from a target neural circuit were predictive of improvement in PTSD symptoms, using leave-one-out cross-validated elastic-net regression models (regions of interest in the target circuit consisted of the dorsal and rostral anterior cingulate cortex, ventromedial prefrontal cortex, anterior hippocampus, anterior insula, and amygdala). Improvements in PTSD severity were associated with increased functional connectivity between the ventromedial prefrontal cortex (vmPFC) and amygdala during emotional face-viewing (change score retained in model with minimum predictive error in left-out subjects, standardized regression coefficient [β] = 2.90). This effect was stronger in participants who received ketamine compared to midazolam (interaction β = 0.86), and persisted following inclusion of concomitant change in depressive symptoms in the analysis model (β = 0.69). Improvement following ketamine was also predicted by decreased dorsal anterior cingulate activity during emotional conflict regulation, and increased task-free connectivity between the vmPFC and anterior insula (βs = -2.82, 0.60). Exploratory follow-up analysis via dynamic causal modelling revealed that whilst improvement in PTSD symptoms following either drug was associated with decreased excitatory modulation of amygdala→vmPFC connectivity during emotional face-viewing, increased top-down inhibition of the amygdala by the vmPFC was only observed in participants who improved under ketamine. Individuals with low prefrontal inhibition of amygdala responses to faces at baseline also showed greater improvements following ketamine treatment. These preliminary findings suggest that, specifically under ketamine, improvements in PTSD symptoms are accompanied by normalization of hypofrontal control over amygdala responses to social signals of threat.

Neural Responsivity to Reward versus Punishment Shortly after Trauma Predicts Long-term Development of Post-Traumatic Stress Symptoms

BACKGROUND

Processing negative and positive valenced stimuli involve multiple brain regions including the amygdala and ventral striatum (VS). Post-Traumatic Stress Disorder (PTSD) is often associated with hyper-responsivity to negatively valenced, yet recent evidence also points to deficient positive valence functioning. It is yet unclear what is the relative contribution of such opposing valence processing shortly after trauma to the development of chronic PTSD.

METHODS

Neurobehavioral indicators of motivational positive vs. negative valence sensitivities were longitudinally assessed in 171 adults (87 females, age=34.19±11.47 years) at 1-, 6-, and 14-months following trauma exposure (TP1, TP2, TP3). Using a gambling fMRI paradigm, amygdala and VS functionality (activity and functional connectivity with the prefrontal cortex) in response to rewards vs. punishments were assessed with relation to PTSD severity at different time-points. The effect of valence processing was depicted behaviorally by the amount of risk taken to maximize reward.

RESULTS

PTSD severity at TP1 was associated with greater neural functionality in the amygdala (but not the VS) towards punishments vs. rewards, and fewer risky choices. PTSD severity at TP3 was associated with decreased neural functionality in both the VS and amygdala towards rewards vs. punishments at TP1 (but not with risky behavior). Explainable machine learning revealed the primacy of VS biased processing, over the amygdala, in predicting PTSD severity at TP3.

CONCLUSIONS

These results highlight the importance of biased neural responsivity to positive relative to negative motivational outcomes in PTSD development. Novel therapeutic strategies early after trauma may thus target both valence fronts.

Targeting the stress response in pediatric pain: current evidence for psychosocial intervention and avenues for future investigation

Nonpharmacological treatments for chronic pain in youth have been identified as first-line treatments over and above medication. Therapies such as cognitive-behavioral therapy and mindfulness-based stress reduction have shown good efficacy in reducing the psychological correlates (eg, anxiety, depression, and stress) and social or behavioral sequelae (eg, limited physical activity and lack of school engagement) associated with pediatric chronic pain. However, minimal research has examined the physiological mechanism(s) of action for these interventions. A recent review (Cunningham, et al., 2019) emphasized the need for objective (ie, physiological) assessment of treatment response in pediatric pain populations. The current review adds to this literature by identifying the physiological stress response as a particular target of interest in interventions for pediatric pain. Research indicates that youth with chronic pain report high rates of psychological stress, posttraumatic stress symptoms, and exposure to adverse childhood experiences (abuse/neglect, etc). In addition, a host of research has shown strong parallels between the neurobiology of pain processing and the neurobiology of stress exposure in both youth and adults. Interventions such as narrative or exposure therapy (eg, trauma-focused cognitive-behavioral therapy) and mindfulness-based or meditation-based therapies have shown particular promise in alleviating the neurobiological impact that stress and pain can have on the body, including reduction in allostatic load and altered connectivity in multiple brain regions. However, no study to date has specifically looked at these factors in the context of pediatric pain treatment. Future research should further explore these constructs to optimize prevention in and treatment of these vulnerable populations.

