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OBJECTIVE: Bulimia nervosa (BN) is associated with loss-of-control (LOC) eating episodes that frequently occur in response to negative emotions. According to recent neurocomputational models, this link could be explained by a failure to accurately update beliefs about the body in states of high arousal. Specifically, these interoceptive inference models suggest that under-relying on signals from ones body about sensory experience (low sensory precision) and/or over-relying on previously held beliefs (excessively precise priors) lead to inaccurate perception and maladaptive behaviors. We conducted an initial test of these core predictions of the interoceptive inference model in BN using self-report measures. METHODS: We compared women with BN (n = 30) and age-, BMI-, and full-scale IQ-matched controls (n = 31) on trust in sensory information from the body and two types of beliefs about what can be done to regulate high negative affect. Within the BN group, we tested interrelations among these measures and explored their associations with LOC eating frequency. RESULTS: Compared with healthy controls, the BN group reported lower levels of trust in sensory information and stronger beliefs that once upset, there is little one can do, apart from eating, to self-regulate. These beliefs were associated with each other and with lower body trust. Beliefs about the uncontrollability of emotion were associated with more frequent subjective binge-eating episodes. CONCLUSIONS: Findings provide initial support for the core predictions of an interoceptive inference account of BN: low trust in sensory information (sensory precision) may promote an overreliance on maladaptive prior beliefs about the effects of eating on negative emotions, ultimately interfering with accurate updating of beliefs about other strategies that could regulate emotions and maintain LOC eating. Low body trust, strong expectations about emotions, and their neurocomputational underpinnings could be promising combined treatment targets for BN.

Affective touch-a slow, gentle, and pleasant form of touch-activates a different neural network than which is activated during discriminative touch in humans. Affective touch perception is enabled by specialized low-threshold mechanoreceptors in the skin with unmyelinated fibers called C tactile (CT) afferents. These CT afferents are conserved across mammalian species, including macaque monkeys. However, it is unknown whether the neural representation of affective touch is the same across species and whether affective touch's capacity to activate the hubs of the brain that compute socioaffective information requires conscious perception. Here, we used functional MRI to assess the preferential activation of neural hubs by slow (affective) vs. fast (discriminative) touch in anesthetized rhesus monkeys (Macaca mulatta). The insula, anterior cingulate cortex (ACC), amygdala, and secondary somatosensory cortex were all significantly more active during slow touch relative to fast touch, suggesting homologous activation of the interoceptive-allostatic network across primate species during affective touch. Further, we found that neural responses to affective vs. discriminative touch in the insula and ACC (the primary cortical hubs for interoceptive processing) changed significantly with age. Insula and ACC in younger animals differentiated between slow and fast touch, while activity was comparable between conditions for aged monkeys (equivalent to >70 y in humans). These results, together with prior studies establishing conserved peripheral nervous system mechanisms of affective touch transduction, suggest that neural responses to affective touch are evolutionarily conserved in monkeys, significantly impacted in old age, and do not necessitate conscious experience of touch.

IntroductionThis study evaluated changes in the white matter of the brain and psychological health variables, resulting from a neuroscience-based mindfulness intervention, the Training for Awareness, Resilience, and Action (TARA), in a population of healthy adolescents.MethodsA total of 100 healthy adolescents (57 female, age ranges 14-18 years) were randomized into the 12-week TARA intervention or a waitlist-control group. All participants were imaged with diffusion MRI to quantify white matter connectivity between brain regions. Imaging occurred at baseline/randomization and after 12 weeks of baseline (pre- and post-intervention in the TARA group). We hypothesized that structural connectivity in the striatum and interoceptive networks would increase following the TARA intervention, and that, this increased connectivity would relate to psychological health metrics from the Strengths and Difficulties Questionnaire (SDQ) and the Insomnia Severity Index (ISI). The TARA intervention and all assessments, except for the MRIs, were fully remotely delivered using secure telehealth platforms and online electronic data capture systems.ResultsThe TARA intervention showed high consistency, tolerability, safety, recruitment, fidelity, adherence, and retention. After 12 weeks, the TARA group, but not controls, also demonstrated significantly improved sleep quality (p = 0.02), and changes in the right putamen node strength were related to this improved sleep quality (r = -0.42, p = 0.006). Similarly, the TARA group, but not controls, had significantly increased right insula node strength related to improved emotional well-being (r = -0.31, p = 0.04). Finally, we used the network-based statistics to identify a white matter interoception network that strengthened following TARA (p = 0.009).DiscussionThese results suggest that the TARA mindfulness-based intervention in healthy adolescents is feasible and safe, and it may act to increase structural connectivity strength in interoceptive brain regions. Furthermore, these white matter changes are associated with improved adolescent sleep quality and emotional well-being. Our results suggest that TARA could be a promising fully remotely delivered intervention for improving psychological well-being in adolescents. As our findings suggest that TARA affects brain regions in healthy adolescents, which are also known to be altered during depression in adolescents, future studies will examine the effects of TARA on depressed adolescents.Clinical trial registrationhttps://clinicaltrials.gov/study/NCT04254796.

Spontaneous thought is a universal, complex, and heterogeneous cognitive activity that significantly impacts mental activity and strongly correlates with mental disorders. Utilizing the think-aloud method, we captured spontaneous thoughts during rest from 38 diagnosed with depression, alongside 36 healthy controls and 137 healthy individuals. Through a comprehensive assessment of various dimensions of thought content, we compared thought content between individuals with depression and healthy controls, and between healthy women and men. Finally, we employed natural language processing (NLP) to develop regression models for multidimensional content assessment and a classification model to differentiate between individuals with and without depression. Compared to healthy controls, individuals with depression had more internally oriented and less externally oriented spontaneous thoughts. They focused more on themselves and negative things, and less on positive things, experiencing higher levels of negative emotions and lower levels of positive emotions. Besides, we found that compared to healthy men, healthy women's spontaneous thoughts focus more on interoception, the self, past events, and negative events, and they experience higher levels of negative emotions. Meanwhile, we identified the potential application of the think-aloud method to collect spontaneous thoughts and integrate NLP in the field of depression. This study offers direct insights into the stream of thought during individuals' resting state, revealing differences between individuals with depression and healthy controls, as well as sex differences in the content of spontaneous thoughts. It enhances our understanding of spontaneous thought and offers a new perspective for preventing, diagnosing, and treating depression. • Content characteristics of spontaneous thoughts in depression • Characteristics and differences in spontaneous thoughts between healthy men and women • Application of natural language processing combined with think-aloud method in depression diagnosis [ABSTRACT FROM AUTHOR]

Alterations in interoception have been linked to psychopathology. Recent findings suggest that both the attention to and the accuracy of, interoceptive perceptions may be oppositely related to subclinical symptomatology. Thus, providing well-validated tools that tap into these interoceptive processes is crucial for understanding the relation between interoceptive processing and subclinical psychopathology. In the current study (N = 642), we aimed to (1) validate the German version of the Interoceptive Attention Scale (IATS; Gabriele et al., 2022), and (2) test the differential association of self-reported interoceptive attention and accuracy with subclinical symptomatology, including alexithymia, depressive, and anxious symptomatology. We observed that a one-factor solution is a well-fitting model for the IATS. Further, the IATS showed good internal consistency, convergent, and divergent validity, but poor test-retest reliability. Self-reported interoceptive attention and accuracy were unrelated to each other. However, IATS scores were positively related to all measures of psychopathology (except depressive symptomatology), whereas self-reported interoceptive accuracy scores showed negative or nonsignificant relations with these. Our data suggest that the IATS is a good instrument to measure self-report interoceptive attention in the German population. Further, we highlight the need to distinguish between constructs of interoception to better understand the relation between interoception and psychopathology. [ABSTRACT FROM AUTHOR]

