Dysregulated functional brain connectivity in response to acute social-evaluative stress in adolescents with PTSD symptoms

Neurobiological correlates of resilience during childhood and adolescence - A systematic review

Research examining the neurobiological mechanisms of resilience has grown rapidly over the past decade. However, there is vast heterogeneity in research study design, methods, and in how resilience is operationalized, making it difficult to gauge what we currently know about resilience biomarkers. This preregistered systematic review aimed to review and synthesize the extant literature to identify neurobiological correlates of resilience to adversity during childhood and adolescence. Literature searches on MEDLINE and PsycINFO yielded 3834 studies and a total of 49 studies were included in the final review. Findings were synthesized based on how resilience was conceptualized (e.g., absence of psychopathology, trait resilience), and where relevant, the type of outcome examined (e.g., internalizing symptoms, post-traumatic stress disorder). Our synthesis showed that findings were generally mixed. Nevertheless, some consistent findings suggest that resilience neural mechanisms may involve prefrontal and subcortical regions structure/activity, as well as connectivity between these regions. Given substantial heterogeneity in the definition and operationalization of resilience, more methodological consistency across studies is required for advancing knowledge in this field.

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.

Biological markers in clinical psychological research - A systematic framework applied to HPA axis regulation in PTSD

Biological markers, particularly endocrine measurements, are increasingly being integrated into clinical psychological research. We introduce a systematic framework that classifies different functions of such biomarkers. The framework distinguishes between diagnostic biomarkers which add a biological perspective to conventional clinical assessments, prognostic biomarkers that inform about an individual’s risk to develop or maintain a mental health disorder, and intervention-related biomarkers. Regarding interventions, including prevention and treatment, it further distinguishes between prescriptive biomarkers which predict an individual’s response to an intervention, outcome biomarkers which evaluate intervention-related changes on a biological level and indicators of change mechanisms. We demonstrate how to apply the framework by exemplarily classifying and describing previously published systematic reviews and primary empirical studies on endogenous, peripheral cortisol concentrations as a biomarker for posttraumatic stress disorder (PTSD). The evidence on cortisol’s diagnostic and prognostic value is heterogeneous and still sparse regarding parameters based on multiple cortisol measurements, such as the cortisol awakening response. With regard to interventions, most research focused on trauma-focused psychotherapy and cortisol reactivity to trauma reminders. This field of research appears to be growing and very promising due to its potential to optimize PTSD-related interventions. The proposed framework can help in gaining a systematic overview of existing research. It can assist in structuring, comparing, summarizing and evaluating empirical studies, and in identifying research gaps.

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Iagnostic biomarkers can inform about biological alterations in mental disorders.

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Prognostic biomarkers can help to predict the development of a mental disorder.

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Biomarkers can indicate the outcome, differential effects, or mechanisms of change of clinical psychological interventions.

The Neurobiology of Infant Attachment-Trauma and Disruption of Parent-Infant Interactions

Current clinical literature and supporting animal literature have shown that repeated and profound early-life adversity, especially when experienced within the caregiver-infant dyad, disrupts the trajectory of brain development to induce later-life expression of maladaptive behavior and pathology. What is less well understood is the immediate impact of repeated adversity during early life with the caregiver, especially since attachment to the caregiver occurs regardless of the quality of care the infant received including experiences of trauma. The focus of the present manuscript is to review the current literature on infant trauma within attachment, with an emphasis on animal research to define mechanisms and translate developmental child research. Across species, the effects of repeated trauma with the attachment figure, are subtle in early life, but the presence of acute stress can uncover some pathology, as was highlighted by Bowlby and Ainsworth in the 1950s. Through rodent neurobehavioral literature we discuss the important role of repeated elevations in stress hormone corticosterone (CORT) in infancy, especially if paired with the mother (not when pups are alone) as targeting the amygdala and causal in infant pathology. We also show that following induced alterations, at baseline infants appear stable, although acute stress hormone elevation uncovers pathology in brain circuits important in emotion, social behavior, and fear. We suggest that a comprehensive understanding of the role of stress hormones during infant typical development and elevated CORT disruption of this typical development will provide insight into age-specific identification of trauma effects, as well as a better understanding of early markers of later-life pathology.

Autonomic nervous system correlates of posttraumatic stress symptoms in youth: Meta-analysis and qualitative review

Physiological dysregulation is a key diagnostic criterion for posttraumatic stress disorder (PTSD). While PTSD is defined by trauma exposure, symptom presentations are varied. Similarly, findings of autonomic nervous system (ANS), including parasympathetic (PNS) and sympathetic nervous system (SNS), function in youth exposed to trauma are mixed (e.g., hyporeactivity and hyperreactivity). The present meta-analysis quantitatively assesses the relation between ANS measures broadly, and PNS- and SNS-specific measures, and posttraumatic stress symptoms (PTSS) in youth (ages 4.98 to 19.55 years) across 38 cross-sectional and longitudinal studies (N = 3488). Findings demonstrate that heightened ANS activity is related to increased PTSS during stress tasks (r = 0.07), while decreased SNS activity at rest corresponded to increased PTSS (r = -0.09). The correlation between PNS measures and PTSS was non-significant. The moderation effect of age on the relation between PNS activity measured during stress tasks and PTSS approached significance, such that younger children showed a stronger negative relation between symptoms and PNS activity compared to older youth. Qualitative review of included studies revealed significant variability across sample and stressor characteristics and study methodology. Findings indicate the importance of autonomic dysregulation in youth with PTSS. Additional considerations for future research are discussed.