PTSD: Past, present and future implications for China

There has been a long history since human beings began to realize the existence of post-traumatic symptoms. Posttraumatic stress disorder (PTSD), a diagnostic category adopted in 1980 in the Diagnostic and Statistical Manual of Mental Disorders-Ⅲ, described typical clusters of psychiatric symptoms occurring after traumatic events. Abundant researches have helped deepen the understanding of PTSD in terms of epidemiological features, biological mechanisms, and treatment options. The prevalence of PTSD in general population ranged from 6.4% to 7.8% and was significantly higher among groups who underwent major public traumatic events. There has been a long way in the studies of animal models and genetic characteristics of PTSD. However, the high comorbidity with other stress-related psychiatric disorders and complexity in the pathogenesis of PTSD hindered the effort to find specific biological targets for PTSD. Neuroimage was widely used to elucidate the underlying neurophysiological mechanisms of PTSD. Functional MRI studies have showed that PTSD was linked to medial prefrontal cortex, anterior cingulate cortex and sub-cortical structures like amygdala and hippocampus, and to explore the functional connectivity among these brain areas which might reveal the possible neurobiological mechanism related to PTSD symptoms. For now, cognitive behavior therapy-based psychotherapy, including combination with adjunctive medication, showed evident treatment effects on PTSD. The emergence of more effective PTSD pharmacotherapies awaits novel biomarkers from further fundamental research. Several natural disasters and emergencies have inevitably increased the possibility of suffering from PTSD in the last two decades, making it critical to strengthen PTSD research in China. To boost PTSD study in China, the following suggestions might be helpful: (1) establishing a national psychological trauma recover project, and (2) exploring the mechanisms of PTSD with joint effort and strengthening the indigenized treatment of PTSD.

Resting-state functional connectivity in patients with a complex PTSD or complex dissociative disorder before and after inpatient trauma treatment

INTRODUCTION

Recent research suggests that traumatized patients are characterized by disrupted resting-state functional connectivity. We examined whether neural networks involved in resting-state change over the course of a phase-oriented inpatient treatment for complex traumatized and dissociative disorder patients. We also investigated associations between these network alterations and clinical symptoms and emotion regulation skills.

METHODS

Pre- and post-treatment, electroencephalography (EEG) was recorded during resting-state in patients (n = 23) with a complex dissociative disorder (CDD) or complex posttraumatic stress disorder (cPTSD). Patients also completed clinical and emotion regulation questionnaires. To reduce variance in the collected data, patients were exclusively tested as one prototypical dissociative part referred to as Apparently Normal Part (ANP). Functional network connectivity was examined and compared with a matched healthy control group (n = 37), also measured twice.

RESULTS

Prior to treatment and compared with controls, patients had a significantly lower functional connectivity strength within eyes-open and eyes-closed resting-state networks in the theta and alpha frequency band. Following treatment, functional connectivity strength within these networks was comparable to the control group and comprised areas belonging to the default mode network (DMN) and prefrontal as well as anterior cingulate control regions. Treatment-related network normalizations in the theta frequency band were associated with a self-reported increase in the use of cognitive reappraisal strategies and reduction in emotion regulation difficulties.

CONCLUSION

Phase-oriented trauma treatment can strengthen resting-state network connectivity and can increase the capacity of complex traumatized and dissociative patients as ANP to handle emotional challenges effectively.

