Interoception and stress

Post-COVID breathlessness: a mathematical model of respiratory processing in the brain

Breathlessness is among the most common post-COVID symptoms. In a considerable number of patients, severe breathlessness cannot be explained by peripheral organ impairment. Recent concepts have described how such persistent breathlessness could arise from dysfunctional processing of respiratory information in the brain. In this paper, we present a first quantitative and testable mathematical model of how processing of respiratory-related signals could lead to breathlessness perception. The model is based on recent theories that the brain holds an adaptive and dynamic internal representation of a respiratory state that is based on previous experiences and comprises gas exchange between environment, lung and tissue cells. Perceived breathlessness reflects the brain's estimate of this respiratory state signaling a potentially hazardous disequilibrium in gas exchange. The internal respiratory state evolves from the respiratory state of the last breath, is updated by a sensory measurement of CO2 concentration, and is dependent on the current activity context. To evaluate our model and thus test the assumed mechanism, we used data from an ongoing rebreathing experiment investigating breathlessness in patients with post-COVID without peripheral organ dysfunction (N = 5) and healthy control participants without complaints after COVID-19 (N = 5). Although the observed breathlessness patterns varied extensively between individual participants in the rebreathing experiment, our model shows good performance in replicating these individual, heterogeneous time courses. The model assumes the same underlying processes in the central nervous system in all individuals, i.e., also between patients and healthy control participants, and we hypothesize that differences in breathlessness are explained by different weighting and thus influence of these processes on the final percept. Our model could thus be applied in future studies to provide insight into where in the processing cascade of respiratory signals a deficit is located that leads to (post-COVID) breathlessness. A potential clinical application could be, e.g., the monitoring of effects of pulmonary rehabilitation on respiratory processing in the brain to improve the therapeutic strategies.

Spinal Afferent Innervation From Left Dorsal Root Ganglia in the Flat-Mounts of Whole Atria of Rats: Anterograde Tracing

The spinal afferent innervation of the heart helps to regulate cardiac functions by sending sensory information through the dorsal root ganglia (DRG) to the brain. However, the distribution and morphology of spinal afferents in the heart are not well characterized due to tracer selections, the surgical access to upper thoracic DRGs, and the thickness of the heart tissues. In this study, we injected tracer dextran biotin (DB) into the left DRGs (C8-T3) of male Sprague-Dawley rats (3-5 months). After 16 days, flat-mounts of the whole left and right atria were prepared and diaminobenzidine stained. Then, the DB-labeled axons in the tissues were imaged, traced, and digitized using the Neurolucida system. Our results showed that the DB-labeled axons from left DRGs entered the left precaval vein and projected to the left and right atria, with predominant projection in the left atrial wall. DB-labeled varicose axons were observed in different layers, mostly in the epicardium and myocardium, but much less in the endocardium. In those layers, these spinal afferent axons branched out into simple to complex terminal arborizations, forming close appositions with cardiac muscles, intrinsic cardiac ganglia, blood vessels, and fat tissue. This work, for the first time, characterized cardiac spinal afferent distribution of the rat atria using anterograde tracing, which will provide the foundation for future studies of topographical cardiac spinal afferent innervation and remodeling in heart disease models.

Heart Rate Variability and Interoception in Periodic Limb Movements in Sleep: Interference with Psychiatric Disorders?

Periodic limb movements in sleep (PLMS) are a prevalent disorder characterized by rhythmic, involuntary movements of the lower limbs, such as dorsiflexion of the ankle and extension of the big toe, occurring in periodic intervals during sleep. These movements are often linked to disrupted autonomic nervous system (ANS) activity and altered interoception. Interoception involves perceiving internal bodily states, like heartbeat, breathing, hunger, and temperature, and plays a crucial role in maintaining homeostasis and the mind-body connection. This review explores the complex relationships between PLMS, heart rate variability (HRV), ANS dysregulation, and their impact on psychiatric disorders. By synthesizing the existing literature, it provides insights into how ANS dysregulation and altered interoceptive processes, alongside PLMS, contribute to psychiatric conditions. The review highlights the potential for integrated diagnostic and therapeutic approaches and presents a cause-and-effect model illustrating the mutual influence of psychiatric disorders, ANS dysregulation, PLMS, and interoception.

Unpredictable threat increases early event-related potential amplitudes and cardiac acceleration: A brain-heart coupling study

In the face of unpredictable threat, rapid processing of external events and behavioral mobilization through early psychophysiological responses are crucial for survival. While unpredictable threat generally enhances early processing, it would seem adaptive to particularly increase sensitivity for unexpected events as they may signal danger. To examine this possibility, n = 77 participants performed an auditory oddball paradigm and received unpredictable shocks in threat but not in safe contexts while a stream of frequent (standard) and infrequent (deviant) tones was presented. We assessed event-related potentials (ERP), heart period (HP), and time-lagged within-subject correlations of single-trial EEG and HP (cardio-EEG covariance tracing, CECT) time-locked to the tones. N1 and P2 ERP amplitudes were generally enhanced under threat. The P3 amplitude was enhanced to deviants versus standards and this effect was reduced in the threat condition. Regarding HP, both threat versus safe and unexpected versus expected tones led to stronger cardiac acceleration, suggesting separate effects of threat and stimulus expectancy on HP. Finally, CECTs revealed two correlation clusters, indicating that single-trial EEG magnitudes in the N1/P2 and P3 time-windows predicted subsequent cardiac acceleration. The current results show that an unpredictable threat context enhances N1 and P2 amplitudes and cardiac acceleration to benign auditory stimuli. They further suggest separable cortical correlates of different effects on cardiac activity: an early N1/P2 correlate associated with threat-effects on HP and a later P3 correlate associated with expectedness-effects. Finally, the results indicate that unpredictable threat attenuates rather than enhances the processing of unexpected benign events during the P3 latency.

BODY AWARENESS, STRESS AND SYMPTOMS IN AUTONOMIC DYSFUNCTION IN PATIENTS WITH CHRONIC PAIN: AN EXPLORATIVE STUDY

Objective

To assess pain outcomes, stress levels and body awareness among patients with chronic pain and explore potential associations between these variables.

Design

An explorative study.

Methods

Patients with chronic pain in primary and specialist care were assessed regarding pain intensity using the Numerical Rating Scale (NRS; 0-10 point scale) and stress levels using the Stress and Crisis Inventory (SCI-93; 0-140). To assess body awareness, multidimensional assessment of interoceptive awareness (MAIA; 0-5), a widely used self-report measure of interoceptive bodily awareness was used.

Results

Participants (n = 42) reported an average NRS of 4.4, elevated stress levels and low body awareness. Stress levels were moderately correlated with pain intensity (r = 0.53; p < 0.001; 95% confidence interval [CI] 0.25-0.72) and number of pain sites (r = 0.58; p < 0.001; 95% CI 0.32-0.76). The regression analysis showed that pain outcomes predicted stress level scores and explained almost 50% of variance (R 2 = 0.47, p < 0.001). Moreover, shorter pain duration predicted a higher body awareness (p = 0.04).

Conclusion

In patients with chronic pain, high pain intensity and multiple painful sites seem to be associated with impaired stress regulation. The patients had low body awareness, which was negatively influenced by pain duration.

Cardiac interoception in the museum: A novel measure of experience

Interoception is the perception of the body's internal signals in response to various external and internal stimuli. The present study uses a novel method adapted from the CARdiac Elevation Detection Task to examine cardiac interoception objectively and subjectively in a unique context-in the presence of art. Self-report questionnaires were used to measure subjective interoceptive awareness, subjective interoceptive accuracy, and aesthetic appreciation. For objective interoceptive accuracy and sensibility, a wearable device (Shimmer) measured heart rate (HR) and connected to a mobile application to prompt two questions: "Is your heart beating faster than usual?" and "How confident are you in your previous response?" Participants explored an art gallery for 40 minutes while the Shimmer measured their HR and randomly prompted them to answer the questions. Using a Generalized Estimating Equation model, interoceptive sensibility was not found to predict the odds of submitting a correct response. It was also found that art does not improve participants' perceptions of their HR. Finally, there was no relation between aesthetic appreciation and subjective or objective cardiac interoception. Despite lack of statistical significance, the current study's method presents an improved method by examining interoceptive accuracy in the moment under ecological conditions. To date, findings and methods used in interoception are inconsistent or flawed; the value in the current study lies in the development and demonstration of a method to examine how the environment influences the body and self-awareness across a wide variety of contexts, thereby offering a possible standardized measure of interoception for investigators to adopt.

Interoceptive awareness in a clinical setting: the need to bring interoceptive perspectives into clinical evaluation

Interoceptive awareness (IA) is crucial to understanding mental health. The Multidimensional Assessment of Interoceptive Awareness (MAIA) scale, available in approximately 30 languages, has gained global recognition for its research applicability. This review highlights the critical importance of integrating IA evaluation in clinical settings, advocating for the MAIA scale's potential as a screening tool. Through an examination of academic databases, including Scopus, PubMed, Google Scholar, and J-STOR, our analysis spans seven mental health domains: eating disorders (ED), depression, stress, anxiety, autism spectrum disorder (ASD), chronic pain, and suicide ideation (SI). Thirty-eight studies showed links between several dimensions of IA with different disorders. That is, ED was related to Body Trust and Self-Regulation; anxiety to Body Listening, Emotional Awareness, and Self-Regulation; depression to Noticing and Emotional Awareness; ASD to Trusting, Emotional Awareness, and Noticing; chronic pain to Not-Worrying and Self-Regulation; and SI with Trusting. These insights hold profound implications for both clinical practice and mental health research. Integrating IA assessments into standard clinical protocols has the potential to improve our understanding of pathology, enrich patient care, and enhance therapeutic strategies.