Objective: Disrupted interoception has been found in individuals with body image concerns and related psychiatric conditions (i.e., eating disorders, body dysmorphic disorder). However, few studies have explored the role of interoception in the relationship between body image concern and self‐objectification (SO). As components of the bodily self, interoception and body image may also contribute to the fostering of self‐consciousness. Methods: The current study estimated the network model of body image concern, adaptive and maladaptive interoceptive sensibility (IS), self‐consciousness, and SO, with data from 743 neurotypical adults. The centrality of nodes and the robustness of the network were verified. Results: Our network showed that interoception correlated with certain characteristics of body image concern (BIC) with varying strength and different directions. The most central node described beliefs of BIC, namely, negative evaluation toward appearance. Self‐objectification and maladaptive IS presented the highest bridge centrality. Interoception also linked BICs with SO and self‐consciousness. Conclusion: Findings suggested that SO, adaptive and maladaptive interoception might be the targets of intervention for individuals with BIC, specifically for those with high levels of appearance‐related negative self‐evaluations. [ABSTRACT FROM AUTHOR]

The perception of signals from within the body, known as interoception, is increasingly recognized as a prerequisite for physical and mental health. This study is dedicated to the development of effective technological approaches for enhancing interoceptive abilities. We provide evidence of the effectiveness and practical feasibility of a novel real‐time haptic heartbeat supplementation technology combining principles of biofeedback and sensory augmentation. In a randomized controlled study, we applied the developed naturalistic haptic feedback on a group of 30 adults, while another group of 30 adults received more traditional real‐time visual heartbeat feedback. A single session of haptic, but not visual heartbeat feedback resulted in increased interoceptive accuracy and confidence, as measured by the heart rate discrimination task, and in a shift of attention toward the body. Participants rated the developed technology as more helpful and pleasant than the visual feedback, thus indicating high user satisfaction. The study highlights the importance of matching sensory characteristics of the feedback provided to the natural bodily prototype. Our work suggests that real‐time haptic feedback might be a superior approach for strengthening the mind–body connection in interventions for physical and mental health. In the study, we evaluate the efficacy of a newly developed interoceptive training—supplementation of heartbeat sensations through real‐time haptic feedback. We revealed that the haptic feedback technology improves interoceptive accuracy, increases confidence, and shifts attention toward bodily sensations more effectively than the traditional visual feedback approach, opening new possibilities for clinical and neurowellness applications. [ABSTRACT FROM AUTHOR]

Breast cancer impairs physical and psychological well-being, even some years after treatments. Oncological treatments can strongly affect the body due to scars and breast(s) removal, for example, increasing symptoms of anxiety and depression. Psychological studies are effective in improving breast cancer survivors' emotions and behaviors through several approaches to interventions. Over years, the Mindfulness-Based Stress Reduction (MBSR) has been evaluated as an effective intervention to promote well-being in breast cancer survivors. The present study protocol aims to evaluate the effectiveness of a MBSR intervention in regulating interoceptive sensations, as the ability to be aware of inner sensations. Second, it seeks to identify changes in interoceptive feelings, mood, and body perception following the intervention. These changes will be evaluated across three data collection times to assess differences about emotions and body perception over time, focusing on their relevance for breast cancer survivors' well-being. Finally, the present study protocol aims to detect improvements in anxiety, depression, and body awareness, considering the potential positive impact of the MBSR approach on emotional well-being. Direction for future psychological intervention are given. [ABSTRACT FROM AUTHOR]

Objective: People commonly cope with chronic low back pain (cLBP) by ignoring and distraction. Can mindful interoceptive exposure to the pain sensation itself and its phenomenological components be an alternative approach? Methods: Single-arm feasibility study in patients with cLBP using a 2-minute attention exercise guided by a smartphone app several times per day over 8 weeks. We assessed feasibility, pre/post pain, function, and psychological parameters using mixed methods: standard questionnaires, ecological momentary assessment, and exit interviews that included micro-phenomenology technique and subsequent reflexive thematic qualitative analysis. Results: We enrolled 31 participants, mostly female, mean age 48, the majority had pain for >5 years; 29 completed. Mean pain intensity [0–10] improved from 4.8 ±1.7 to 3.1 ±1.9 (p <.0001); mean PEG scores (intensity and interference with daily life; range 0–30) improved from 13.7 ±6.2 to 8.4 ±6.6 (p <.0001); pain impact (9 items incl physical function) 22.3 ±8.7 to 19.7 ±8.1 (p =.0010). Twenty-one of 29 improved PEG score ≥30%. There were significant improvements in PCS Rumination and MAIA Not-Worrying. Participants became aware of their usual habit of avoidance and the challenge of and resistance to focusing on pain. They were surprised how pain sensations varied over time, and that pain intensity and the threat value of pain could diminish by focusing on it. They described a variety of 3D pain shapes (e.g., football, pool ball, rod, nail, brick, stars) with a range of colors, transparency, temperature, and density that for some changed with mindful attention. Most struggled to find appropriate words for sensory awareness and attention regulation and found that the threat value of their pain diminished. Conclusions: Mindful interoceptive exposure to the sensations of their cLBP using a 2-minute attention exercise with a phone app—rather than ignoring and distracting from it—may be a beneficial intervention for cLBP. Trial registration: ClinicalTrials.gov #NCT06186193. [ABSTRACT FROM AUTHOR]

Aims Methods Results Conclusions To investigate the factors associated with interoception in patients with alcohol use disorder and determine whether treatment causes changes in their interoception.The Body Perception Questionnaire‐Body Awareness ultra‐short version Japanese version (BPQ‐BAVSF‐J) was used to measure interoception in 50 alcohol‐dependent participants (27 in the inpatient group and 23 in the outpatient group). The BPQ‐BAVSF‐J was administered and data on aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma‐glutamyl transpeptidase (γ‐GTP), mean corpuscular volume, platelet count, and Fib‐4 index were extracted at admission and immediately before discharge for the inpatient group and at the first outpatient visit and approximately 3 months after the visit for the outpatient group.The mean age of the 50 participants was 51.0 ± 12.3 years. Significant associations were found between the BPQ‐BAVSF‐J and Fib‐4 index and AST. The BPQ‐BAVSF‐J score significantly decreased at discharge in the inpatient group. AST, ALT, γ‐GTP, and Fib‐4 index of liver function were also significantly lower at discharge. In contrast, in the outpatient group, there were no significant changes in the BPQ‐BAVSF‐J score, AST level, ALT level, γ‐GTP level, and Fib‐4 index between at the first outpatient visit and approximately 3 months after the visit.Interoception in patients with alcohol use disorder increased with worsening liver function and decreased with improvement in liver function owing to treatment. This suggests that the BPQ‐BAVSF‐J score, an easily accessible scale, may be used to detect early deterioration of liver function through regular administration. [ABSTRACT FROM AUTHOR]

