Brain Networks, Neurotransmitters and Psychedelics: Towards a Neurochemistry of Self-Awareness.

PURPOSE OF REVIEW: Self-awareness can be defined as the capacity of becoming the object of one's own awareness and, increasingly, it has been the target of scientific inquiry. Self-awareness has important clinical implications, and a better understanding of the neurochemical basis of self-awareness may help clarifying causes and developing interventions for different psychopathological conditions. The current article explores the relationship between neurochemistry and self-awareness, with special attention to the effects of psychedelics. RECENT FINDINGS: The functioning of self-related networks, such as the default-mode network and the salience network, and how these are influenced by different neurotransmitters is discussed. The impact of psychedelics on self-awareness is reviewed in relation to specific processes, such as interoception, body ownership, agency, metacognition, emotional regulation and autobiographical memory, within a framework based on predictive coding. Improved outcomes in emotional regulation and autobiographical memory have been observed in association with the use of psychedelics, suggesting higher-order self-awareness changes, which can be modulated by relaxation of priors and improved coping mechanisms linked to cognitive flexibility. Alterations in bodily self-awareness are less consistent, being potentially impacted by doses employed, differences in acute/long-term effects and the presence of clinical conditions. Future studies investigating the effects of different molecules in rebalancing connectivity between resting-state networks may lead to novel therapeutic approaches and the refinement of existing treatments.

Allostatic Interoceptive Overload Across Psychiatric and Neurological Conditions.

Emerging theories emphasize the crucial role of allostasis (anticipatory and adaptive regulation of the body's biological processes) and interoception (integration, anticipation, and regulation of internal bodily states) in adjusting physiological responses to environmental and bodily demands. In this review, we explore the disruptions in integrated allostatic interoceptive mechanisms in psychiatric and neurological disorders, including anxiety, depression, Alzheimer's disease, and frontotemporal dementia. We assess the biological mechanisms associated with allostatic interoception, including whole-body cascades, brain structure and function of the allostatic interoceptive network, heart-brain interactions, respiratory-brain interactions, the gut-brain-microbiota axis, peripheral biological processes (inflammatory, immune), and epigenetic pathways. These processes span psychiatric and neurological conditions and call for developing dimensional and transnosological frameworks. We synthesize new pathways to understand how allostatic interoceptive processes modulate interactions between environmental demands and biological functions in brain disorders. We discuss current limitations of the framework and future transdisciplinary developments. This review opens a new research agenda for understanding how allostatic interoception involves brain predictive coding in psychiatry and neurology, allowing for better clinical application and the development of new therapeutic interventions.

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

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

Interoceptive experiences and ecological care: an embodied approach within therapeutical realms.

The conventional dichotomy between human health and disease has historically been approached through reductionist models that emphasize the exclusive causal relevance of physiological and pathological processes. Consequently, self-awareness and affective dimensions, integral to a phenomenological perspective, are often relegated to secondary traits, affording little consideration for the causal role of embodied living organization. Our interest lies in exploring the potential relevance of the phenomenology of embodied self-awareness in relation to interoceptive processes within therapeutic settings. As we illustrate, when the unfolding processes of interoceptive awareness and its affective capacity take precedence, the agent assumes an active, rather than passive, role in their own experience of health or illness. Departing from an enactive, phenomenological, and ecological standpoint, we propose a distinctive perspective on interoceptive processes, relying on an affective conceptualization of a spectrum of experiences of bodily being-in-the-world. Our primary argument posits that considering interoceptive processes from an embodied and ecological viewpoint of the self, interacting with the material and social environment, enables an approach to the gradient of affective experiences of embodied self-awareness-where pleasure or suffering is perceived and felt-in a naturalized, non-reductive, and relational manner. We discern two ways in which interoceptive processes interrelate with the experience of embodied self-awareness: sensitivity (self-affective) and affective-laden perception. Drawing on this distinction, we provide a nuanced description of these experiences within communities of cis-women, exemplified through the contexts of menstruation and endometriosis. This exploration seeks to enhance our understanding of the phenomenology of embodied, ecological, and affective self-experience from within diverse and situated bodies. The goal is to contribute to their autonomy and ability to adapt and self-regulate within therapeutic contexts.

The cognitive neuroscience of self-awareness: Current framework, clinical implications, and future research directions.