Corticolimbic Circuitry in Chronic Pain Tracks Pain Intensity Relief Following Exposure In Vivo

Background

A subset of patients with chronic pain who receive exposure in vivo (EXP) treatment experience clinically relevant relief of pain intensity. Although pain relief is not an explicit therapeutic target, it is important to understand how and why this concomitant effect occurs in some patients but not others. This longitudinal study therefore aimed to characterize brain plasticity as well as to explore pretreatment factors related to pain relief.

Methods

Resting-state functional magnetic resonance imaging data were acquired in 30 patients with chronic pain. Twenty-three patients completed EXP, and 6-month follow-up data were available in 20 patients (magnetic resonance imaging data in 17 patients). Pain-free control data were acquired at two time points (n = 29, n = 21). Seed-based resting-state functional connectivity (rsFC) analyses were performed, with seeds in the amygdala, hippocampus, and nucleus accumbens.

Results

Pain relief after EXP was highly variable, with 60% of patients reporting a clinically relevant improvement. Amygdala rsFC with the middle frontal gyrus decreased significantly over time in patients but was not associated with pain relief. In contrast, greater pain relief was associated with greater decreases over time in hippocampus rsFC with the precuneus, which was related to reductions in catastrophizing (EXP therapeutic target) as well. Greater pain relief was also associated with lower pretreatment rsFC between nucleus accumbens and postcentral gyrus.

Conclusions

While changes in hippocampus rsFC were associated with pain relief after EXP, pretreatment nucleus accumbens rsFC showed potential prognostic value. Our findings further support the importance of corticolimbic circuitry in chronic pain, emphasizing its relation to pain relief and identifying potential underlying mechanisms and prognostic factors, warranting further testing in independent samples.

Amygdala and Insula Connectivity Changes Following Psychotherapy for Posttraumatic Stress Disorder: A Randomized Clinical Trial

BACKGROUND

Exposure-based psychotherapy is a first-line treatment for posttraumatic stress disorder (PTSD), but its mechanisms are poorly understood. Functional brain connectivity is a promising metric for identifying treatment mechanisms and biosignatures of therapeutic response. To this end, we assessed amygdala and insula treatment-related connectivity changes and their relationship to PTSD symptom improvements.

METHODS

Individuals with a primary PTSD diagnosis (N = 66) participated in a randomized clinical trial of prolonged exposure therapy (n = 36) versus treatment waiting list (n = 30). Task-free functional magnetic resonance imaging was completed prior to randomization and 1 month following cessation of treatment/waiting list. Whole-brain blood oxygenation level-dependent responses were acquired. Intrinsic connectivity was assessed by subregion in the amygdala and insula, limbic structures key to the disorder pathophysiology. Dynamic causal modeling assessed evidence for effective connectivity changes in select nodes informed by intrinsic connectivity findings.

RESULTS

The amygdala and insula displayed widespread patterns of primarily subregion-uniform intrinsic connectivity change, including increased connectivity between the amygdala and insula; increased connectivity of both regions with the ventral prefrontal cortex and frontopolar and sensory cortices; and decreased connectivity of both regions with the left frontoparietal nodes of the executive control network. Larger decreases in amygdala-frontal connectivity and insula-parietal connectivity were associated with larger PTSD symptom reductions. Dynamic causal modeling evidence suggested that treatment decreased left frontal inhibition of the left amygdala, and larger decreases were associated with larger symptom reductions.

CONCLUSIONS

PTSD psychotherapy adaptively attenuates functional interactions between frontoparietal and limbic brain circuitry at rest, which may reflect a potential mechanism or biosignature of recovery.