Previous work suggests that interoception – the capacity to detect and interpret internal states of the body – may be disrupted in affective disorders. A related body of work suggests that reduced understanding of how interoceptive sensations relate to emotions (alexithymia) is also linked to these disorders. One route by which these deficits could maintain affective symptoms is poor emotion regulation – as perception and regulation of internal states share bidirectional links. However, depression and anxiety symptoms are highly co-morbid, and it remains unclear whether one or both are primarily affected. In this study, we sought to replicate prior results suggesting emotion dysregulation mediates the relationship between interoception/alexithymia and depressive symptoms, and to further determine whether co-morbid anxiety plays an additional, or alternative, explanatory role. Participants in two consecutive, non-clinical samples (Sample 1: N = 445, Mage=23.68; Sample 2: N = 196, Mage=24.99) completed measures of interoception (MAIA), alexithymia (TAS-20), emotion dysregulation (DERS), depression (BDI-II), and anxiety (STAI). Results in both samples confirmed that emotion dysregulation mediated the relationship between interoception and depressive symptoms and found a similar relationship with trait anxiety. When accounting for co-morbidity, anxiety – and not depression – appeared to best explain previous findings for interoception. In contrast, results suggested that depression – and not anxiety – explained prior links to alexithymia. These results may help guide interpretation of prior results when considering the high comorbidity in depression and anxiety symptoms and suggest unique treatment targets for each. Future research should examine these measures in clinical samples and with longitudinal data that can better disentangle the directional nature of these relationships. [ABSTRACT FROM AUTHOR]

Introduction: Alcohol craving, characterized by a strong desire or compulsion to consume alcohol, is a prominent symptom of substance dependence syndrome. Research indicates that alcohol craving is a significant factor leading to the termination of abstinence. The mechanisms underlying the activation of alcohol craving remain not fully understood. The urge to reach for alcohol may be stimulated by emotions, memories, thoughts, or bodily sensations, as well as external factors. It has been postulated that individuals with high levels of interoceptive sensibility tend to exhibit a high degree of alexithymia and emotion dysregulation in the context of alcohol craving. Deficits in identifying and verbalizing emotions, along with an operational thinking style, facilitate alcohol consumption by impeding accurate insight into one's mental state, thereby hindering the comprehension of bodily states, emotions, and the regulation of self. Method: This study involved 160 inmates incarcerated in a prison in Poland, awaiting participation in therapy for individuals with substance dependence following psychiatric diagnosis. Four questionnaires were used in the study: multidimensional Assessment of Interoceptive Sensibility (MAIA) for interoceptive sensibility, Toronto Alexithymia Scale (TAS-20) for alexithymia, Difficulties in Emotion Regulation Scale (DERS) for emotional dysregulation, and the Penn Alcohol Craving Scale (PACS) for alcohol craving assessment. Results: The results of the study are as follows: the study findings indicated that alexithymia and emotional dysregulation significantly mediates the relationship between interoceptive sensibility and alcohol craving. The indirect effect for both factors was found to be significant, similar to the indirect effect observed for alexithymia as an mediator. However, in the case of emotional dysregulation, no significant indirect effect was observed. Conclusion: Our study provides insights into the potential contribution of interoceptive sensibility to the heightened risk of alcohol dependence. Specifically, impaired interoceptive sensibility may be associated with the development of alexithymia and emotional dysregulation, potentially rendering individuals more susceptible to alcohol craving. Interoceptive sensibility could serve as a prerequisite for the cultivation of positive emotional processing skills. [ABSTRACT FROM AUTHOR]

The subjective experience of emotions is linked to the contextualized perception and appraisal of changes in bodily (e.g., heart) activity. Increased emotional arousal has been related to attenuated high‐frequency heart rate variability (HF‐HRV), lower EEG parieto‐occipital alpha power, and higher heartbeat‐evoked potential (HEP) amplitudes. We studied emotional arousal‐related brain–heart interactions using immersive virtual reality (VR) for naturalistic yet controlled emotion induction. Twenty‐nine healthy adults (13 women, age: 26 ± 3) completed a VR experience that included rollercoasters while EEG and ECG were recorded. Continuous emotional arousal ratings were collected during a video replay immediately after. We analyzed emotional arousal‐related changes in HF‐HRV as well as in BHIs using HEPs. Additionally, we used the oscillatory information in the ECG and the EEG to model the directional information flows between the brain and heart activity. We found that higher emotional arousal was associated with lower HEP amplitudes in a left fronto‐central electrode cluster. While parasympathetic modulation of the heart (HF‐HRV) and parieto‐occipital EEG alpha power were reduced during higher emotional arousal, there was no evidence for the hypothesized emotional arousal‐related changes in bidirectional information flow between them. Whole‐brain exploratory analyses in additional EEG (delta, theta, alpha, beta and gamma) and HRV (low‐frequency, LF, and HF) frequency bands revealed a temporo‐occipital cluster, in which higher emotional arousal was linked to decreased brain‐to‐heart (i.e., gamma→HF‐HRV) and increased heart‐to‐brain (i.e., LF‐HRV → gamma) information flow. Our results confirm previous findings from less naturalistic experiments and suggest a link between emotional arousal and brain–heart interactions in temporo‐occipital gamma power. [ABSTRACT FROM AUTHOR]

The evidence base for the effectiveness of art therapy continues to grow, even as a mechanistic understanding of how art therapy works remains limited. One promising avenue for increasing our understanding of how and why art therapy works is through the lens of neuroscience. A neuroscience-based approach to art therapy provides opportunities for improving understanding of the neural processes that underlie the complex interaction between perception, cognition, emotion and behavior that play out in the art therapy process. Understanding how therapeutic change occurs can result in improved treatment and better outcomes for clients. However, it can be tricky to connect art therapy and psychological theory directly to neural responses. The purposes of this perspective are to provide an overview of the current evidence and limits of neurobiological concepts of neuroplasticity, mirror systems, and interoception as applied to art therapy practice, and to provide updated information about outdated concepts that are still actively used in clinical practice. Critical analysis and understanding of the current scientific knowledge base can then be used to guide art therapy practice and support the development of hypothesis-based research to determine the primary mechanisms that drive the observed effects of art therapy interventions. [ABSTRACT FROM AUTHOR]

Background: Schizophrenia (SZ) is characterized by abnormalities in selfrepresentation, including a disturbed sense of agency (SoA). The continuous processing of sensory information concerning the internal state of the body (interoception) is argued to be fundamental to neural representations of the self. We, therefore, tested if aberrant interoception underpins disturbances in SoA in SZ, focusing on cardiac interoceptive signaling. Methods: Forty-two SZ and 29 non-clinical participants (healthy controls; HC) performed an intentional binding task tomeasure SoA during concurrent heartbeat recording. The effect of cardiac interoceptive signals on SoA was measured by the difference in intentional binding effect during systole and diastole. This measure was standardized based on the overall intentional binding effect to control for noncardiac factors, and then compared between SZ and HC. Results: Our study revealed a significant difference between SZ and HC groups, with opposite effects of cardiac systole on SoA. Specifically, cardiac systole disrupted SoA in SZ, contrasting with the enhanced SoA in HC. Across the SZ group, the extent to which SoA was disrupted by cardiac systole correlated significantly with a clinical proxy for symptom instability, namely the number of hospital admissions for hallucinations and delusions. Furthermore, the disruption was particularly observed in patients with severe hallucinations. Conclusions: This study revealed a disturbance in the impact of cardiac interoceptive signals on an implicit index of SoA in schizophrenia. This supports the notion that pathophysiological disruption of the central integration of interoceptive information increases vulnerability to disturbances in self-representation and the associated expression of schizophrenic symptoms. [ABSTRACT FROM AUTHOR]

