Posterior and prefrontal contributions to the development posttraumatic stress disorder symptom severity: an fMRI study of symptom provocation in acute stress disorder

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.

Traumatic stress symptoms among Spanish healthcare workers during the COVID-19 pandemic: a prospective study

AIM

To investigate the occurrence of traumatic stress symptoms (TSS) among healthcare workers active during the COVID-19 pandemic and to obtain insight as to which pandemic-related stressful experiences are associated with onset and persistence of traumatic stress.

METHODS

This is a multicenter prospective cohort study. Spanish healthcare workers (N = 4,809) participated at an initial assessment (i.e., just after the first wave of the Spain COVID-19 pandemic) and at a 4-month follow-up assessment using web-based surveys. Logistic regression investigated associations of 19 pandemic-related stressful experiences across four domains (infection-related, work-related, health-related and financial) with TSS prevalence, incidence and persistence, including simulations of population attributable risk proportions (PARP).

RESULTS

Thirty-day TSS prevalence at T1 was 22.1%. Four-month incidence and persistence were 11.6% and 54.2%, respectively. Auxiliary nurses had highest rates of TSS prevalence (35.1%) and incidence (16.1%). All 19 pandemic-related stressful experiences under study were associated with TSS prevalence or incidence, especially experiences from the domains of health-related (PARP range 88.4-95.6%) and work-related stressful experiences (PARP range 76.8-86.5%). Nine stressful experiences were also associated with TSS persistence, of which having patient(s) in care who died from COVID-19 had the strongest association. This association remained significant after adjusting for co-occurring depression and anxiety.

CONCLUSIONS

TSSs among Spanish healthcare workers active during the COVID-19 pandemic are common and associated with various pandemic-related stressful experiences. Future research should investigate if these stressful experiences represent truly traumatic experiences and carry risk for the development of post-traumatic stress disorder.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Cortical thickness abnormalities in patients with post-traumatic stress disorder: A vertex-based meta-analysis

Neuroimaging studies report altered cortical thickness in patients with post-traumatic stress disorder (PTSD), but the results are inconsistent. Using anisotropic effect-size seed-based d mapping (AES-SDM) software with its recently-developed meta-analytic thickness mask, we conducted a meta-analysis of published studies which used whole-brain surface-based morphometry, in order to define consistent cortical thickness alterations in PTSD patients. Eleven studies with 438 patients and 396 controls were included. Compared with all controls, patients with PTSD showed increased cortical thickness in right superior temporal gyrus, and in left and right superior frontal gyrus; the former survived in subgroup analysis of adult patients, and in subgroup comparison with only non-PTSD trauma-exposed controls, the latter in subgroup comparison with only non-trauma-exposed healthy controls. Cortical thickness in right superior frontal gyrus was positively associated with percentage of female patients, and cortical thickness in left superior frontal gyrus was positively associated with symptom severity measured by the clinician-administered PTSD scale. These robust results may help to elucidate the pathophysiology of PTSD.

Neural contributors to trauma resilience: a review of longitudinal neuroimaging studies

Resilience in the face of major life stressors is changeable over time and with experience. Accordingly, differing sets of neurobiological factors may contribute to an adaptive stress response before, during, and after the stressor. Longitudinal studies are therefore particularly effective in answering questions about the determinants of resilience. Here we provide an overview of the rapidly-growing body of longitudinal neuroimaging research on stress resilience. Despite lingering gaps and limitations, these studies are beginning to reveal individual differences in neural circuit structure and function that appear protective against the emergence of future psychopathology following a major life stressor. Here we outline a neural circuit model of resilience to trauma. Specifically, pre-trauma biomarkers of resilience show that an ability to modulate activity within threat and salience networks predicts fewer stress-related symptoms. In contrast, early post-trauma biomarkers of subsequent resilience or recovery show a more complex pattern, spanning a number of major circuits including attention and cognitive control networks as well as primary sensory cortices. This novel synthesis suggests stress resilience may be scaffolded by stable individual differences in the processing of threat cues, and further buttressed by post-trauma adaptations to the stressor that encompass multiple mechanisms and circuits. More attention and resources supporting this work will inform the targets and timing of mechanistic resilience-boosting interventions.

