Neural correlates of individual differences in anxiety sensitivity: an fMRI study using semantic priming

The Neurophysiology of Interoceptive Disruptions in Trauma-Exposed Populations

In the aftermath of psychological trauma, many individuals experience perturbations in interoception, a term that broadly references the ability to accurately detect body signals and integrate these signals with emotional states. These interoceptive disruptions can manifest in different ways, including blunting or amplification of sensitivity to internal physiological signals. In this chapter we review extant neurophysiological research on interoception in trauma-exposed populations, with a particular focus on the effects of chronic interpersonal trauma, such as childhood maltreatment and racial discrimination. We explore research that used different types of interoceptive assays, from self-report measures to electrophysiological and neuroimaging tools to characterize the disruptions in pain perception, interoceptive acuity, and physiological responses that may arise after a traumatic event. Finally, we discuss interventions that are designed to target interoceptive mechanisms, from exposure-based therapies to mindfulness-based practices, as well as future directions in trauma interoception research.

Association between dimensions of trauma-related psychopathology and asthma in trauma-exposed women

Introduction

Exposure to traumatic events and stressful life experiences are associated with a wide range of adverse mental and physical health outcomes. Studies have found post-traumatic stress disorder (PTSD), depression, and anxiety sensitivity occurrence to be common in addition to inflammatory diseases like asthma, especially in women. Moreover, overlapping neurobiological mechanisms have been linked to both PTSD and asthma.

Methods

In the current study, n = 508 women reported on presence of lifetime asthma diagnosis and symptoms of trauma-related psychopathology including PTSD and depression. A separate group of female participants (n = 64) reported on asthma, PTSD, depression and anxiety sensitivity, and underwent functional MRI scans during a fearful faces task, and their anterior insula responses were analyzed.

Results

Overall, PTSD and depression severity were significantly higher in those with asthma versus those without asthma. There was a positive association between anterior insula response to social threat cues and depression symptoms only among individuals without a lifetime presence of asthma.

Discussion

These findings provide continued evidence on the interactions between stress, neural mechanisms involved in interoception and salience detection, and trauma-related psychopathology.

Processing negative emotion in two languages of bilinguals: Accommodation and assimilation of the neural pathways based on a meta-analysis

Numerous functional magnetic resonance imaging (fMRI) studies have examined the neural mechanisms of negative emotional words, but scarce evidence is available for the interactions among related brain regions from the functional brain connectivity perspective. Moreover, few studies have addressed the neural networks for negative word processing in bilinguals. To fill this gap, the current study examined the brain networks for processing negative words in the first language (L1) and the second language (L2) with Chinese-English bilinguals. To identify objective indicators associated with negative word processing, we first conducted a coordinate-based meta-analysis on contrasts between negative and neutral words (including 32 contrasts from 1589 participants) using the activation likelihood estimation method. Results showed that the left medial prefrontal cortex (mPFC), the left inferior frontal gyrus (IFG), the left posterior cingulate cortex (PCC), the left amygdala, the left inferior temporal gyrus (ITG), and the left thalamus were involved in processing negative words. Next, these six clusters were used as regions of interest in effective connectivity analyses using extended unified structural equation modeling to pinpoint the brain networks for bilingual negative word processing. Brain network results revealed two pathways for negative word processing in L1: a dorsal pathway consisting of the left IFG, the left mPFC, and the left PCC, and a ventral pathway involving the left amygdala, the left ITG, and the left thalamus. We further investigated the similarity and difference between brain networks for negative word processing in L1 and L2. The findings revealed similarities in the dorsal pathway, as well as differences primarily in the ventral pathway, indicating both neural assimilation and accommodation across processing negative emotion in two languages of bilinguals.