The influence of cardiac phases on cognitive and sensorimotor functions is noteworthy. Specifically, during systole, as opposed to diastole, there is an observed enhancement in tasks demanding the suppression of instructed responses. This suggests that systole contributes to inhibitory control in motor functions. However, the extent to which systolic inhibition is significant in volitional free‐choice actions, such as choosing to execute or refrain from a cue‐initiated response, remains to be clarified. To fill this gap in the current literature, the purpose of this study was to test whether during the systole phase, compared with the diastole phase, the tendency to enact volitional actions decreased due to the systolic inhibitory effect. We used a modified version of the Go/No‐Go task with an added condition for volitional free‐choice actions, where participants could decide whether to respond or not, to test whether systolic inhibition could affect the volitional decision to act. The results showed that participants' responses were less frequent in systole than in diastole in the volitional action condition. Then, to test the robustness of the cardiac effect on volitional actions, we used two established manipulations: the Straw Breathing Manipulation and the Cold Pressor Test, which were able to induce anxiety and increase the heart rate, respectively. Results showed that the systole/diastole difference in the number of volitional action trials in which participants decided to respond tended to remain the same despite all manipulations. Overall, our results provide convergent evidence for the effect of the heart on the decision to act, an effect that appears independent of manipulations of both the physiological and psychological state of the individual. [ABSTRACT FROM AUTHOR]

Physiological regulation strategies can be effective in reducing anxiety. However, while these strategies are often learned and practised under low‐stress conditions, they are more likely to be required under conditions of high stress. We created virtual reality (VR) biofeedback games to both teach participants a breathing technique and then practise that technique under stress. We present two studies: the first provides a proof of concept, demonstrating that participants can apply the breathing technique during stress, with a significant lowering of both respiration rate and increase in heart rate variability (HRV) under stress (p < .001). The second study explicitly evaluated the effectiveness of training by comparing trained and untrained groups. Training was associated with a significantly greater HRV (p = .008) under stress. In within‐group comparisons of HRV during stress compared to a baseline stressor presented before training, the trained group showed a significantly greater increase compared to untrained controls (p = .025). Our results show the feasibility and potential effectiveness of VR‐based games for biofeedback training under experimentally applied stress. This may offer the opportunity for clinical techniques to more closely reflect the circumstances under which those techniques will be required. [ABSTRACT FROM AUTHOR]

The enfacement illusion is a facial version of the rubber hand illusion, in which participants experience tactile stimulation of their own faces synchronously with the observation of the same stimulation applied to another's face. In previous studies, participants have reported experiencing an illusory embodiment of the other's face following synchronous compared to asynchronous stimulation. In a series of three experiments, we addressed the following three questions: (i) how does similarity between the self and the other, operationalized here as being of the same or different gender to the other, impact the experience of embodiment in the enfacement illusion; (ii) does the experience of embodiment result from alterations to the self-concept; and (iii) is susceptibility to the experience of embodiment associated with interoceptive processing, i.e. perception of the internal state of the body? Results indicate that embodiment is facilitated by the similarity between the self and the other and is mediated by the incorporation of the other into the self-concept, but sensitivity to one's own internal states does not impact upon embodiment within the enfacement illusion. This article is part of the theme issue 'Minds in movement: embodied cognition in the age of artificial intelligence'. [ABSTRACT FROM AUTHOR]

The article "Probing the embodiment of sleep functions: Insights from cardiac responses to word-induced relaxation during sleep" published in the Journal of Sleep Research explores the relationship between bodily functions, particularly cardiac activity, and cognitive functions during sleep. The study suggests that the presentation of relaxing words during non-rapid eye movement (NREM) sleep can lead to an increase in slow-wave sleep duration and subjective sleep quality. The research findings indicate that cardiac activity slows down in response to word-induced relaxation during NREM sleep, highlighting the importance of considering bodily signals in understanding sleep functions. The study aims to promote the investigation of cardiac responses in sleep research to provide a more comprehensive understanding of sleep functions and their modulation by sensory stimulation. [Extracted from the article]

Interoception, the processing of internal bodily signals, is proposed as the fundamental mechanism underlying emotional experiences. Interoceptive and emotional processing appear distorted in psychiatric disorders. However, our understanding of the neural structures involved in both processes remains limited. To explore the feasibility of enhancing interoception and emotion, we conducted two studies using high‐definition transcranial direct current stimulation (HD‐tDCS) applied to the right anterior insula. In study one, we compared the effects of anodal HD‐tDCS and sham tDCS on interoceptive abilities (sensibility, confidence, accuracy, emotional evaluation) in 52 healthy subjects. Study two additionally included physical activation through ergometer cycling at the beginning of HD‐tDCS and examined changes in interoceptive and emotional processing in 39 healthy adults. In both studies, HD‐tDCS was applied in a single‐blind cross‐over online design with two separate sessions. Study one yielded no significant effects of HD‐tDCS on interoceptive dimensions. In study two, significant improvements in interoceptive sensibility and confidence were observed over time with physical preactivation, while no differential effects were found between sham and insula stimulation. The expected enhancement of interoceptive and emotional processing following insula stimulation was not observed. We conclude that HD‐tDCS targeting the insula does not consistently increase interoceptive or emotional variables. The observed increase in interoceptive sensibility may be attributed to the activation of the interoceptive network through physical activity or training effects. Future research on HD‐tDCS involving interoceptive network structures could benefit from protocols targeting larger regions within the network, rather than focusing solely on insula stimulation. This is the first report on the feasibility of enhancing interoceptive and emotion processing through insula stimulation using HD‐tDCS. In contrast to research suggesting an attenuation of interoceptive and emotional processes through the inhibition of this interoceptive network structure, our findings highlight the complexity of enhancing these processes by neurostimulation of the anterior insula. We derive recommendations to increase the effectiveness of HD‐tDCS in the context of interoceptive abilities stimulation. [ABSTRACT FROM AUTHOR]

Interoception, which refers to the perception of body's internal state, is implicated in emotional processes and psychopathological disorders. Over the last decades, different tools have been developed to measure interoceptive accuracy, or the ability to accurately perceive physiological signals. Most of these tools have focused on cardiac interoception, but respiratory interoception has been less investigated due to the more complex and less portable equipment required. In this study, we suggest a new duration discrimination respiratory (DDR) task that does not require complex equipment. Using an adaptive staircase procedure, this task aims to determine an individual's ability to detect exhalation longer than their resting reference duration. One hundred and twenty‐three healthy subjects completed the DDR task, an interoceptive task of heart rate discrimination, and filled out questionnaires on interoceptive awareness (Multidimensional Assessment of Interoceptive Awareness), alexithymia (Toronto Alexithymia Scale [TAS]), affects (Positive and Negative Affect Scale [PANAS]), and anamnestic. Results demonstrated a good internal consistency (Cronbach's alpha =.93) of the DDR task. On average, subjects needed 99.22% (SD = 36.38) of their reference exhalation time in addition to reference exhalation to detect a prolonged exhalation. Higher self‐reported fitness levels, not counting during the DDR task and lower difficulty in describing feelings (TAS subscale), predicted higher respiratory discrimination duration. In conclusion, this study demonstrates the utility of the DDR task as a valid measure of interoception. Growing interest in interoception highlights the need for reliable measures. Respiratory interoception is understudied compared to cardiac interoception. Non‐portable equipment for respiratory measures is limiting clinical research. Our task provides a portable and ecological measure of respiratory interoception. [ABSTRACT FROM AUTHOR]