A roadmap to understanding interoceptive awareness and post-traumatic stress disorder: a scoping review

The concept of interoception has existed since the beginning of the 1900s. It is suggested that humans can observe feelings arising from the body that allows them to develop a sense of their emotional status and physical condition. The term interoceptive awareness appears to originate with clinicians working with individuals who had experienced trauma, in particular Post Traumatic Stress Disorder (PTSD). The purpose of this scoping review was to provide an overview of the existing literature surrounding the combination of these two themes: interoceptive awareness and PTSD. A total of 226 articles were initially screened and 52 articles were retained for comprehensive review. Nine articles were excluded, resulting in 43 studies included in the review. The review aimed to answer: (a) how is interoceptive awareness defined? (b) how is interoceptive awareness measured? (c) what is the function of interoceptive awareness? (d) is there/what is the relationship between interoceptive awareness and PTSD? The scoping review identified nine terms that are used synonymously throughout the literature surrounding interoceptive awareness and PTSD, and three primary ways in which interoceptive awareness is measured in relation to PTSD. The primary function documented was the role interoceptive awareness played in an individual's ability to regulate their emotions, and the most common and compelling function emerging was the association with emotion regulation. The evidence supports the utilisation of a definition of interoceptive awareness to include one that includes the quality of cognitive appraisal and focuses on the adaptive mindful approach to internal physical sensations as opposed to the heightened ruminative self-focus. Limitations and future research are suggested.

Dissociative Symptoms and Interoceptive Integration

Dissociative symptoms and disorders of dissociation are characterised by disturbances in the experience of the self and the surrounding world, manifesting as a breakdown in the normal integration of consciousness, memory, identity, emotion, and perception. This paper aims to provide insights into dissociative symptoms from the perspective of interoception, the sense of the body's internal physiological state, adopting a transdiagnostic framework.Dissociative symptoms are associated with a blunting of autonomic reactivity and a reduction in interoceptive precision. In addition to the central function of interoception in homeostasis, afferent visceral signals and their neural and mental representation have been shown to shape emotional feeling states, support memory encoding, and contribute to self-representation. Changes in interoceptive processing and disrupted integration of interoceptive signals into wider cognition may contribute to detachment from the body and the world, blunted emotional experience, and altered subjective recall, as experienced by individuals who suffer from dissociation.A better understanding of the role of altered interoceptive integration across the symptom areas of dissociation could thus provide insights into the neurophysiological mechanisms underlying dissociative disorders. As new therapeutic approaches targeting interoceptive processing emerge, recognising the significance of interoceptive mechanisms in dissociation holds potential implications for future treatment targets.

The Relationship Between Interoceptive Awareness, Emotion Regulation and Clinical Symptoms Severity of Depression, Anxiety and Somatization

OBJECTIVE

The primary objective of this study was to examine the associations among emotion regulation strategies, interoceptive awareness, and psychological distress measures-namely, depression, anxiety, and somatization. Additionally, we aimed to explore the predictive power of various facets of interoceptive awareness in determining the severity of symptoms for each mental disorder.

METHODS

A cohort of 130 outpatients diagnosed with depression/anxiety disorder were recruited, and 20 subjects exhibiting incomplete responses were excluded from the dataset, leading to a final sample size of 110 outpatients. The clinical symptoms were measured by Patient Health Questionnaire-9, State-Trait Anxiety Inventory Form Y, and Symptom Checklist-90-Revised, and the usage of emotion-regulation strategies and interoceptive awareness was assessed with Emotion Regulation Questionnaire and Multidimensional Assessment of Interoceptive Awareness (MAIA), respectively. A hierarchical regression analysis was performed to examine whether emotion-regulation strategies and interoceptive awareness explain the statistically significant variance in each of the symptoms.

RESULTS

In the depression model, cognitive reappraisal, accept, and attention regulation showed significant associations, while in the anxiety model, cognitive reappraisal, attention regulation, trust, and notice emerged as significant factors. Lastly, cognitive reappraisal and attention regulation were found to be significant contributors to the final model for somatization.

CONCLUSION

The inclusion of MAIA subscales improved the predictive ability of the regression model, highlighting the independent association between interoceptive awareness-particularly attention regulation-and clinical symptoms of anxiety and depression. Additionally, the study underscores the relevance of considering the specific pathological context when implementing interventions, as evidenced by the positive associations between the accept subscale and depression and between the notice subscale and anxiety, respectively.

Age-related positive emotional reactivity decline associated with the anterior insula based resting-state functional connectivity

Recent studies have suggested that emotional reactivity changes with age, but the neural basis is still unclear. The insula may be critical for the emotional reactivity. The current study examined how ageing affects emotional reactivity using the emotional reactivity task data from a human sample (Cambridge Center for Age and Neuroscience, N = 243, age 18-88 years). The resting-state magnetic resonance measurements from the same sample were used to investigate the potential mechanisms of the insula. In the initial analysis, we conducted partial correlation assessments to examine the associations between emotional reactivity and age, as well as between the gray matter volume (GMV) of the insula and age. Our results revealed that emotional reactivity, especially positive emotional reactivity, decreased with age and that the GMV of the insula was negatively correlated with age. Subsequently, the bilateral insula was divided into six subregions to calculate the whole brain resting-state functional connectivity (rsFC). The mediating effect of the rsFC on age and emotional reactivity was then calculated. The results showed that the rsFC of the left anterior insula (AI) with the right hippocampus, and the rsFCs of the right AI with the striatum and the thalamus were mediated the relationship between positive emotional reactivity and age. Our findings suggest that attenuating emotional reactivity with age may be a strategic adaptation fostering emotional stability and diminishing emotional vulnerability. Meanwhile, the findings implicate a key role for the AI in the changes in positive emotional reactivity with age.

Interoceptive beliefs moderate the link between physiological and emotional arousal during an acute stressor

Growing work suggests that interoception, that is, representations of one's internal bodily changes, plays a role in shaping emotional experiences. Past studies primarily examine how behavioral accuracy in detecting interoceptive signals (interoceptive ability) relates to emotional states, with less work examining self-reported interoceptive facets such as the characterizations of one's interoceptive abilities (interoceptive sensibility) or evaluative beliefs about the value versus danger of interoceptive signals (interoceptive beliefs). However, existing studies rarely examine physiological reactivity, behavioral, and self-reported dimensions of interoception together in the same sample. As such, it remains unclear whether and how much individual differences in interoceptive facets uniquely and in interaction with physiological reactivity may matter for emotional experience. Herein, 250 healthy young adults completed a heartbeat detection task assessing interoceptive ability and questionnaire measures of interoceptive sensibility and beliefs during an initial laboratory visit. At a follow-up session, 227 participants returned to undergo an acute psychosocial stressor. Measures of physiological arousal such as preejection period (PEP) and heart rate variability were acquired throughout the stressor with self-reported emotions acquired immediately after. Linear regressions revealed that greater sympathetic nervous system reactivity (i.e., PEP), poorer interoceptive ability (i.e., accuracy), and less positive interoceptive beliefs were related to more intense high arousal emotions during the stressor. Importantly, across models, interoceptive beliefs was the only interoceptive facet to moderate the concordance between physiological and emotional arousal. Implications for psychological theories of emotion, stress, and interoception are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The role of interoception in reducing trauma-associated distress: a feasibility study

Background: Altered interoception plays an important role in chronic stress and posttraumatic stress disorder. The aim of this study was to evaluate the feasibility of a Trauma Sensitive Yoga (TSY) intervention for improving emotional distress and psychological discomfort in women living under circumstances of social and gender vulnerability. We assessed the effect of the treatment on the interoceptive mechanisms, and whether the psychological improvements were mediated by the changes in these mechanisms.Methods: The study involved a sample of 62 women who attended public community centres dedicated to supporting women victims of gender-based violence or who were socially and economically disadvantaged because of their gender. Participants underwent a six-week TSY programme. We evaluated dropout rate, adherence, and intervention satisfaction. We measured emotional distress, psychological discomfort, interoceptive mechanisms, and two nonequivalent dependent variables to enhance internal validity. We compared pre-post differences using paired samples t-test and a structural equation model (SEM) analysis was performed to compare the changes in the outcomes with the changes in the nonequivalent dependent variables. Mediation models were adjusted to evaluate the role of changes in interoception on outcome changes.Results: Fourteen (23%) women dropped out, mainly after the first intervention session. Intervention adherence (mean attendance 5.3 over 6 sessions) and acceptability were high (mean satisfaction 3.4 over 4). We observed post-intervention improvements in anxiety, depression, psychological discomfort, body responsiveness, and interoceptive awareness. The changes in the outcomes were larger than the changes in the nonequivalent dependent variables. Additionally, we found that the changes in body responsiveness partially mediated the change in anxiety and psychological discomfort but not in depression.Conclusions: TSY could be an interesting therapeutic approach for women experiencing chronic posttraumatic stress symptomatology. Our findings underscore the role of interoceptive mechanisms in traumatic stress and emphasize the importance of addressing these aspects.

