Interoception: the sense of the physiological condition of the body

Changes in Interoception in Mind-body Therapies for Chronic Pain: A Systematic Review and Meta-Analysis

BACKGROUND

Emerging literature has demonstrated deficits in interoception (i.e., the perception of physical sensations from inside the body) in individuals with chronic pain conditions. Mind-body therapies (MBTs) are purported to improve chronic pain in part through improving or restoring interoceptive abilities. The present systematic review and meta-analysis aimed to examine changes in interoception in MBTs for chronic pain conditions.

METHODS

A systematic search of PubMed, PsycINFO, Scopus, CINAHL, and ProQuest Dissertation and Theses was conducted from database inception to February 2023. English language intervention studies evaluating the effect of MBTs on interoception in adults with chronic pain conditions were examined. Changes in pain (severity and interference) following treatment were examined as secondary outcomes.

RESULTS

A total of 11 studies (10 unique samples) were identified. Meta-analytic results reveal significant improvements in total interoceptive awareness (Becker's d = 1.168, p < .01) as well as improvements in seven of eight subdomains of interoceptive awareness (ds = 0.28 to 0.81). MBTs were also associated with reductions in both pain intensity (d = -1.46, p = .01) and pain interference (d = -1.07, p < .001).

CONCLUSIONS

Preliminary research suggests that MBTs demonstrate improvements in interoceptive awareness and reduce pain in adults with chronic pain. Literature on changes in other domains of interoception, such as interoceptive accuracy, following MBTs is severely lacking. Although more rigorous studies are needed to corroborate results, the present findings lay an important foundation for future research to examine interoception as a possible underlying mechanism of MBTs to improve pain outcomes.

Skin sympathetic nerve activity in symptomatic and asymptomatic paroxysmal atrial fibrillation

BACKGROUND

The causes of symptoms in patients with paroxysmal atrial fibrillation (AF) remains unclear.

OBJECTIVE

The purpose of this study was to correlate the magnitudes of skin sympathetic nerve activity (SKNA) with symptoms in patients with AF.

METHODS

We prospectively enrolled patients with symptomatic paroxysmal AF for ambulatory electrocardiography and SKNA recording. Heart rhythms at the time of symptoms were categorized as AF or normal sinus rhythm (NSR). Maximal and average skin sympathetic nerve activity (aSKNA) and heart rate (HR) were compared between symptomatic and asymptomatic AF and NSR episodes using mixed effects models to account for within-patient correlations.

RESULTS

Among the 31 enrolled patients, 16 (52%) had at least 1 episode of AF, and 24 (77%) endorsed symptoms during the monitoring period. Compared with asymptomatic AF episodes, symptomatic AF episodes had higher maximal aSKNA (1.260 [interquartile range (IQR) 1.114-1.723] μV vs 1.108 [IQR 0.974-1.312] μV; P <0.001) and higher maximal HR (152 ± 24 bpm vs 132 ± 19 bpm; P <.001). Symptomatic NSR episodes were associated with higher maximal aSKNA (1.612 [IQR 1.287-2.027] μV vs 1.332 [IQR 1.033-1.668] μV; P = .001) and higher maximal HR (152 ± 24 bpm vs 105 ± 16 bpm; P <.001) than asymptomatic NSR episodes. Of the symptomatic episodes, 66 (73%) occurred during NSR and 24 (27%) during AF. All P values were obtained from mixed effects models.

CONCLUSION

Symptomatic episodes in patients with paroxysmal AF were more frequently associated with NSR than AF. Symptomatic AF and NSR episodes were associated with higher aSKNA than asymptomatic episodes. In patients with paroxysmal AF, symptoms correlate better with SKNA than heart rhythm.

Listen to the beat: Behavioral and neurophysiological correlates of slow and fast heartbeat sounds

BACKGROUND

Listening to heartbeat sounds have been found to affect cardiac activity and behavior. However, less is known about the effects of these stimuli on brain activity and cognition. Alpha oscillations (8-13 Hz) are considered markers of cortical activation. Frontal alpha Asymmetry (FαA) reflects the valence attributed to the stimulus and the tendency to approach/avoid it.

AIM

This study investigates the effects of sounds mimicking heart pulsations at different rhythms on reaction times and neurophysiological activity.

METHOD

EEG data were collected during a resting-state condition and two Simple Reaction Time tasks (SRT), during which artificially generated heartbeat sounds at fast (120 bpm, FastBeat condition) or slow (60 bpm, SlowBeat condition) rhythms were administered. Alpha power was compared across the three conditions. Differences in the SRT and FαA values were examined between the FastBeat and SlowBeat conditions.

RESULTS

Compared to the resting-state condition, decreased alpha activity over bilateral frontocentral regions was observed in both tasks. The comparison between the FastBeat and the SlowBeat conditions revealed faster response times, a pattern of alpha suppression over right frontal regions, and lower FαA values in the former.

CONCLUSIONS

The similarity of alpha reductions elicited in the comparison between the resting-state and the two task conditions suggests that these patterns were ascribable to processes common to both conditions (SRT task, auditory stimulation). In contrast, the differences between the two conditions suggest that fast heartbeat sounds are perceived as more adverse and stressful stimuli, inducing cortical activation over regions associated with negative states and avoidant tendencies.

The relationship between self-reported interoception and anxiety: A systematic review and meta-analysis

Interoception, the processing of internal bodily sensations, is associated with various mental health conditions. In particular, anxiety is often considered to be the prototypical interoceptive disorder. However, empirical evidence is mixed, with meta-analytic work reporting no relationship between anxiety and cardiac interoceptive accuracy. Less explored, however, are the mixed results relating to anxiety and self-reported interoception. This meta-analysis of 71 studies explored the relationship between self-report measures of interoception and anxiety. Across 12 measures (20 subscales), anxiety was associated with increased negative evaluations of, frequency of, and sensitivity to, bodily signals. Anxiety was also associated with greater (negative) attention to bodily signals, and difficulties describing bodily signals and emotions. However, anxiety was not associated with the use of bodily signals to inform emotions (e.g., noticing emotionally induced bodily signals). Results are discussed considering the overlap between anxiety and interoception questionnaires, the lack of specificity of certain measures, and the potential confound of individual differences in questionnaire interpretation. We also discuss limitations of anxiety measures and the clinical relevance of findings.

Emotion specificity, coherence, and cultural variation in conceptualizations of positive emotions: a study of body sensations and emotion recognition

The present study examines the association between people's interoceptive representation of physical sensations and the recognition of vocal and facial expressions of emotion. We used body maps to study the granularity of the interoceptive conceptualisation of 11 positive emotions (amusement, awe, compassion, contentment, desire, love, joy, interest, pride, relief, and triumph) and a new emotion recognition test (Emotion Expression Understanding Test) to assess the ability to recognise emotions from vocal and facial behaviour. Overall, we found evidence for distinct interoceptive conceptualizations of 11 positive emotions across Asian American, European American, and Latino/a American cultures, as well as the reliable identification of emotion in facial and vocal expressions. Central to new theorising about emotion-related representation, the granularity of physical sensations did not covary with emotion recognition accuracy, suggesting that two kinds of emotion conceptualisation processes might be distinct.

Let's focus on the insula in addiction: A refined anatomical exploration of insula in severe alcohol and cocaine use disorders

BACKGROUND

Theoretical and empirical contributions have identified insula as key in addiction. However, anatomical modifications of the insula in addictive states, and their variations across substance use disorders (SUDs), remain to be specifically explored. We therefore explored the specificities and commonalities of insula gray matter (GM) alterations in severe alcohol use disorder (sAUD) and severe cocaine use disorder (sCUD).

METHODS

We explored insula GM volume through a refined parcellation in 12 subregions (six bilateral): anterior inferior cortex (AIC), anterior short gyrus, middle short gyrus, posterior short gyrus, anterior long gyrus (ALG), and posterior long gyrus (PLG). Using a linear mixed model analysis, we explored the insula volume profiles of 50 patients with sAUD, 61 patients with sCUD, and 36 healthy controls (HCs).

RESULTS

In both sAUD and sCUD, we showed overall insular lower volume with a right-sided lateralization effect, and a major volume deficit in bilateral ALG. Moreover, differences emerged across groups, with higher left AIC and PLG volume deficits in sCUD compared to sAUD and HC.