Many organs are designed to move: the heart pumps each second, the gastrointestinal tract squeezes and churns to digest food, and we contract and relax skeletal muscles to move our bodies. Sensory neurons of the peripheral nervous system detect signals from bodily tissues, including the forces generated by these movements, to control physiology. The processing of these internal signals is called interoception, but this is a broad term that includes a wide variety of both chemical and mechanical sensory processes. Mechanical senses are understudied, but rapid progress has been made in the last decade, thanks in part to the discovery of the mechanosensory PIEZO ion channels (Coste et al., 2010). The role of these mechanosensors within the interoceptive nervous system is the focus of this review. In defining the transduction molecules that govern mechanical interoception, we will have a better grasp of how these signals drive physiology. [ABSTRACT FROM AUTHOR]

Sensory signals from the body's visceral organs (e.g. the heart) can robustly influence the perception of exteroceptive sensations. This interoceptive--exteroceptive interaction has been argued to underlie self-awareness by situating one's perceptual awareness of exteroceptive stimuli in the context of one's internal state, but studies probing cardiac influences on visual awareness have yielded conflicting findings. In this study, we presented separate grating stimuli to each of subjects' eyes as in a classic binocular rivalry paradigm -- measuring the duration for which each stimulus dominates in perception. However, we caused the gratings to 'pulse' at specific times relative to subjects' real-time electrocardiogram, manipulating whether pulses occurred during cardiac systole, when baroreceptors signal to the brain that the heart has contracted, or in diastole when baroreceptors are silent. The influential 'Baroreceptor Hypothesis' predicts the effect of baroreceptive input on visual perception should be uniformly suppressive. In contrast, we observed that dominance durations increased for systole-entrained stimuli, inconsistent with the Baroreceptor Hypothesis. Furthermore, we show that this cardiac-dependent rivalry effect is preserved in subjects who are at-chance discriminating between systole-entrained and diastole-presented stimuli in a separate interoceptive awareness task, suggesting that our results are not dependent on conscious access to heartbeat sensations. [ABSTRACT FROM AUTHOR]

Human beings perceive the emotions of others through various cues, such as facial expressions, voice, and bodily posture. These social signals have been acquired evolutionarily, and reports suggest that emotions are recognized to some extent in a culturally universal pattern. It has also been suggested that an observer's approach or avoidance responses toward the expressor occur at the initial stage of emotion perception. However, such approach–avoidance reactions have hitherto been examined mainly in response to facial expressions and not bodily postures. Therefore, this study examined approach–avoidance responses to anger and fear as visualized through facial expressions and bodily postures. The study sample comprised 58 university students. The results showed that, as in a previous study, approach responses to fear and avoidance responses to anger were dominant in both facial expression and bodily posture conditions. This suggests that bodily posture and facial expression are social signals that can elicit an approach–avoidance response from the observer. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: Chemotherapy-induced peripheral neurotoxicity (CIPN) is a prevalent, dose-limiting, tough-to-treat toxicity involving numbness, tingling, and pain in the extremities with enigmatic pathophysiology. This randomized controlled pilot study explored the feasibility and preliminary efficacy of exercise during chemotherapy on CIPN and the role of the interoceptive brain system, which processes bodily sensations. Methods: Nineteen patients (65 ± 11 years old, 52% women; cancer type: breast, gastrointestinal, multiple myeloma) starting neurotoxic chemotherapy were randomized to 12 weeks of exercise (home-based, individually tailored, moderate intensity, progressive walking, and resistance training) or active control (nutrition education). At pre-, mid-, and post-intervention, we assessed CIPN symptoms (primary clinical outcome: CIPN-20), CIPN signs (tactile sensitivity using monofilaments), and physical function (leg strength). At pre- and post-intervention, we used task-free (“resting”) fMRI to assess functional connectivity in the interoceptive brain system, involving the salience and default mode networks. Results: The study was feasible (74–89% complete data across measures) and acceptable (95% retention). We observed moderate/large beneficial effects of exercise on CIPN symptoms (CIPN-20, 0–100 scale: − 7.9 ± 5.7, effect size [ES] = − 0.9 at mid-intervention; − 4.8 ± 7.3, ES = − 0.5 at post-intervention), CIPN signs (ES = − 1.0 and − 0.1), and physical function (ES = 0.4 and 0.3). Patients with worse CIPN after neurotoxic chemotherapy had lower functional connectivity within the default mode network (R2 = 40–60%) and higher functional connectivity within the salience network (R2 = 20–40%). Exercise tended to increase hypoconnectivity and decrease hyperconnectivity seen in CIPN (R2 = 12%). Conclusion: Exercise during neurotoxic chemotherapy is feasible and may attenuate CIPN symptoms and signs, perhaps via changes in interoceptive brain circuitry. Future work should test for replication with larger samples. Trial registration: Registered Jan 2017 on ClinicalTrials.gov as NCT03021174. [ABSTRACT FROM AUTHOR]

Remote photoplethysmography (rPPG) is a low-cost technique to measure physiological parameters such as heart rate by analyzing videos of a person. There has been growing attention to this technique due to the increased possibilities and demand for running psychological experiments on online platforms. Technological advancements in commercially available cameras and video processing algorithms have led to significant progress in this field. However, despite these advancements, past research indicates that suboptimal video recording conditions can severely compromise the accuracy of rPPG. In this study, we aimed to develop an open-source rPPG methodology and test its performance on videos collected via an online platform, without control of the hardware of the participants and the contextual variables, such as illumination, distance, and motion. Across two experiments, we compared the results of the rPPG extraction methodology to a validated dataset used for rPPG testing. Furthermore, we then collected 231 online video recordings and compared the results of the rPPG extraction to finger pulse oximeter data acquired with a validated mobile heart rate application. Results indicated that the rPPG algorithm was highly accurate, showing a significant degree of convergence with both datasets thus providing an improved tool for recording and analyzing heart rate in online experiments. [ABSTRACT FROM AUTHOR]

Human beings perceive the emotions of others through various cues, such as facial expressions, voice, and bodily posture. These social signals have been acquired evolutionarily, and reports suggest that emotions are recognized to some extent in a culturally universal pattern. It has also been suggested that an observer's approach or avoidance responses toward the expressor occur at the initial stage of emotion perception. However, such approach–avoidance reactions have hitherto been examined mainly in response to facial expressions and not bodily postures. Therefore, this study examined approach–avoidance responses to anger and fear as visualized through facial expressions and bodily postures. The study sample comprised 58 university students. The results showed that, as in a previous study, approach responses to fear and avoidance responses to anger were dominant in both facial expression and bodily posture conditions. This suggests that bodily posture and facial expression are social signals that can elicit an approach–avoidance response from the observer. [ABSTRACT FROM AUTHOR]