Cortical gyrification morphology in PTSD: A neurobiological risk factor for severity?

Post-traumatic stress disorder (PTSD) is a prevalent psychiatric disorder, particularly among military personnel and veterans. Cortical gyrification, as a specific metric derived from structural MRI, is an index of the convoluted folding and patterning of the gyri and sulci, and is thought to facilitate the efficiency of local neuronal wiring. It has the potential to act as a neurobiological risk factor for emergent psychiatric disorders – to date, it has been understudied in PTSD. Here, using a local measure of the degree of gyrification (local Gyrification Index, lGI) we investigate cortical gyrification morphology in 48 adult male soldiers with (n = 23) and without (n = 25) a PTSD diagnosis. We also examine the relation between lGI and PTSD severity within the PTSD group. General linear models yielded significant between-group differences with greater lGI found in PTSD in a cluster located in the medial occipito-parietal lobe on the left hemisphere and reduced lGI in a cluster located on the lateral surface of the parietal lobe on the right hemisphere. Brain-behaviour analyses within the PTSD group yielded significant positive associations between lGI and PTSD severity in a cluster located in the frontal cortex of the left hemisphere and scattered clusters located within all lobes of the right hemisphere. After accounting for the effects of comorbid psychiatric symptoms common in PTSD, the associations in the right hemisphere reduced to clusters only located in the frontal lobe, while the cluster in the left hemisphere remained significant. Our results suggest that atypical cortical gyrification in parietal and occipital regions may be implicated in the psychopathology of PTSD diagnosis, and properties of prefrontal gyrification associated with the emergent severity of PTSD after trauma. The importance of these regions in PTSD may be attributed to a pre-existing neurobiological risk factor, or neuromorphological changes after trauma precipitating emergent psychiatric illness. Our brain-behaviour relations provide support for the existing literature by highlighting the importance of the frontal lobe in the pathogenesis of PTSD. Future large-scale longitudinal studies including female participants may infer causal implications of atypical gyrification in PTSD and shed light on the potential effect of sex on this brain metric.

Reduced gray matter volume in the left prefrontal, occipital, and temporal regions as predictors for posttraumatic stress disorder: a voxel-based morphometric study

The concept of acute stress disorder (ASD) was introduced as a diagnostic entity to improve the identification of traumatized people who are likely to develop posttraumatic stress disorder (PTSD). Neuroanatomical models suggest that changes in the prefrontal cortex, amygdala, and hippocampus play a role in the development of PTSD. Using voxel-based morphometry, this study aimed to investigate the predictive power of gray matter volume (GMV) alterations for developing PTSD. The GMVs of ASD patients (n = 21) were compared to those of PTSD patients (n = 17) and healthy controls (n = 18) in whole-brain and region-of-interest analyses. The GMV alterations seen in ASD patients shortly after the traumatic event (T1) were also correlated with PTSD symptom severity and symptom clusters 4 weeks later (T2). Compared with healthy controls, the ASD patients had significantly reduced GMV in the left visual cortex shortly after the traumatic event (T1) and in the left occipital and prefrontal regions 4 weeks later (T2); no significant differences in GMV were seen between the ASD and PTSD patients. Furthermore, a significant negative association was found between the GMV reduction in the left lateral temporal regions seen after the traumatic event (T1) and PTSD hyperarousal symptoms 4 weeks later (T2). Neither amygdala nor hippocampus alterations were predictive for the development of PTSD. These data suggest that gray matter deficiencies in the left hemispheric occipital and temporal regions in ASD patients may predict a liability for developing PTSD.