Brain and cortisol responses to smoking cues are linked in tobacco-smoking individuals

Cues associated with smoking can induce relapse, which is likely driven by cue-induced neurobiological and physiological mechanisms. For instance, greater relapse vulnerability is associated with increases in cue-induced insula activation and heightened cortisol concentrations. Determining if there is a link between such cue-induced responses is critical given the need for biomarkers that can be easily measured in clinical settings and used to drive targeted treatment. Further, comprehensively characterising biological reactions to cues promises to aid in the development of therapies that address this specific relapse risk factor. To determine whether brain and cortisol responses to smoking cues are linked, this study recruited 27 nicotine-dependent tobacco-smoking individuals and acquired whole-brain functional activation during a cue reactivity task; salivary cortisol was measured before and after scanning. The results showed that increases in blood-oxygen-level-dependent activation in the right anterior insula and right dorsolateral prefrontal cortex (DLPFC) when viewing smoking versus neutral cues were positively correlated with a post-scan rise in salivary cortisol concentrations. These brain regions have been previously implicated in substance use disorders for their role in salience, interoception and executive processes. These findings show that those who have a rise in cortisol following smoking cue exposure also have a related rise in cue-induced brain reactivity, in brain regions previously linked with heightened relapse vulnerability. This is clinically relevant as measuring cue-induced cortisol responses is a more accessible proxy for assessing the engagement of cue-induced neurobiological processes associated with the maintenance of nicotine dependence.

The development of compulsive coping behavior depends on dorsolateral striatum dopamine-dependent mechanisms

Humans greatly differ in how they cope with stress, a natural behavior learnt through negative reinforcement. Some individuals engage in displacement activities, others in exercise or comfort eating, and others still in alcohol use. Across species, adjunctive behaviors, such as polydipsic drinking, are used as a form of displacement activity that reduces stress. Some individuals, in particular those that use alcohol to self-medicate, tend to lose control over such coping behaviors, which become excessive and compulsive. However, the psychological and neural mechanisms underlying this individual vulnerability have not been elucidated. Here we tested the hypothesis that the development of compulsive adjunctive behaviors stems from the functional engagement of the dorsolateral striatum (DLS) dopamine-dependent habit system after a prolonged history of adjunctive responding. We measured in longitudinal studies in male Sprague Dawley rats the sensitivity of early established vs compulsive polydipsic water or alcohol drinking to a bilateral infusion into the anterior DLS (aDLS) of the dopamine receptor antagonist α-flupentixol. While most rats acquired a polydipsic drinking response with water, others only did so with alcohol. Whether drinking water or alcohol, the acquisition of this coping response was insensitive to aDLS dopamine receptor blockade. In contrast, after prolonged experience, adjunctive drinking became dependent on aDLS dopamine at a time when it was compulsive in vulnerable individuals. These data suggest that habits may develop out of negative reinforcement and that the engagement of their underlying striatal system is necessary for the manifestation of compulsive adjunctive behaviors.

Lower gastric sensitivity in quiescent inflammatory bowel disease than in irritable bowel syndrome

OBJECTIVE

Visceral hypersensitivity is considered a key symptom in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), both of which seriously affect health-related quality of life (HrQoL). Previous findings are mostly based on invasive procedures that may interfere with the assessment of visceral perception. The current study, therefore, investigates whether IBD and IBS are characterized by altered perception of 'natural' gastric distensions ('interoception').

METHODS

Twenty IBD patients in remission (13 Crohn's disease, 7 ulcerative colitis), 12 IBS patients, and 20/12 matched healthy control (HC) individuals, respectively, underwent the water load test, in which they could drink ad libitum until the subjective thresholds of satiation (stage 1) and fullness (stage 2) were reached. Gastric motility was assessed using electrogastrography.

RESULTS

IBD patients drank significantly more water until satiation than IBS patients, whereas no differences between patients and HC groups were observed. Electrogastrographic patterns were comparable between groups, suggesting no pathologies in gastric motility in IBD or IBS. The amount of water consumed until satiation negatively correlated with HrQoL related to bowel symptoms in IBD patients, but was positively associated with emotional well-being in IBS patients.

CONCLUSION

Our findings implicate relative gastric hypersensitivity in IBS, and relative hyposensitivity in IBD patients, which are both related to specific HrQoL aspects.

Is intuitive eating a privileged approach? Cross-sectional and longitudinal associations between food insecurity and intuitive eating

OBJECTIVE

To examine: (1) cross-sectional and longitudinal associations between measures of food insecurity (FI; household status and youth-reported) and intuitive eating (IE) from adolescence to emerging adulthood; and (2) the association between FI persistence and IE in emerging adulthood.

DESIGN

Longitudinal population-based study. Young people reported IE and FI (two items from the US Household Food Security Module) in adolescence and emerging adulthood. Parents provided data on household FI via the six-item US Household Food Security Module in adolescence.

SETTING

Adolescents (Mage = 14·3 ± 2 years) and their parents, recruited from Minneapolis/St. Paul public schools in 2009-2010 and again in 2017-2018 as emerging adults (Mage = 22·1 ± 2 years).

PARTICIPANTS

The analytic sample (n 1372; 53·1 % female, 46·9 % male) was diverse across race/ethnicity (19·8 % Asian, 28·5 % Black, 16·6 % Latinx, 14·7 % Multiracial/Other and 19·9 % White) and socio-economic status (58·6 % low/lower middle, 16·8 % middle and 21·0 % upper middle/high).

RESULTS

In cross-sectional analyses, youth-reported FI was associated with lower IE during adolescence (P = 0·02) and emerging adulthood (P < 0·001). Longitudinally, household FI, but not adolescent experience of FI, was associated with lower IE in emerging adulthood (P = 0·01). Those who remained food-insecure (P = 0·05) or became food-insecure (P = 0·02) had lower IE in emerging adulthood than those remaining food-secure. All effect sizes were small.

CONCLUSIONS

Results suggest FI may exert immediate and potentially lasting impacts on IE. As evidence suggests IE is an adaptive approach conferring benefits beyond eating, it would be valuable for interventions to address social and structural barriers that could impede IE.

A Primer on Interoception and its Importance in Psychiatry

Interoception is the perception of signals from inside the body. It plays a significant role in the nervous, cardiovascular, respiratory, gastrointestinal, genitourinary, and endocrine systems. It is also closely related to the autonomic nervous system and inflammatory pathways and plays a significant role in our optimal functioning. Recently, interoception has gained more attention in neuropsychiatric research. Anatomical and physiological aspects of interoception like relevant brain areas, the role of the vagus nerve, and the autonomic nervous system are gradually being understood. Different facets of interoception like interoceptive attention, detection, magnitude, discrimination, accuracy, awareness, and appraisal have been proposed and their assessments and importance are being evaluated. Further, interoception is often dysregulated or abnormal in psychiatric disorders. It has been implicated in the psychopathology, etiopathogenesis, clinical features and treatment of mood, anxiety, psychotic, personality and addiction-related disorders. This narrative review attempts to provide a nuanced understanding of the pathway(s), components, functions, assessments, and problems of interoception and will help us to detect its disturbances and evaluate its impact on psychiatric disorders, leading to a better perspective and management. This will also advance interoception-related research.

Connecting dots in disorders of gut-brain interaction: the interplay of stress and sex hormones in shaping visceral pain

Visceral pain and stress are tightly intertwined bodily and emotional phenomena, which enable a flexible adaptation to environmental challenges by activating a response repertoire to restore homeostasis along the gut-brain axis. However, visceral pain and stress can persist widely independent of the initial cause, acquiring independent disease values and posing major health burdens as predominant features in disorders of gut-brain interaction (DGBI). Epidemiological data consistently documents an increased prevalence for women to suffer from chronic visceral pain, possibly shaped by sex hormones and modulated by stress and its biological and psychosocial correlates. Yet, mechanisms underlying the complex interactions between altered visceroception, stress and sex remain widely elusive, especially in clinical populations with DGBI. We herein selectively review mechanisms of interactions between stress and sex in the complex pathophysiology of DGBI. A particular emphasis is laid on visceral pain, in which stress constitutes a major risk factor as well as mediator, and sex-related differences are particularly pronounced. Building on the neurobiology of stress and mechanisms of gut-brain interactions, we highlight putative target mechanisms via which visceral pain and stress may converge with sex effects into a triad. Accommodating a global demographic shift, we propose a lifespan perspective in future research, which may enable a more fine-tuned evaluation of this complex interplay exerting distinct challenges during vulnerable developmental phases. This viewpoint may advance our understanding of pathophysiological processes and can ultimately inspire novel tailored prevention strategies and therapeutic approaches in the treatment of chronic visceral pain and DGBI across the lifespan.