Background and aims: Functional motor disorders (FMD) present a prevalent, yet misunderstood spectrum of neurological conditions characterized by abnormal movements (i.e., functional limb weakness, tremor, dystonia, gait impairments), leading to substantial disability and diminished quality of life. Despite their high prevalence, FMD often face delayed diagnosis and inadequate treatment, resulting in significant social and economic burdens. The old concept of psychological factors as the primary cause (conversion disorder) has been abandoned due to the need for more evidence about their causal role. According to a predictive coding account, the emerging idea is that symptoms and disability may depend on dysfunctions of a specific neural system integrating interoception, exteroception, and motor control. Consequently, symptoms are construed as perceptions of the body's state. Besides the main pathophysiological features (abnormal attentional focus, beliefs/expectations, and sense of agency), the lived experience of symptoms and their resulting disability may depend on an altered integration at the neural level of interoception, exteroception, and motor control. Methods and materials: Our proposal aims to elucidate the pathophysiological mechanisms of FMD through a three-stage research approach. Initially, a large cohort study will collect behavioral, neurophysiological, and MRI biomarkers from patients with FMD and healthy controls, employing eXplainable Artificial Intelligence (XAI) to develop a diagnostic algorithm. Subsequently, validation will occur using patients with organic motor disorders. Finally, the algorithm's prognostic value will be explored post-rehabilitation in one subgroup of patients with FMD. Results: Data collection for the present study started in May 2023, and by May 2025, data collection will conclude. Discussion: Our approach seeks to enhance early diagnosis and prognostication, improve FMD management, and reduce associated disability and socio-economic costs by identifying disease-specific biomarkers. Trial registration: This trial was registered in clinicaltrials.gov (NCT06328790). [ABSTRACT FROM AUTHOR]

Previous evidence suggests males and females differ with respect to interoception—the processing of internal bodily signals—with males typically outperforming females on tasks of interoceptive accuracy. However, interpretation of existing evidence in the cardiac domain is hindered by the limitations of existing tools. In this investigation, we pooled data from several samples to examine sex differences in cardiac interoceptive accuracy on the phase adjustment task, a new measure that overcomes several limitations of the existing tools. In a sample of 266 individuals, we observed that females outperformed males, indicative of better cardiac interoceptive accuracy, but had lower confidence than males. These results held after controlling for sex differences in demographic, physiological and engagement factors. Importantly, these results were specific to the measure of cardiac interoceptive accuracy. No sex differences were observed for individuals who completed the structurally identical screener task, although a similar pattern of results was observed in relation to confidence. These surprising data suggest the presence of a female advantage for cardiac interoceptive accuracy and potential differences in interoceptive awareness (metacognition). Possible reasons for mixed results in the literature, as well as implications for theory and future research, are discussed. [ABSTRACT FROM AUTHOR]

This article introduces a special issue on body representation and body transformations in neuropsychology and embodied neuroscience. It discusses the concept of body representations and their plasticity, exploring how factors such as aging, weight changes, technology, and social interactions influence them. The special issue includes papers on various aspects of body representation, including historical reviews, virtual reality assessments, and the impact of pain on body representation. The text emphasizes the need for an interdisciplinary approach to studying body representation and highlights the relevance of this research in understanding the complex interactions between the brain, body, and environment. It also introduces the concept of predictive processing and Bayesian inference as frameworks for understanding how the brain represents and updates internal models of the body. The document is a list of references to scientific articles and studies related to body schema and body image, covering a wide range of topics in this field. [Extracted from the article]

Background: Awareness of one's own states is a particularly important part of cognition and emotion regulation. Recently, the concept of alexisomia has been used to refer to lack of awareness and expression of somatic sensations. Developing self-reported questionnaires to evaluate alexisomia represents a challenge for clinical psychology and medicine. In this context, we suggested to adapt the Body Awareness Questionnaire in French to measure alexisomia and its relation to alexithymia. In fact, we carried out a backtranslation and studied the validity of the construct in relation to proximal constructs around emotional awareness. Methods: For this study, 610 university students completed questionnaires measuring a three dimensions alexithymia concept [with The Toronto Alexithymia Scale (TAS-20)] or the five dimensions alexithymia concept [with The Bermond-Vorts Alexithymia Questionnaire (BVAQ-B)] and alexisomia (with the BAQ). Results: Confirmatory factor analyses showed that the BAQ can be envisaged through 4 factors as well as a unidimensional model to refer to alexisomia. We also found that body awareness was negatively related to scores of alexithymia. Conclusion: Results are discussed in light of the construct of alexisomia and its clinical implications in somatic as well as mental disorders. We suggest that the BAQ, which assesses interoception, can contribute, in part, to the assessment of alexisomia. Like alexithymia, this is a key concept to take into consideration when designing treatment and prevention programs. [ABSTRACT FROM AUTHOR]

Introduction: In the US, women are one of the fastest-growing segments of the prison population and more than a quarter of women in state prison are incarcerated for drug offenses. Substance use criminal diversion programs can be effective. It may be beneficial to identify individuals who are most likely to complete the program versus terminate early as this can provide information regarding who may need additional or unique programming to improve the likelihood of successful program completion. Prior research investigating prediction of success in these programs has primarily focused on demographic factors in male samples. Methods: The current study used machine learning (ML) to examine other nondemographic factors related to the likelihood of completing a substance use criminal diversion program for women. A total of 179 women who were enrolled in a criminal diversion program consented and completed neuropsychological, self-report symptom measures, criminal history and demographic surveys at baseline. Model one entered 145 variables into a machine learning (ML) ensemble model, using repeated, nested cross-validation, predicting subsequent graduation versus termination from the program. An identical ML analysis was conducted for model two, in which 34 variables were entered, including the Women's Risk/Needs Assessment (WRNA). Results: ML models were unable to predict graduation at an individual level better than chance (AUC = 0.59 [SE = 0.08] and 0.54 [SE = 0.13]). Post-hoc analyses indicated measures of impulsivity, trauma history, interoceptive awareness, employment/financial risk, housing safety, antisocial friends, anger/hostility, and WRNA total score and risk scores exhibited medium to large effect sizes in predicting treatment completion (p < 0.05; ds = 0.29 to 0.81). Discussion: Results point towards the complexity involved in attempting to predict treatment completion at the individual level but also provide potential targets to inform future research aiming to reduce recidivism. [ABSTRACT FROM AUTHOR]

This document is a summary of a collection of articles on the roles of temporal precision, synchronization, and neural oscillations in brain function. The articles discuss innovative methodologies for analyzing brain oscillations and their importance in understanding neural circuit dynamics and brain functions. They also highlight the relevance of neural oscillations in speech and music processing, as well as in neurodevelopmental disorders like dyslexia and stuttering. The articles offer valuable perspectives for both research and clinical applications. [Extracted from the article]

The goal of the current study was to investigate the differential effects of three interoception dimensions on psychophysiological stress responses (reactivity and recovery) in adolescents. A total of 102 adolescents (Mage = 14.10 years, SDage = 0.63; 50 males) completed the heartbeat counting task with adapted instructions to assess interoceptive accuracy, sensibility, and awareness. During a follow‐up session, participants underwent a standardized stressful task, throughout which measures of negative affect and respiratory sinus arrythmia (RSA) were collected. Results from multilevel models indicated that adolescents with higher interoceptive accuracy reported less pronounced increases in negative affect during stress induction, and subsequently experienced a less steep decrease in negative affect during recovery, compared to those with lower accuracy. Regarding RSA, adolescents with higher interoceptive accuracy exhibited greater decreases in RSA from baseline to stress, while those with higher interoceptive awareness maintained higher RSA levels throughout the experiment. In contrast, individuals with higher interoceptive sensibility exhibited lower levels of RSA during the experiment. These findings add to the limited literature on interoception in adolescents by illuminating its role in emotional experiences, stress responses, and recovery processes. Our study suggests that examining distinct dimensions of interoception, along with physiological measures during stress and recovery, is crucial for understanding its beneficial or adverse effects in adolescence. The complexity and potential significance of interoceptive dimensions extend beyond their correlations with traditional self‐report measures, warranting further investigation to clarify their implications and underlying mechanisms. [ABSTRACT FROM AUTHOR]