CONCLUSIONS

We offered the first joint exploration of GM insular volumes in two SUD through refined parcellation, thus unveiling the similarities and dissimilarities in volume deficit profiles. Our results bring evidence complementing prior ones suggesting the core role of the right and posterior insula in craving and interoception, two crucial processes in addiction. Left AIC and PLG group differences also show that, while insula is a region of interest in SUD, sCUD and sAUD generate distinct insular profiles, which might parallel clinical differences across SUD.

Electrophysiological indices of reward anticipation as ADHD risk and prognostic biomarkers

The attention-deficit/hyperactivity disorder (ADHD) clinical phenotype has limitations for deciphering ADHD etiology and predicting prognosis. Although relative to the clinical phenotype, intermediate phenotypes may have better explanatory and prognostic power, the extent to which ADHD intermediate phenotypes are associated with ADHD risk and prognosis is unknown. The aim of this study was to evaluate evidence for event-related potential (ERP) measures of reward anticipation as ADHD risk and prognostic biomarkers. We examined, whether (1) in a sample of adolescents (N = 304; Mage = 15.78 years, SD = 1.08; 39.5% female), accounting for the effects of age, sex, ADHD severity and depression, ERPs are associated with ADHD polygenic risk scores (PRSs) (ADHD risk) and (2) in a sample of adolescents at-risk for ADHD (n = 99; Mage = 15.78 years, SD = 1.08; 39.5% female), accounting for the effects of age, sex, ADHD severity, depression, and baseline outcome values, ERPs are associated, prospectively, with alcohol misuse (ADHD prognosis). In adolescents, greater ADHD PRSs were associated with lower electrophysiological anticipatory attention to motivationally relevant feedback (b = -0.115, p = .046 95%CI [-0.228; -0.002]). The predictors accounted for 5% of the variance in the outcome. In adolescents at-risk for ADHD, at 18-month follow-up, lower electrophysiological anticipatory attention to motivationally relevant feedback was associated with greater alcohol consumption (b = -7.454, p = .007, 95%CI [-12.873; -2.034]). The predictors accounted for 31% of the variance in this outcome. These findings were replicated in sensitivity analyses with behavioral performance variables added as covariates. The current findings support the hypothesis that ERP amplitudes of reward anticipation may be ADHD risk and prognostic biomarkers and suggest that intermediate phenotypes may confer advantages over the ADHD clinical phenotype in delineating etiology and predicting prognosis.

How Does Our Voice Reflect Who We Are? Connecting the Voice and the Self Using Implicit Association Tests

PURPOSE

This study examined the contribution of voice to the self via implicit associations.

METHOD

An implicit association test (IAT) of the voice and the self was created and presented to vocal performers and community controls. One-hundred eleven participants completed this voice-self IAT, the Vocal Congruence Scale (VCS), and the Voice Handicap Index (VHI) via an in-person, monitored, and timed Qualtrics survey. Student t tests comparing timing differences between congruent and incongruent conditions revealed the presence of an implicit relationship.

RESULTS

The findings demonstrated an implicit relationship between the voice and the self as measured using the IAT. Strength of implicit relationships between self and voice was significantly greater for community controls than vocal performers. Additionally, this IAT revealed divergent validity with the VCS, and the VHI using Spearman's correlation.

CONCLUSION

Implications suggest that even if overt declarations are absent, individuals with an implicit voice-self relationship rely on their voice to contribute to their sense of self. This implicit relationship is greater for community members than vocal performers.

The Insular Cortex: An Interface Between Sensation, Emotion and Cognition

The insula is a complex brain region central to the orchestration of taste perception, interoception, emotion, and decision-making. Recent research has shed light on the intricate connections between the insula and other brain regions, revealing the crucial role of this area in integrating sensory, emotional, and cognitive information. The unique anatomical position and extensive connectivity allow the insula to serve as a critical hub in the functional network of the brain. We summarize its role in interoceptive and exteroceptive sensory processing, illustrating insular function as a bridge connecting internal and external experiences. Drawing on recent research, we delineate the insular involvement in emotional processes, highlighting its implications in psychiatric conditions, such as anxiety, depression, and addiction. We further discuss the insular contributions to cognition, focusing on its significant roles in time perception and decision-making. Collectively, the evidence underscores the insular function as a dynamic interface that synthesizes diverse inputs into coherent subjective experiences and decision-making processes. Through this review, we hope to highlight the importance of the insula as an interface between sensation, emotion, and cognition, and to inspire further research into this fascinating brain region.

Breathlessness, but not breathing instability, varies with posttraumatic stress symptoms in university students

Obstructive sleep apnea (OSA) is a chronic sleep-related breathing disorder that is highly prevalent in individuals with posttraumatic stress disorder (PTSD). The reason for this high prevalence remains unclear. We hypothesized that breathing instability, one of the key contributors to OSA, may be altered in PTSD and predispose OSA. Healthy participants (214 females, 98 males) aged 17 to 42 (M = 19.92; SD = 2.85) completed online questionnaires measuring PTSD symptomatology, sleep disturbances, and self-reported breathlessness. A subset of these participants (16 females, 14 males) aged 18 to 42 (M = 23.50; SD = 7.18) completed an in-lab breathing instability assessment, whereby they performed a series of 20-second and maximal duration breath-holds. PTSD severity positively predicted subjective perceptions of breathlessness (P < 0.001) but not objective measures of breathing instability, namely ventilation following 20-s breath-holds (P = 0.93) and maximal breath-hold duration (P = 0.41). These results suggest that breathing instability may not be the driving factor behind the high prevalence of OSA in PTSD. Instead, other factors such as a low arousal threshold, elevated ventilatory responses to arousal, or coexisting insomnia may explain the high rates of OSA in PTSD. One explanation for the discrepancy between subjective breathlessness and breathing stability measures relating to PTSD severity may be that hypervigilance and increased anxiety impacted self-perceptions of breathlessness while not altering breathing instability per se.NEW & NOTEWORTHY Obstructive sleep apnea (OSA) is more common in individuals with posttraumatic stress disorder (PTSD) than the general population for unknown reasons. This study assessed one of the key contributors to OSA, respiratory control instability, in young students with a range of posttraumatic stress symptoms. Although individuals with high PTSD symptoms reported increased subjective breathlessness, objectively measured breathing instability was not altered, suggesting respiratory instability is unlikely to increase the risk of OSA in PTSD.

Immediate Effects of Mindful Awareness in Body-Oriented Therapy as an Adjunct to Medication for Opioid Use Disorder

The need for improve medication for opioid use disorder (MOUD) treatment outcomes can be limited by co-occurring polysubstance use, mental health, and chronic pain conditions. Interoceptive training may facilitate well-being and support medication treatment for MOUD.

Objectives

While effective, medication for opioid use disorder (MOUD) treatment outcomes can be limited by co-occurring polysubstance use, mental health, and chronic pain conditions. Interoceptive training may facilitate well-being and support medication treatment for MOUD. This study examined the pre-post effects of the mindfulness-based intervention Mindful Awareness in Body-oriented Therapy (MABT) as an adjunct to MOUD. MABT teaches interoceptive awareness skills to promote self-care and emotion regulation.

Method

Participants stabilized on medication for opioid use disorder (OUD) (n = 303) from six community clinics in North-western United States were recruited and randomly assigned to MABT plus MOUD or MOUD only. In a mixed-methods study, we used an intent-to-treat approach (analyzing participants based on their assigned group, regardless of adherence) to examine the proportion of days abstinent from non-prescribed opioids, and other substance use (primary outcomes) at baseline and 3 months post-intervention. Secondary outcomes included symptoms of mental health distress, emotional regulation difficulties, pain and physical symptom indicators, interoceptive awareness, and mindfulness skills. Participant experience of MABT was collected through post-intervention surveys. Changes in outcomes were assessed using linear mixed models; content analysis was used to analyze the qualitative data.

Results

Levels of overall substance use were low and did not differ between groups. Significant improvements in PTSD symptoms, interoceptive awareness, pain severity, pain activity interference, and physical symptom frequency were found for those who received MABT compared to MOUD only.

Conclusions

In this stable MOUD population, substance use outcomes were not improved; however, MABT demonstrated significant positive changes across multiple health outcomes critical for improving MOUD treatment.

Preregistration

ClinicalTrials.gov identifer: NCT04082637.

