The sentient self

Modulation of dorsal raphe nucleus connectivity and serotonergic signalling to the insular cortex in the prosocial effects of chronic fluoxetine

Long-term exposure to fluoxetine and other selective serotonin reuptake inhibitors alters social and anxiety-related behaviours, including social withdrawal, which is a symptom of several neuropsychiatric disorders. Adaptive changes in serotonergic neurotransmission likely mediate this delayed effect, although the exact mechanisms are still unclear. Here we investigated the functional circuitry underlying the biphasic effects of fluoxetine on social approach-avoidance behaviour and explored the place of serotonergic dorsal raphe nucleus (DR) ensembles in this network, using c-Fos-immunoreactivity as a correlate of activity. Graph theory-based network analysis revealed changes in patterns of functional connectivity and identified neuronal populations in the insular cortex (IC) and serotonergic populations in the DR as central targets to the prosocial effects of chronic fluoxetine. To determine the role of serotonergic projections to the IC, a retrograde tracer was micro-injected in the IC prior to fluoxetine treatment and social behaviour testing. Chronic fluoxetine increased c-Fos immunoreactivity in insula-projecting neurons of the rostral, ventral part of the DR (DRV). Using a virally delivered Tet-Off platform for temporally-controlled marking of neuronal activation, we observed that chronic fluoxetine may affect social behaviour by influencing independent but interconnected populations of serotonergic DR ensembles. These findings suggest that sustained fluoxetine exposure causes adaptive changes in functional connectivity due to altered serotonergic neurotransmission in DR projection targets, and the increased serotonergic signalling to the IC likely mediates some of the therapeutic effects of fluoxetine on social behaviour.

Where creativity meets aesthetics: The Mirror Model of Art revisited with fMRI

How meaning is conveyed from creator to observer is debated in the psychology of art. The Mirror Model of Art represents a theoretical framework for bridging the psychological processes that underpin creative production and aesthetic appreciation of art. Specifically, it postulates that creating art and having an aesthetic experience are "mirrored" processes such that the early stage of aesthetic appreciation corresponds to the late stage of creative production, and conversely, that the late stage of aesthetic appreciation corresponds to the early stage of creative production. We conducted a meta-analysis of fMRI studies in the visual domain to test this hypothesis. Our results reveal that creative production engages the prefrontal cortex, which we attribute to its role in idea generation, whereas aesthetic appreciation engages the visual cortex, anterior insula, parahippocampal gyrus, the fusiform gyrus, and the frontal lobes, regions involved primarily in sensory, perceptual, reward and mnemonic processing. Their direct comparison revealed that creative production was associated with greater activation in the prefrontal cortex, whereas aesthetic appreciation was associated with greater activation in the visual cortex. This meta-analysis largely supports predictions derived from the Mirror Model of Art, by providing a snapshot of neural activity in the relatively early stages in art creators' and observers' minds. Future studies that capture brain function across longer spans of time are needed to understand the expression of creativity and aesthetic appreciation in different stages of information processing in relation to the Mirror Model of Art.

Proposition of Two Subtypes of Patients at Risk of Suicide: Pain Hypersensitive Vs. Dissociative

PURPOSE OF REVIEW

The pain-suicide relationship is one of the most debated in recent literature, but theories and clinical evidence have often reached contrasting conclusions. Through a critical overview of theoretical, meta-analytical and empirical contributions, we aimed at advancing the conversation on the pain-suicide relationship by integrating research on related concepts, specifically inflammation and dissociation, and their effects on interoceptive processes and pain perception.