Altered resting-state functional connectivity of the default mode and central executive networks following cognitive processing therapy for PTSD

Psychotherapy research is increasingly targeting both psychological and neurobiological mechanisms of therapeutic change. This trend is evident in and applicable to post-traumatic stress disorder (PTSD) treatment research given the high nonresponse rate of individuals with PTSD who undergo cognitive-behavioral therapy (CBT). Functional connectivity analyses investigating disrupted brain networks across mental disorders have been employed to understand both mental disorder symptoms and therapeutic mechanisms. However, few studies have examined pre-post CBT brain changes in PTSD using functional connectivity analyses. The current study investigated a) whether brain networks commonly implicated in psychopathology (e.g., default mode network [DMN], central executive network [CEN], and salience network [SN]) changed following Cognitive Processing Therapy (CPT) for PTSD and b) whether change in these networks was associated with PTSD and/or transdiagnostic symptom change. Independent components analysis was implemented to investigate resting-state functional connectivity in DMN, CEN, and SN in 42 women with PTSD and 18 trauma-exposed controls (TEC). Results indicated decreased CEN-cerebellum connectivity in PTSD participants versus TEC prior to CPT and decreased DMN connectivity in PTSD participants after CPT. Additionally, DMN and SN connectivity was related to change in positive and negative affectivity, while exploratory analyses at a cluster threshold of pFDR < .10 indicated DMN and SN connectivity was also related to change in PTSD symptoms and rumination. These findings provide evidence for normalization of CEN connectivity with treatment and implicate the DMN and SN in clinical symptom change following CPT.

Defining focal brain stimulation targets for PTSD using neuroimaging

INTRODUCTION

Focal brain stimulation has potential as a treatment for posttraumatic stress disorder (PTSD). In this review, we aim to inform selection of focal brain stimulation targets for treating PTSD by examining studies of the functional neuroanatomy of PTSD and treatment response. We first briefly review data on brain stimulation interventions for PTSD. Although published data suggest good efficacy overall, the neurobiological rationale for each stimulation target is not always clear.

METHODS

Therefore, we assess pre- and post-treatment (predominantly psychotherapy) functional neuroimaging studies in PTSD to determine which brain changes seem critical to treatment response. Results of these studies are presented within a previously proposed functional neural systems model of PTSD.

RESULTS

While not completely consistent, research suggests that downregulating the fear learning and threat and salience detection circuits (i.e., amygdala, dorsal anterior cingulate cortex and insula) and upregulating the emotion regulation and executive function and contextual processing circuits (i.e., prefrontal cortical regions and hippocampus) may mediate PTSD treatment response.

CONCLUSION

This literature review provides some justification for current focal brain stimulation targets. However, the examination of treatment effects on neural networks is limited, and studies that include the stimulation targets are lacking. Further, additional targets, such as the cingulate, medial prefrontal cortex, and inferior parietal lobe, may also be worth investigation, especially when considering how to achieve network level changes. Additional research combining PTSD treatment with functional neuroimaging will help move the field forward by identifying and validating novel targets, providing better rationale for specific treatment parameters and personalizing treatment for PTSD.

Functional coupling of the orbitofrontal cortex and the basolateral amygdala mediates the association between spontaneous reappraisal and emotional response

Emotional regulation is known to be associated with activity in the amygdala. The amygdala is an emotion-generative region that comprises of structurally and functionally distinct nuclei. However, little is known about the contributions of different frontal-amygdala sub-region pathways to emotion regulation. Here, we investigated how functional couplings between frontal regions and amygdala sub-regions are involved in different spontaneous emotion regulation processes by using an individual-difference approach and a generalized psycho-physiological interaction (gPPI) approach. Specifically, 50 healthy participants reported their dispositional use of spontaneous cognitive reappraisal and expressive suppression in daily life and their actual use of these two strategies during the performance of an emotional-picture watching task. Results showed that functional coupling between the orbitofrontal cortex (OFC) and the basolateral amygdala (BLA) was associated with higher scores of both dispositional and actual uses of reappraisal. Similarly, functional coupling between the dorsolateral prefrontal cortex (dlPFC) and the centromedial amygdala (CMA) was associated with higher scores of both dispositional and actual uses of suppression. Mediation analyses indicated that functional coupling of the right OFC-BLA partially mediated the association between reappraisal and emotional response, irrespective of whether reappraisal was measured by dispositional use (indirect effect(SE)=-0.2021 (0.0811), 95%CI_(BC)= [-0.3851, -0.0655]) or actual use (indirect effect(SE)=-0.1951 (0.0796), 95%CI_(BC)= [-0.3654, -0.0518])). These findings suggest that spontaneous reappraisal and suppression involve distinct frontal- amygdala functional couplings, and the modulation of BLA activity from OFC may be necessary for changing emotional response during spontaneous reappraisal.