The association between interoception and olfactory affective responses

Odors are known to affect an individual's emotions and physiological states. Recent research has revealed that olfaction is linked to the mental representation of internal sensations, known as interoception. However, little research has examined how interoception relates to emotional responses to odors. This research aimed to fill this gap in the literature. We conducted two studies with a total of 548 Japanese women (n = 500 and n = 48 in Studies 1 and 2, respectively). Study 1 used an online survey to assess the relationship between self-reported interoceptive traits and the intensity of positive emotions in response to daily odors. Study 2 examined how self-reported interoceptive traits modulated the arousal ratings of odors presented in the laboratory and the concordance between these perceived arousal ratings and odor-evoked physiological responses. Study 1 confirmed that self-reported interoceptive traits were significant predictors of positive emotional intensity of odors. In Study 2, individuals with high interoceptive measure scores showed concordance between their perceived emotional arousal and the physiological responses associated with that emotion, whereas individuals with low scores did not. These findings suggest that how people perceive their internal sensations contributes to shaping their olfactory affective experiences, thereby broadening the scope of interoception research and aromachology. The practical implications of these findings for the development of commercial fragrances are discussed.

Music in the Air and in the Body: An Interoceptive System's Perspective on Musical Emotions, Awareness, and Time

Performing and perceiving music requires the integration of multimodal information, including sensations of one's own body. Research on musical engagement investigated emotional responses and the peripheral physiological activations involved, as well as bodily action tendencies, effects on time perception, and the role of awareness and focus of attention. The concept of interoception dedicates a central role to the insular cortex, as suggested by Craig and others, and offers a unifying framework for studying music as an activity that has always had a key role for individuals, groups, societies, with a strong bodily component. Chances and challenges of an interoceptive perspective on music are discussed.

Insights from Ecstatic Epilepsy: From Uncertainty to Metacognitive Feelings

Ecstatic epilepsy is a rare form of focal epilepsy linked to the anterior insula in which patients experience a blissful state with a unique set of symptoms, including a feeling of physical well-being, mental clarity, a sense of oneness with the universe, and time dilation. In this chapter, we reflect on how these symptoms coincide with our current knowledge of the insula's functions and explore how this stunning natural model can further inform our understanding of the insula's role in the sentient self, uncertainty and surprise monitoring, and metacognitive feelings.

Differences in motivational dynamics between experienced cyclists and untrained participants during an incremental endurance exercise task

PURPOSE

The conflict between the desire to reduce effort during exercise and the performance goal of the exercise task contributes to explaining endurance exercise performance. However, whether the trajectories of these two motivational responses systematically differ across individuals with different characteristics is poorly understood. The present study examined whether changes in desire to reduce effort and performance goal value across moderate, heavy, and severe exercise intensity domains differed between cyclists and untrained, but active participants.

METHODS

Fifty participants (14 cyclists and 36 untrained) completed an incremental step test on a cycle ergometer, in which work rate was increased by 25 W every 4 min until voluntary exhaustion. Desire to reduce effort, performance goal value, and blood lactate concentration (for determination of exercise intensity domains) were measured every 4 min and the data were analysed using multilevel modelling.

RESULTS

Desire to reduce effort increased quicker for untrained participants in the moderate exercise intensity domain (b = 1.66, p < .001) and across the whole trial (b = 1.64, p < .001), compared to cyclists (b = .69, and b = 1.14, respectively, both p < .001). Untrained participants reported similar performance goal value at the beginning of the trial (b = 16.02, p < .001), compared to cyclists (b = 17.25, p < .001). Beyond moderate intensities, the performance goal value decreased significantly for the untrained participants (b = -.70, p < .001) but significantly increased for cyclists (b = .45, p = .01). This pattern was also observed when focusing solely on the severe intensity domain (cyclists: b = .90, p < .001; untrained: b = -.84, p < .001).

CONCLUSION

There are distinct differences in the desire to reduce effort and performance goal value between cyclists and untrained athletes. Identifying these systematic differences enhances the credibility of the desire-goal conflict framework in explaining endurance performance and provides insight into the type and timing of interventions that might be successful in improving performance.

Development and Psychometric Validation of the Body Trust Scale

Interoception (e.g., abilities to recognize/attend to internal sensations) is robustly associated with psychopathology. One form of interoception, body trust, is relevant for the development of disordered eating and suicidal thoughts/behaviors. However, measures of body trust are narrow, despite research suggesting body trust is multifaceted. The aim of this study was to develop a comprehensive measure of body trust: The Body Trust Scale (BTS). 479 U.S. adults completed self-report surveys containing the BTS and psychopathology measures. Exploratory and confirmatory factor analyses revealed a three-factor structure: Comfort with One's Body, Physical Attractiveness, and Comfort with Internal Sensations. Factors showed strong construct, convergent, and divergent validity, as well as moderate predictive validity for suicidal thoughts/non-suicidal self-injury. Furthermore, factors showed strong internal consistency, test-retest reliability, and were invariant across the gender binary. The BTS can be used in research and clinical settings to understand how specific facets of body trust relate to psychopathology.

Insights from triggers and prodromal symptoms on how migraine attacks start: The threshold hypothesis

BACKGROUND

The prodrome or premonitory phase is the initial phase of a migraine attack, and it is considered as a symptomatic phase in which prodromal symptoms may occur. There is evidence that attacks start 24-48 hours before the headache phase. Individuals with migraine also report several potential triggers for their attacks, which may be mistaken for premonitory symptoms and hinder migraine research.

METHODS

This review aims to summarize published studies that describe contributions to understanding the fine difference between prodromal/premonitory symptoms and triggers, give insights for research, and propose a way forward to study these phenomena. We finally aim to formulate a theory to unify migraine triggers and prodromal symptoms. For this purpose, a comprehensive narrative review of the published literature on clinical, neurophysiological and imaging evidence on migraine prodromal symptoms and triggers was conducted using the PubMed database.

RESULTS

Brain activity and network connectivity changes occur during the prodromal phase. These changes give rise to prodromal/premonitory symptoms in some individuals, which may be falsely interpreted as triggers at the same time as representing the early manifestation of the beginning of the attack. By contrast, certain migraine triggers, such as stress, hormone changes or sleep deprivation, acting as a catalyst in reducing the migraine threshold, might facilitate these changes and increase the chances of a migraine attack. Migraine triggers and prodromal/premonitory symptoms can be confused and have an intertwined relationship with the hypothalamus as the central hub for integrating external and internal body signals.

CONCLUSIONS

Differentiating migraine triggers and prodromal symptoms is crucial for shedding light on migraine pathophysiology and improve migraine management.

Enhancing chronic low back pain management: an initial neuroimaging study of a mobile interoceptive attention training

Introduction

Chronic low back pain (cLBP) poses significant challenges, often addressed through avoidance or distraction. Emerging evidence suggests that mind-body interventions, like our novel Mind Your Pain (MyP) smartphone mobile application, may offer relief. We conducted a single-arm, mixed-methods neuroimaging study to assess the degree to which treatment response to our 8-week intervention, as measured by the reduction in the Pain, Enjoyment of Life and General Activity Scale (PEG), was associated with enhanced pain-related insula activation over time.

Methods

Twenty-nine individuals with cLBP completed patient-reported assessments, qualitative sensory testing (QST) measures, and neuroimaging pre- and post-MyP. Functional MRI data during experimental heat pain on the left forearm were collected and analyzed, comparing responders (≥50% reduction in PEG scores) and non-responders.

Results

MyP led to significant decreases in PEG scores overall. Furthermore, MyP responders exhibited increased pain-related activation in key brain regions, including the contralateral posterior insula, bilateral ventral anterior insula, ventral anterior cingulate, dorsolateral prefrontal cortex, and nucleus accumbens. Although baseline behavioral and sensory measures did not differ between the two responder groups, baseline neural differences related to the impact of the endogenous back pain were observed.

Discussion

MyP appears to modify pain response and underlying neural circuitry, suggesting neural changes in interoception may serve as biomarkers for mind-body interventions in cLBP. This study highlights the potential of MyP as a novel approach for cLBP management, warranting further investigation.

Differences in brain connectivity between older adults practicing Tai Chi and Water Aerobics: a case-control study

Background

This study aimed to investigate the neural mechanisms that differentiate mind-body practices from aerobic physical activities and elucidate their effects on cognition and healthy aging. We examined functional brain connectivity in older adults (age > 60) without pre-existing uncontrolled chronic diseases, comparing Tai Chi with Water Aerobics practitioners.

Methods

We conducted a cross-sectional, case-control fMRI study involving two strictly matched groups (n = 32) based on gender, age, education, and years of practice. Seed-to-voxel analysis was performed using the Salience, and Frontoparietal Networks as seed regions in Stroop Word-Color and N-Back tasks and Resting State.