RECENT FINDINGS

Ideation-to-action theories consider increased pain tolerance a key risk factor for the transition from suicidal ideation to attempt. However, several meta-analytical findings suggest that suicidal thoughts and behaviors are associated with inflammation-induced pain sensitization. On the one hand, inflammation contributes to the development and maintenance of chronic pain conditions and mood disorders, and is associated with interoceptive hypervigilance and pain hypersensitivity. Moreover, a trait of increased pain tolerance does not seem to distinguish the individuals attempting suicide among those living with suicidal thoughts. On the other, temporary hypoalgesia is often activated by dissociative experiences. Highly dissociative individuals can indeed be exposed to frequent disintegration of interoceptive processes and transitory hyposensitivity to pain. In light of this, two different patterns of responses to stress (i.e. inflammation vs. dissociation) may characterize different kinds of patients at risk of suicide, associated with specific patterns of interoceptive functioning, pain sensitivity and possibly suicidal ideation. This proposition is partially supported by neuroimaging studies on post-traumatic stress disorder and psychodynamic perspectives on neurodevelopment, as well as alternative clustering models of suicidal behavior. Theoretical, meta-analytical and neurobiological evidence highlight two opposite directions in the pain-suicide relationship: hyper- vs. hyposensitivity. Such contrasts may be explained by the existence of two tendencies in stress-response, namely inflammation and dissociation, defining two different subtypes of patients at risk of suicide. We thus propose the existence of a hypersensitive subtype, defined by underlying neuroinflammatory processes, increased vulnerability to chronic pain and mood disorders, interoceptive hypervigilance, pain hypersensitivity and potentially more persistent suicidal ideation. We further hypothesize a dissociative subtype, characterized by greater trait dissociation, vulnerability to depersonalization and derealization, frequent disintegration of interoceptive processes, transient pain hyposensitivity and abrupt peaks in suicidal ideation.

The Life and Legacy of Arthur D. Craig, Jr.: A Pioneer in Interoception

A.D. (Bud) Craig (1951-2023) redefined the concept of interoception and provided a novel, revolutionary understanding of the neural basis for human awareness. In unsurpassed anatomical-physiological studies in monkeys, Craig showed that the insular cortex is the primary sensory cortex for interoception, or the image of the "material me" that provides a homeostatic representation of the physiological condition of the body. He showed that the insula contains a postero-anteriorly organized somatotopic map of the interoceptive sensations, and that it encodes both the localization and the intensity discrimination of interoceptive sensations. In seminal work in humans, he demonstrated that the interoceptive feelings are re-represented, and multimodally integrated, in anterior portions of the insula in sequence of increasingly homeostatically efficient representations that integrate all salient neural activity. He further showed that subjective awareness is associated with activation of the anterior insular cortex and suggested that this brain region also is critical for fluid intelligence and the perception of time. His work has led to a paradigm shift in our understanding of interoception and how interoceptive sensations underlie consciousness, a topic that long has been considered elusive, or even beyond our comprehension.

Human insula neurons respond to simple sounds during passive listening

The insula is critical for integrating sensory information from the body with that arising from the environment. Although previous studies suggest that posterior insula is sensitive to sounds, auditory response properties of insula neurons have not previously been reported. Here, we provide the first report of a population of human single neuron data from the insula and provide comparative data from the primary auditory cortex, recorded intracranially from human participants during passive listening. In each condition, more than 330 single neurons were recorded in 11 participants. Almost a third of neurons in posterior insula and a smaller subset in anterior insula responded to simple tones and clicks. Responsive neurons were distributed throughout posterior and anterior insula and showed preferred frequency tuning. Onset latencies in the insula were similar to those in the primary auditory cortex but response durations were significantly shorter. Overall, these data highlight that insula neurons respond to auditory stimuli even in non-behaviorally relevant contexts and suggest an important contribution of audition to the postulated integrative functions of insular cortex.

The contribution of cutaneous thermal signals to bodily self-awareness

Thermosensory signals may contribute to the sense of body ownership, but their role remains highly debated. We test this assumption within the framework of pathological body ownership, hypothesising that skin temperature and thermoception differ between right-hemisphere stroke patients with and without Disturbed Sensation of Ownership (DSO) for the contralesional plegic upper limb. Patients with DSO exhibit lower basal hand temperatures bilaterally and impaired perception of cold and warm stimuli. Lesion mapping reveals associations in the right Rolandic Operculum and Insula, with these regions linked to lower skin temperature located posterior to those associated with thermoception deficits. Disconnections in bilateral parietal regions are associated with lower hand temperature, while disconnections in a right-lateralized thalamus-parietal hub correlate with thermoception deficits. We discuss the theoretical implications of these findings in the context of the ongoing debate on the role of homeostatic signals in shaping a coherent sense of body ownership.