Anxiety sensitivity and bodily kinematics

Anxiety sensitivity (AS) is an individual difference factor reflecting the fear of anxiety-related sensations and is one of the best researched risk factors for psychopathology. Decades of research have focused on exploring the relations between AS and clinical symptoms and disorders, although most of the research has employed self-report or interview-based methodologies to index primary dependent measures. No past research has sought to characterize the explanatory relevance of AS from a body kinematics perspective. The present study explored AS in relation to body kinematics to AS-specific images using a dual-task attentional control paradigm (i.e., approach versus avoidance) that employs AS-specific stimuli and motion-tracking technology. Participants included 108 young adults (58.3% female, M age = 25.3) who took part in a ball catching game to index their measures of behavioral engagement with the AS-specific and neutral stimuli presented at either side of the game environment. After adjusting for age, gender, race, handedness, physical functioning, and negative affectivity, self-reported AS was significantly associated with biokinematically-driven behavioral engagement with the AS-specific stimuli. The present study provides novel empirical evidence that AS is related to anxiety-related bodily kinematics. Future work is needed to extend the current results to clinical samples.

Cognitive Vulnerability in the Context of Panic: Assessment of Panic-Related Associations and Interpretations in Individuals with Varying Levels of Anxiety Sensitivity

Background

Cognitive models of panic disorder (PD) highlight the role of panic-related associations and interpretations. However, results are mixed and rely on specific measures. This study examined panic-related associations and interpretations using established and new paradigms in individuals varying on anxiety sensitivity (AS).

Methods

Associations were measured using a priming task and a novel Single Target Implicit Association Test (STIAT); interpretations were assessed using the Interpretation Bias Questionnaire (IBQ) and a novel Scrambled Sentences Task (SST). Symptoms were assessed via a provocation task (Straw Breathing Task, SBT).

Results

Panic-related interpretations correlated with AS and other PD-related measures. Of the association tasks, only the priming task correlated with one of the other PD-related measures. Panic-related interpretations assessed via the SST, but not priming, STIAT, and IBQ, predicted SBT reactivity. The relationship between AS and SBT reactivity was mediated by panic-related interpretations.

Conclusions

Our data provide support for panic-related interpretations as an important cognitive mechanism.

Prefrontal-amygdala connectivity in trait anxiety and generalized anxiety disorder: Testing the boundaries between healthy and pathological worries

BACKGROUND

Current brain-based theoretical models of generalized anxiety disorder (GAD) suggest a dysfunction of amygdala-ventromedial prefrontal cortex emotional regulatory mechanisms. These alterations might be reflected by an altered resting state functional connectivity between both areas and could extend to vulnerable non-clinical samples such as high worriers without a GAD diagnosis. However, there is a lack of information in this regard.

METHODS

We investigated differences in resting state functional connectivity between the basolateral amygdala and the ventromedial prefrontal cortex (amygdala-vmPFC) in 28 unmedicated participants with GAD, 28 high-worriers and 28 low-worriers. We additionally explored selected clinical variables as predictors of amygdala-vmPFC connectivity, including anxiety sensitivity.

RESULTS

GAD participants presented higher left amygdala-vmPFC connectivity compared to both groups of non-GAD participants, and there were no differences between the latter two groups. In our exploratory analyses, concerns about the cognitive consequences of anxiety (the cognitive dimension of anxiety sensitivity) were found to be a significant predictor of the left amygdala-vmPFC connectivity.

LIMITATIONS

The cross-sectional nature of our study preclude us from assessing if functional connectivity measures and anxiety sensitivity scores entail an increased risk of GAD.

CONCLUSIONS

These results suggest a neurobiological qualitative distinction at the level of the amygdala-vmPFC emotional-regulatory system in GAD compared to non-GAD participants, either high- or low-worriers. At this neural level, they question previous hypotheses of continuity between high worries and GAD development. Instead, other anxiety traits such as anxiety sensitivity might confer a greater proneness to the amygdala-vmPFC connectivity alterations observed in GAD.