Results

During Resting State condition and using Salience network as a seed, Tai Chi group exhibited a stronger correlation between Anterior Cingulate Cortex and Insular Cortex areas (regions related to interoceptive awareness, cognitive control and motor organization of subjective aspects of experience). In N-Back task and using Salience network as seed, Tai Chi group showed increased correlation between Left Supramarginal Gyrus and various cerebellar regions (related to memory, attention, cognitive processing, sensorimotor control and cognitive flexibility). In Stroop task, using Salience network as seed, Tai Chi group showed enhanced correlation between Left Rostral Prefrontal Cortex and Right Occipital Pole, and Right Lateral Occipital Cortex (areas associated with sustained attention, prospective memory, mediate attention between external stimuli and internal intention). Additionally, in Stroop task, using Frontoparietal network as seed, Water Aerobics group exhibited a stronger correlation between Left Posterior Parietal Lobe (specialized in word meaning, representing motor actions, motor planning directed to objects, and general perception) and different cerebellar regions (linked to object mirroring).

Conclusion

Our study provides evidence of differences in functional connectivity between older adults who have received training in a mind-body practice (Tai Chi) or in an aerobic physical activity (Water Aerobics) when performing attentional and working memory tasks, as well as during resting state.

Neurobiological research on N,N-dimethyltryptamine (DMT) and its potentiation by monoamine oxidase (MAO) inhibition: from ayahuasca to synthetic combinations of DMT and MAO inhibitors

The potent hallucinogen N,N-dimethyltryptamine (DMT) has garnered significant interest in recent years due to its profound effects on consciousness and its therapeutic psychopotential. DMT is an integral (but not exclusive) psychoactive alkaloid in the Amazonian plant-based brew ayahuasca, in which admixture of several β-carboline monoamine oxidase A (MAO-A) inhibitors potentiate the activity of oral DMT, while possibly contributing in other respects to the complex psychopharmacology of ayahuasca. Irrespective of the route of administration, DMT alters perception, mood, and cognition, presumably through agonism at serotonin (5-HT) 1A/2A/2C receptors in brain, with additional actions at other receptor types possibly contributing to its overall psychoactive effects. Due to rapid first pass metabolism, DMT is nearly inactive orally, but co-administration with β-carbolines or synthetic MAO-A inhibitors (MAOIs) greatly increase its bioavailability and duration of action. The synergistic effects of DMT and MAOIs in ayahuasca or synthetic formulations may promote neuroplasticity, which presumably underlies their promising therapeutic efficacy in clinical trials for neuropsychiatric disorders, including depression, addiction, and post-traumatic stress disorder. Advances in neuroimaging techniques are elucidating the neural correlates of DMT-induced altered states of consciousness, revealing alterations in brain activity, functional connectivity, and network dynamics. In this comprehensive narrative review, we present a synthesis of current knowledge on the pharmacology and neuroscience of DMT, β-carbolines, and ayahuasca, which should inform future research aiming to harness their full therapeutic potential.

In Humans, Insulo-striate Structural Connectivity is Largely Biased Toward Either Striosome-like or Matrix-like Striatal Compartments

The insula is an integral component of sensory, motor, limbic, and executive functions, and insular dysfunction is associated with numerous human neuropsychiatric disorders. Insular efferents project widely, but insulo-striate projections are especially numerous. The targets of these insulo-striate projections are organized into tissue compartments, the striosome and matrix. These striatal compartments have distinct embryologic origins, afferent and efferent connectivity, dopamine pharmacology, and susceptibility to injury. Striosome and matrix appear to occupy separate sets of cortico-striato-thalamo-cortical loops, so a bias in insulo-striate projections toward one compartment may also embed an insular subregion in distinct regulatory and functional networks. Compartment-specific mapping of insulo-striate structural connectivity is sparse; the insular subregions are largely unmapped for compartment-specific projections. In 100 healthy adults, diffusion tractography was utilized to map and quantify structural connectivity between 19 structurally-defined insular subregions and each striatal compartment. Insulo-striate streamlines that reached striosome-like and matrix-like voxels were concentrated in distinct insular zones (striosome: rostro- and caudoventral; matrix: caudodorsal) and followed different paths to reach the striatum. Though tractography was generated independently in each hemisphere, the spatial distribution and relative bias of striosome-like and matrix-like streamlines were highly similar in the left and right insula. 16 insular subregions were significantly biased toward 1 compartment: 7 toward striosome-like voxels and 9 toward matrix-like voxels. Striosome-favoring bundles had significantly higher streamline density, especially from rostroventral insular subregions. The biases in insulo-striate structural connectivity that were identified mirrored the compartment-specific biases identified in prior studies that utilized injected tract tracers, cytoarchitecture, or functional MRI. Segregating insulo-striate structural connectivity through either striosome or matrix may be an anatomic substrate for functional specialization among the insular subregions.

Connecting Mindfulness Practice to Generative Semiotic Activity-Self-Other Referent in Umwelt and Semiosphere

In this comment paper on von Fircks (2023a), I would like to focus on four issues and offer some reflections on them: first, what is happening in the process of a new I arising through mindfulness meditation practice? I would like to supplement the dialogue between Buber and Rogers in 1957 on the dynamism of I and Me, which is the basis of Mead's theory of self formation, in which I and Me separate, discover and meet a new self. The second, is that meditation, which at first glance appears to be an internal meditation practice and a personal activity, leads to a semiotic mediated social process. The Tao and early Buddhist ideas that form the background to the experiential process of mindfulness meditation will be reviewed, and the significance of people experiencing the interdependence of non-human nature and the environment through the practice will be discussed. Third, connecting this to the idea of Umwelt (Uexküll) and the semiosphere (Lotman), an attempt is made to extend the otherness as a collating body of self formation to Umwelt. Fourth, mindfulness meditation focuses attention on the breath. In relation to Mead's focus on the environment under the skin, i.e. corporeality, I will supplement the psychological meaning of cultivating the body's sense of interoception through the sensing of repetitive movements of tension and relaxation. Through the above, what kind of semiotic mediating function does mindfulness meditation have in relation to the construction of the new I, and how does it lead to the creation of social meaning? We would like to discuss these points. CLINICAL TRIAL REGISTRATION: The article does not contain any studies with clinical trial. This, clinical Trial registration is not applicable.

Identifying subgroups of urge suppression in Obsessive-Compulsive Disorder using machine learning

Obsessive-compulsive disorder (OCD) is phenomenologically heterogeneous. While predominant models suggest fear and harm prevention drive compulsions, many patients also experience uncomfortable sensory-based urges ("sensory phenomena") that may be associated with heightened interoceptive sensitivity. Using an urge-to-blink eyeblink suppression paradigm to model sensory-based urges, we previously found that OCD patients as a group had more eyeblink suppression failures and greater activation of sensorimotor-interoceptive regions than controls. However, conventional approaches assuming OCD homogeneity may obscure important within-group variability, impeding precision treatment development. This study investigated the heterogeneity of urge suppression failure in OCD and examined relationships with clinical characteristics and neural activation. Eighty-two patients with OCD and 38 controls underwent an fMRI task presenting 60-s blocks of eyeblink suppression alternating with free-blinking blocks. Latent profile analysis identified OCD subgroups based on number of erroneous blinks during suppression. Subgroups were compared on behavior, clinical characteristics, and brain activation during task. Three patient subgroups were identified. Despite similar overall OCD severity, the subgroup with the most erroneous eyeblinks had the highest sensory phenomena severity, interoceptive sensitivity, and subjective urge intensity. Compared to other subgroups, this subgroup exhibited more neural activity in somatosensory and interoceptive regions during the early phase (first 30 s) of blink suppression and reduced activity in the middle frontal gyrus during the late phase (second 30 s) as the suppression period elapsed. Heterogeneity of urge suppression in OCD was associated with clinical characteristics and brain function. Our results reveal potential treatment targets that could inform personalized medicine.

Needing: An Active Inference Process for Physiological Motivation

Need states are internal states that arise from deprivation of crucial biological stimuli. They direct motivation, independently of external learning. Despite their separate origin, they interact with reward processing systems that respond to external stimuli. This article aims to illuminate the functioning of the needing system through the lens of active inference, a framework for understanding brain and cognition. We propose that need states exert a pervasive influence on the organism, which in active inference terms translates to a "pervasive surprise"-a measure of the distance from the organism's preferred state. Crucially, we define needing as an active inference process that seeks to reduce this pervasive surprise. Through a series of simulations, we demonstrate that our proposal successfully captures key aspects of the phenomenology and neurobiology of needing. We show that as need states increase, the tendency to occupy preferred states strengthens, independently of external reward prediction. Furthermore, need states increase the precision of states (stimuli and actions) leading to preferred states, suggesting their ability to amplify the value of reward cues and rewards themselves. Collectively, our model and simulations provide valuable insights into the directional and underlying influence of need states, revealing how this influence amplifies the wanting or liking associated with relevant stimuli.