Transformative process in narratives of bodily autobiographical memories: A psychological clinical group intervention with breast cancer survivors

Breast cancer survivors often report internal sensations of discomfort that influence body image or the subjective representation of one's appearance, which can cause a disconnection between body and personal identity. 12 breast cancer survivors were involved in a group psychological intervention which focused on the management of autobiographical memories related to their own body after breast cancer. Three open questions related to their body autobiographical memories were administered pre, post and 1 month later after the intervention. Autobiographical memories were analyzed with a qualitative methodology to explore the transformative process at three time points. Findings highlight three main themes: (1) narratives of cancer-related memories (2) narratives of emotion towards the body after cancer (3) narratives of memories of internal reflections. This innovative psychological group intervention appears to support breast cancer survivors in re-taking control of their own autobiographical memories related to the body and their related emotions.

Change starts with the body: Interoceptive appreciation mediates the effect of mindfulness training on behavior change - an effect moderated by depression severity

Mindfulness catalyzes health behavior change. Yet, interoception is dysregulated in depression, potentially impairing behavioral activation. We examined the mediating role of interoceptive appreciation, as measured by how much one trusts and listens to internal bodily signals, on behavior change. Primary care patients with depression, anxiety, or stress disorders related to chronic illness were randomized to Mindfulness Training for Primary Care (MTPC) using the Mindful Behavior Change curriculum or a low-dose mindfulness comparator. Participants (N = 274) completed the Multidimensional Assessment of Interoceptive Awareness (MAIA) at 0 and 8 weeks. At week 7, participants chose a health behavior action plan. During weeks 8-10, participants reported their action plan initiation (API) level. We investigated the effect of MTPC on API level (MTPC-API), the mediating role of interoceptive appreciation (Body Listening [MAIA-BL] + Trusting [MAIA-T]), and baseline depression severity as a moderator. MTPC had a significant direct effect on API. Interoceptive appreciation (MAIA-BL + MAIA-T) had a significant indirect effect on API (CI=0.15-0.56). Without depression (n = 76), MAIA-BL partially mediated MTPC-API (CI=0.02-0.87). With moderate-to-severe depression (n = 132), MAIA-T partially mediated MTPC-API (CI=0.01-0.85). Interoceptive appreciation helps people listen to motivating bodily signals. In depression, regaining body trust may be an important step on a mindful path towards change.

Beyond Dehumanized Gender Identity: Critical Reflection on Neuroscience, Power Relationship and Law

The gender movement comprising feminist and queer group movements addressed various issues of prejudices in the legal domain. This article discusses the question of power in the context of neuroscience, gender, and law. It elaborates on how the stereotypical view corresponding to the mythology and parasitic view prevalent in history was made as fact through discourse construction and scientific appropriations. Thus, identifying the simplistic psychology of one's agency, societal framing of the methods of socialization, and institutionalizing the common sense of inferiority about one's identity including the process of internalization along with the biological inferiority has maintained the gap in gender equality. The article further elaborates how gender and self-image have taken a turn with the voices of social change and critical engagement with the reified gender categories.

Interoceptive Processing in Substance Use Disorders (SUDs): From the Neuroanatomy to Insights from Computational Models and Predictive Coding Frameworks

Substance use disorders (SUDs) represent complex public health challenges characterized by a blend of genetic, cognitive, environmental, and psychosocial factors. This chapter explores the critical role of interoceptive processing - the internal sensing of physiological states - in the neurobiology and treatment of SUDs. Interoceptive dysfunctions are highlighted as central to the craving, emotional regulation, and decision-making processes that underpin addictive behaviors. The importance of the insula in sustaining drug use, particularly nicotine, underscores a broader involvement of interoceptive pathways in SUDs. Altered interoceptive processing is evident across various SUDs, where individuals demonstrate both a heightened sensitivity to drug-related cues and a diminished ability to process aversive stimuli, suggesting substantial neurobiological underpinnings that complicate treatment outcomes. Moreover, we delve into the theoretical and computational approach to understanding interoceptive processing in SUDs. This perspective utilizes a predictive coding framework, positing that the brain continuously generates and updates predictions about internal states based on sensory inputs. In SUDs, disruptions in this predictive mechanism can lead to inaccuracies in interoceptive perception, contributing significantly to the compulsive nature of drug-seeking behaviors and the challenges associated with treatment. We explore how computational models, such as Bayesian inference, provide insights into the interplay between expected and received interoceptive signals, highlighting the role of hyper-precise prior beliefs in the persistence of craving and impulsivity. This theoretical approach not only deepens our understanding of the neural and cognitive bases of addiction but also suggests novel intervention strategies. By recalibrating interoceptive predictions through targeted therapies, such as neuromodulation and mindfulness training, we can potentially restore the interoceptive accuracy, thereby offering new avenues for effective treatment of SUDs.