The Role of the Thalamus in Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) has a high lifetime prevalence and is one of the more serious challenges in mental health care. Fear-conditioned learning involving the amygdala has been thought to be one of the main causative factors; however, recent studies have reported abnormalities in the thalamus of PTSD patients, which may explain the mechanism of interventions such as eye movement desensitization and reprocessing (EMDR). Therefore, I conducted a miniature literature review on the potential contribution of the thalamus to the pathogenesis of PTSD and the validation of therapeutic approaches. As a result, we noticed the importance of the retinotectal pathway (superior colliculus−pulvinar−amygdala connection) and discussed therapeutic indicators.

Neural changes following equine-assisted therapy for posttraumatic stress disorder: A longitudinal multimodal imaging study

Background

While effective treatments for posttraumatic stress disorder (PTSD) exist, many individuals, including military personnel and veterans fail to respond to them. Equine‐assisted therapy (EAT), a novel PTSD treatment, may complement existing PTSD interventions. This study employs longitudinal neuro‐imaging, including structural magnetic resonance imaging (sMRI), resting state‐fMRI (rs‐fMRI), and diffusion tensor imaging (DTI), to determine mechanisms and predictors of EAT outcomes for PTSD.

Method

Nineteen veterans with PTSD completed eight weekly group sessions of EAT undergoing multimodal MRI assessments before and after treatment. Clinical assessments were conducted at baseline, post‐treatment and at 3‐month follow‐up.

Results

At post‐treatment patients showed a significant increase in caudate functional connectivity (FC) and reduction in the gray matter density of the thalamus and the caudate. The increase of caudate FC was positively associated with clinical improvement seen immediately at post‐treatment and at 3‐month follow‐up. In addition, higher baseline caudate FC was associated with greater PTSD symptom reduction post‐treatment.

Conclusions

This exploratory study is the first to demonstrate that EAT can affect functional and structural changes in the brains of patients with PTSD. The findings suggest that EAT may target reward circuitry responsiveness and produce a caudate pruning effect from pre‐ to post‐treatment.

Does trauma-focused psychotherapy change the brain? A systematic review of neural correlates of therapeutic gains in PTSD

BACKGROUND

Meta-analytic results indicate that posttraumatic stress disorder (PTSD) is associated with hypoactivation of the medial prefrontal cortex (mPFC), hyperactivation of the amygdala, and volume reductions of the hippocampus. Effective psychotherapeutic treatments were hypothesized to normalize these neural patterns via upregulation of prefrontal structures, which in turn downregulate limbic regions.

OBJECTIVE

To gain a sound understanding of the effects of successful psychotherapy on the brain, neural changes from pre- to post-treatment in PTSD patients will be aggregated.

METHOD

A systematic literature search identified 24 original studies employing structural or functional MRI measurements both before and after treatment of patients diagnosed with PTSD.

RESULTS

In conjunction, the review returned little evidence of an activation increase in the mPFC/rostral anterior cingulate cortex (rACC) following successful treatment. Five out of 12 studies observed such an increase (especially during emotion processing tasks), albeit in partially non-overlapping brain regions. Conversely, neither the putative related activation decrease in the amygdala nor volumetric changes or altered activation during the resting state could be convincingly established.

CONCLUSION

Successful psychological treatments might potentially work via upregulation of the mPFC, which thus may be involved in symptom reduction. However, the role of the amygdala in recovery from PTSD remains unclear. There is currently no indication that the various PTSD treatment approaches employed by the reviewed studies differ regarding their action mechanisms, but further research on this topic is needed.