Summary The present study aimed to characterise the relationship between sleep and interoception in two independent studies. Theoretical grounds for such a relationship include a weak relationship between subjectively‐ and objectively‐measured sleep, the covariance of sleep with pain, as well as the mass regulation of a number of visceral biological systems. In addition, such a relationship is often reflected in our language (i.e., ‘feeling’ tired). In both studies (Study 1: N = 118, 73% female, mean age 20.98 years; Study 2: N = 830, 49% female, mean age 38.04 years) sleep over the last month was self‐reported. Confidence in interoceptive accuracy, which is the precision with which a person can monitor visceral signals, was measured using the Interoceptive Accuracy Scale, while interoceptive attention, which is the dispositional tendency to attend to bodily signals, was measured using the Body Perception Questionnaire. Study 1 revealed a relationship between long sleep latency and low confidence in interoceptive accuracy (β = −0.222, p = 0.021) and poor sleep quality and less interoceptive attention (β = −0.226, p = 0.016). Study 2 replicated these results as well as made clear a more general pattern whereby poor sleep—characterised by short duration, poor quality, less efficiency, long latency, and more frequent nighttime awakenings—related to an interoceptive phenotype of less confidence in interoceptive accuracy and more interoceptive attention (all β ≥ 0.047, p ≤ 0.17). In conclusion, results from these two independent studies provide robust cross‐sectional evidence for associations between various dimensions of poor sleep and greater interoceptive attention, but less confidence in interoceptive accuracy. [ABSTRACT FROM AUTHOR]

Interoception, the representation of our bodily state derived from physiological signals, is fundamental to our sense of self. Previous studies using cardiac feedback paradigms demonstrated interoceptive effects on self-perception. However, it remains unclear whether interoceptive information can extend selfattribution to non-bodily objects. This study aimed to elucidate whether cardiac signals can induce self-attribution to non-bodily objects and how interoceptive accuracy modulates this effect. A total of 44 male volunteers participated in an emotion assignment task where they viewed images of palms (bodily targets) and spheres (non-bodily targets) flashing in or out of sync with their heartbeat and assigned emotional images (positive/negative) to these targets. A heartbeat discrimination task was used to measure the interoceptive accuracy. The results showed no significant effect of synchronisation on emotion assignment for either the target type or the valence of the emotional images. However, participants with high interoceptive accuracy attributed both positive and negative images more to synchronised targets than those with low interoceptive accuracy. These findings suggest that although cardiac synchronisation may not uniformly facilitate the self-attribution of external objects, interoceptive accuracy may mediate attention to synchrony. Future studies should explore the conditions under which cardiac signals influence self-attribution. [ABSTRACT FROM AUTHOR]

Previous research has found that nature connectedness, an experiential close connection to nature with cognitive, affective and physical benefits, profoundly impacts individual wellbeing and subsequently increases pro-environmental behaviors. However, little is known about the personal and contextual factors that predict nature connectedness. Testing theory derived from a qualitative interpretative phenomenological analysis study, this research addresses the lacuna in the literature. A structural equation model analysis finds that interoceptive awareness significantly predicts nature connection, that secure attachment to nature significantly explains this relationship, and that these inter-related constructs predict both pro-environmental behavior and wellbeing. This revised model of nature connection indicates important antecedents for the human-nature bond, illuminating in particular that the interpersonal relational processes foundational for close bonding with humans also occur in bonding with nature. Structural equation modeling indicates that emotional awareness is the dimension of interoceptive awareness that most significantly predicts nature connection, suggesting that the more aware a person is of the connection between inner bodily sensations and emotions, the more likely they can bond with nature. Given that interoceptive awareness indicates a coherent relationship with the self, including effective communication between body, mind and feelings, this process is therefore implicated in the capacity for humans to bond with nature. In sum, this present research points to the efficacy of an embodied, secure attachment with nature to help close both the human-nature disconnection chasm, and the environmental value-action gap. Theoretical and methodological implications for research and policy are discussed. [ABSTRACT FROM AUTHOR]

An interoceptive homeostatic reflex monitors levels of CO2/H+ to maintain blood gas homeostasis and rapidly regulate tissue acid–base balance by driving lung ventilation and CO2 excretion—this CO2-evoked increase in respiration is the hypercapnic ventilatory reflex (HCVR). Retrotrapezoid nucleus (RTN) neurons provide crucial excitatory drive to downstream respiratory rhythm/pattern-generating circuits, and their activity is directly modulated by changes in CO2/H+ . RTN neurons express GPR4 and TASK-2, global deletion of which abrogates CO2/H+ activation of RTN neurons and the HCVR. It has not been determined if the intrinsic pH sensitivity of these proton detectors is required for these effects. We used CRISPR/Cas9 genome editing to generate mice with mutations in either of two pH-sensing histidine residues in GPR4 to determine effects on RTN neuronal CO2/H+ sensitivity and the HCVR. In global GPR4(H81F) and GPR4(H167F) mice, CO2-stimulated breathing and CO2-induced RTN neuronal activation were strongly blunted, with no effect on hypoxia-stimulated breathing. In brainstem slices from GPR4(H81F) mice, peak firing of RTN neurons during bath acidification was significantly reduced compared with GPR4 wild-type mice, and a subpopulation of RTN neurons was rendered pH-insensitive, phenocopying previous results from GPR4-deleted mice. These effects were independent of changes in RTN number/distribution, neuronal excitability or transcript levels for GPR4 and TASK-2. CO2-stimulated breathing was reduced to a similar extent in GPR4(H81F) and TASK-2-deleted mice, with combined mutation yielding no additional deficit in the HCVR. Together, these data demonstrate that the intrinsic pH sensitivity of GPR4 is necessary for full elaboration of the HCVR. [ABSTRACT FROM AUTHOR]

Background: People with functional neurological disorder (FND) have abnormalities in sensory processing. Loss of ticklishness has been rarely reported. Objectives: To describe associated clinical features in people with FND and loss of ticklishness and explore correlations with sensory changes. Methods: Retrospective audit of clinical letters of people diagnosed with FND in a tertiary clinic and further cases identified in a general neurology clinic. Results: Thirty‐eight patients with loss of ticklishness are described, of which most had other functional sensory symptoms and signs. It was more often localized to one limb, rather than generalized, in those with pain or weakness. Dissociation for the affected body part was often described. Conclusions: Loss of ticklishness in FND is frequently described and offers insights into mechanisms of agency, sensory processing and interoception, which are known to be altered in FND. [ABSTRACT FROM AUTHOR]