Linking the inner and outer mental representations of the body to social cognition skills: A systematic review and meta-analysis

An interesting interpretation of embodiment highlights the critical role of mental body representations (BR), including motor, somatosensory, and interoceptive formats, for social cognition. However, the nature of this relationship is still debated at the empirical level, with various studies arriving at different conclusions. Here, we present a systematic review and meta-analysis aimed to summarize data from 3466 participants in 21 studies to provide a more comprehensive understanding of the relationship between inner and outer BR and social cognition. We focused on two core social cognition aspects: empathy and Theory of Mind (ToM). Concerning the inner BR, our meta-analytic findings reveal a significant correlation between specific interoceptive dimensions (i.e., interoceptive sensibility and accuracy) and social cognition, which was stronger for empathy than ToM. Conversely, although further research is needed, functional BR that mainly involve the outer body processing (i.e., nonaction-oriented BR) may show positive links with ToM. These findings point to specific interactions between BR and social cognition skills, supporting multi-faceted and embodied social cognition models. However, we also identified critical knowledge gaps and highlighted the need for further investigation to deepen our theoretical understanding of these relationships and their implications for clinical practice.

Subjective Time in Ordinary and Non-ordinary States of Consciousness: How Interoceptive Feelings Inform Us About the Passage of Time

In accordance with Bud (A.D.) Craig's theories, we maintain that ascending physiological signals in their temporal dynamics are a necessary prerequisite for human time judgments. Functional neuroimaging and psychophysiological evidence have increasingly demonstrated that the subjective judgment of time is based on the physical and emotional self. The psychological literature reveals how emotions and related body feelings shape subjective time. Empirical studies of altered states of consciousness, namely meditative states, are also of prime interest as the perception of the physical state is strongly modulated and thereby affects the subjective experience of time. Our conclusion is that the sense of time is strongly embodied.

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

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

WATSU (Water-Shiatsu) increases body awareness and improves pain and mood: A randomised controlled study

BACKGROUND AND PURPOSE

WATSU (Water-Shiatsu) is a body-oriented therapy in warm-water pool with passive movements, massage and breathing techniques. The present study investigated the short-term effect of a single session of WATSU on body awareness.

MATERIALS AND METHODS

In a randomized-controlled study 60 volunteers (18-65 years) were assigned to a 20-min intervention of WATSU or to a 20-min lecture on WATSU. Immediately before and after the intervention they had to answer questionnaires. Primary endpoint of the investigation was the change of the total score of the non-verbal Awareness Body Chart (ABC). Secondary endpoints were the changes of the scores of the 14 single body parts of the ABC, of the Visual Analogue Pain Scale, of a German self-perception questionnaire (KEKS) and changes in mood scored with a German questionnaire on mood (Bf-SR). To compare groups, Mann-Whitney U tests were used.

RESULTS

The WATSU group had a significantly higher increase in the ABC total score in comparison to the lecture group (WATSU: 0.3 (IQR 0 - 0.8), lecture: 0.1 (IQR -0.2 - 0.2), p = 0.014). In the KEKS no group differences were seen. In WATSU a significantly stronger improvement of pain (Visual Analogue Pain Scale: WATSU: -15 (IQR -29 to -8), lecture: -4 (IQR -9 - 2), p < 0.001) and of mood (Bf-SR: WATSU: -6 (IQR -14 to -2), lecture: -1 (IQR -5 - 1), p = 0.003) could be observed.

CONCLUSION

This study showed that WATSU immediately increases body awareness and improves pain and mood.

Effects of unconscious tactile stimuli on autonomic nervous activity and afferent signal processing

Autonomic nervous system (ANS) is a mechanism that regulates our internal environment. In recent years, the interest in how tactile stimuli presented directly to the body affect ANS function and cortical processing in humans has been renewed. However, it is not yet clear how subtle tactile stimuli below the level of consciousness affect human heart rate and cortical processing. To examine this, subthreshold electrical stimuli were presented to the left forearm of 43 participants during an image-viewing task, and electrocardiogram (ECG) and electroencephalogram (EEG) data were collected. The changes in the R-wave interval of the ECG immediately after the subthreshold electrical presentation and heartbeat-evoked potential (HEP), the afferent signal processing of cardiac activity, were measured. The results showed that heart rate decelerated immediately after the presentation of subthreshold electrical stimuli. The HEP during stimulus presentation was amplified for participants with greater heart rate acceleration immediately after this deceleration. The magnitude of these effects depended on the type of the subthreshold tactile stimuli. The results suggest that even with subthreshold stimulation, the changes in autonomic activity associated with orienting response and related afferent signal processing differ depending on the clarity of the tactile stimuli.