Self-awareness, the ability to take oneself as the object of awareness, has been an enigma for our species, with different answers to this question being provided by religion, philosophy, and, more recently, science. The current review aims to discuss the neurocognitive mechanisms underlying self-awareness. The multidimensional nature of self-awareness will be explored, suggesting how it can be thought of as an emergent property observed in different cognitive complexity levels, within a predictive coding approach. A presentation of alterations of self-awareness in neuropsychiatric conditions will ground a discussion on alternative frameworks to understand this phenomenon, in health and psychopathology, with future research directions being indicated to fill current gaps in the literature. This article is categorized under: Philosophy > Consciousness Psychology > Brain Function and Dysfunction Neuroscience > Cognition.

Caresses, whispers and affective faces: A theoretical framework for a multimodal interoceptive mechanism underlying ASMR and affective touch: An evolutionary and developmental perspective for understanding ASMR and affective touch as complementary processes within affiliative interactions.

Autonomous sensory meridian response (ASMR) and affective touch (AT) are two phenomena that have been independently investigated from separate lines of research. In this article, I provide a unified theoretical framework for understanding and studying them as complementary processes. I highlight their shared biological basis and positive effects on emotional and psychophysiological regulation. Drawing from evolutionary and developmental theories, I propose that ASMR results from the development of biological mechanisms associated with early affiliative behaviour and self-regulation, similar to AT. I also propose a multimodal interoceptive mechanism underlying both phenomena, suggesting that different sensory systems could specifically respond to affective stimulation (caresses, whispers and affective faces), where the integration of those inputs occurs in the brain's interoceptive hubs, allowing physiological regulation. The implications of this proposal are discussed with a view to future research that jointly examines ASMR and AT, and their potential impact on improving emotional well-being and mental health.

Self-reported interoception, worries and protective behaviors during the COVID-19 pandemic: a longitudinal study.

BACKGROUND: Protective behaviors were essential for minimizing the spread of the virus during the coronavirus disease 2019 (COVID-19) pandemic. It is often assumed that awareness of bodily sensations (interoception) can improve decision-making and facilitate adaptive behavior. OBJECTIVE: This paper investigates cross-sectional and longitudinal relationships between different aspects of self-reported interoception, trait anxiety, COVID-related worry, and health protective behaviors. METHODS: The study was conducted on a community sample of 265 adults. The two data collection phases took place online, before (baseline) and during the second wave of the COVID-19 pandemic in Hungary. RESULTS: Contrary to our expectations, neither cross-sectional nor longitudinal associations were found between protective behaviors and indicators of self-reported interoception. However, worry at baseline predicted protective behaviors during the second wave, even after controlling for socio-economical characteristics and protective behaviors at baseline. CONCLUSION: Our results highlight the adaptivity of health-related worry when behavioral steps to avoid threats are known and available. Also, higher level of perceived interoception did not appear to be health protective under these circumstances.

Intensity-Dependent Influence of Interoceptive Accuracy on Psychophysiological Responses During Aerobic Exercise in Physically Inactive Men.

We aimed to investigate the influence of interoceptive accuracy on affective valence, arousal, and ratings of perceived exertion (RPE) during 20 minutes of aerobic exercise at both moderate and heavy intensity among physically inactive men. We divided our participant sample into men with poor heartbeat perception (PHP, n = 13) and good heartbeat perception (GHP, n = 15), based on their cardioceptive accuracy. We measured their heart rate reserve (%HRreserve), perceived affective valence (Feeling Scale; +5/-5), perceived arousal (Felt Arousal Scale, 0-6), and ratings of perceived effort (RPE; Borg scale 6-20) every five minutes during an exercise session on a bicycle ergometer. During moderate-intensity aerobic exercise, the GHP group presented a greater decline in affective valence (p = 0.010; d = 1.06) and a greater increase in RPE (p = 0.004; d = 1.20) compared to the PHP group, with no group differences in %HRreserve (p = 0.590) and arousal (p = 0.629). Psychophysiological and physiological responses to the heavy-intensity aerobic exercise were not different between groups. We concluded that the influence of interoceptive accuracy on psychophysiological responses during submaximal fixed-intensity aerobic exercise was intensity-dependent in these physically inactive men.

Psychometric Properties of the Multidimensional Assessment of Interoceptive Awareness (MAIA) Questionnaire in Colombian University Students.

