Threatening faces induce fear circuitry hypersynchrony in soldiers with post-traumatic stress disorder

A Literature Review of Mental Health Symptom Outcomes in U.S. Veterans and Servicemembers Following Combat Exposure and Military Sexual Trauma

Combat exposure (CE) and military sexual trauma (MST) are among the most common types of traumatic experiences faced by veterans and active duty servicemembers and, as such, have both garnered increased research focus over the past decades. However, there has not yet been a critical review of the literature to examine the distinct clinical presentations associated with different trauma types. This is particularly important, as understanding distinct clinical profiles could help researchers and clinicians refine treatment approaches based on trauma type. To address this question, we conducted a search of the available literature in PsycINFO and PubMed prior to October 2022. We identified 43 articles evaluating the distinct and overlapping clinical symptoms of CE and MST. Study findings were conceptually organized by psychiatric condition. In general, there was substantial variability in study methodology including sample size, composition, and operationalizations of CE and MST. Despite this variability, notable patterns emerged across studies. Specifically, MST and CE uniquely predicted posttraumatic stress disorder symptoms, MST was more related to depressive symptoms and suicidality than CE, and CE appeared to be more related to alcohol use and other externalizing behaviors. Gender also played a significant role in the relationship between CE, MST, and clinical variables across studies. This review suggests that individuals with a history of MST and CE likely have distinct clinical presentations and more research into these presentations could better inform assessment and treatment. Important methodological gaps in the literature are also discussed.

Preliminary Observations of Resting-State Magnetoencephalography in Nonmedicated Children with Obsessive-Compulsive Disorder

Background: Cortico-striato-thalamo-cortical (CSTC) network alterations are hypothesized to contribute to symptoms of obsessive-compulsive disorder (OCD). To date, very few studies have examined whether CSTC network alterations are present in children with OCD, who are medication naive. Medication-naive pediatric imaging samples may be optimal to study neural correlates of illness and identify brain-based markers, given the proximity to illness onset. Methods: Magnetoencephalography (MEG) data were analyzed at rest, in 18 medication-naive children with OCD (M = 12.1 years ±2.0 standard deviation [SD]; 10 M/8 F) and 13 typically developing children (M = 12.3 years ±2.2 SD; 6 M/7 F). Whole-brain MEG-derived resting-state functional connectivity (rs-fc), for alpha- and gamma-band frequencies were compared between OCD and typically developing (control) groups. Results: Increased MEG-derived rs-fc across alpha- and gamma-band frequencies was found in the OCD group compared to the control group. Increased MEG-derived rs-fc at alpha-band frequencies was evident across a number of regions within the CSTC circuitry and beyond, including the cerebellum and limbic regions. Increased MEG-derived rs-fc at gamma-band frequencies was restricted to the frontal and temporal cortices. Conclusions: This MEG study provides preliminary evidence of altered alpha and gamma networks, at rest, in medication-naive children with OCD. These results support prior findings pointing to the relevance of CSTC circuitry in pediatric OCD and further support accumulating evidence of altered connectivity between regions that extend beyond this network, including the cerebellum and limbic regions. Given the substantial portion of children and youth whose OCD symptoms do not respond to conventional treatments, our findings have implications for future treatment innovation research aiming to target and track whether brain patterns associated with having OCD may change with treatment and/or predict treatment response.

Classification of posttraumatic stress disorder and related outcomes in women veterans using magnetoencephalography

Women veterans represent a unique population whose experiences and neurobiology differ from that of their male counterparts. Thus, while previous research has demonstrated the utility of synchronous neural interactions (SNI) as a biomarker of posttraumatic stress disorder (PTSD) in male veterans, the utility of SNI as a biomarker of PTSD in women veterans is unclear. Here we extend that line of research to evaluate classification of women veterans with and without PTSD and other trauma-related outcomes based on functional connectivity using magnetoencephalography (MEG). A total of 121 U.S. women veterans completed diagnostic interviews and underwent a task-free MEG scan from which SNI was computed. Linear discriminant analysis was used to classify PTSD and control groups according to SNI. That discriminant function was then used to classify each individual in the partial recovery and full recovery diagnostic groups as PTSD or control. All individuals were classified correctly (100% accuracy) according to their SNI in their PTSD and control groups. Seventy-seven percent of the full recovery group and 69% of the partial recovery group were classified as control. Individual staging in PTSD recovery was captured by the Mahalanobis D² distances from the center of the control and PTSD centroid clusters. These findings provide compelling evidence supporting the utility of task-free SNI as a biomarker of PTSD and related outcomes in women veterans.