Interoceptive and Bodily Processing in Prospective and Retrospective Timing

This chapter reviews some directions along which Craig's proposal of subjective time as emergent from interoceptive and bodily dynamics allows to frame recent findings on prospective and retrospective time processing. Behavioral and neuroimaging evidence from prospective timing studies demonstrates that an interoceptive-insular system may support the development of a primary representation of time in the context of large-scale networks involved in duration processing. Studies showing a tight link between episodic memory and interoceptive, emotional, and sensorimotor states further provide insights on processes supporting retrospective timing. These lines of evidence show that acknowledging its dependence on bodily states is most likely a crucial step toward a mechanistic understanding of time perception.

How Bud Craig's Insights Reshape the Research on Pain and Mind-Body Therapies

With his elegant studies, Bud Craig determined the structural neural basis for interoception and critically expanded our conceptual understanding of it. Importantly, he placed pain in the framework of interoception and redefined pain as a homeostatic emotion. Craig understood emotions and pain as experiences based on inferential brain processes within the theoretical model of prediction processing. This chapter aims to give a brief overview of relevant research. Mind-body therapies, such as meditation, mindfulness, yoga, Tai Chi, and others, are included as first-line non-pharmacological approaches in clinical guidelines for the management of chronic pain. Craig's groundbreaking work provided the background for our contemporary understanding of mind-body therapies and for the key role that interoceptive processes play in these therapies as they apply to a wide range of clinical conditions, including pain. This chapter reviews the tremendous influence that Craig's work had on the current state of research on mind-body therapies for managing chronic pain and how it led to new directions for cutting-edge clinical and neuroscientific research.

Enhancing interoceptive sensibility through exteroceptive-interoceptive sensory substitution

Exploring a novel approach to mental health technology, this study illuminates the intricate interplay between exteroception (the perception of the external world), and interoception (the perception of the internal world). Drawing on principles of sensory substitution, we investigated how interoceptive signals, particularly respiration, could be conveyed through exteroceptive modalities, namely vision and hearing. To this end, we developed a unique, immersive multisensory environment that translates respiratory signals in real-time into dynamic visual and auditory stimuli. The system was evaluated by employing a battery of various psychological assessments, with the findings indicating a significant increase in participants' interoceptive sensibility and an enhancement of the state of flow, signifying immersive and positive engagement with the experience. Furthermore, a correlation between these two variables emerged, revealing a bidirectional enhancement between the state of flow and interoceptive sensibility. Our research is the first to present a sensory substitution approach for substituting between interoceptive and exteroceptive senses, and specifically as a transformative method for mental health interventions, paving the way for future research.

Hepatic interoception in health and disease

The liver is a large organ with crucial functions in metabolism and immune defense, as well as blood homeostasis and detoxification, and it is clearly in bidirectional communication with the brain and rest of the body via both neural and humoral pathways. A host of neural sensory mechanisms have been proposed, but in contrast to the gut-brain axis, details for both the exact site and molecular signaling steps of their peripheral transduction mechanisms are generally lacking. Similarly, knowledge about function-specific sensory and motor components of both vagal and spinal access pathways to the hepatic parenchyma is missing. Lack of progress largely owes to controversies regarding selectivity of vagal access pathways and extent of hepatocyte innervation. In contrast, there is considerable evidence for glucose sensors in the wall of the hepatic portal vein and their importance for glucose handling by the liver and the brain and the systemic response to hypoglycemia. As liver diseases are on the rise globally, and there are intriguing associations between liver diseases and mental illnesses, it will be important to further dissect and identify both neural and humoral pathways that mediate hepatocyte-specific signals to relevant brain areas. The question of whether and how sensations from the liver contribute to interoceptive self-awareness has not yet been explored.