INTRODUCTION: The university student population is influenced by multiple factors that affect body awareness. Identifying the body awareness status of students is crucial in creating self-care and emotion management programs to prevent diseases and promote health. The Multidimensional Assessment of Interoceptive Awareness (MAIA) questionnaire evaluates interoceptive body awareness in eight dimensions through 32 questions. It is one of the few tools that enable a comprehensive assessment of interoceptive body awareness by involving eight dimensions of analysis. METHOD: The objective of this study is to present the psychometric properties of the Multidimensional Assessment of Interoceptive Awareness (MAIA) to observe to what extent the hypothesized model fits the population of university students in Colombia. A descriptive cross-sectional study was conducted with 202 students who met the inclusion criterion of being undergraduate university students. Data were collected in May 2022. RESULTS: A descriptive analysis of the sociodemographic variables of age, gender, city, marital status, discipline, and history of chronic diseases was performed. JASP 0.16.4.0 statistical software was used to conduct confirmatory factor analysis. A confirmatory factor analysis was performed based on the proposed eight-factor model of the original MAIA, giving a significant p-value and 95% confidence interval. However, when performing loading factor analysis, a low p-value was found for item 6 of the Not Distracting factor, and for the entire Not Worrying factor. DISCUSSION: A seven-factor model with modifications is proposed. CONCLUSIONS: The results of this study confirmed the validity and reliability of the MAIA in the Colombian university student population.

Modelos neuroeconómicos explicativos de la relación entre aversión al riesgo, impulsividad y cardiocepción en estudiantes universitarios: revisión de alcance / Explanatory neuroeconomics models of the relation between risk-aversion, impulsivity and cardioception in university students: a scoping review

Introducción: los modelos neuroeconómicos explican la toma de decisiones a partir de procesos neurofisiológicos, cognitivos y emocionales. La toma de decisiones se estudia a partir de otros subprocesos como la aversión al riesgo. La relación entre aversión al riesgo, impulsividad y/o interocepción es importante para determinar el rol de la conducta y cognición humanas en el mantenimiento de problemas de salud. Esto se ha estudiado en población universitaria, en la que se presentan factores de riesgo para la salud. Objetivo: sintetizar los modelos neuroeconómicos descritos en la literatura para establecer la relación entre la aversión al riesgo, impulsividad y/o la cardiocepción en estudiantes universitarios. Metodología: revisión tipo alcance realizada del 01 de junio al 30 de septiembre de 2021 en los recursos; PubMed, PsyInfo, Google Scholar, Sciencedirect, Scopus, Open dissertations y OpenGrey. Como criterio de inclusión se estableció que se tratara de investigaciones experimentales y observacionales en inglés o español en estudiantes universitarios que evaluaran la relación entre toma de decisiones, impulsividad y/o interocepción. No se filtró por fecha ni por tipo de acceso. Resultados: se rastrearon 1035 documentos, 14 cumplieron con los criterios de inclusión. Se identificaron cuatro modelos: neuroeconómico conductual, paradigma de descuento temporal, teoría biopsicológica de Gray y diferencias individuales. Se hallaron correlaciones positivas y negativas entre impulsividad, aversión al riesgo e interocepción. Conclusiones: según los estudios existe una relación entre impulsividad y aversión al riesgo, que dependiendo del modelo implementado será positiva o negativa. Las asociaciones con interocepción son poco concluyentes y requieren mayor investigación.

Introduction: neuroeconomic models explain decision making based on neurophysiological, cognitive, and emotional processes. Decision making is studied from other threads such as risk aversion. The relationship between risk aversion, impulsivity and/or interoception is important to determine the role of human behavior and cognition in the maintenance of health problems. This has been studied in the university population, in which health risk factors are present. Objective: to synthesize the neuroeconomic models described in the literature to establish the relationship between risk aversion, impulsivity and/or cardioception in university students. Methodology: scoping review carried out from June 1 to September 30, 2021, in the resources; PubMed, PsyInfo, Google Scholar, Sciencedirect, Scopus, Open dissertations, and OpenGrey. As inclusion criteria, it was established that they were experimental and observational investigations in English or Spanish in university students that evaluated the relationship between decision-making, impulsivity and/or interoception. It was not filtered by date or by type of access. Results: 1035 documents were searched, 14 met the inclusion criteria. Four models were identified: behavioral neuroeconomic, delaying discount paradigm, Gray's biopsychological theory, and individual differences. Positive and negative correlations were found between impulsivity, risk aversion, and interoception. Conclusions: according to the studies, there is a relationship between impulsivity and risk aversion, which depending on the model implemented will be positive or negative. Associations with interoception are inconclusive and require further investigation.

Autonomous sensory meridian response is associated with a larger heartbeat-evoked potential amplitude without differences in interoceptive awareness.