The effect of stress and reward on encoding future fear memories

Prior experience changes the way we learn about our environment. Stress predisposes individuals to developing psychological disorders, just as positive experiences protect from this eventuality (Kirkpatrick & Heller, 2014; Koenigs & Grafman, 2009; Pechtel & Pizzagalli, 2011). Yet current models of how the brain processes information often do not consider a role for prior experience. The considerable literature that examines how stress impacts the brain is an exception to this. This research demonstrates that stress can bias the interpretation of ambiguous events towards being aversive in nature, owed to changes in amygdala physiology (Holmes et al., 2013; Perusini et al., 2016; Rau et al., 2005; Shors et al., 1992). This is thought to be an important model for how people develop anxiety disorders, like post-traumatic stress disorder (PTSD; Rau et al., 2005). However, more recent evidence suggests that experience with reward learning can also change the neural circuits that are involved in learning about fear (Sharpe et al., 2021). Specifically, the lateral hypothalamus, a region typically restricted to modulating feeding and reward behavior, can be recruited to encode fear memories after experience with reward learning. This review discusses the literature on how stress and reward change the way we acquire and encode memories for aversive events, offering a testable model of how these regions may interact to promote either adaptive or maladaptive fear memories.

Social cognition in post-traumatic stress disorder: A systematic review

OBJECTIVES

Post-traumatic stress disorder (PTSD) is a common psychiatric condition. Patients with PTSD have marked symptoms that significantly impair their social and emotional abilities, and numerous studies have explored this issue. We hypothesized that impairment of social cognition takes part in functional disability of individuals with PTSD.

METHODS

We conducted a systematic review by querying PubMed database for the titles of articles published up to February 2018 with the terms [PTSD] [Post traumatic disorder] AND [Emotion recognition] OR [Facial expression of emotion] OR [Facial expression perception] OR [Empathy] OR [Affective empathy] OR [Mentalizing] OR [Social cognition] OR [Theory of Mind] OR [Mental state attribution] OR [Cognitive empathy] OR [Emotional empathy] OR [Social behaviour deficits].

RESULTS

Our results suggest that affective and cognitive aspect of theory of mind is comprehensively disturbed in patients with PTSD, showing a significant impairment in their ability to predict what others feel, think, or believe. They could also be massively altered in their perception of basic emotional expressions whether it is an expression of threat or happiness. Their affective empathy appears to be systematically disturbed and correlated to verbal and/or physical aggressive behaviour.

CONCLUSIONS

Social cognition is disturbed in PTSD and should be regarded as an important symptom. Damages in social cognition seem to take part in the functional disability of people with PTSD. We highlight the interest of a systematic assessment of social cognition in the care of patients with PTSD and suggest which tests could be the most relevant for this evaluation.

PRACTITIONER POINTS

•PTSD is no longer regarded as a subtype of anxiety disorder, but as part of a new category in the DSM-5. In clinical practice, symptoms tied to alterations in arousal and reactivity - such as irritability and vigilance - and to the disturbance of cognition and mood, are particularly closely correlated with poorer quality of life. Impaired social cognition clearly impacts the functional disability of people with PTSD. There are potential benefits of individualized cognitive remediation based on empathy and the emotional component of ToM (cognitive remediation, cognitive-behavioural therapy, therapeutic education, etc.) in PTSD people.

Spatial and spectral trajectories in typical neurodevelopment from childhood to middle age

Detailed characterization of typical human neurodevelopment is key if we are to understand the nature of mental and neurological pathology. While research on the cellular processes of neurodevelopment has made great advances, in vivo human imaging is crucial to understand our uniquely human capabilities, as well as the pathologies that affect them. Using magnetoencephalography data in the largest normative sample currently available (324 participants aged 6-45 years), we assess the developmental trajectory of resting-state oscillatory power and functional connectivity from childhood to middle age. The maturational course of power, indicative of local processing, was found to both increase and decrease in a spectrally dependent fashion. Using the strength of phase-synchrony between parcellated regions, we found significant linear and nonlinear (quadratic and logarithmic) trajectories to be characterized in a spatially heterogeneous frequency-specific manner, such as a superior frontal region with linear and nonlinear trajectories in theta and gamma band respectively. Assessment of global efficiency revealed similar significant nonlinear trajectories across all frequency bands. Our results link with the development of human cognitive abilities; they also highlight the complexity of neurodevelopment and provide quantitative parameters for replication and a robust footing from which clinical research may map pathological deviations from these typical trajectories.

Angry and Fearful Face Conflict Effects in Post-traumatic Stress Disorder

In the presence of threatening stimuli, post-traumatic stress disorder (PTSD) can manifest as hypervigilance for threat and disrupted attentional control. PTSD patients have shown exaggerated interference effects on tasks using trauma-related or threat stimuli. In studies of PTSD, faces with negative expressions are often used as threat stimuli, yet angry and fearful facial expressions may elicit different responses. The modified Eriksen flanker task, or the emotional face flanker, has been used to examine response interference. We compared 23 PTSD patients and 23 military controls on an emotional face flanker task using angry, fearful and neutral expressions. Participants identified the emotion of a central target face flanked by faces with either congruent or incongruent emotions. As expected, both groups showed slower reaction times (RTs) and decreased accuracy on emotional target faces, relative to neutral. Unexpectedly, both groups showed nearly identical interference effects on fearful and neutral target trials. However, post hoc testing suggested that PTSD patients showed faster RTs than controls on congruent angry faces (target and flanker faces both angry) relative to incongruent, although this finding should be interpreted with caution. This possible RT facilitation effect with angry, but not fearful faces, also correlated positively with self-report measures of PTSD symptoms. These results suggest that PTSD patients may be more vigilant for, or primed to respond to, the appearance of angry faces, relative to fearful, but further study is needed.