Associations between resting-state functional connectivity and treatment response in a randomized clinical trial for posttraumatic stress disorder

BACKGROUND

Alterations in resting-state functional connectivity (rsFC) have been reported in posttraumatic stress disorder (PTSD). Here, we examined pre- and post-treatment rsFC during a randomized clinical trial to characterize alterations and examine predictors of treatment response.

METHODS

Sixty-four combat veterans with PTSD were randomly assigned to prolonged exposure (PE) plus placebo, sertraline plus enhanced medication management, or PE plus sertraline. Symptom assessment and resting-state functional magnetic resonance imaging (fMRI) scans occurred before and after treatment. Twenty-nine trauma-exposed combat veterans without PTSD served as a control group at intake. Seed-based and region of interest (ROI)-to-ROI connectivities, as well as an exploratory connectome-based approach were used to analyze rsFC patterns. Based on previously reported findings, analyses focused on Salience Network (SN) and Default-Mode Network (DMN).

RESULTS

At intake, patients with PTSD showed greater DMN-dorsal attention network (DAN) connectivity (between ventromedial prefrontal cortex and superior parietal lobule; family-wise error corrected p = .011), greater SN-DAN connectivity (between insula and middle frontal gyrus; corrected p = .003), and a negative correlation between re-experiencing symptoms and within-DMN connectivity (between posterior cingulate cortex (PCC) and middle temporal gyrus; corrected p < .001). We also found preliminary evidence for associations between rsFC and treatment response. Specifically, high responders (≥50% PTSD symptom improvement), compared with low responders, had greater SN-DMN segregation (i.e., less pre-treatment amygdala-PCC connectivity; p = .011) and lower pre-treatment global centrality (p = .042).

CONCLUSIONS

Our findings suggest neural abnormalities in PTSD and may inform future research examining neural biomarkers of PTSD treatment response.

Intrinsic connectomes underlying response to trauma-focused psychotherapy in post-traumatic stress disorder

Although trauma-focused cognitive behavior therapy (TF-CBT) is the frontline treatment for post-traumatic stress disorder (PTSD), up to one-half of patients are treatment nonresponders. To understand treatment nonresponse, it is important to understand the neural mechanisms of TF-CBT. Here, we used whole-brain intrinsic functional connectivity analysis to identify neural connectomic signatures of treatment outcome. In total, 36 PTSD patients and 36 healthy individuals underwent functional MRI at pre-treatment baseline. Patients then underwent nine sessions of TF-CBT and completed clinical and follow-up MRIs. We used an established large-scale brain network atlas to parcellate the brain into 343 brain regions. Pairwise intrinsic task-free functional connectivity was calculated and used to identify pre-treatment connectomic features that were correlated with reduction of PTSD severity from pretreatment to post treatment. We formed a composite metric of intrinsic connections associated with therapeutic outcome, and then interrogated this composite metric to determine if it distinguished PTSD treatment responders and nonresponders from healthy control status and changed post treatment. Lower pre-treatment connectivity for the cingulo-opercular, salience, default mode, dorsal attention, and frontoparietal executive control brain networks was associated with treatment improvement. Treatment responders had lower while nonresponders had significantly greater connectivity than controls at pretreatment. With therapy, connectivity significantly increased for responders and decreased for nonresponders, while controls remain unchanged over this time period. We provide evidence that the intrinsic functional architecture of the brain, specifically connectivity within and between brain networks associated with external vigilance, self-awareness, and cognitive control, may characterize a positive response to TF-CBT for PTSD.

Multi-voxel pattern analysis of amygdala functional connectivity at rest predicts variability in posttraumatic stress severity

INTRODUCTION

Resting state functional magnetic resonance imaging (rsfMRI) studies demonstrate that individuals with posttraumatic stress disorder (PTSD) exhibit atypical functional connectivity (FC) between the amygdala, involved in the generation of emotion, and regions responsible for emotional appraisal (e.g., insula, orbitofrontal cortex [OFC]) and regulation (prefrontal cortex [PFC], anterior cingulate cortex). Consequently, atypical amygdala FC within an emotional processing and regulation network may be a defining feature of PTSD, although altered FC does not seem constrained to one brain region. Instead, altered amygdala FC involves a large, distributed brain network in those with PTSD. The present study used a machine-learning data-driven approach, multi-voxel pattern analysis (MVPA), to predict PTSD severity based on whole-brain patterns of amygdala FC.