Autonomous sensory meridian response (ASMR) describes the experience of a pleasant body sensation accompanied by a feeling of well-being and relaxation in response to specific audiovisual stimuli, such as whispers and personal attention. Previous work suggests a relationship between this experience with the processing of affective and body states; however, no research has explored differences in interoception between people experiencing ASMR and those who do not. We hypothesized that the ASMR experience is based on interoception processing. To test this, we assessed group differences across different dimensions of interoception: Interoceptive sensibility (IS), measured using the multidimensional assessment of interoceptive awareness (MAIA); Interoceptive accuracy score (IAS), measured by calculating performance in a heartbeat counting task (HCT), and the electrophysiological index of interoception, the heartbeat evoked potential (HEP), which was calculated during the HCT and an ASMR tingle reporting task (ASMR-TRT). Our results showed that IS and IAS, dimensions requiring conscious awareness, showed no differences between groups. However, HEP amplitude was larger in the ASMR group in both tasks. We concluded that the ASMR experience is based on an unconscious interoceptive mechanism, reflected by HEP, where exteroceptive social-affective stimuli are integrated to represent a body state of positive affective feelings and relaxation, as has been described for affective touch. The relevance of this finding relies on that interoceptive function, body regulation, and emotional/affective experiences are fundamental for well-being, and the relationship between ASMR and interoception opens the way to future research exploring the causal relationship between them and their potential clinical applications.

Reliability of the Heartbeat Tracking Task to Assess Interoception.

Interoception refers to the competence in perceiving and interpreting internal sensations emerging from the body. The most common approach to assess interoception is through cardiac interoceptive tests like the heartbeat tracking task (HTT), which measures the accuracy on perceive and counting heartbeats during a period. However, the literature is scarce in providing adequate reliability evidence for this measure so that the interoception assessment may be threaten. In addition to HTT accuracy, it is possible to determine sensibility (self-reported confidence) and interoceptive awareness (correspondence between accuracy and sensibility). Thus, we measured the test-retest reliability of HTT and also investigated the behavior of HTT outcomes along the task. Therefore, 31 healthy adults (16 males) with 27.8 (9.4) years old performed two consecutive HTT interspersed by one day. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable difference (MD) analyzes showed 'Good' relative reliability for interoceptive accuracy (ICC = 0.880; SEM = 0.263; MD = 0.728; p < 0.001) and 'Moderate' for sensibility (ICC = 0.617; SEM = 0.648; MD = 1.797; p < 0.001) and awareness (ICC = 0.593; SEM = 0.227; MD = 0.628; p < 0.001). The absolute reliability shows low threshold values for observing true effects in HTT outcomes. The results also showed that reducing the number of HTT blocks did not impact the outcomes. The HTT showed to be reliable in determine the interoceptive competences in healthy adults.

Self-reported interoception, worries and protective behaviors during the COVID-19 pandemic: a longitudinal study

Background Protective behaviors were essential for minimizing the spread of the virus during the coronavirus disease 2019 (COVID-19) pandemic. It is often assumed that awareness of bodily sensations (interoception) can improve decision-making and facilitate adaptive behavior. Objective This paper investigates cross-sectional and longitudinal relationships between different aspects of self-reported interoception, trait anxiety, COVID-related worry, and health protective behaviors. Methods The study was conducted on a community sample of 265 adults. The two data collection phases took place online, before (baseline) and during the second wave of the COVID-19 pandemic in Hungary. Results Contrary to our expectations, neither cross-sectional nor longitudinal associations were found between protective behaviors and indicators of self-reported interoception. However, worry at baseline predicted protective behaviors during the second wave, even after controlling for socio-economical characteristics and protective behaviors at baseline. Conclusion Our results highlight the adaptivity of health-related worry when behavioral steps to avoid threats are known and available. Also, higher level of perceived interoception did not appear to be health protective under these circumstances. (AU)

A predictive coding framework of allostatic-interoceptive overload in frontotemporal dementia.

Recent allostatic-interoceptive explanations using predictive coding models propose that efficient regulation of the body's internal milieu is necessary to correctly anticipate environmental needs. We review this framework applied to understanding behavioral variant frontotemporal dementia (bvFTD) considering both allostatic overload and interoceptive deficits. First, we show how this framework could explain divergent deficits in bvFTD (cognitive impairments, behavioral maladjustment, brain atrophy, fronto-insular-temporal network atypicality, aberrant interoceptive electrophysiological activity, and autonomic disbalance). We develop a set of theory-driven predictions based on levels of allostatic interoception associated with bvFTD phenomenology and related physiopathological mechanisms. This approach may help further understand the disparate behavioral and physiopathological dysregulations of bvFTD, suggesting targeted interventions and strengthening clinical models of neurological and psychiatric disorders.