Insular cortex subregions have distinct roles in cued heroin seeking after extinction learning and prolonged withdrawal in rats

Evidence indicates that the anterior (aIC), but not posterior (pIC), insular cortex promotes cued reinstatement of cocaine seeking after extinction in rats. It is unknown whether these subregions also regulate heroin seeking and whether such involvement depends on prior extinction learning. To address these questions, we used baclofen and muscimol (BM) to inactivate the aIC or pIC bilaterally during a seeking test after extinction or prolonged withdrawal from heroin. Male Sprague-Dawley rats in the extinction groups underwent 10+ days of heroin self-administration, followed by 6+ days of extinction sessions, and subsequent cued or heroin-primed reinstatement. Results indicate that aIC inactivation increased cued reinstatement of heroin seeking after extinction, whereas pIC inactivation prevented cued reinstatement. To determine whether these effects were extinction-dependent, we conducted a subsequent study using both sexes with prolonged withdrawal. Male and female rats in the withdrawal groups underwent 10+ days of heroin self-administration, followed by cued seeking tests after 1 and 14 days of homecage withdrawal to measure incubation of heroin craving. In this case, the findings indicate that aIC inactivation had no effect on incubation of heroin craving after withdrawal in either sex, whereas pIC inactivation decreased heroin craving only in males. These findings suggest that the aIC and pIC have opposing roles in suppressing vs promoting cued heroin seeking after extinction and that these roles are distinct from those in cocaine seeking. Moreover, the incubation of craving results suggest that new contingency learning is necessary to recruit the aIC in cued heroin seeking.

Neuroimaging of autobiographical memory in dementia with Lewy bodies: a story of insula

Although deficits in learning and retrieving new information are well characterized in dementia with Lewy bodies, autobiographical memory has never been explored in this disease. Yet, autobiographical memory impairments are a pervasive feature of dementia, well characterized in other neurodegenerative diseases. Moreover, autobiographical memory corresponds to an extension over time of the self, which we hypothesize is altered in dementia with Lewy bodies and impairment of which could be linked to the insular atrophy occurring from an early stage of the disease. In this study, we sought to characterize autobiographical memory impairments and explore their neural correlates in dementia with Lewy bodies, on the assumption that insular damage could impact the self, including its most elaborate components, such as autobiographical memory. Twenty patients with prodromal to mild dementia with Lewy bodies were selected to participate in this exploratory study along with 20 healthy control subjects. The Autobiographical Interview was used to assess autobiographical memory. Performances were compared between patients and control subjects, and an analysis across life periods and recall conditions was performed. 3D magnetic resonance images were acquired for all participants, and correlational analyses were performed in the patient group using voxel-based morphometry. The behavioural results of the Autobiographical Interview showed that autobiographical memory performances were significantly impaired in dementia with Lewy body patients compared to control subjects in a temporally ungraded manner, for both the free recall and the specific probe conditions (P < 0.0001), though with greater improvement after probing in the patient group. Furthermore, autobiographical memory impairments were correlated with grey matter volume within right insular cortex, temporoparietal junction, precuneus, putamen, left temporal cortex, bilateral parahippocampus and cerebellum, using a threshold of P = 0.005 uncorrected. The behavioural results confirm the existence of temporally ungraded autobiographical memory impairments in dementia with Lewy bodies, from the early stage of the disease. As we expected, neuroimaging analysis revealed a role for the insula and the precuneus in autobiographical memory retrieval, two regions associated with elementary aspects of the self, among other brain regions classically associated with autobiographical memory, such as medial temporal lobe and temporoparietal junction. Our findings provide important insights regarding the involvement of the insula in the self and suggest that insular damage could lead to a global collapse of the self, including its more elaborated components, such as autobiographical memory.

The Posterior Insular Cortex is Necessary for Feeding-Induced Jejunal Myoelectrical Activity in Male Rats

The gastrointestinal tract exhibits coordinated muscle motility in response to food digestion, which is regulated by the central nervous system through autonomic control. The insular cortex is one of the brain regions that may regulate the muscle motility. In this study, we examined whether, and how, the insular cortex, especially the posterior part, regulates gastrointestinal motility by recording jejunal myoelectrical signals in response to feeding in freely moving male rats. Feeding was found to induce increases in jejunal myoelectrical signal amplitudes. This increase in the jejunal myoelectrical signals was abolished by vagotomy and pharmacological inhibition of the posterior insular cortex. Additionally, feeding induced a decrease and increase in sympathetic and parasympathetic nervous activities, respectively, both of which were eliminated by posterior insular cortical inhibition. These results suggest that the posterior insular cortex regulates jejunal motility in response to feeding by modulating autonomic tone.

Functional brain networks associated with the urge for action: Implications for pathological urge

Tics in Tourette syndrome (TS) are often preceded by sensory urges that drive the motor and vocal symptoms. Many everyday physiological behaviors are associated with sensory phenomena experienced as an urge for action, which may provide insight into the neural correlates of this pathological urge to tic that remains elusive. This study aimed to identify a brain network common to distinct physiological behaviors in healthy individuals, and in turn, examine whether this network converges with a network we previously localized in TS, using novel 'coordinate network mapping' methods. Systematic searches were conducted to identify functional neuroimaging studies reporting correlates of the urge to micturate, swallow, blink, or cough. Using activation likelihood estimation meta-analysis, we identified an 'urge network' common to these physiological behaviors, involving the bilateral insula/claustrum/inferior frontal gyrus/supplementary motor area, mid-/anterior- cingulate cortex (ACC), right postcentral gyrus, and left thalamus/precentral gyrus. Similarity between the urge and TS networks was identified in the bilateral insula, ACC, and left thalamus/claustrum. The potential role of the insula/ACC as nodes in the network for bodily representations of the urge to tic are discussed.

Investigations on the Ability of the Insular Cortex to Process Peripheral Immunosuppression

The brain and immune system communicate through complex bidirectional pathways, but the specificity by which the brain perceives or even remembers alterations in immune homeostasis is still poorly understood. Recent data revealed that immune-related information under peripheral inflammatory conditions, termed as "immunengram", were represented in specific neuronal ensembles in the insular cortex (IC). Chemogenetic reactivation of these neuronal ensembles was sufficient to retrieve the inflammatory stages, indicating that the brain can store and retrieve specific immune responses. Against this background, the current approach was designed to investigate the ability of the IC to process states of immunosuppression pharmacologically induced by the mechanistic target of rapamycin (mTOR) inhibitor rapamycin. We here show that the IC perceives the initial state of immunosuppression, reflected by increased deep-brain electroencephalography (EEG) activity during acute immunosuppressive drug treatment. Following an experienced period of immunosuppression, though, diminished splenic cytokine production as formerly induced by rapamycin could not be reinstated by nonspecific chemogenetic activation or inhibition of the IC. These findings suggest that the information of a past, or experienced status of pharmacologically induced immunosuppression is not represented in the IC. Together, the present work extends the view of immune-to-brain communication during the states of peripheral immunosuppression and foster the prominent role of the IC for interoception.

Resting-State Functional Connectivity Profile of Insular Subregions

The insula is often considered the fifth lobe of the brain and is increasingly recognized as one of the most connected regions in the brain, with widespread connections to cortical and subcortical structures. As a follow-up to our previous tractography work, we investigated the resting-state functional connectivity (rsFC) profiles of insular subregions and assessed their concordance with structural connectivity. We used the CONN toolbox to analyze the rsFC of the same 19 insular regions of interest (ROIs) we used in our prior tractography work and regrouped them into six subregions based on their connectivity pattern similarity. Our analysis of 50 healthy participants confirms the known broad connectivity of the insula and shows novel and specific whole-brain and intra-connectivity patterns of insular subregions. By examining such subregions, our findings provide a more detailed pattern of connectivity than prior studies that may prove useful for comparison between patients.

Functional Movement Disorder Is Associated with Abnormal Interoceptive Brain Activity: A Task-based Functional MRI Study

Background

Aberrant interoceptive processing has been hypothesized to contribute to the pathophysiology of functional neurological disorder, although findings have been inconsistent. Here, we utilized functional magnetic resonance imaging (fMRI) to examine neural correlates of interoceptive attention - the conscious focus and awareness of bodily sensations - in functional movement disorder (FMD).