METHODS

Trauma-exposed adults (N = 90) completed the PTSD Checklist-Civilian Version to assess symptoms and a 5-min rsfMRI. Whole-brain FC values to bilateral amygdala were extracted and used in a relevance vector regression analysis with a leave-one-out approach for cross-validation with permutation testing (1,000) to obtain significance values.

RESULTS

Results demonstrated that amygdala FC predicted PCL-C scores with statistically significant accuracy (r = .46, p = .001; mean sum of squares = 130.46, p = .001; R²  = 0.21, p = .001). Prediction was based on whole-brain amygdala FC, although regions that informed prediction (top 10%) included the OFC, amygdala, and dorsolateral PFC.

CONCLUSION

Findings demonstrate the utility of MVPA based on amygdala FC to predict individual severity of PTSD symptoms and that amygdala FC within a fear acquisition and regulation network contributed to accurate prediction.

Altered large-scale functional brain organization in posttraumatic stress disorder: A comprehensive review of univariate and network-level neurocircuitry models of PTSD

Classical neural circuitry models of posttraumatic stress disorder (PTSD) are largely derived from univariate activation studies and implicate the fronto-limbic circuit as a main neural correlate of PTSD symptoms. Though well-supported by human neuroimaging literature, these models are limited in their ability to explain the widely distributed neural and behavioral deficits in PTSD. Emerging interest in the application of large-scale network methods to functional neuroimaging provides a new opportunity to overcome such limitations and conceptualize the neural circuitry of PTSD in the context of network patterns. This review aims to evaluate both the classical neural circuitry model and a new, network-based model of PTSD neural circuitry using a breadth of functional brain organization research in subjects with PTSD. Taken together, this literature suggests global patterns of reduced functional connectivity (FC) in PTSD groups as well as altered FC targets that reside disproportionately in canonical functional networks, especially the default mode network. This provides evidence for an integrative model that includes elements of both the classical models and network-based models to characterize the neural circuitry of PTSD.

Animal models of post-traumatic stress disorder and novel treatment targets

Understanding the neurobiological basis of post-traumatic stress disorder (PTSD) is fundamental to accurately diagnose this neuropathology and offer appropriate treatment options to patients. The lack of pharmacological effects, too often observed with the most currently used drugs, the selective serotonin reuptake inhibitors (SSRIs), makes even more urgent the discovery of new pharmacological approaches. Reliable animal models of PTSD are difficult to establish because of the present limited understanding of the PTSD heterogeneity and of the influence of various environmental factors that trigger the disorder in humans. We summarize knowledge on the most frequently investigated animal models of PTSD, focusing on both their behavioral and neurobiological features. Most of them can reproduce not only behavioral endophenotypes, including anxiety-like behaviors or fear-related avoidance, but also neurobiological alterations, such as glucocorticoid receptor hypersensitivity or amygdala hyperactivity. Among the various models analyzed, we focus on the social isolation mouse model, which reproduces some deficits observed in humans with PTSD, such as abnormal neurosteroid biosynthesis, changes in GABAA receptor subunit expression and lack of pharmacological response to benzodiazepines. Neurosteroid biosynthesis and its interaction with the endocannabinoid system are altered in PTSD and are promising neuronal targets to discover novel PTSD agents. In this regard, we discuss pharmacological interventions and we highlight exciting new developments in the fields of research for novel reliable PTSD biomarkers that may enable precise diagnosis of the disorder and more successful pharmacological treatments for PTSD patients.

Cognitive flexibility in PTSD individuals following nature adventure intervention: is it really that good?