Optoception: Perception of Optogenetic Brain Perturbations.

How do animals experience brain manipulations? Optogenetics has allowed us to manipulate selectively and interrogate neural circuits underlying brain function in health and disease. However, little is known about whether mice can detect and learn from arbitrary optogenetic perturbations from a wide range of brain regions to guide behavior. To address this issue, mice were trained to report optogenetic brain perturbations to obtain rewards and avoid punishments. Here, we found that mice can perceive optogenetic manipulations regardless of the perturbed brain area, rewarding effects, or the stimulation of glutamatergic, GABAergic, and dopaminergic cell types. We named this phenomenon optoception, a perceptible signal internally generated from perturbing the brain, as occurs with interoception. Using optoception, mice can learn to execute two different sets of instructions based on the laser frequency. Importantly, optoception can occur either activating or silencing a single cell type. Moreover, stimulation of two brain regions in a single mouse uncovered that the optoception induced by one brain region does not necessarily transfer to a second not previously stimulated area, suggesting a different sensation is experienced from each site. After learning, they can indistinctly use randomly interleaved perturbations from both brain regions to guide behavior. Collectively taken, our findings revealed that mice's brains could "monitor" perturbations of their self-activity, albeit indirectly, perhaps via interoception or as a discriminative stimulus, opening a new way to introduce information to the brain and control brain-computer interfaces.

The Relationship Between Auditory-Motor Integration, Interoceptive Awareness, and Self-Reported Stuttering Severity.

Stuttering is a neurodevelopmental speech disorder associated with motor timing that differs from non-stutterers. While neurodevelopmental disorders impacted by timing are associated with compromised auditory-motor integration and interoception, the interplay between those abilities and stuttering remains unexplored. Here, we studied the relationships between speech auditory-motor synchronization (a proxy for auditory-motor integration), interoceptive awareness, and self-reported stuttering severity using remotely delivered assessments. Results indicate that in general, stutterers and non-stutterers exhibit similar auditory-motor integration and interoceptive abilities. However, while speech auditory-motor synchrony (i.e., integration) and interoceptive awareness were not related, speech synchrony was inversely related to the speaker's perception of stuttering severity as perceived by others, and interoceptive awareness was inversely related to self-reported stuttering impact. These findings support claims that stuttering is a heterogeneous, multi-faceted disorder such that uncorrelated auditory-motor integration and interoception measurements predicted different aspects of stuttering, suggesting two unrelated sources of timing differences associated with the disorder.

Allostatic-Interoceptive Overload in Frontotemporal Dementia.

BACKGROUND: The predictive coding theory of allostatic-interoceptive load states that brain networks mediating autonomic regulation and interoceptive-exteroceptive balance regulate the internal milieu to anticipate future needs and environmental demands. These functions seem to be distinctly compromised in behavioral variant frontotemporal dementia (bvFTD), including alterations of the allostatic-interoceptive network (AIN). Here, we hypothesize that bvFTD is typified by an allostatic-interoceptive overload. METHODS: We assessed resting-state heartbeat evoked potential (rsHEP) modulation as well as its behavioral and multimodal neuroimaging correlates in patients with bvFTD relative to healthy control subjects and patients with Alzheimer's disease (N = 94). We measured 1) resting-state electroencephalography (to assess the rsHEP, prompted by visceral inputs and modulated by internal body sensing), 2) associations between rsHEP and its neural generators (source location), 3) cognitive disturbances (cognitive state, executive functions, facial emotion recognition), 4) brain atrophy, and 5) resting-state functional magnetic resonance imaging functional connectivity (AIN vs. control networks). RESULTS: Relative to healthy control subjects and patients with Alzheimer's disease, patients with bvFTD presented more negative rsHEP amplitudes with sources in critical hubs of the AIN (insula, amygdala, somatosensory cortex, hippocampus, anterior cingulate cortex). This exacerbated rsHEP modulation selectively predicted the patients' cognitive profile (including cognitive decline, executive dysfunction, and emotional impairments). In addition, increased rsHEP modulation in bvFTD was associated with decreased brain volume and connectivity of the AIN. Machine learning results confirmed AIN specificity in predicting the bvFTD group. CONCLUSIONS: Altogether, these results suggest that bvFTD may be characterized by an allostatic-interoceptive overload manifested in ongoing electrophysiological markers, brain atrophy, functional networks, and cognition.