Neural responses to negative facial emotions: Sex differences in the correlates of individual anger and fear traits

Studies have examined sex differences in emotion processing in health and illness. However, it remains unclear how these neural processes may relate to individual differences in affective traits. We addressed this issue with a dataset of 970 subjects (508 women) curated from the Human Connectome Project. Participants were assessed with the NIH Toolbox Emotion Measures and fMRI while identifying negative facial emotion and neutral shape targets in alternating blocks. Imaging data were analyzed with published routines and the results were reported at a corrected threshold. Men scored similarly in Anger- but lower in Fear-Affect, as compared to women. Men as compared with women engaged the occipital-temporal visual cortex, retrosplenial cortex (RSC), and both anterior and posterior cingulate cortex to a greater extent during face versus shape identification. Women relative to men engaged higher activation of bilateral middle frontal cortex. In regional brain responses to face versus shape identification, men relative to women showed more significant modulations by both Anger- and Fear- Affect traits. The left RSC and right RSC/precuneus each demonstrated activities during face vs. shape identification in negative correlation with Anger- and Fear- Affect scores in men only. Anger affect was positively correlated with prolonged RT in identifying face vs. shape target in men but not women. In contrast, women relative to men showed higher Fear-Affect score and higher activation in the right middle frontal cortex, which was more strongly correlated with prolonged RT during face vs. shape identification. Together, men and women with higher Fear-Affect demonstrated lower accuracy in identifying negative facial emotion versus neutral shape target, a relationship mediated by activity of the RSC. These findings add to the literature of sex and trait individual differences in emotion processing and may help research of sex-shared and sex-specific behavioral and neural markers of emotional disorders.

Processing of Positive Visual Stimuli Before and After Symptoms Provocation in Posttraumatic Stress Disorder - A Functional Magnetic Resonance Imaging Study of Trauma-Affected Male Refugees

Background

Symptoms of anhedonia are often central to posttraumatic stress disorder (PTSD), but it is unclear how anhedonia is affected by processes induced by reliving past traumatic memories.

Methods

Sixty-nine male refugees (PTSD = 38) were interviewed and scanned with functional magnetic resonance imaging while viewing positive, neutral and Scrambled Pictures after being read personalized scripts evoking an emotionally neutral memory and a traumatic memory. We further measured postprovocation state symptoms, physiological measures and PTSD symptoms. We tested whether neural activity associated with positive picture viewing in participants with PTSD was differentially affected by symptom provocation compared to controls.

Results

For the pictures > scrambled contrast (Positive contrast), PTSD participants had significantly less activity than controls in fusiform gyrus, right inferior temporal gyrus and left middle occipital gyrus. The Positive contrast activity in fusiform gyrus scaled negatively with anhedonia symptoms in PTSD participants after controlling for total PTSD severity. Relative to the emotionally Neutral Script, the Trauma Script decreased positive picture viewing activity in posterior cingulate cortex, precuneus and left calcarine gyrus, but there was no difference between PTSD participants and controls.

Conclusions

We found reduced responsiveness of higher visual processing of emotionally positive pictures in PTSD. The significant correlation found between positive picture viewing activity and anhedonia suggests the reduced responsiveness to be due to the severity of anhedonia.

The neural correlates of trauma-related autobiographical memory in posttraumatic stress disorder: A meta-analysis

BACKGROUND

Autobiographical memory (AM) refers to memories of events that are personally relevant and are remembered from one's own past. The AM network is a distributed brain network comprised largely by prefrontal medial and posteromedial cortical brain regions, which together facilitate AM. Autobiographical memories with high arousal and negatively valenced emotional states are thought to be retrieved more readily and re-experienced more vividly. This is critical in the case of trauma-related AMs, which are related to altered phenomenological experiences as well as aberrations to the underlying neural systems in posttraumatic stress disorder (PTSD). Critically, these alterations to the AM network have not been explored recently and have never been analyzed with consideration to the different processes of AM, them being retrieval and re-experiencing.

METHODS

We conducted a series of effect-size signed differential mapping meta-analyses across twenty-eight studies investigating the neural correlates of trauma-related AMs in participants with PTSD as compared with controls. Studies included either trauma-related scripts or trauma-related materials (i.e., sounds, images, pictures) implemented to evoke the recollection of a trauma-related memory.

RESULTS

The meta-analyses revealed that control and PTSD participants displayed greater common brain activation of prefrontal medial and posteromedial cortices, respectively. Whereby the prefrontal medial cortices are suggested to facilitate retrieval monitoring, the posteromedial cortices are thought to enable the visual imagery processes of AM.