Dynamic fluctuations in ascending heart-to-brain communication under mental stress

Dynamical information exchange between central and autonomic nervous systems, as referred to functional brain-heart interplay, occurs during emotional and physical arousal. It is well documented that physical and mental stress lead to sympathetic activation. Nevertheless, the role of autonomic inputs in nervous system-wise communication under mental stress is yet unknown. In this study, we estimated the causal and bidirectional neural modulations between electroencephalogram (EEG) oscillations and peripheral sympathetic and parasympathetic activities using a recently proposed computational framework for a functional brain-heart interplay assessment, namely the sympathovagal synthetic data generation model. Mental stress was elicited in 37 healthy volunteers by increasing their cognitive demands throughout three tasks associated with increased stress levels. Stress elicitation induced an increased variability in sympathovagal markers, as well as increased variability in the directional brain-heart interplay. The observed heart-to-brain interplay was primarily from sympathetic activity targeting a wide range of EEG oscillations, whereas variability in the efferent direction seemed mainly related to EEG oscillations in the γ band. These findings extend current knowledge on stress physiology, which mainly referred to top-down neural dynamics. Our results suggest that mental stress may not cause an increase in sympathetic activity exclusively as it initiates a dynamic fluctuation within brain-body networks including bidirectional interactions at a brain-heart level. We conclude that directional brain-heart interplay measurements may provide suitable biomarkers for a quantitative stress assessment and bodily feedback may modulate the perceived stress caused by increased cognitive demand.

A longitudinal study of interoception changes in the times of COVID-19: Effects on psychophysiological health and well-being

Background

Interoception - the processing of the internal state of the body - has been consistently tied to well-being and mental health, which in turn have been severely challenged by the COVID-19 pandemic. Moreover, the fact that symptoms of COVID-19 (high temperature, shortness of breath, fatigue, and even gastro-intestinal problems) directly alter interoceptive signals has fueled people's tendency to constantly check their internal bodily state.

Objectives

In this longitudinal study we tested for changes in interoception and psychophysiological health and well-being during different stages of the pandemic in 2020 and assessed their potential association. To highlight this association, we combined both subjective (i.e., self-reported questionnaires) and objective (i.e., measures of heart rate variability, HRV and of interoceptive accuracy) measures.

Methods

245 Italian participants who had completed the Multidimensional Assessment of Interoceptive Awareness (MAIA-2) prior to the onset of the pandemic, repeated the questionnaire during the first national lockdown in Italy, and four months after restrictions. Participants also completed survey measures of depression (PHQ-9), anxiety (STAI), and sleep disturbance (PSQI). A sub-sample of 28 participants, who had completed the heartbeat counting task (HCT) and a measure of heart rate variability (HRV), was tested again remotely, in the same time windows, using phone applications and photoplethysmography.

Results

While performance in the HCT remained unvaried, MAIA-2 scores consistently increased from before the pandemic to the national lockdown, and remained largely unvaried after four months. The national lockdown was associated with the lowest psychophysiological health and well-being, as evidenced by a decrease in HRV compared to before the pandemic and by higher scores in self-reported depression, anxiety, and sleep disturbance compared to four months after the lockdown. Interestingly, psychophysiological health and well-being were predicted by specific regulatory components of interoception (e.g., the ability to regulate distress by focusing on body sensations and experiencing one's body as safe and trustworthy).

Conclusions

Our results suggest an increased attention towards visceral signals during the COVID-19 pandemic, and highlight the positive role of specific components of interoception in contributing to well-being, suggesting that novel interventions aimed at increasing interoception may be developed to protect against stressful life events such as COVID-19.

The impact of traumatic childhood experiences on interoception: disregarding one's own body

BACKGROUND

Deficient interoception, the processing and perception of internal bodily signals, has been discussed as a mechanism underlying various mental disorders. First results indicate a mediating role of interoception in the interplay of traumatic childhood experiences and adult mental disorders. Traumatic childhood experiences may hinder the adequate processing, integration, and trust in bodily signals that are important in order to understand and regulate own needs and emotions, thereby increasing the vulnerability for mental disorders. However, an overarching study investigating alterations in different interoceptive measures and trauma-related disorders as well as their mediating role between early trauma and emotion dysregulation is still missing.

METHODS

One hundred thirty-six individuals with varying levels of traumatic childhood experiences who either had a current diagnosis of major depression, posttraumatic stress disorder, or somatic symptom disorder, or no mental disorder, took part in a multidimensional assessment of interoceptive processes, including interoceptive accuracy, sensibility, and awareness. Kruskal-Wallis tests were used to compare groups regarding interoceptive processes and associations with traumatic childhood experiences and emotion dysregulation were analyzed with Spearman correlations. Furthermore, mediation analyses were computed to examine and compare interoceptive processes as potential mediators between traumatic childhood experiences and emotion dysregulation.

RESULTS

Only body dissociation, a measure for interoceptive sensibility, was significantly reduced in individuals with a current mental disorder. Body dissociation was also the only interoceptive measure significantly associated with traumatic childhood experiences and emotion dysregulation and the only significant mediator in the relationship between traumatic childhood experiences and emotion dysregulation across groups.

CONCLUSION

Results suggest body dissociation, but not other interoceptive measures, as an important feature linking traumatic childhood experiences to current emotion dysregulation, an important transdiagnostic feature. As body dissociation refers to a habitual non-attendance or disregard of interoceptive signals, integrative therapeutic interventions could help affected individuals to overcome difficulties in emotion perception and regulation.

TRIAL REGISTRATION

The general study design was preregistered; see the German Clinical Trials Register (DRKS-ID: DRKS00015182). This study's analysis plan was not preregistered.

Effects of respiratory phases on the processing of emotional and non-emotional visual stimuli

The number of studies investigating the relationship between respiratory phases and cognitive/neural processing of external events has been increasing, but the findings remain controversial. This registered report examined the effect of the respiratory phase on the discrimination accuracy of visual stimuli in the emotional and non-emotional domains. Forty-two healthy young participants were asked to choose fearful over neutral facial expressions and to choose high-contrast over low-contrast Gabor patches during spontaneous nasal respiration. Event-related potentials (ERPs) were also recorded for each type of stimulus presented during each respiratory phase. It was hypothesized that discrimination accuracy would be higher when the stimuli were presented during inhalation than during exhalation. It was also hypothesized that the amplitudes of ERPs elicited by the stimuli would be greater during inhalation than during exhalation. For comparison, the effect of the cardiac phase was examined, with the expectation that discrimination accuracy would be higher when the stimuli were presented during systole than during diastole. It was also hypothesized that the amplitudes of ERPs elicited by the stimuli would be greater during systole than during diastole. As expected, the results indicated that fear discrimination accuracy was higher during inhalation than exhalation and during systole than diastole. However, this was not the case for contrast discrimination. No differences in ERPs were observed between respiratory phases in either task. These results suggest that natural breathing in through the nose facilitates the discrimination of emotional stimuli, possibly via subcortical processes.

A chatbot-based intervention with ELME to improve stress and health-related parameters in a stressed sample: Study protocol of a randomised controlled trial

Background

Stress levels in the general population had already been increasing in recent years, and have subsequently been exacerbated by the global pandemic. One approach for innovative online-based interventions are "chatbots" - computer programs that can simulate a text-based interaction with human users via a conversational interface. Research on the efficacy of chatbot-based interventions in the context of mental health is sparse. The present study is designed to investigate the effects of a three-week chatbot-based intervention with the chatbot ELME, aiming to reduce stress and to improve various health-related parameters in a stressed sample.

Methods

In this multicenter, two-armed randomised controlled trial with a parallel design, a three-week chatbot-based intervention group including two daily interactive intervention sessions via smartphone (á 10-20 min.) is compared to a treatment-as-usual control group. A total of 130 adult participants with a medium to high stress levels will be recruited in Germany. Assessments will take place pre-intervention, post-intervention (after three weeks), and follow-up (after six weeks). The primary outcome is perceived stress. Secondary outcomes include self-reported interoceptive accuracy, mindfulness, anxiety, depression, personality, emotion regulation, psychological well-being, stress mindset, intervention credibility and expectancies, affinity for technology, and attitudes towards artificial intelligence. During the intervention, participants undergo ecological momentary assessments. Furthermore, satisfaction with the intervention, the usability of the chatbot, potential negative effects of the intervention, adherence, potential dropout reasons, and open feedback questions regarding the chatbot are assessed post-intervention.

Discussion

To the best of our knowledge, this is the first chatbot-based intervention addressing interoception, as well as in the context with the target variables stress and mindfulness. The design of the present study and the usability of the chatbot were successfully tested in a previous feasibility study. To counteract a low adherence of the chatbot-based intervention, a high guidance by the chatbot, short sessions, individual and flexible time points of the intervention units and the ecological momentary assessments, reminder messages, and the opportunity to postpone single units were implemented.

Trial registration

The trial is registered at the WHO International Clinical Trials Registry Platform via the German Clinical Trials Register (DRKS00027560; date of registration: 06 January 2022). This is protocol version No. 1. In case of important protocol modifications, trial registration will be updated.