Veterans with PTSD demonstrate amygdala hyperactivity while viewing threatening faces: A MEG study

Posttraumatic stress disorder (PTSD) is a major psychiatric disorder that is prevalent in combat veterans. Previous neuroimaging studies have found elevated amygdala activity in PTSD in response to threatening stimuli, but previous work has lacked the temporal specificity to study fast bottom-up fear responses involving the amygdala. Forty-four combat veterans, 28 with PTSD and 16 without, completed psychological testing and then a face-processing task during magnetoencephalography (MEG). The resulting MEG data were pre-processed, transformed into the time-frequency domain, and then imaged using a beamforming approach. We found that veterans with PTSD exhibited significantly stronger oscillatory activity from 50 to 450 ms in the left amygdala compared to veterans without PTSD while processing threatening faces. This group difference was not present while viewing neutral faces. The current study shows that amygdala hyperactivity in response to threatening cues begins quickly in PTSD, which makes theoretical sense as an adaptive bottom-up fear response.

Separable Effects of Childhood Maltreatment and Adult Adaptive Functioning on Amygdala Connectivity During Emotion Processing

BACKGROUND

Individuals with a history of maltreatment show altered amygdala reactivity to emotional stimuli, atypical frontal regulatory control, and differences in frontolimbic connectivity compared with nonmaltreated controls. However, despite early trauma, many individuals who experience maltreatment show resilience or adaptive functioning in adulthood including positive social, educational, and occupational outcomes.

METHODS

The present study used a psychophysiological interaction model to examine the effect of adult adaptive functioning on group differences between maltreated and nonmaltreated adults in task-based amygdala functional connectivity. The task used was a facial emotion-matching paradigm. Functional magnetic resonance imaging scans were collected from 41 adults with a history of substantiated childhood maltreatment and 39 nonmaltreated adults who were well matched on demographic variables, all of whom had been studied since childhood. Adaptive functioning was measured with a composite score of success on stage-salient developmental tasks.

RESULTS

Consistent with previous research, we found differences in task-related amygdala functional connectivity between the maltreated and nonmaltreated groups. Effects were seen in the left hippocampus, right dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and right thalamus. However, when adult functioning was included in the model, maltreatment-related differences in amygdala connectivity were observed only in the hippocampus. Adult adaptive functioning independently predicted task-related amygdala connectivity in frontal and parietal regions across the entire sample.

CONCLUSIONS

These results suggest that frontolimbic functional connectivity is predicted by positive developmental adaptation in this high-risk population, regardless of maltreatment history, whereas intralimbic connectivity (amygdala and hippocampus) is more specifically associated with maltreatment history.

Paradoxical Prefrontal-Amygdala Recruitment to Angry and Happy Expressions in Pediatric Posttraumatic Stress Disorder

The neural substrates of pediatric posttraumatic stress disorder (PTSD) remain incompletely understood, but likely involve abnormal function and development of emotion processing circuitry. Valence-specific and age-related abnormalities during emotion processing have not been elucidated. We examined implicit emotional face processing in pediatric PTSD, predicting abnormalities specific to threat-related emotion. Youth (ages 8-18 years) with PTSD (n=25) and healthy youth (n=28) completed a dynamic emotional face task during fMRI, viewing faces changing from neutral to angry or happy, or changing shape control. Group and cross-sectional age-related differences in activation and functional connectivity were examined in amygdala/hippocampus, medial prefrontal cortex (mPFC), and whole-brain analyses. The post hoc analyses examined the relationship of neural abnormalities with symptom measures of PTSD, anxiety, and depression. Compared with decreased activation with age in healthy youth, PTSD youth showed increased amygdala activation to emotional faces with age. In a group by emotion interaction, PTSD youth showed dorsal (d)ACC hyperactivation to happy faces relative to healthy youth, with no difference for angry faces. Connectivity analyses revealed paradoxical coupling in prefrontal-amygdala circuits, including dACC-dorsomedial (dm)PFC, amygdala-dmPFC, and amygdala-ventrolateral (vl)PFC. In each case, PTSD youth showed reduced connectivity to angry faces, but increased connectivity to happy faces, the reverse of healthy youth. Valence-abnormal recruitment was associated with greater symptom severity, implicating a role in trauma-related psychopathology in youth. Notably, impaired recruitment during angry faces and heightened recruitment to happy faces may reflect increased salience and ambiguity of positive emotional expressions in pediatric PTSD. Finally, age-related findings suggest a developmental sensitization of the amygdala across emotional expressions in youth with PTSD. These findings provide novel insights into the underlying pathophysiology of pediatric PTSD, extending beyond abnormal neural responses to canonical threat.