CONCLUSIONS

Taken together, reduced common activation of prefrontal cortices may be interpreted as a bias toward greater re-experiencing, where the more salient elements of the traumatic memory are relived as opposed to retrieved in a controlled manner in PTSD.

Temporal effect of electroacupuncture on anxiety-like behaviors and c-Fos expression in the anterior cingulate cortex in a rat model of post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is a psychiatric disease which leads to a series of anxiety-like behaviors. In this study, we investigated the temporal effects of electroacupuncture (EA) at acupoint ST36 on anxiety-like behaviors and the expression of c-Fos in the anterior cingulate cortex (ACC) in a rat model of PTSD. PTSD was induced by a single prolonged stress procedure comprising three stages: restraint for 2 h, forced swim for 20 min, and pentobarbital sodium anesthesia. EA at acupoint ST36 was performed from 7:00-9:00 once a day for 7 consecutive days. Open field test (OFT) and elevated plus maze (EPM) test were used to assess the success of the model and evaluate anxiety-like behaviors. Immunohistochemistry was used to detect Fos-positive nuclei in the ACC. We observed that EA performed from 7:00-9:00 was associated with significantly more time spent in the center area during the OFT and in the open arm during the EPM, as well as lower corticosterone response compared with that of regular EA (P < 0.05). PTSD rats expressed significantly less c-Fos in the ACC. Timed EA significantly increased c-Fos expression in the ACC. The effect of timed EA acting on PTSD rats was linked to altered neuronal activation in the ACC. Compared to regular EA, timed EA exhibited superior therapeutic effects by attenuating anxiety-like behaviors in PTSD rats. These results emphasize the association between temporal parameters of EA manipulation and acupuncture effects. Timed acupuncture therapy may be a novel therapeutic application in the treatment of PTSD.

The Current Evidence for Acute Stress Disorder

PURPOSE OF REVIEW

The aim of this review is to provide a summary of the current evidence pertaining to the course of acute and chronic posttraumatic stress, the diagnosis of acute stress disorder (ASD), and treatment of acute stress disorder and prevention of posttraumatic stress disorder (PTSD).

RECENT FINDINGS

Although acute stress disorder was introduced partly to predict subsequent PTSD, longitudinal studies indicate that ASD is not an accurate predictor of PTSD. Recent analytic approaches adopting latent growth mixture modeling have shown that trauma-exposed people tend to follow one of four trajectories: (a) resilient, (b) worsening, (c) recovery, and (d) chronically distressed. The complexity of the course of posttraumatic stress limits the capacity of the ASD diagnosis to predict subsequent PTSD. Current evidence indicates that the treatment of choice for ASD is trauma-focused cognitive behavior therapy, and this intervention results in reduced chronic PTSD severity. Recent attempts to limit subsequent PTSD by early provision of pharmacological interventions have been promising, especially administration of corticosterone to modulate glucocorticoid levels. Although the ASD diagnosis does not accurately predict chronic PTSD, it describes recently trauma-exposed people with severe distress. Provision of CBT in the acute phase is the best available strategy to limit subsequent PTSD.

Assault-related self-blame and its association with PTSD in sexually assaulted women: an MRI inquiry

Sexual assault is a frequent interpersonal trauma, which often leads to post-traumatic stress disorder (PTSD). Among other postassault characteristics, self-blame attributions were suggested to play an important role in sexually assaulted individuals' coping and were consistently associated with PTSD in this population. The present study aimed to elucidate the neural underpinnings that may associate self-blame and PTSD in women who experienced sexual assault at adulthood, using structural and resting-state functional MRI. Thirty-eight sexually assaulted women and 24 non-exposed matched controls were studied (mean age: 25 years). Among the sexually assaulted participants, assault-related self-blame was negatively correlated with gray matter volume (GMV) bilaterally in the lingual gyrus and adjacent intracalcarine cortex. GMV in this cluster was also predicted by intrusion symptoms and negative social reactions. Resting-state functional connectivity (rs-FC) of this cluster with the left anterior temporal fusiform cortex significantly differed between PTSD and non-PTSD sexually assaulted participants, and was inversely correlated with intrusion symptoms and with peritraumatic dissociation. Finally, lingual cluster's GMV and rs-FC with the anterior fusiform mediated the association between self-blame and intrusion symptoms across sexually assaulted participants. These findings link assault-related self-blame, disrupted postassault recovery and the neural circuitry involved in the processing of traumatic memories.