The Impact of Adverse Childhood Experiences and Community Violence Exposure on a Sample of Anxious, Treatment-Seeking Children

Screening for adverse childhood experiences (ACEs) can help prevent and reduce adverse outcomes on child development, including increased risk for anxiety disorders. Emerging studies strongly support the inclusion of community-level adversities in ACE screeners to consider diverse contexts and populations. Recent studies suggest that community violence exposure (CVE) may have a distinct impact on youth mental health. Although recent studies have examined the association between ACEs, CVE, and mental health in primary care settings, this association has not been examined on treatment-seeking children in urban mental health settings. The present study employs a mediation model using the PROCESS macro to examine community violence exposure mediating the effect on the association between ACEs and somatic symptoms (SS) on a sample of anxious treatment-seeking children. A total of 98 participants (Mage = 11.7, SD = 3.79, 51.6% males, 54.1% ethnic minority children) who sought services at a specialized anxiety clinic completed self-report measures. Results indicated that exposure to ACEs is associated with endorsement of somatic symptoms as a result of reporting hearing, witnessing, or experiencing CVE. Evidence of mediation was found in a statistically significant indirect effect of ACEs on SS through CREV (Effect = .17, 95% CI = .069-.294). These findings support recent evidence that CVE is a distinct ACE as it contributes to toxic stress similar to individual-level ACEs. The use of a comprehensive ACE screening that includes CVE is warranted, particularly when working with culturally and socioeconomically diverse populations, as it would better capture a broader range of adversities across demographic groups.

The Long-Term Efficacy of "Social Buffering" in Artificial Social Agents: Contextual Affective Perception Matters

In dynamic (social) environments, an affective state of "stress" can be adaptive and promote agent wellbeing, but maladaptive if not appropriately regulated. The presence of (and interactions with) affect-based social support has been hypothesised to provide mechanisms to regulate stress (the "social buffering" hypothesis), though the precise, underlying mechanisms are still unclear. However, the hormone oxytocin has been implicated in mediating these effects in at least two ways: by improving social appraisals and reducing the short-term release of stress hormones (i.e., cortisol), and adapting an agent's long-term stress tolerance. These effects likely facilitate an agent's long-term adaptive ability by grounding their physiological and behavioural adaptation in the (affective) social environment, though these effects also appear to be context-dependent. In this paper, we investigate whether two of the hypothesised hormonal mechanisms that underpin the "social buffering" phenomenon affect the long-term wellbeing of (artificial) social agents who share affective social bonds, across numerous social and physical environmental contexts. Building on previous findings, we hypothesise that "social buffering" effects can improve the long-term wellbeing of agents who share affective social bonds in dynamic environments, through regular prosocial interactions with social bond partners. We model some of the effects associated with oxytocin and cortisol that underpin these hypothesised mechanisms in our biologically-inspired, socially-adaptive agent model, and conduct our investigation in a small society of artificial agents whose goal is to survive in challenging environments. Our results find that, while stress can be adaptive and regulated through affective social support, long-term behavioural and physiological adaptation is determined by the contextual perception of affective social bonds, which is influenced by early-stage interactions between affective social bond partners as well as the degree of the physical and social challenges. We also show how these low-level effects associated with oxytocin and cortisol can be used as "biomarkers" of social support and environmental stress. For socially-situated artificial agents, we suggest that these "social buffering" mechanisms can adapt the (adaptive) stress mechanisms, but that the long-term efficacy of this adaptation is related to the temporal dynamics of social interactions and the contextual perception of the affective social and physical environments.

Acute physical-activity related increases in interoceptive ability are not enhanced with simultaneous interoceptive attention

Interoception, the sense of the internal body, is proposed to support self-regulation, and consequently influence mental health. Researchers have therefore shown interest in improving the ability to accurately monitor internal signals (i.e., interoceptive accuracy, IAcc). Research suggests that cardiac IAcc is modifiable by both manipulations of interoceptive attention (guided attention towards the internal body), and interoceptive exposure (strategically inducing somatic signals e.g., via physical activity). Whilst successful in isolation, it is unclear whether a combined approach (i.e., directing attention towards the internal body when signals are more salient) could elicit greater benefits. In a 2 × 2 within-subject design, 48 healthy adults (M_age = 25.98 ± 4.73 years, 50% female) completed four 20-min conditions varying in both attentional focus (interoceptive vs exteroceptive) and physical activity (active vs rest), with cardiac IAcc measured immediately after. Results revealed a main effect for physical activity (p < 0.001), however, there was no effect for attentional focus (p = 0.397), and no interaction effect (p = 0.797). Differential analyses showed that a higher sporting background increased sensitivity to physical activity-related increases in cardiac IAcc (p = 0.031). Findings indicate that (irrespective of attentional focus) moderate-vigorous physical activity-based interventions have the potential to increase cardiac IAcc, with certain individuals potentially benefiting more.

Grounding Context in Embodied Cognitive Robotics

Biological agents are context-dependent systems that exhibit behavioral flexibility. The internal and external information agents process, their actions, and emotions are all grounded in the context within which they are situated. However, in the field of cognitive robotics, the concept of context is far from being clear with most studies making little to no reference to it. The aim of this paper is to provide an interpretation of the notion of context and its core elements based on different studies in natural agents, and how these core contextual elements have been modeled in cognitive robotics, to introduce a new hypothesis about the interactions between these contextual elements. Here, global context is categorized as agent-related, environmental, and task-related context. The interaction of their core elements, allows agents to first select self-relevant tasks depending on their current needs, or for learning and mastering their environment through exploration. Second, to perform a task and continuously monitor its performance. Third, to abandon a task in case its execution is not going as expected. Here, the monitoring of prediction error, the difference between sensorimotor predictions and incoming sensory information, is at the core of behavioral flexibility during situated action cycles. Additionally, monitoring prediction error dynamics and its comparison with the expected reduction rate should indicate the agent its overall performance on executing the task. Sensitivity to performance evokes emotions that function as the driving element for autonomous behavior which, at the same time, depends on the processing of the interacting core elements. Taking all these into account, an interactionist model of contexts and their core elements is proposed. The model is embodied, affective, and situated, by means of the processing of the agent-related and environmental core contextual elements. Additionally, it is grounded in the processing of the task-related context and the associated situated action cycles during task execution. Finally, the model proposed here aims to guide how artificial agents should process the core contextual elements of the agent-related and environmental context to give rise to the task-related context, allowing agents to autonomously select a task, its planning, execution, and monitoring for behavioral flexibility.

The Effects of a 3-Week Heartbeat Perception Training on Interoceptive Abilities

Recent studies showed promising short-term effects of heartbeat perception training on interoceptive abilities. Research on the effects of heartbeat perception training on interoceptive abilities over time is sparse. Therefore, the aim of this study was to examine the short-term effects and the effects of a 3-week heartbeat perception training over time on interoceptive abilities, namely, cardiac interoceptive accuracy (IAc) and interoceptive sensibility (IS). A total of 40 healthy participants were randomized to the intervention group (n = 20) or the control group (n = 20). The intervention group conducted three cardiac biofeedback sessions (one per week) at the laboratory, whereas the control group watched a documentary instead. Interoceptive abilities were assessed via the heartbeat perception task (IAc) and confidence ratings (IS) at baseline, after each laboratory session, and 1 week after the last session (post-measurement). IAc was significantly increased in the intervention group compared to the control group after the first training session (short-term effect). There were no significant improvements in IS due to the first session, and neither on IAc nor IS over time. Descriptive trends of improved interoceptive abilities over time were found in both groups. Single session of heartbeat perception training seems to be a promising approach to improve IAc. Future research should further investigate the long-term effects of diverse heartbeat perception training varying in frequency and intensity of the training sessions in diverse samples aiming to improve interoceptive abilities.

Measuring psychosocial stress with heart rate variability-based methods in different health and age groups

Autonomic nervous system function and thereby bodily stress and recovery reactions may be assessed by wearable devices measuring heart rate (HR) and its variability (HRV). So far, the validity of HRV-based stress assessments has been mainly studied in healthy populations. In this study, we determined how psychosocial stress affects physiological and psychological stress responses in both young (18-30 yrs) and middle-aged (45-64 yrs) healthy individuals as well as in patients with arterial hypertension and/or either prior evidence of prediabetes or type 2 diabetes. We also studied how an HRV-based stress index (Relax-Stress Intensity, RSI) relates to perceived stress (PS) and cortisol (CRT) responses during psychosocial stress.

APPROACH

A total of 197 participants were divided into three groups: 1) healthy young (HY, N=63), 2) healthy middle-aged (HM, N=61) and 3) patients with cardiometabolic risk factors (Pts, N=73, 32-65 yrs). The participants underwent a group version of Trier Social Stress Test (TSST-G). HR, HRV (quantified as root mean square of successive differences of R-R intervals, RMSSD), RSI, PS, and salivary CRT were measured regularly during TSST-G and a subsequent recovery period.

MAIN RESULTS

All groups showed significant stress reactions during TSST-G as indicated by significant responses of HR, RMSSD, RSI, PS, and salivary CRT. Between-group differences were also observed in all measures. Correlation and regression analyses implied RSI being the strongest predictor of CRT response, while HR was more closely associated with PS.

SIGNIFICANCE

The HRV-based stress index mirrors responses of CRT, which is an independent marker for physiological stress, around TSST-G. Thus, the HRV-based stress index may be used to quantify physiological responses to psychosocial stress across various health and age groups.