Effect of CBT on Biased Semantic Network in Panic Disorder: A Multicenter fMRI Study Using Semantic Priming

OBJECTIVE

Cognitive-behavioral therapy (CBT) has been hypothesized to act by reducing the pathologically enhanced semantic, anxiety-related associations of patients with panic disorder. This study investigated the effects of CBT on the behavioral and neural correlates of the panic-related semantic network in patients with panic disorder.

METHODS

An automatic semantic priming paradigm specifically tailored for panic disorder, in which panic symptoms (e.g., "dizziness") were primed by panic triggers (e.g., "elevator") compared with neutral words (e.g., "bottle"), was performed during functional MRI scanning with 118 patients with panic disorder (compared with 150 healthy control subjects) before and 42 patients (compared with 52 healthy control subjects) after an exposure-based CBT. Neural correlates were investigated by comparing 103 pairs of matched patients and control subjects at the baseline (for patients) or T1 (for control subjects) assessment and 39 pairs at the posttreatment or T2 assessment.

RESULTS

At baseline or T1, patients rated panic-trigger/panic-symptom word pairs with higher relatedness and higher negative valence compared with healthy control subjects. Patients made faster lexical decisions to the panic-symptom words when they were preceded by panic-trigger words. This panic-priming effect in patients (compared with control subjects) was reflected in suppressed neural activation in the left and right temporal cortices and insulae and enhanced activation in the posterior and anterior cingulate cortices. After CBT, significant clinical improvements in the patient group were observed along with a reduction in relatedness and negative valence rating and attenuation of neural activation in the anterior cingulate cortex for processing of panic-trigger/panic-symptom word pairs.

CONCLUSIONS

The findings support a biased semantic network in panic disorder, which is normalized after CBT. Attenuation of anterior cingulate cortex activation for processing of panic-related associations provides a potential mechanism for future therapeutic interventions.

Characterizing the nature of emotional-associative learning deficits in panic disorder: An fMRI study on fear conditioning, extinction training and recall

Emotional-associative learning represents a translational model for the development, maintenance and treatment of anxiety disorders such as panic disorder (PD). The exact nature of the underlying fear learning and extinction deficits however, remains under debate. Using a three-day paradigm to separate the distinct learning and consolidation processes, we aimed to gain insights into the neurofunctional substrates of altered fear conditioning, extinction training and recall in PD. In contrast to studies employing one-session fear conditioning paradigms, a differential fear conditioning and delayed extinction task was conducted for the purpose of disentangling neural networks involved in fear acquisition, extinction training and recall of extinction memories. Using functional magnetic resonance imaging (fMRI), quality-controlled datasets from 10 patients with PD and 10 healthy controls were available from three consecutive days (day 1: acquisition; day 2: extinction training; day 3: extinction recall) with neutral faces serving as CSs and an aversive auditory stimulus (panic scream) as US. PD patients showed heightened fear circuitry (e.g. right amygdala and left insula) activation during early acquisition and prolonged activation in the right insula, left inferior frontal operculum and left inferior frontal gyrus during extinction recall compared to healthy controls. Stronger neural activation in structures conferring defensive reactivity during early acquisition and extinction recall may indicate the accelerated acquisition of conditioned responses, while extinction recall may be attenuated as a function of PD pathophysiology. Future studies should investigate the predictive value of experimental measures of extinction recall for clinical relapse.

Functional criticality in the human brain: Physiological, behavioral and neurodevelopmental correlates