Methods

We used voxelwise analyses to compare blood oxygenation level-dependent responses between 13 adults with hyperkinetic FMD and 13 healthy controls (HCs) during a task requiring attention to different bodily sensations and to an exteroceptive stimulus. Additionally, we examined between-group differences in self-reported measures of interoception and evaluated their relationship with neural activity.

Results

Interoceptive conditions (heartbeat, stomach and 'body', indicating sensations from the body part or limb affected in FMD participants) activated a network involving the precuneus, the posterior cingulate cortex (PCC) and caudate nucleus (CN) bilaterally, and the right anterior insula (aINS) (p <0.05, corrected). Group differences in brain activity were mainly driven by processing of disease-related interoceptive signals, which in the FMD group was associated with a broader neural activation than monitoring gastric interoception, while no group differences were detected during cardiac interoception. Differences based on interoceptive focus (body vs heartbeat and stomach) between FMD subjects and HCs were found in PCC, CN, angular gyrus, thalamus, and in the mid-insula (p <0.05, corrected).

Conclusions

This is, to our knowledge, the first study showing that FMD is associated with abnormal interoceptive processing in regions involved in monitoring body state, attentional focus, and homeostatic inference.

Immediate Effects of Mindful Awareness in Body-oriented Therapy as an Adjunct to Medication for Opioid Use Disorder

Objective

While effective, medication for opioid use disorder (MOUD) treatment outcomes can be limited by co-occurring polysubstance use, mental health and chronic pain conditions. Interoceptive training may facilitate well-being and support medication treatment for MOUD. This study examined the pre-post effects of the mindfulness-based intervention Mindful Awareness in Body-oriented Therapy (MABT) as an adjunct to MOUD. MABT teaches interoceptive awareness skills to promote self-care and emotion regulation.

Methods

People stabilized on medication for OUD (N = 303) from 6 community clinics in Northwestern United States were recruited and randomly assigned to MABT plus MOUD or MOUD only. In a mixed-methods study, we used an intent-to-treat approach to examine the proportion of days abstinent from non-prescribed opioids, and other substance use (primary outcomes) at baseline and 3 months post-intervention. Secondary outcomes included symptoms of mental health distress; emotional regulation difficulties; pain and physical symptom indicators; interoceptive awareness and mindfulness skills. Participant experience of MABT was collected through post-intervention surveys. Changes in outcomes were assessed using linear mixed models; content analysis was used to analyze the qualitative data.

Results

Levels of overall substance use were low and did not differ between groups. Significant improvements in PTSD symptoms, interoceptive awareness, pain severity, pain activity interference, and physical symptom frequency were found for those who received MABT compared to MOUD only.

Conclusion

In this stable MOUD population, substance use outcomes were not improved, however MABT demonstrated significant positive changes across multiple health outcomes critical for improving MOUD treatment. Clinical Trials Registration: NCT04082637 on 9/3/2019.

Interoception in anxiety, depression, and psychosis: a review

Research has examined the relationship between interoception and anxiety, depression, and psychosis; however, it is unclear which aspects of interoception have been systematically examined, what the combined findings are, and which areas require further research. To answer these questions, we systematically searched and narratively synthesised relevant reviews, meta-analyses, and theory papers (total n = 34). Existing systematic reviews and meta-analyses (anxiety n = 2; depression n = 2; psychosis n = 0), focus on cardiac interoceptive accuracy (heartbeat perception), and indicate that heartbeat perception is not systematically impaired in anxiety or depression. Heartbeat perception might be poorer in people with psychosis, but further evidence is needed. Other aspects of interoception, such as different body systems and processing levels, have been studied but not systematically reviewed. We highlight studies examining these alternative bodily domains and levels, review the efficacy of interoception-based psychological interventions, and make suggestions for future research.

Funding

Wellcome Trust UK.

Interoceptive bodily awareness in patients seeking pain relief with osteopathic manipulative treatment: an observational cohort pilot study

CONTEXT

Interoceptive bodily awareness (IBA) is one's attentional focus on and relationship with comfortable and uncomfortable (e.g., pain) internal body sensations. Integrating IBA into research on osteopathic manipulative treatment (OMT) is growing, both as an outcome and predictor of treatment outcomes; however, it has yet to be studied in a clinical setting.

OBJECTIVES

We aimed to conduct a pilot study to measure IBA, with the Multidimensional Assessment of Interoceptive Awareness (MAIA), in patients seeking OMT for pain, and to test if OMT exposure may be associated with higher IBA as measured by the MAIA. The primary outcome was the change in MAIA scores, and the secondary outcomes were reduction in pain intensity, reduction in pain interference, and increase in participants' perception of change post-OMT.

METHODS

A convenience sample was recruited from individuals presenting for OMT appointments at a College of Osteopathic Medicine OMT teaching clinic. Participants were recruited into our single-arm observational cohort study (n=36), and categorized into one of two groups, OMT-naïve (n=19) or OMT-experienced (n=17), based on prior exposure to OMT. We measured MAIA scores and clinical pain-related outcomes prior to, immediately after, and at 1 and 3 weeks after a usual-care OMT session in the clinic. Covariates including experience with mind-body activities, non-OMT body work, and physical and emotional trauma were also collected to explore potential relationships. We utilized t tests to compare MAIA scores and pain outcomes between groups and across time points. Stepwise regression models were utilized to explore potential relationships with covariates.

RESULTS

The OMT-experienced group scored higher on the MAIA scales "Not-worrying" (p=0.002) and "Trusting" (p=0.028) at baseline. There were no significant changes in the MAIA scores before and after the single OMT session. Analysis of secondary outcomes revealed that all pain outcomes significantly decreased post-OMT (p<0.05), with the largest relative improvements in the acute pain and OMT-naïve subgroups, with diminishing effects over time.

CONCLUSIONS

Assessing IBA with MAIA in a clinical OMT setting is feasible. There were significant positive correlations between OMT exposure and two of the eight MAIA scales. Future studies are justified to further explore this relationship.

The Relationship Between Brain Activation for Taking Others' Perspective and Interoceptive Abilities in Autism Spectrum Disorder: An fMRI Study

Objectives

In this functional magnetic resonance imaging study, we aimed to investigate the differences in brain activation between individuals with autism spectrum disorder (ASD) and typically developing (TD) individuals during perspective taking. We also examined the association between brain activation and empathic and interoceptive abilities.

Methods

During scanning, participants from the ASD (n=17) and TD (n=22) groups were shown pain stimuli and asked to rate the level of the observed pain from both self- and other-perspectives. Empathic abilities, including perspective taking, were measured using an empathic questionnaire, and three dimensions of interoception were assessed: interoceptive accuracy, interoceptive sensibility, and interoceptive trait prediction errors.

Results

During self-perspective taking, the ASD group exhibited greater activation in the left precuneus than the TD group. During other-perspective taking, relative hyperactivation extended to areas including the right precuneus, right superior frontal gyrus, left caudate nucleus, and left amygdala. Brain activation levels in the right superior frontal gyrus while taking other-perspective were negatively correlated with interoceptive accuracy, and those in the left caudate were negatively correlated with perspective taking ability in the ASD group.

Conclusion

Individuals with ASD show atypical brain activation during perspective taking. Notably, their brain regions associated with stress reactions and escape responses are overactivated when taking other-perspective. This overactivity is related to poor interoceptive accuracy, suggesting that individuals with ASD may experience difficulties with the self-other distinction or atypical embodiment when considering another person's perspective.

An Interoception- Based Intervention for Improving Emotional Regulation in Children in a Special Education Classroom: Feasibility Study

Interoception supports the ability to notice, interpret, and react to internal sensations and impacts emotional regulation and participation in meaningful activities. This study aimed to expand evidence regarding the efficacy of a 7-week intervention based on The Interoception Curriculum: A Guide to Developing Mindful Self-Regulation in improving interoception and emotional regulation. We purposefully sampled middle-school participants (N = 9) with several diagnoses from a special education classroom. Self-report and teacher-report measures on interoceptive awareness and emotional regulation were collected before and after implementation of the interoception intervention. Statistically significant correlations were seen between the interoceptive awareness and emotional regulation and improvements in interoceptive awareness and emotional regulation were found following the intervention. In a small one group pretest/post-test design, a seven-week intervention based on the interoception curriculum demonstrated feasibility of this approach for children in a special education classroom and outcomes showed that interoceptive awareness and emotional regulation could improve after participation in this intervention.