Real-time fMRI amygdala neurofeedback positive emotional training normalized resting-state functional connectivity in combat veterans with and without PTSD: a connectome-wide investigation

Self-regulation of brain activation using real-time functional magnetic resonance imaging neurofeedback (rtfMRI-nf) is an emerging approach for treating mood and anxiety disorders. The effect of neurofeedback training on resting-state functional connectivity warrants investigation as changes in spontaneous brain activation could reflect the association between sustained symptom relief and brain alteration. We investigated the effect of amygdala-focused rtfMRI-nf training on resting-state functional connectivity in combat veterans with and without posttraumatic stress disorder (PTSD) who were trained to increase a feedback signal reflecting left amygdala activity while recalling positive autobiographical memories (Zotev et al., 2018). The analysis was performed in three stages: i) first, we investigated the connectivity in the left amygdala region; ii) next, we focused on the abnormal resting-state functional connectivity identified in our previous analysis of this data (Misaki et al., 2018); and iii) finally, we performed a novel data-driven longitudinal connectome-wide analysis. We introduced a longitudinal multivariate distance matrix regression (MDMR) analysis to comprehensively examine neurofeedback training effects beyond those associated with abnormal baseline connectivity.

These comprehensive exploratory analyses suggested that abnormal resting-state connectivity for combat veterans with PTSD was partly normalized after the training. This included hypoconnectivities between the left amygdala and the left ventrolateral prefrontal cortex (vlPFC) and between the supplementary motor area (SMA) and the dorsal anterior cingulate cortex (dACC). The increase of SMA-dACC connectivity was associated with PTSD symptom reduction. Longitudinal MDMR analysis found a connectivity change between the precuneus and the left superior frontal cortex. The connectivity increase was associated with a decrease in hyperarousal symptoms. The abnormal connectivity for combat veterans without PTSD - such as hypoconnectivity in the precuneus with a superior frontal region and hyperconnectivity in the posterior insula with several regions - could also be normalized after the training. These results suggested that the rtfMRI-nf training effect was not limited to a feedback target region and symptom relief could be mediated by brain modulation in several regions other than in a feedback target area. While further confirmatory research is needed, the results may provide valuable insight into treatment effects on the whole brain resting-state connectivity.

•

fMRI neurofeedback training effect on resting-state connectivity was examined

•

Left amygdala activity was trained to increase with positive memory

•

Neurofeedback normalized altered connectivity in veterans with and without PTSD

•

PTSD symptom reductions were significant but not specific to group (exp/ctrl)

•

Connectivity-symptom association was seen in mPFC and precuneus

Neurocognitive, emotional and neuroendocrine correlates of exposure to sexual assault in women

BACKGROUND

Survivors of sexual assault are vulnerable to long-term negative psychological and physical health outcomes, but few studies have investigated changes in cognition, emotional processing and brain function in the early stages after sexual assault. We used a multimodal approach to identify the cognitive and emotional correlates associated with sexual assault in women.

METHODS

Twenty-seven female survivors of sexual assault were included within 4 weeks of the traumatic event, and they were compared with 20 age-matched controls. Participants underwent functional MRI while performing cognitive/emotional tasks (n-back, emotional go/no-go, mental imagery). We also measured diurnal salivary cortisol and conducted neuropsychological assessments of attention and memory abilities.

RESULTS

Relative to the control group, the survivors group had lower levels of morning cortisol and showed attentional deficits. We observed no between-group differences in brain activation during the n-back or mental imagery tasks. During the emotional go/no-go task, however, the survivors group showed a lack of deactivation in the dorsal anterior cingulate cortex when processing emotional material, relative to neutral material. Exploratory analyses in the survivors group indicated that symptom severity was negatively associated with cerebellar activation when positive emotional (happy) content interfered with response inhibition, and positively associated with cerebellar activation when thinking of positive (happy) memories.