Heart rate variability biofeedback intero-nociceptive emotion exposure therapy for adverse childhood experiences

Background: Psychiatric patients with adverse childhood experiences (ACE) tend to have dysfunctions in the interoceptive part of their emotional experience. The integration of interoceptive emotional activity in the insular and cingulate cortices is linked to the regulation of sympathovagal balance. This makes heart rate variability (HRV) an ideal measure for providing feedback on emotion regulation in real-time.

Methods: A sample of one hundred (n=100) outpatients was evaluated. Participants underwent eight 30-minutes ACE exposure sessions during which patients were guided to experience bodily sensations related to ACE while their HRV was monitored using a commercial biofeedback device.

Results: Comparing the results of the first to last therapeutic session, a significant decrease in heart rate and an increase in HRV at the onset of the session were observed.

Conclusions: This study suggests a physiological impact of therapeutic interventions on autonomic balance and underlines the interest in HRV biofeedback as clinical practice.

Pain catastrophizing, pain sensitivity and fear of pain are associated with early life environmental unpredictability: a path model approach

BACKGROUND

Socioeconomic disadvantages in the childhood environment might strongly influence beliefs and behavior characterizing the adult years. When children experience unpredictable and adverse situations, they develop an unpredictability schema with the core belief that situations are unpredictable.

METHODS

In two studies, we examined the association of childhood socioeconomic disadvantages with self-reported pain sensitivity, pain catastrophizing, and pain-related fear. Multidimensional survey measures were used to assess environmental conditions experienced in childhood. In addition, participants completed the Pain Catastrophizing Scale, Pain Sensitivity Questionnaire, Body Awareness Questionnaire, Unpredictability Schema Questionnaire, and Fear of Pain Questionnaire. In Study 1 (N = 252), in separate models, we examined pain sensitivity and pain catastrophizing of a community sample of pain-free young individuals in association with their childhood experiences. In Study 2 (N = 293), in a new sample, but with a wider age range, we examined the association of early life socioeconomic disadvantages with pain-related fear. In both studies, the predictions were tested with Structural Equation Modeling. Our models constituted a path from childhood socioeconomic status and household unpredictability to pain variables via the factors of family resources, unpredictability schemas, and body awareness.

RESULTS AND CONCLUSIONS

The findings converged on the conclusion that individuals experiencing disadvantageous early life conditions tended to have an elevated level of pain catastrophizing, higher perceived sensitivity to pain, and higher level of pain-related fear. These associations were mediated by an unpredictability schema and body awareness.

Psychological Stress and Vocal Symptoms Among University Professors in Israel: Implications of the Shift to Online Synchronous Teaching During the COVID-19 Pandemic

OBJECTIVES

Psychological stress may have an adverse impact on the voice. The purpose of the present cross-sectional study was to investigate the relationship between the change in levels of perceived psychological stress and vocal symptoms among Israeli academic college professors required to shift to synchronous online teaching during the global COVID-19 pandemic.

METHODS

An online questionnaire was completed by 313 professors (156 men and 157 women) from 14 academic colleges in Israel at the end of the first week of online synchronous teaching during the COVID-19 pandemic, which was assumed to be the most burdened and stressful week of the transition. Participants provided self-reports for the current levels of psychological stress and vocal symptoms during the transition to online synchronous teaching, as well as general psychological stress and general vocal symptoms during previous periods of teaching.

RESULTS

The results revealed higher levels of psychological stress but not vocal symptoms during the transition to online synchronous teaching compared with previous periods of teaching. Psychological stress during the transition to online synchronous teaching was positively associated with vocal symptoms during this period but this association was moderated by general stress. Although there was a positive association between psychological stress and vocal symptoms for individuals who reported low levels of psychological stress during previous periods of teaching, this association was especially strong for individuals who reported high levels of psychological stress during previous periods of teaching.

CONCLUSIONS

It is important to examine vocal symptoms of professors in specific contexts that are potentially stressful. The psychological stress surrounding the transition to online synchronous teaching was associated with elevated levels of vocal symptoms especially for those who reported high levels of psychological stress during previous periods of teaching. These results with professors accord with the notion that psychological stress may have a negative impact on the voice.

Sensory Processing, Perceived Stress and Burnout Symptoms in a Working Population during the COVID-19 Crisis

Although previous research suggests an association between sensory processing and perceived stress in a broad spectrum of mental health conditions, it remains unclear whether this phenomenon occurs independently from psychopathology. The present study investigated the association between sensory processing patterns, perceived stress and occupational burnout as a stress-related condition in a working population. We focused on different aspects of sensory processing and used the momentum of a particularly stressful period: during the first months of the global COVID-19 crisis. A total of 116 workers at a mental healthcare institution in The Netherlands completed the Adolescent/Adult Sensory Profile (AASP), the Perceived Stress Scale (PSS-10) and the Burnout Assessment Tool (BAT). Our results demonstrated that higher scores on sensory sensitivity and low registration were associated with higher scores on perceived stress and core burnout symptoms. Sensory hypersensitivity was also associated with more secondary burnout symptoms. Associations were not driven by underlying sensory-related disorders (e.g., ASD or ADHD). In conclusion, sensory processing difficulties are relevant predictors of stress and occupational burnout, also in healthy employees. This phenomenon warrants further attention, as relatively simple adjustments in working environment may possess important preventive effects.

Adult hippocampal neurogenesis shapes adaptation and improves stress response: a mechanistic and integrative perspective

Adult hippocampal neurogenesis (AHN) represents a remarkable form of neuroplasticity that has increasingly been linked to the stress response in recent years. However, the hippocampus does not itself support the expression of the different dimensions of the stress response. Moreover, the main hippocampal functions are essentially preserved under AHN depletion and adult-born immature neurons (abGNs) have no extrahippocampal projections, which questions the mechanisms by which abGNs influence functions supported by brain areas far from the hippocampus. Within this framework, we propose that through its computational influences AHN is pivotal in shaping adaption to environmental demands, underlying its role in stress response. The hippocampus with its high input convergence and output divergence represents a computational hub, ideally positioned in the brain (1) to detect cues and contexts linked to past, current and predicted stressful experiences, and (2) to supervise the expression of the stress response at the cognitive, affective, behavioral, and physiological levels. AHN appears to bias hippocampal computations toward enhanced conjunctive encoding and pattern separation, promoting contextual discrimination and cognitive flexibility, reducing proactive interference and generalization of stressful experiences to safe contexts. These effects result in gating downstream brain areas with more accurate and contextualized information, enabling the different dimensions of the stress response to be more appropriately set with specific contexts. Here, we first provide an integrative perspective of the functional involvement of AHN in the hippocampus and a phenomenological overview of the stress response. We then examine the mechanistic underpinning of the role of AHN in the stress response and describe its potential implications in the different dimensions accompanying this response.

Interoception and alcohol: Mechanisms, networks, and implications

Interoception refers to the perception of the internal state of the body and is increasingly being recognized as an important factor in mental health disorders. Drugs of abuse produce powerful interoceptive states that are upstream of behaviors that drive and influence drug intake, and addiction pathology is impacted by interoceptive processes. The goal of the present review is to discuss interoceptive processes related to alcohol. We will cover physiological responses to alcohol, how interoceptive states can impact drinking, and the recruitment of brain networks as informed by clinical research. We also review the molecular and brain circuitry mechanisms of alcohol interoceptive effects as informed by preclinical studies. Finally, we will discuss emerging treatments with consideration of interoception processes. As our understanding of the role of interoception in drug and alcohol use grows, we suggest that the convergence of information provided by clinical and preclinical studies will be increasingly important. Given the complexity of interoceptive processing and the multitude of brain regions involved, an overarching network-based framework can provide context for how focused manipulations modulate interoceptive processing as a whole. In turn, preclinical studies can systematically determine the roles of individual nodes and their molecular underpinnings in a given network, potentially suggesting new therapeutic targets and directions. As interoceptive processing drives and influences motivation, emotion, and subsequent behavior, consideration of interoception is important for our understanding of processes that drive ongoing drinking and relapse.

Effects of a Single Yoga Session on Cardiac Interoceptive Accuracy and Emotional Experience

BACKGROUND

There is an increasing body of research supporting the idea that cardiac interoceptive accuracy (IAc) can be improved by training. Findings concerning the effects of a single yoga session on IAc and the related construct emotional experience are sparse. The aim of this study was to examine if a single yoga session increases IAc and improves emotional experience.

METHODS

137 students were randomly assigned to a 20-min yoga session (n = 47), an endurance session (n = 46), or an inactive control condition (n = 44). IAc and emotional experience were assessed before and after the sessions.

RESULTS

There were no significant changes in IAc, or positive and negative affect. IAc at baseline and the change in positive effect were found as predictors for IAc after the yoga session.

CONCLUSION

A 20-min yoga session seems to be not applicable to improve IAc and emotional experience. Future studies should investigate long-term interventions and diverse healthy and clinical populations.

The Effects of a Standardized Cognitive-Behavioural Therapy and an Additional Mindfulness-Based Training on Interoceptive Abilities in a Depressed Cohort

BACKGROUND

Interoceptive accuracy and sensibility are decreased in depressive samples. However, different studies showed that cognitive-behavioural therapy (CBT) and mindfulness interventions are promising approaches to improve interoceptive abilities. Based on these findings, the study aims to investigate the pre-post effect of CBT in a depressive sample. Additionally, we examined the effect of mindfulness-based stress reduction (MBSR) training in the context of CBT.