The neurobiology of interoception and affect

Scholars have argued for centuries that affective states involve interoception, or representations of the state of the body. Yet, we lack a mechanistic understanding of how signals from the body are transduced, transmitted, compressed, and integrated by the brains of humans to produce affective states. We suggest that to understand how the body contributes to affect, we first need to understand information flow through the nervous system's interoceptive pathways. We outline such a model and discuss how unique anatomical and physiological aspects of interoceptive pathways may give rise to the qualities of affective experiences in general and valence and arousal in particular. We conclude by considering implications and future directions for research on interoception, affect, emotions, and human mental experiences.

Silence between words: Is solitude important for relatedness?

Chronic loneliness is a risk factor for physical and health problems, in part due to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system. In contrast, temporary moments of positive solitude (passing good times alone and not feeling lonely) appear to have positive effects on mental health, social life, and creativity, and seems to be a buffer against loneliness. Herein, three ways of how solitude may have positive effects on health and relatedness are discussed, namely effects on enhancement of mind-wandering, interoceptive awareness, and spirituality. Solitude may facilitate (1) activation of the default mode network (DMN) underlying mind-wandering including daydreaming about other people; (2) activation of brain areas supporting interoceptive awareness; (3) deactivation of prefrontal cortex, or deactivation and decreased connectivity of the DMN, giving raise to susceptibility to spiritual experiences. The capacity to handle and enjoy solitude is a developmental process that may be difficult for many persons. Craving for social connections and external stimulation with digital technologies (e.g., internet, smartphones, social media) might be interfering with the development of the capacity for solitude and thereby increasing loneliness; this might be partly due to impaired interoceptive awareness and impaired functional mind-wandering (common in solitude). Congruently, overuse of digital technologies was associated with reduced activity, and reduced gray matter volume and density, in brain areas supporting interoceptive awareness, as well as with decreased connectivity of the DMN supporting creative insights. Solitude has been a relatively dismissed topic in neuroscience and health sciences, but a growing number of studies is highlighting its importance for well-being.

Practicing Interoceptive Sensitivity as a Couple: A Mixed-Methods Acceptance Analysis of a Dyadic vs. Single Pilot Randomized Controlled Trial

Training interoceptive sensitivity (IS) might be a first step in effectively promoting intuitive eating (IE). A dyadic interoception-based pilot randomized controlled trial was conducted to increase IE among couples aged 50+. The training consisted of three exercises, a Body Scan (BS), a hunger exercise (HU), and a satiety (SA) exercise. This study explored how spouses accepted the (dyadic vs. single) training. In a mixed-methods convergence design, the findings of a survey (n = 68 couples) and focus groups (n = 4) were synthesized. Moderate general acceptance (e.g., regarding feasibility and low burden) and a hierarchical gradient in favor of the BS (e.g., pleasantness and improved sleep quality) emerged. Barriers concerned a perceived lack of the exercises' usefulness and a limited understanding of the training purpose. A wish for regular feedback and exchange with the study stuff and other participants was expressed. Spousal training involvement was experienced as being rather beneficial. Previously harmonized dietary practices and daily routines appeared as constructive pre-conditions for the joint training. This study highlights the potential and implications of training couples in IS. Future interventions should involve a regular exchange and closer guidance by study staff to promote a better understanding of the processes and goals of IS and IE.

Brain Structural and Functional Damage Network Localization of Suicide

BACKGROUND

Extensive neuroimaging research on brain structural and functional correlates of suicide has produced inconsistent results. Despite increasing recognition that damage in multiple different brain locations that causes the same symptom can map to a common brain network, there is still a paucity of research investigating network localization of suicide.

METHODS

To clarify this issue, we initially identified brain structural and functional damage locations in relation to suicide from 63 published studies with 2135 suicidal and 2606 nonsuicidal individuals. By applying novel functional connectivity network mapping to large-scale discovery and validation resting-state functional magnetic resonance imaging datasets, we mapped these affected brain locations to 3 suicide brain damage networks corresponding to different imaging modalities.

RESULTS

The suicide gray matter volume damage network comprised widely distributed brain areas primarily involving the dorsal default mode, basal ganglia, and anterior salience networks. The suicide task-induced activation damage network was similar to but less extensive than the gray matter volume damage network, predominantly implicating the same canonical networks. The suicide resting-state activity damage network manifested as a localized set of brain regions encompassing the orbitofrontal cortex and middle cingulate cortex.

CONCLUSIONS

Our findings not only may help reconcile prior heterogeneous neuroimaging results, but also may provide insights into the neurobiological mechanisms of suicide from a network perspective, which may ultimately inform more targeted and effective strategies to prevent suicide.

Detection of latent brain states from baseline neural activity in the amygdala

The amygdala responds to a large variety of socially and emotionally salient environmental and interoceptive stimuli. The context in which these stimuli occur determines their social and emotional significance. In canonical neurophysiological studies, the fast-paced succession of stimuli and events induce phasic changes in neural activity. During inter-trial intervals neural activity is expected to return to a stable and relatively featureless baseline. Context, such as the presence of a social partner, or the similarity of trials in a blocked design, induces brain states that can transcend the fast-paced succession of stimuli and can be recovered from the baseline firing rate of neurons. Indeed, the baseline firing rates of neurons in the amygdala change between blocks of trials of gentle grooming touch, delivered by a trusted social partner, and non-social airflow stimuli, delivered by a computer-controlled air valve. In this experimental paradigm, the presence of the groomer alone was sufficient to induce small but significant changes in baseline firing rates. Here, we examine local field potentials (LFP) recorded during these baseline periods to determine whether context was encoded by network dynamics that emerge in the local field potentials from the activity of large ensembles of neurons. We found that machine learning techniques can reliably decode social vs. non-social context from spectrograms of baseline local field potentials. Notably, decoding accuracy improved significantly with access to broad-band information. No significant differences were detected between the nuclei of the amygdala that receive direct or indirect inputs from areas of the prefrontal cortex known to coordinate flexible, context-dependent behaviors. The lack of nuclear specificity suggests that context-related synaptic inputs arise from a shared source, possibly interoceptive inputs that signal the sympathetic- vs. parasympathetic-dominated states characterizing non-social and social blocks, respectively.

Ingestible pills reveal gastric correlates of emotions

Although it is generally held that gastrointestinal (GI) signals are related to emotions, direct evidence for such a link is currently lacking. One of the reasons why the internal milieu of the GI system is poorly investigated is because visceral organs are difficult to access and monitor. To directly measure the influence of endoluminal markers of GI activity on the emotional experience, we asked a group of healthy male participants to ingest a pill that measured pH, pressure, and temperature of their GI tract while they watched video clips that consistently induced disgust, fear, happiness, sadness, or a control neutral state. In addition to the objective physiological markers of GI activity, subjective ratings of perceived emotions and visceral (i.e. gastric, respiratory and cardiac) sensations were recorded, as well as changes in heart rate (HR), heart rate variability (HRV) and spontaneous eyes blinks as non-gastric behavioral and autonomic markers of the emotional experience. We found that when participants observed fearful and disgusting video clips, they reported to perceive not only cardiac and respiratory sensations but also gastric sensations, such as nausea. Moreover, we found that there was a clear relation between the physiology of the stomach and the perceived emotions. Specifically, when disgusting video clips were displayed, the more acidic the pH, the more participants reported feelings of disgust and fear; the less acidic the pH, the more they reported happiness. Complementing the results found in the deep gastric realm, we found that disgusting stimuli induced a significant increase in HRV compared to the neutral scenarios, and together with fearful video clips a decrease in HR. Our findings suggest that gastric signals contribute to unique emotional states and that ingestible pills may open new avenues for exploring the deep-body physiology of emotions.

Hippocampus diffusivity abnormalities in classical trigeminal neuralgia

Introduction

Patients with chronic pain frequently report cognitive symptoms that affect memory and attention, which are functions attributed to the hippocampus. Trigeminal neuralgia (TN) is a chronic neuropathic pain disorder characterized by paroxysmal attacks of unilateral orofacial pain. Given the stereotypical nature of TN pain and lack of negative symptoms including sensory loss, TN provides a unique model to investigate the hippocampal implications of chronic pain. Recent evidence demonstrated that TN is associated with macrostructural hippocampal abnormalities indicated by reduced subfield volumes; however, there is a paucity in our understanding of hippocampal microstructural abnormalities associated with TN.