The insula: Leveraging cellular and systems-level research to better understand its roles in health and schizophrenia

Schizophrenia is a highly heterogeneous disorder characterized by a multitude of complex and seemingly non-overlapping symptoms. The insular cortex has gained increasing attention in neuroscience and psychiatry due to its involvement in a diverse range of fundamental human experiences and behaviors. This review article provides an overview of the insula's cellular and anatomical organization, functional and structural connectivity, and functional significance. Focusing on specific insula subregions and using knowledge gained from humans and preclinical studies of insular tracings in non-human primates, we review the literature and discuss the functional roles of each subregion, including in somatosensation, interoception, salience processing, emotional processing, and social cognition. Building from this foundation, we then extend these findings to discuss reported abnormalities of these functions in individuals with schizophrenia, implicating insular involvement in schizophrenia pathology. This review underscores the insula's vast role in the human experience and how abnormal insula structure and function could result in the wide-ranging symptoms observed in schizophrenia.

DRD2 TaqIA polymorphism-related functional connectivity between anterior insula and dorsolateral prefrontal cortex predicts the retention time in heroin-dependent individuals under methadone maintenance treatment

BACKGROUND

Dopamine receptor D2 (DRD2) TaqIA polymorphism has an influence on addiction treatment response and prognosis by mediating brain dopaminergic system efficacy. Insula is crucial for conscious urges to take drugs and maintain drug use. However, it remains unclear about the contribution of DRD2 TaqIA polymorphism to the regulation of insular on addiction behavioral and its relation with the therapeutic effect of methadone maintenance treatment (MMT).

METHODS

57 male former heroin dependents receiving stable MMT and 49 matched male healthy controls (HC) were enrolled. Salivary genotyping for DRD2 TaqA1 and A2 alleles, brain resting-state functional MRI scan and a 24-month follow-up for collecting illegal-drug-use information was conducted and followed by clustering of functional connectivity (FC) patterns of HC insula, insula subregion parcellation of MMT patients, comparing the whole brain FC maps between the A1 carriers and non-carriers and analyzing the correlation between the genotype-related FC of insula sub-regions with the retention time in MMT patients by Cox regression.

RESULTS

Two insula subregions were identified: the anterior insula (AI) and the posterior insula (PI) subregion. The A1 carriers had a reduced FC between the left AI and the right dorsolateral prefrontal cortex (dlPFC) relative to no carriers. And this reduced FC was a poor prognostic factor for the retention time in MMT patients.

CONCLUSION

DRD2 TaqIA polymorphism affects the retention time in heroin-dependent individuals under MMT by mediating the functional connectivity strength between left AI and right dlPFC, and the two brain regions are promising therapeutic targets for individualized treatment.

Neural correlates of mindfulness meditation and hypnosis on magnetic resonance imaging: similarities and differences. A scoping review

BACKGROUND

Mindfulness meditation (MM) and hypnosis practices are gaining interest in mental health, but their physiological mechanisms remain poorly understood. This study aimed to synthesize the functional, morphometric and metabolic changes associated with each practice using magnetic resonance imaging (MRI), and to identify their similarities and differences.

METHODS

MRI studies investigating MM and hypnosis in mental health, specifically stress, anxiety, and depression, were systematically screened following PRISMA guidelines from four research databases (PubMed, Web of Science, Embase, PsycINFO) between 2010 and 2022.

RESULTS

In total, 97 references met the inclusion criteria (84 for MM and 13 for hypnosis). This review showed common and divergent points regarding the regions involved and associated brain connectivity during MM practice and hypnosis. The primary commonality between mindfulness and hypnosis was decreased default mode network intrinsic activity and increased central executive network - salience network connectivity. Increased connectivity between the default mode network and the salience network was observed in meditative practice and mindfulness predisposition, but not in hypnosis.

CONCLUSIONS

While MRI studies provide a better understanding of the neural basis of hypnosis and meditation, this review underscores the need for more rigorous studies.