LIMITATIONS

The small sample size was the main limitation of this study.

CONCLUSION

Dysfunctions in the dorsal anterior cingulate cortex and the cerebellum may represent early functional brain modifications that alter higher cognitive processes when emotional material is involved.

The Temporal Propagation of Intrinsic Brain Activity Associate With the Occurrence of PTSD

The abnormal brain activity is a pivotal condition for the occurrence of posttraumatic stress disorder. However, the dynamic time features of intrinsic brain activities still remain unclearly in PTSD patients. Our study aims to perform the resting-state lag analysis (RS-LA) method to explore potential propagated patterns of intrinsic brain activities in PTSD patients. We recruited 27 drug-naive patients with PTSD, 33 trauma-exposed controls (TEC), and 30 demographically matched healthy controls (HC) in the final data statistics. Both RS-LA and conventional voxel-wise functional connectivity strength (FCS) methods were employed on the same dataset. Then, Spearman correlation analysis was conducted on time latency values of those abnormal brain regions with the clinical assessments. Compared with HC group, the time latency patterns of PTSD patients significantly shifted toward later in posterior cingulate cortex/precuneus, middle prefrontal cortex, right angular, and left pre- and post-central cortex. The TEC group tended to have similar time latency in right angular. Additionally, significant time latency in right STG was found in PTSD group relative to TEC group. Spearman correlation analysis revealed that the time latency value of mPFC negatively correlated to the PTSD checklist-civilian version scores (PCL_C) in PTSD group (r = -0.578, P < 0.05). Furthermore, group differences map of FCS exhibited parts of overlapping areas with that of RS-LA, however, less specificity in detecting PTSD patients. In conclusion, apparent alterations of time latency were observed in DMN and primary sensorimotor areas of PTSD patients. These findings provide us with new evidence to explain the neural pathophysiology contributing to PTSD.

Connectome-wide investigation of altered resting-state functional connectivity in war veterans with and without posttraumatic stress disorder

Altered resting-state functional connectivity in posttraumatic stress disorder (PTSD) suggests neuropathology of the disorder. While seed-based fMRI connectivity analysis is often used for the studies, such analysis requires defining a seed location a priori, which restricts search scope and could bias findings toward presupposed areas. Recently, a comprehensive exploratory voxel-wise connectivity analysis, the connectome-wide association approach, has been introduced using multivariate distance matrix regression (MDMR) for resting-state functional connectivity analysis. The current study performed a connectome-wide investigation of resting-state functional connectivity for war veterans with and without PTSD compared to non-trauma-exposed healthy controls using MDMR. Thirty-five male combat veterans with PTSD (unmedicated), 18 male combat veterans without PTSD (veterans control, VC), and 28 age-matched non-trauma-exposed healthy males (NC) participated in a resting-state fMRI scan. MDMR analysis was used to identify between-groups differences in regions with altered connectivity. The identified regions were used as a seed for post-hoc functional connectivity analysis. The analysis revealed that PTSD patients had hypoconnectivity between the left lateral prefrontal regions and the salience network regions as well as hypoconnectivity between the parahippocampal gyrus and the visual cortex areas. Connectivity between the ventromedial prefrontal cortex and the middle frontal gyrus and between the parahippocampal gyrus and the anterior insula were negatively correlated with PTSD symptom severity. VC subjects also had altered functional connectivity compared to NC, including increased connectivity between the posterior insula and several brain regions and decreased connectivity between the precuneus region and several other brain areas. The decreased connectivity between the lateral prefrontal regions and the salience network regions in PTSD was consistent with previous reports that indicated lowered emotion-regulation function in these regions. The decreased connectivity between the parahippocampal gyrus and visual cortex supported the dual representation theory of PTSD, which suggests dissociation between sensory and contextual memory representations in PTSD. The theory also supposes that the precuneus is a region that triggers retrieval of sensory memory of traumatic events. The decreased connectivity at the precuneus for VC might be associated with suppressing such a process.