Objectives

To explore diffusivity metrics within the hippocampus, along with its functional and structural subfields, in patients with TN.

Methods

To examine hippocampal microstructure, we utilized diffusion tensor imaging in 31 patients with TN and 21 controls. T1-weighted magnetic resonance images were segmented into hippocampal subfields and registered into diffusion-weighted imaging space. Fractional anisotropy (FA) and mean diffusivity were extracted for hippocampal subfields and longitudinal axis segmentations.

Results

Patients with TN demonstrated reduced FA in bilateral whole hippocampi and hippocampal body and contralateral subregions CA2/3 and CA4, indicating microstructural hippocampal abnormalities. Notably, patients with TN showed significant correlation between age and hippocampal FA, while controls did not exhibit this correlation. These effects were driven chiefly by female patients with TN.

Conclusion

This study demonstrates that TN is associated with microstructural hippocampal abnormalities, which may precede and potentially be temporally linked to volumetric hippocampal alterations demonstrated previously. These findings provide further evidence for the role of the hippocampus in chronic pain and suggest the potential for targeted interventions to mitigate cognitive symptoms in patients with chronic pain.

Individual differences of white matter characteristic along the anterior insula-based fiber tract circuit for pain empathy in healthy women and women with primary dysmenorrhea

Pain empathy, defined as the ability of one person to understand another person's pain, shows large individual variations. The anterior insula is the core region of the pain empathy network. However, the relationship between white matter (WM) properties of the fiber tracts connecting the anterior insula with other cortical regions and an individual's ability to modulate pain empathy remains largely unclear. In this study, we outline an automatic seed-based fiber streamline (sFS) analysis method and multivariate pattern analysis (MVPA) to predict the levels of pain empathy in healthy women and women with primary dysmenorrhoea (PDM). Using the sFS method, the anterior insula-based fiber tract network was divided into five fiber cluster groups. In healthy women, interindividual differences in pain empathy were predicted only by the WM properties of the five fiber cluster groups, suggesting that interindividual differences in pain empathy may rely on the connectivity of the anterior insula-based fiber tract network. In women with PDM, pain empathy could be predicted by a single cluster group. The mean WM properties along the anterior insular-rostroventral area of the inferior parietal lobule further mediated the effect of pain on empathy in patients with PDM. Our results suggest that chronic periodic pain may lead to maladaptive plastic changes, which could further impair empathy by making women with PDM feel more pain when they see other people experiencing pain. Our study also addresses an important gap in the analysis of the microstructural characteristics of seed-based fiber tract network.

The relationship between childhood psychological abuse and depression in college students: a moderated mediation model

BACKGROUND

Childhood psychological abuse (CPA) are highly correlated with depression among college students, but the underlying mechanisms between variables need further exploration. This study aims to investigate internet addiction as a mediating factor and alexithymia as a moderating factor, in order to further elucidate the potential risk factors between CPA and depression among college students.

METHODS

A self-report survey was conducted among 1196 college students from four universities in three provinces in China. The survey included measures of CPA, internet addiction, alexithymia, and depression. Descriptive and correlational analyses were performed on these variables, and a moderated mediation model was constructed.

RESULTS

CPA was positively correlated with depression among college students, as well as internet addiction with alexithymia. Internet addiction partially mediated the relationship between CPA and depression among college students, while alexithymia strengthened the relationships among the paths in the moderated mediation model.

CONCLUSION

This study provides further insights into the psychological mechanisms underlying the relationship between CPA and depression among college students. Internet addiction serves as a mediating factor in this relationship, while alexithymia may enhance the strength of the relationships among the three variables.

The relationship between childhood psychological abuse and depression in college students: a moderated mediation model

Background

Childhood psychological abuse (CPA) are highly correlated with depression among college students, but the underlying mechanisms between variables need further exploration. This study aims to investigate internet addiction as a mediating factor and alexithymia as a moderating factor, in order to further elucidate the potential risk factors between CPA and depression among college students.

Methods

A self-report survey was conducted among 1196 college students from four universities in three provinces in China. The survey included measures of CPA, internet addiction, alexithymia, and depression. Descriptive and correlational analyses were performed on these variables, and a moderated mediation model was constructed.

Results

CPA was positively correlated with depression among college students, as well as internet addiction with alexithymia. Internet addiction partially mediated the relationship between CPA and depression among college students, while alexithymia strengthened the relationships among the paths in the moderated mediation model.

Conclusion

This study provides further insights into the psychological mechanisms underlying the relationship between CPA and depression among college students. Internet addiction serves as a mediating factor in this relationship, while alexithymia may enhance the strength of the relationships among the three variables.

Interoceptive Awareness Mediates Effects of Sleep Disturbance on Pain Outcomes in Chronic Pain Patients

Background

Sleep disorders are common in adults with chronic pain and are multifactorial. Recent evidence suggest sleep disturbance may affect interoceptive awareness (IA) in healthy adults. Less is known about the relationship between IA, sleep, and pain in adults with chronic pain.

Purpose

This cross-sectional study investigated the relationships between perceived sleep disruption (PROMIS Sleep), pain interference (PROMIS Pain Interference Short Form), pain intensity (PROMIS Pain Intensity Scale), and IA (Multidimensional Interoceptive Awareness Scale-2 [MAIA-2]), and subsequently, delineated potential direct and indirect links among constructs.

Methods

Online surveys were administered to 301 individuals with chronic pain. Strategic sampling targeted respondents to reflect the 2010 census. Pearson's correlation characterized the overall relationship between variables. Hierarchical multiple regression analyses were conducted to investigate direct links between sleep disturbance, pain outcomes, and IA. Path analyses assessed mediational effects of IA on the relationship between sleep disturbance and pain outcomes.

Results

Increased perceptions of sleep disturbance predicted increased pain interference (p ≤ 0.001, β = 0.42), increased pain intensity (p ≤ 0.001, β = 0.36), and reduced IA (p ≤ 0.001, β = -0.38) when controlling for pain duration. IA partially mediated the relationship between sleep disturbance and pain interference (point estimate = 0.16; 95% bootstrap confidence interval [CI] = 0.08-0.24) and between sleep disturbance and pain intensity (point estimate = 0.06; 95% bootstrap CI = 0.02-0.09).

Conclusions

Findings show increased sleep disturbance predicted increased pain interference and increased pain intensity and reduced IA, and that IA partially mediated the relationship between sleep disturbance and pain characteristics. Findings support future research to explore causal relationships of these variables in longitudinal studies.

PACAP38/mast-cell-specific receptor axis mediates repetitive stress-induced headache in mice

BACKGROUND

Pain, an evolutionarily conserved warning system, lets us recognize threats and motivates us to adapt to those threats. Headache pain from migraine affects approximately 15% of the global population. However, the identity of any putative threat that migraine or headache warns us to avoid is unknown because migraine pathogenesis is poorly understood. Here, we show that a stress-induced increase in pituitary adenylate cyclase-activating polypeptide-38 (PACAP38), known as an initiator of allosteric load inducing unbalanced homeostasis, causes headache-like behaviour in male mice via mas-related G protein-coupled receptor B2 (MrgprB2) in mast cells.

METHODS

The repetitive stress model and dural injection of PACAP38 were performed to induce headache behaviours. We assessed headache behaviours using the facial von Frey test and the grimace scale in wild-type and MrgprB2-deficient mice. We further examined the activities of trigeminal ganglion neurons using in vivo Pirt-GCaMP Ca2+ imaging of intact trigeminal ganglion (TG).

RESULTS

Repetitive stress and dural injection of PACAP38 induced MrgprB2-dependent headache behaviours. Blood levels of PACAP38 were increased after repetitive stress. PACAP38/MrgprB2-induced mast cell degranulation sensitizes the trigeminovascular system in dura mater. Moreover, using in vivo intact TG Pirt-GCaMP Ca2+ imaging, we show that stress or/and elevation of PACAP38 sensitized the TG neurons via MrgprB2. MrgprB2-deficient mice showed no sensitization of TG neurons or mast cell activation. We found that repetitive stress and dural injection of PACAP38 induced headache behaviour through TNF-a and TRPV1 pathways.

CONCLUSIONS

Our findings highlight the PACAP38-MrgprB2 pathway as a new target for the treatment of stress-related migraine headache. Furthermore, our results pertaining to stress interoception via the MrgprB2/PACAP38 axis suggests that migraine headache warns us of stress-induced homeostatic imbalance.