Understanding the critical features of the human brain at multiple time scales is vital for both normal development and disease research. A recently proposed method, the vertex-wise Index of Functional Criticality (vIFC) based on fMRI, has been testified as a sensitive neuroimaging marker to characterize critical transitions of human brain dynamics during Alzheimer's disease progression. However, it remains unclear whether vIFC in healthy brains is associated with neuropsychological and neurophysiological measurements. Using the Nathan Kline Institute/Rockland lifespan cross-sectional datasets and openfMRI single participant longitudinal datasets, we found consistent spatial patterns of vIFC across the entire cortical mantle: the inferior parietal and the precuneus exhibited high vIFC. On a time scale of years, we observed that vIFC increased with age in the left ventral posterior cingulate gyrus. On a time scale of days and weeks, vIFC demonstrated the capacity to identify a link between anxiety and pulse. These results showed that vIFC can serve as a useful neuroimaging marker for detecting physiological, behavioral, and neurodevelopmental transitions. Based on the criticality theory in nonlinear dynamics, the current vIFC study sheds new light on human brain studies from a nonlinear perspective and opens potential new avenues for normal and abnormal human brain studies.

Treating breathlessness via the brain: changes in brain activity over a course of pulmonary rehabilitation

Breathlessness in chronic obstructive pulmonary disease (COPD) is often discordant with airway pathophysiology ("over-perception"). Pulmonary rehabilitation profoundly affects breathlessness, without influencing lung function. Learned associations influence brain mechanisms of sensory perception. We hypothesised that improvements in breathlessness with pulmonary rehabilitation may be explained by changing neural representations of learned associations.In 31 patients with COPD, we tested how pulmonary rehabilitation altered the relationship between brain activity during a breathlessness-related word-cue task (using functional magnetic resonance imaging), and clinical and psychological measures of breathlessness.Changes in ratings of breathlessness word cues positively correlated with changes in activity in the insula and anterior cingulate cortex. Changes in ratings of breathlessness-anxiety negatively correlated with activations in attention regulation and motor networks. Baseline activity in the insula, anterior cingulate cortex and prefrontal cortex correlated with improvements in breathlessness and breathlessness-anxiety.Pulmonary rehabilitation is associated with altered neural responses related to learned breathlessness associations, which can ultimately influence breathlessness perception. These findings highlight the importance of targeting learned associations within treatments for COPD, demonstrating how neuroimaging may contribute to patient stratification and more successful personalised therapy.

White matter correlates of anxiety sensitivity in panic disorder

BACKGROUND

Anxiety sensitivity (AS) refers to a fear of anxiety-related sensations and is a dispositional variable especially elevated in patients with panic disorder (PD). Although several functional imaging studies of AS in patients with PD have suggested the presence of altered neural activity in paralimbic areas such as the insula, no study has investigated white matter (WM) alterations in patients with PD in relation to AS. The objective of this study was to investigate the WM correlates of AS in patients with PD.

METHODS

One-hundred and twelve right-handed patients with PD and 48 healthy control (HC) subjects were enrolled in this study. The Anxiety Sensitivity Inventory-Revised (ASI-R), the Panic Disorder Severity Scale (PDSS), the Albany Panic and Phobia Questionnaire (APPQ), the Beck Anxiety Inventory (BAI), and the Beck Depression Inventory (BDI) were administered. Tract-based spatial statistics were used for diffusion tensor magnetic resonance imaging analysis.

RESULTS

Among the patients with PD, the ASI-R total scores were significantly correlated with the fractional anisotropy values of the WM regions near the insula, the splenium of the corpus callosum, the tapetum, the fornix/stria terminalis, the posterior limb of the internal capsule, the retrolenticular part of the internal capsule, the posterior thalamic radiation, the sagittal striatum, and the posterior corona radiata located in temporo-parieto-limbic regions and are involved in interoceptive processing (p<0.01; threshold-free cluster enhancement [TFCE]-corrected). These WM regions were also significantly correlated with the APPQ interoceptive avoidance subscale and BDI scores in patients with PD (p<0.01, TFCE-corrected). Correlation analysis among the HC subjects revealed no significant findings.

LIMITATIONS

There has been no comparative study on the structural neural correlates of AS in PD.

CONCLUSIONS

The current study suggests that the WM correlates of AS in patients with PD may be associated with the insula and the adjacent temporo-parieto-limbic WM regions, which may play important roles in interoceptive processing in the brain and in depression in PD.