Food Consciousness Intervention Improves Interoceptive Sensitivity and Expression of Exteroception in Women.

The perception of the body's internal state (interoception) and the perception and processing of environmental sensory stimuli (exteroception) act together to modulate adaptive behaviour, including eating behaviour, and are related to bodyweight control. This study evaluated the impact of the Food and Nutrition Education Program with Sensory and Cognitive Exercises on interoceptive sensitivity and on the expression of exteroceptive perception in women who experienced difficulty in controlling their body weight. Thirty-seven women were randomized into two groups and evaluated at two moments: before and after the intervention or before and after a 3- to 4-week waiting period. A heartbeat tracking task was used for interoception evaluation. Participants were asked to write a text describing three foods after tasting them for exteroception evaluation. After the intervention, the participants showed an increase in interoceptive sensitivity, and an increase in the expression of exteroceptive stimuli perception through a semantic assessment of their writing related to the tasting experience. In addition, the results point to a possible connection between the mechanisms governing interoception and exteroception. This work brings important contributions to the search for strategies capable of promoting the perception and integration of physiological and environmental stimuli in food consumption.

Self-awareness in Dementia: a Taxonomy of Processes, Overview of Findings, and Integrative Framework.

PURPOSE OF REVIEW: Self-awareness, the capacity of becoming the object of one's own awareness, has been a frontier of knowledge, but only recently scientific approaches to the theme have advanced. Self-awareness has important clinical implications, and a finer understanding of this concept may improve the clinical management of people with dementia. The current article aims to explore self-awareness, from a neurobiological perspective, in dementia. RECENT FINDINGS: A taxonomy of self-awareness processes is presented, discussing how these can be structured across different levels of cognitive complexity. Findings on self-awareness in dementia are reviewed, indicating the relative preservation of capacities such as body ownership and agency, despite impairments in higher-level cognitive processes, such as autobiographical memory and emotional regulation. An integrative framework, based on predictive coding and compensatory abilities linked to the resilience of self-awareness in dementia, is discussed, highlighting possible avenues for future research into the topic.

Interoception Primes Emotional Processing: Multimodal Evidence from Neurodegeneration.

Recent frameworks in cognitive neuroscience and behavioral neurology underscore interoceptive priors as core modulators of negative emotions. However, the field lacks experimental designs manipulating the priming of emotions via interoception and exploring their multimodal signatures in neurodegenerative models. Here, we designed a novel task that involves interoceptive and control-exteroceptive priming conditions followed by post-interoception and post-exteroception facial emotion recognition (FER). We recruited 114 participants, including healthy controls (HCs) as well as patients with behavioral variant frontotemporal dementia (bvFTD), Parkinson's disease (PD), and Alzheimer's disease (AD). We measured online EEG modulations of the heart-evoked potential (HEP), and associations with both brain structural and resting-state functional connectivity patterns. Behaviorally, post-interoception negative FER was enhanced in HCs but selectively disrupted in bvFTD and PD, with AD presenting generalized disruptions across emotion types. Only bvFTD presented impaired interoceptive accuracy. Increased HEP modulations during post-interoception negative FER was observed in HCs and AD, but not in bvFTD or PD patients. Across all groups, post-interoception negative FER correlated with the volume of the insula and the ACC. Also, negative FER was associated with functional connectivity along the (a) salience network in the post-interoception condition, and along the (b) executive network in the post-exteroception condition. These patterns were selectively disrupted in bvFTD (a) and PD (b), respectively. Our approach underscores the multidimensional impact of interoception on emotion, while revealing a specific pathophysiological marker of bvFTD. These findings inform a promising theoretical and clinical agenda in the fields of nteroception, emotion, allostasis, and neurodegeneration.SIGNIFICANCE STATEMENT We examined whether and how emotions are primed by interoceptive states combining multimodal measures in healthy controls and neurodegenerative models. In controls, negative emotion recognition and ongoing HEP modulations were increased after interoception. These patterns were selectively disrupted in patients with atrophy across key interoceptive-emotional regions (e.g., the insula and the cingulate in frontotemporal dementia, frontostriatal networks in Parkinson's disease), whereas persons with Alzheimer's disease presented generalized emotional processing abnormalities with preserved interoceptive mechanisms. The integration of both domains was associated with the volume and connectivity (salience network) of canonical interoceptive-emotional hubs, critically involving the insula and the anterior cingulate. Our study reveals multimodal markers of interoceptive-emotional priming, laying the groundwork for new agendas in cognitive neuroscience and behavioral neurology.