Alcohol use disorder (AUD) has been associated with changes in the processing of internal body signals, known as interoception. Changes in brain structure, particularly in the insula, are thought to underlie impaired interoception. As studies specifically investigating this association are largely lacking, this analysis takes an approach that compares meta‐analytic results on interoception with recently published meta‐analytic results on gray matter reduction in AUD. A systematic literature search identified 25 eligible interoception studies. Activation likelihood estimation (ALE) was used to test for spatial convergence of study results. Overlap between interoception and AUD clusters was tested using conjunction analysis. Meta‐analytic connectivity modeling (MACM) and resting‐state functional connectivity were used to identify the functional network of interoception and to test where this network overlapped with AUD meta‐analytic clusters. The results were characterized using behavioral domain analysis. The interoception ALE identified a cluster in the left middle insula. There was no overlap with clusters of reduced gray matter in AUD. MACM analysis of the interoception cluster revealed a large network located in the insulae, thalami, basal nuclei, cingulate and medial frontal cortices, and pre‐ and postcentral gyri. Resting state analysis confirmed this result, showing the strongest connections to nodes of the salience‐ and somatomotor network. Five of the eight clusters that showed a structural reduction in AUD were located within these networks. The behavioral profiles of these clusters were suggestive of higher‐level processes such as salience control, somatomotor functions, and skin sensations. The results suggest an altered salience mapping of interoceptive signals in AUD, consistent with current models. Connections to the somatomotor network may be related to action control and integration of skin sensations. Mindfulness‐based interventions, pleasurable touch, and (deep) transcranial magnetic stimulation may be targeted interventions that reduce interoceptive deficits in AUD and thus contribute to drug use reduction and relapse prevention. [ABSTRACT FROM AUTHOR]

Simulation theories predict that the observation of other's expressions modulates neural activity in the same centres controlling their production. This hypothesis has been developed by two models, postulating that the visual input is directly projected either to the motor system for action recognition (motor resonance) or to emotional/interoceptive regions for emotional contagion and social synchronization (emotional resonance). Here we investigated the role of frontal/insular regions in the processing of observed emotional expressions by combining intracranial recording, electrical stimulation and effective connectivity. First, we intracranially recorded from prefrontal, premotor or anterior insular regions of 44 patients during the passive observation of emotional expressions, finding widespread modulations in prefrontal/insular regions (anterior cingulate cortex, anterior insula, orbitofrontal cortex and inferior frontal gyrus) and motor territories (Rolandic operculum and inferior frontal junction). Subsequently, we electrically stimulated the activated sites, finding that (i) in the anterior cingulate cortex and anterior insula, the stimulation elicited emotional/interoceptive responses, as predicted by the 'emotional resonance model'; (ii) in the Rolandic operculum it evoked face/mouth sensorimotor responses, in line with the 'motor resonance' model; and (iii) all other regions were unresponsive or revealed functions unrelated to the processing of facial expressions. Finally, we traced the effective connectivity to sketch a network-level description of these regions, finding that the anterior cingulate cortex and the anterior insula are reciprocally interconnected while the Rolandic operculum is part of the parieto-frontal circuits and poorly connected with the former. These results support the hypothesis that the pathways hypothesized by the 'emotional resonance' and the 'motor resonance' models work in parallel, differing in terms of spatio-temporal fingerprints, reactivity to electrical stimulation and connectivity patterns. [ABSTRACT FROM AUTHOR]

The complex interplay of fear, attention, and behavior toward bodily sensations with psychopathological symptoms and how they mutually influence and potentially reinforce one another remains to be fully elucidated. In this study, we used a network analytical approach to unravel these complex interactions. Specifically, we aimed to identify central symptoms and etiologically relevant factors that might be associated with anxiety and depressive core symptoms. To this end, the following clusters were assessed in 791 adults: interoceptive fear, interoceptive attention, maladaptive behaviors related to bodily sensations, and core symptoms of anxiety and depression. This network was modeled using a Gaussian Graphical Model. Central variables (nodes) were identified using centrality indices and bridge analysis. Self-examination and attention to bodily sensations emerged as central nodes. Moreover, time spent paying attention to bodily sensations, fear of anxiety-related sensations, and self-examination were identified as central bridge nodes, that is, central nodes connecting psychopathologically relevant symptom clusters. The present study indicates that fear of bodily sensations, the amount of attention and time spent focusing on somatic sensations, and self-examination are central factors. The findings suggest potential targets for future longitudinal studies on the impact of these factors for the escalation of anxiety and depressive symptoms. Central variables were identified through centrality indices and bridge analysis Attention to bodily sensations and self-examination were identified as central nodes Fear of bodily sensations and self-examination emerged as central bridge nodes Time spent paying attention to body sensations also emerged as central bridge node Results suggest possible targets for future experimental and longitudinal research [ABSTRACT FROM AUTHOR]

Interoception, the sense of the physiological condition of our body, is impaired in individuals with autism spectrum disorders. Evidence suggests that subclinical autistic traits are mild manifestations of autistic symptoms, present in the general population. We examined the resting-state functional connectivity (rsFC) associating with interoception and autistic traits in 62 healthy young adults. Autistic traits correlated negatively with the rsFC between the lateral ventral anterior insula and anterior cingulate cortex. Interoceptive accuracy and sensibility correlated positively with the rsFC between interoceptive brain networks and the cerebellum, supplementary motor area, and visual regions. The results suggest that a negative relationship between interoception and autistic traits is largely accounted for by both self-report measures and decreased rsFC amongst the interoceptive brain network. [ABSTRACT FROM AUTHOR]

Recent theoretical perspectives have advanced that autobiographical memory processes are supported by interoception, the perception of internal bodily sensations. Yet, this relationship remains largely underexplored. The present study addressed this critical gap in the literature by systematically investigating the association between self-reported Interoceptive Sensibility and various individual differences measures of autobiographical memory. In Study 1, using a correlational approach in a large sample of participants (N = 247), we identified significant correlations between standardised measures of interoception and the general experience of autobiographical memory and the frequency of involuntary mental time travel. These associations remained significant even after controlling for potential confounding factors in terms of age, gender, and trait affectivity, underscoring their robustness. Study 2 replicated and extended the associations identified in Study 1 in another large participant sample (N = 257), further validating them by accounting for the potential confounding effect of well-being. Our findings demonstrate that individuals' ability to perceive and understand bodily signals robustly relates to how they experience autobiographical memories. By adopting an exploratory approach based on individual differences, our results provide novel and concrete insights into the association between interoception and autobiographical memory, providing a strong foundation for future investigations into the causal mechanisms connecting these two constructs. [ABSTRACT FROM AUTHOR]

The thermosensory system is relevant to both the conceptualization and treatment of depression. There is evidence that depression is associated with changes in thermoregulatory functioning, and that thermosensory pathways can be recruited to influence affect and reduce depressive symptoms. In this study, we investigated the relationship between severity of depressive symptoms and changes to measures of subjective experiences associated with thermoregulatory processes as well as the relationship between severity of depressive symptoms and affective responses to warm stimuli, specifically frequency of warmth-seeking behavior. Participants (N = 529) completed measures of depressive symptoms, subjective experiences associated with thermoregulatory processes (i.e., perceived sweating and preferred ambient temperature) and frequency of warmth-seeking behavior (e.g., long hot baths, saunas, etc.). We demonstrate that, controlling for age and gender, greater severity of depressive symptoms is associated with greater perceived sweating and lower preferred ambient temperature. Furthermore, we demonstrate that greater severity of depressive symptoms is associated with more frequent warmth-seeking behavior, and that something other than thermal preference (i.e., stated preference for warmer temperature) is driving this behavior. These data highlight the importance of incorporating the thermoregulatory system in our conceptualization of the pathophysiology of depression and support the potential to recruit thermosensory pathways to target depressive symptoms. [ABSTRACT FROM AUTHOR]