METHODS

Sixty depressive patients were investigated over four weeks, with two conditions-CBT vs. CBT + MBSR. Further, the changes in interoceptive abilities (interoceptive accuracy and sensibility) of the depressive patients were compared to baseline data of healthy controls.

RESULTS

The depressive patients showed significantly higher levels of depression and lower mindfulness and interoceptive abilities than healthy controls. The depressive sample showed a significant decrease in depressive symptoms and increased mindfulness and interoceptive abilities after CBT. Lastly, depressive patients of the CBT + MBSR condition did not differ from those who only received CBT in the levels of depression, mindfulness or interoceptive abilities over the time course.

DISCUSSION

This study demonstrates a positive effect of CBT on interoceptive abilities in a depressive sample. It is shown that the depressive sample did not profit from additional mindfulness training. It can be concluded that CBT is an efficient treatment, resulting in increased interoceptive abilities. Unexpectedly, the combination of CBT and MBSR has no additional effect on these changes. Future studies should investigate the effect of MBSR as a stand-alone therapy.

The relationship between cortisol reactivity and emotional brain function is differently moderated by childhood trauma, in bipolar disorder, schizophrenia and healthy individuals

Childhood trauma is a risk factor for psychotic and mood disorders that is associated with abnormal hypothalamic-pituitary-adrenal (HPA) axis function in response to stress and abnormal social brain function. Here, we aimed to determine whether childhood trauma exposure would differently moderate associations between cortisol reactivity and social brain function, among cases with schizophrenia (SZ), bipolar disorder (BD) and in healthy individuals (HC). Forty cases with SZ, 35 with BD and 34 HCs underwent functional magnetic resonance imaging while performing an emotional face-matching task. Participants completed the Childhood Trauma Questionnaire and cortisol reactivity (i.e. the slope indexing the within-subject difference between pre- and post-imaging salivary cortisol levels) was determined. The severity of childhood trauma moderated the relationship between cortisol reactivity and brain activation in the bilateral temporo-parieto-insular junctions, right middle cingulum, right pre/postcentral gyri, left cerebellum and right lingual gyrus, differently depending on the clinical group. When exposed to high levels of trauma, the cortisol slope was negatively associated with activation in these regions in HC, while the cortisol slope was positively associated with activation in these regions in SZ cases. Similarly, there were differences between the groups in how trauma severity moderated the relationship between cortisol reactivity and functional connectivity between the amygdala and dorsolateral prefrontal cortex. In addition to reflecting typical associations between cortisol reactivity and emotional brain function when not exposed to childhood trauma, these findings provide new evidence that trauma exposure disrupts these relationships in both healthy individuals and in cases with SZ or BD.

Subsurface Confinement: Evidence from Submariners of the Benefits of Mindfulness

Objectives

The subsurface ballistic missile nuclear submarine (SSBN) is an extreme professional environment in which personnel are both isolated and confined during patrols, which can last longer than 2 months. This environment is known to degrade submariners’ mood and cognition.

Methods

This exploratory, empirical study followed a cohort of 24 volunteer submariners. Dispositional mindfulness was assessed with the Freiburg Mindfulness Inventory, in order to identify two groups (mindful and non-mindful) and compare change in emotional state, interoception, and health behaviors during the patrol.

Results

Overall, psychological health deteriorated during the patrol. However, mindful submariners demonstrated better psychological adaptation and interoception than the non-mindful group. This was associated with better subjective health behaviors (sleeping and eating).

Conclusions

Dispositional mindfulness appears to protect against the negative effects of long-term containment in a professional environment, such as a submarine patrol. Our work highlights that mindfulness may help individuals to cope with stress in such situations. Developing mindfulness could also be an important preventive healthcare measure during quarantine imposed by the outbreak of a serious infectious disease.

Body connection mediates the relationship between traumatic childhood experiences and impaired emotion regulation in borderline personality disorder

BACKGROUND

Previous studies revealed an association between traumatic childhood experiences and emotional dysregulation in patients with borderline personality disorder (BPD). However, possible mediating pathways are still not fully understood. The aim of the present study was to investigate the potential mediating role of body connection, describing the awareness of the relationship of bodily and mental states, for the association between a history of traumatic childhood experiences and BPD core symptomatology.

METHODS

One-hundred-twelve adult female individuals with BPD and 96 healthy female controls (HC) were included. Impaired emotion regulation, traumatic childhood experiences, and BPD symptomatology were assessed with self-report questionnaires. The Scale of Body Connection was used to assess two dimensions of body connection, that is body awareness, describing attendance to bodily information in daily life and noticing bodily responses to emotions and/or environment and body dissociation, describing a sense of separation from one's own body, due to avoidance or emotional disconnection. Mann-Whitney U tests were employed to test for group differences (BPD vs. HC) on the two SBC subscales and associations with clinical symptoms were analyzed with Spearman correlations. We performed mediation analyses in the BPD group to test the assumption that body connection could act as a mediator between a history of traumatic childhood experiences and emotion dysregulation.

RESULTS

Individuals with BPD reported significantly lower levels of body awareness and significantly higher levels of body dissociation compared to HC. Body dissociation, traumatic childhood experiences, and emotion dysregulation were significantly positively associated. Further analyses revealed that body dissociation, but not body awareness, significantly and fully mediated the positive relationship between traumatic childhood experiences and impaired emotion regulation in the BPD sample. This mediation survived when trait dissociation, i.e., general dissociative experiences not necessarily related to the body, was statistically controlled for.

CONCLUSION

Certain dimensions of body connection seem to be disturbed in BPD patients, with body dissociation being an important feature linking a history of traumatic childhood experiences to current deficits in emotion regulation.

Aging bodies, aging emotions: Interoceptive differences in emotion representations and self-reports across adulthood

Bodily sensations are closely linked to emotional experiences. However, most research assessing the body-emotion link focuses on young adult samples. Inspired by prior work showing age-related declines in autonomic reactivity and interoception, we present 2 studies investigating age-related differences in the extent to which adults (18-75 years) associate interoceptive or internal bodily sensations with emotions. Study 1 (N = 150) used a property association task to assess age effects on adults' tendencies to associate interoceptive sensations, relative to behaviors or situations, with negative emotion categories (e.g., anger, sadness). Study 2 (N = 200) used the Day Reconstruction experience sampling method to assess the effect of age on adults' tendencies to report interoceptive sensations and emotional experiences in daily life. Consistent with prior literature suggesting that older adults have more muted physiological responses and interoceptive abilities than younger adults, we found that older adults' mental representations (Study 1) and self-reported experiences (Study 2) of emotion are less associated with interoceptive sensations than are those of younger adults. Across both studies, age effects were most prominent for high arousal emotions (e.g., anger, fear) and sensations (e.g., racing heart) that are often associated with peripheral psychophysiological concomitants in young adults. These findings are consistent with psychological constructionist models and a "maturational dualism" account of emotional aging, suggesting additional pathways by which emotions may differ across adulthood. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Precision Medicine for Breath-Focused Mind-Body Therapies for Stress and Anxiety: Are We Ready Yet?

In this viewpoint, we present an argument for transdisciplinary "precision medicine" approaches that combine studies of basic neurobiology of breathing in animal and human models of stress that can help characterize physiological and neural biomarkers and mechanisms of breathing control and emotion regulation in humans. Such mechanistic research is fundamental for the development of more effective and mechanism-based mind-body therapies. The potential for this research to positively impact public health is high, as breathing techniques are inexpensive, accessible, and cross-culturally accepted, with fewer complications then observed with other standard therapies for stress-related disorders.

Heartbeat evoked potentials in patients with post-traumatic stress disorder: an unaltered neurobiological regulation system?

BACKGROUND

Early life maltreatment is a risk factor for psychiatric disorders, including post-traumatic stress disorder (PTSD). Post-traumatic stress disorder is a severe and heterogeneous disorder with fluctuating states of emotional over- and undermodulation, including hypervigilance, dissociation, and emotion regulation deficits. The perception and regulation of emotions have been linked to interoception, the cortical representation and sensing of inner bodily processes. Although first therapeutic approaches targeting bodily sensations have been found effective in patients with PTSD, and deficits in interoceptive signal representation have been reported in other trauma-related disorders, such as borderline personality disorder (BPD), the role of interoception remains largely unexplored for PTSD.

OBJECTIVE

The objective was to investigate the cortical representation of cardiac interoceptive signals in patients with PTSD and its associations with early life maltreatment, trait dissociation, and emotion dysregulation.

METHODS

Twenty-four medication-free patients with PTSD and 31 healthy controls (HC) completed a 5-min resting electrocardiogram (ECG) with parallel electroencephalogram (EEG). Heartbeat evoked potential (HEP) amplitudes as a measure for cortical representation of cardiac interoceptive signals were compared between groups and correlated with self-report questionnaires.

RESULTS

We did not find significantly different mean HEP amplitudes in patients with PTSD compared to HC, although HEPs of patients with PTSD were descriptively higher. No significant associations between mean HEP amplitudes and early life maltreatment, trait dissociation or emotion dysregulation were obtained within the groups.