Previous studies have found that PTSD is associated with hippocampal-related impairment in cognitive flexibility. However, little is known about this impairment following nature adventure interventions. The current ex post facto study aimed to examine the relationship between cognitive flexibility, sailing-based intervention and PTSD symptoms. Thirty-nine individuals with PTSD diagnosis (17 who engaged in sailing and 22 who did not engage in sailing) and 38 healthy control (18 who engaged in sailing and 20 who did not engage in sailing) completed a performance-based reversal learning paradigm to assess cognitive flexibility and were evaluated for PTSD, depressive and anxiety symptoms. The results revealed significantly lower levels of PTSD and trait anxiety symptoms in the PTSD-sailing group, compared to the PTSD-no-sailing group. In addition, both PTSD groups showed selective, though different, impairments in reversal learning. Specifically, PTSD-no-sailing individuals showed a selective impairment in reversing the outcome of a negative stimulus- they struggled to learn that a previously negative stimulus was later associated with a positive outcome. PTSD-sailing individuals, on the other hand, displayed a selective impairment in reversing the outcome of a positive stimulus- they had difficulty learning that a previously positive stimulus was later associated with a negative outcome. The results may suggest that although individuals who participated in a sailing-based intervention had lower clinical symptoms, their hippocampal related cognitive flexibility was mot improved, and the impairment exists in a different domain.

Parental Reflective Functioning correlates to brain activation in response to video-stimuli of mother-child dyads: Links to maternal trauma history and PTSD

Parental Reflective Functioning is a parent's capacity to infer mental states in herself and her child. Parental Reflective Functioning is linked to the quality of parent-child attachment and promotes parent-child mutual emotion regulation. We examined neural correlates of parental reflective functioning and their relationship to physical abuse. Participants were mothers with (n = 26) and without (n = 22) history of childhood physical abuse. Parental reflective functioning was assessed by coding transcripts of maternal narrative responses on interviews. All mothers also underwent magnetic resonance imaging while watching video clips of children during mother-child separation and play. Parental reflective functioning was significantly lower among mothers with histories of childhood physical abuse. When mothers without history of childhood physical abuse watched scenes of separation versus play, brain activation was positively correlated with parental reflective functioning in the ventromedial prefrontal cortex, and negatively associated with the dorsolateral prefrontal cortex and insula. These associations were not present when limiting analyses to mothers reporting abuse histories. Regions subserving emotion regulation and empathy were associated with parental reflective functioning; yet these regions were not featured in maltreated mothers. These data suggest that childhood physical abuse exposure may alter the psychobiology that is linked to emotional comprehension and regulation.

Exposure in vivo Induced Changes in Neural Circuitry for Pain-Related Fear: A Longitudinal fMRI Study in Chronic Low Back Pain

Exposure in vivo (EXP) is a cognitive-behavioral treatment aimed at reducing pain-related fear in chronic pain, and has proven successful in reducing pain-related disability in patients with chronic low back pain (cLBP). The current longitudinal study aimed to reveal the neural correlates of changes in pain-related fear as a result of EXP. Twenty-three patients with cLBP were included in this study. Patients with cLBP underwent MRI scanning pre-treatment (pre-EXP), post-treatment (post-EXP), and 6 months after end of treatment (FU-EXP). Pain-free controls were scanned at two time points. In the scanner, participants were presented with pictures involving back-related movements, evoking pain-related fear in patients. Pre-treatment, functional MRI revealed increased activation in right posterior insula and increased deactivation in medial prefrontal cortex (mPFC) in patients compared to controls. Post-treatment, patients reported reduced fear and pre-EXP group differences were no longer present. Contrasting pre- to post- and FU-EXP in patients revealed that stimulus-evoked neural responses changed in sensorimotor as well as cognitive/affective brain regions. Lastly, exploratory analyses revealed a tendency toward an association between changes in neural activation and changes in fear ratings, including the hippocampus and temporal lobe (pre- to post-EXP changes), and mPFC and posterior cingulate cortex (pre- to FU-EXP changes). Taken together, we show evidence that neural circuitry for pain-related fear is modulated by EXP, and that changes are associated with self-reported decreases in pain-related fear.