CONCLUSION

The current finding does not indicate deficits in interoceptive signal representation at rest in individuals with PTSD. Whether patients with PTSD show altered HEP modulations during emotion regulation tasks and might benefit from therapeutic approaches aiming at changing the perception of bodily signals, needs to be investigated in future studies.

Multidimensional Assessment of Interoceptive Abilities, Emotion Processing and the Role of Early Life Stress in Inflammatory Bowel Diseases

Perception of internal bodily sensations includes three dissociable processes: interoceptive accuracy, interoceptive sensibility, and interoceptive awareness. Interoceptive abilities play a crucial role in emotion processing and impairments of these processes have been reported in several psychiatric disorders. Studies investigating interoceptive abilities and their role in emotional experience in individuals with somatic disorders such as inflammatory bowel diseases (IBD) are sparse. Recent findings suggested an association between adverse childhood experiences (ACE) and the development of gastrointestinal disorders. The aim of the current study was to investigate the associations between the different dimensions of interoception and emotional processing in IBD while taking ACE into account. We recruited IBD patients in clinical remission (n = 35) and 35 healthy control participants (HC) matched for age, education and IQ. Interoception was measured as a three-dimensional construct. Interoceptive accuracy was assessed with the heartbeat tracking task and interoceptive sensibility with a self-report measure (Multidimensional Assessment of Interoceptive Awareness questionnaire). Emotional processing was measured using an experimental task, where participants were asked to rate the subjectively perceived valence and arousal when presented with positive, neutral and negative visual stimuli. IBD patients significantly differed in two interoceptive sensibility domains, Emotional awareness and Not-distracting. Patients reported greater awareness of the connection between bodily sensations and emotional states, while showing a stronger tendency to use distraction from unpleasant sensations compared with HC. Higher emotional awareness was linked to higher perceived intensity and arousal of negative stimuli. The strength of this relation was dependent on the severity of ACE, with severer traumatization being associated with a stronger association between emotional awareness and perceived valence and arousal. Our findings suggest that it is the subjective component of interoception, especially the one assessing interoceptive abilities within the scope of emotional experience, which affects emotional processing in IBD. This is the first study providing evidence that IBD patients did not differ in their perception of visceral signals per se but only in the subjective ability to attribute certain physical sensations to physiological manifestations of emotions. Our findings support the hypothesis that ACE affect the association between interoception and emotional processing.

Augmenting aesthetic chills using a wearable prosthesis improves their downstream effects on reward and social cognition

Previous studies on aesthetic chills (i.e., psychogenic shivers) demonstrate their positive effects on stress, pleasure, and social cognition. We tested whether we could artificially enhance this emotion and its downstream effects by intervening on its somatic markers using wearable technology. We built a device generating cold and vibrotactile sensations down the spine of subjects in temporal conjunction with a chill-eliciting audiovisual stimulus, enhancing the somatosensation of cold underlying aesthetic chills. Results suggest that participants wearing the device experienced significantly more chills, and chills of greater intensity. Further, these subjects reported sharing the feelings expressed in the stimulus to a greater degree, and felt more pleasure during the experience. These preliminary results demonstrate that emotion prosthetics and somatosensory interfaces offer new possibilities of modulating human emotions from the bottom-up (body to mind). Future challenges will include testing the device on a larger sample and diversifying the type of stimuli to account for negatively valenced chills and intercultural differences. Interoceptive technologies offer a new paradigm for affective neuroscience, allowing controlled intervention on conscious feelings and their downstream effects on higher-order cognition.

Effectiveness of a guided online mindfulness-focused intervention in a student population: Study protocol for a randomised control trial

BACKGROUND

Previous studies show that university students experience higher psychological stress than the general population, resulting in increased vulnerability for mental disorders for the student population. Online mindfulness interventions will be delivered to students as a potentially promising and more flexible approach compared to face-to-face interventions with the aim of improving their mental health. This study purposes to investigate the effectiveness of a guided online mindfulness-focused intervention for university students by using both self-reported and psychobiological measures.

METHODS AND ANALYSES

In this multicentre, two-armed randomised controlled trial with a parallel design, a guided version of the online mindfulness-focused intervention 'StudiCare Mindfulness' will be compared with a waitlist control group. In total, 120 participants will be recruited at different universities (of Applied Sciences) in (Neu-) Ulm. Data will be assessed prior to randomisation, after eight weeks (post-intervention) and six months after randomisation (follow-up). The primary outcome measure is mindfulness. The secondary outcome measures include depression, anxiety and stress levels, well-being, interoceptive sensibility, emotion regulation and alexithymia. Psychobiological parameters comprise interoceptive accuracy, hair cortisol and FKBP5 genotype. Sociodemographic variables, treatment expectations, side and adverse side effects, as well as intervention satisfaction and adherence will be assessed. All data analyses will be conducted according to the intention-to-treat principle.

ETHICS AND DISSEMINATION

All study procedures have been approved by the Ethics Committee of Ulm University (application No. 48/18). The findings will be disseminated widely through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

DRKS00014701.

[The body hurts, and what about social pain? Does it hurts too?]

This paper studies the concept of «social pain» and its relationship with physical pain. An in-depth review of its physiology has been carried out, including similarities and differences in processing with relation to physical pain, as well as the interactions between both processes. Social pain is defined as an unpleasant emotional experience which is triggered when the individual feels excluded or rejected by people or social groups with whom they wish have a relationship. This perceived situation produces the same feelings of suffering as that of physical pain. This kind of pain is processed in the same brain areas as physical pain in its affective dimension. It may be revived mentally, even though the interpersonal conflictive situation may have ended long ago. Both types of pain are sources of stress. The confluence of both situations in the same individual adds complications and more pressure to that which is already exerted separately by both stressing factors. This circumstance must be taken into account when dealing with patients with chronic pain.

The Role of Chronic Stress in Normal Visceroception: Insights From an Experimental Visceral Pain Study in Healthy Volunteers

Visceroception is a complex phenomenon comprising the sensation, interpretation, and integration of sensations along the gut-brain axis, including pain or defecatory urgency. Stress is considered a crucial risk factor for the development and maintenance of disorders of gut-brain signaling, which are characterized by altered visceroception. Although the broad role of stress and stress mediators in disturbed visceroception is widely acknowledged, the putative contribution of chronic stress to variations in normal visceroception remains incompletely understood. We aimed to elucidate the role of chronic stress in shaping different facets of visceroception. From a well-characterized, large sample of healthy men and women (N = 180, 50% female), volunteers presenting with low (n = 57) and elevated (n = 61) perceived chronic stress were identified based on the validated Trier Inventory for Chronic Stress (TICS). Visceral sensitivity together with perceived and recalled intensity and defecatory urgency induced by repeated rectal distensions was experimentally assessed, and compared between low and elevated stress groups. Subgroups were compared regarding state anxiety and salivary cortisol concentrations across experimental phases and with respect to psychological measures. Finally, in the full sample and in chronic stress subgroups, a recall bias in terms of a discrepancy between the perception of experimentally-induced symptoms and their recall was tested. Participants with elevated chronic stress presented with increased state anxiety and higher cortisol concentrations throughout the experimental phases compared to the group with low chronic stress. Group differences in visceral sensitivity were not evident. The elevated stress group perceived significantly higher urgency during the stimulation phase, and recalled substantially higher feelings of urgency induced by rectal distensions, while perceived and recalled intensity were comparable between groups. Volunteers with elevated stress exhibited a recall bias in terms of a higher recall relative to mean perception of urgency, whereas no such bias was observed for the intensity of experimental visceral stimulation. Our findings in healthy men and women provide first evidence that the troublesome symptom of urgency might be particularly modifiable by chronic stress and support the relevance of memory biases in visceroception. These results may help to disentangle the impact of chronic stress on altered visceroception in disturbances of gut-brain communication.

Multimodal neurocognitive markers of interoceptive tuning in smoked cocaine

Contemporary neurocognitive models of drug addiction have associated this condition with changes in interoception -namely, the sensing and processing of body signals that fulfill homeostatic functions relevant for the onset and maintenance of addictive behavior. However, most previous evidence is inconsistent, behaviorally unspecific, and virtually null in terms of direct electrophysiological and multimodal markers. To circumvent these limitations, we conducted the first assessment of the relation between cardiac interoception and smoked cocaine dependence (SCD) in a sample of (a) 25 participants who fulfilled criteria for dependence on such a drug, (b) 22 participants addicted to insufflated clorhidrate cocaine (only for behavioral assessment), and (c) 25 healthy controls matched by age, gender, education, and socioeconomic status. We use a validated heartbeat-detection (HBD) task and measured modulations of the heart-evoked potential (HEP) during interoceptive accuracy and interoceptive learning conditions. We complemented this behavioral and electrophysiological data with offline structural (MRI) and functional connectivity (fMRI) analysis of the main interoceptive hubs. HBD and HEP results convergently showed that SCD subjects presented ongoing psychophysiological measures of enhanced interoceptive accuracy. This pattern was associated with a structural and functional tuning of interoceptive networks (reduced volume and specialized network segregation). Taken together, our findings provide the first evidence of an association between cardiac interoception and smoked cocaine, partially supporting models that propose hyper-interoception as a key aspect of addiction. More generally, our study shows that multimodal assessments of interoception could substantially inform the clinical and neurocognitive characterization of psychophysiological and neurocognitive adaptations triggered by addiction.