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

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

A spontaneous dissociative episode during an EEG experiment

A depersonalization episode occurred unexpectedly during an electroencephalogram (EEG) recording for a study. Experience reports tracked the time course of this event and, in conjunction, with EEG data, were analyzed. The source activity across canonical frequency bands was analyzed across four periods ended by retrospective experience reports (depersonalization was reported in the 2nd period). Delta and theta decreases occurred across all time periods with no relation to reported events. Theta and alpha increases occurred in right secondary visual areas following depersonalization, which also coincided with surges in beta and gamma. The largest increases occurred in bilateral fronto-polar and medial prefrontal cortex, followed by inferior left lateral fronto-insula-temporal cortices and right secondary visual cortex. A high frequency functional network with a principal hub in left insula closely overlapped inferior left cortical gamma band-power increases. Bilateral frontal increases in gamma are consistent with studies of dissociation. We interpret gamma and later beta, alpha, and theta band increases as arising from the generation of visual priors, in the absence of precise visual signals, which constrain interoceptive and proprioceptive predictions to reestablish a stable sense of physiological-self. Beta showed local increases following the pattern of gamma but showed no changes in functional connectivity.

Connected minds in disconnected bodies: Exploring the role of interoceptive sensibility and alexithymia in problematic use of the internet

INTRODUCTION

The ever-increasing prominence of the internet and digital technology in our society requires a deeper examination of how these developments alter perception of our bodies and emotions. One such consequence is the emergence of Problematic Use of the Internet (PUI) - an array of compulsive or addictive behaviors mediated by the web that detrimentally affect an individual's functioning. This suggests that some people may be shifting their consciousness from the physical realm to the digital world. The objective of this study was to investigate how shortcomings in interoception (the sensibility to bodily signals) and alexithymia (an inability to identify and express emotions) might contribute to PUI.

METHODS

The Internet Addiction Test (IAT), the Toronto Alexithymia Scale (TAS-20), and the Multidimensional Assessment of Interoceptive Awareness (MAIA) were used to assess a sample of 1076 adolescents and young adults aged between 16 and 26 years via an online survey. Data analysis was based on t-test, correlations and multivariate regression.

RESULTS

26.8% (n = 288) of participants met the criteria for moderate PUI. Individuals with PUI displayed higher levels of alexithymia (p < 0.001) and diminished abilities in certain aspects of interoceptive sensibility, including placing trust in their own bodily signals (p = 0.006), not responding excessively to uncomfortable sensations with worry (p < 0.001), and not denying them (p = 0.006). Multivariate modelling revealed associations between PUI and the following factors: having a boyfriend/girlfriend (aOR = 5.70), substance use (aOR = 1.78), difficulty in identifying feelings (aOR = 1.09), externally oriented thinking (aOR = 1.05), low disposition in perceiving body sensations (aOR = 0.25), tendency to become distracted (aOR = 0.82) or excessively worried (aOR = 0.11) in the face of pain. Furthermore, the analysis indicated how these aspects of body perception may be interrelated, either enhancing or reducing the risk of PUI when examined individually, collectively, or in combination.

CONCLUSIONS

This study underlines the potential connection between difficulties in the mind-body interaction and the development of PUI. It suggests a bidirectional relationship between excessive digital device use and distorted bodily interoceptive processes in PUI, reinforcing the notion that individuals struggling with emotion identification and expression may be more prone to excessive internet usage. To further comprehend the relevance of these constructs in PUI, it is necessary to conduct more targeted investigations and longitudinal studies.

Thermosensation and emotion: Thermosensory accuracy in a dynamic thermal matching task is linked to depression and anxiety symptomatology

Interoception is related to the generation of bodily feelings and the awareness of ourselves as 'sentient beings', informing the organism about its bodily needs to guarantee survival. Previous studies have reported links among interoception, emotion processing, and mental health. For example, the alignment of interoceptive dimensions (i.e., accuracy, sensibility, awareness) can predict emotional symptoms, such as anxiety. Here, we aimed to investigate the relationship between the perception of a certain type of skin-mediated interoceptive signal, i.e., thermosensation, and self-reported depression, anxiety, and stress. One hundred seventy participants completed the Depression Anxiety Stress Scale (DASS-21) and a dynamic thermal matching task, a static temperature detection task, and a heartbeat counting task. Our results revealed that self-reported anxiety and depression were related to the perception of temperature on hairy and non-hairy skin, respectively: higher anxiety was related to better performance on the thermal matching task on the forearm, while higher depression was related to poorer performance on dynamic and static temperature tasks on the palm. Discrepancies between thermosensory accuracy and sensibility measures ('trait prediction error') were related to heightened anxiety, in line with previous studies. No significant correlations were found between DASS-21 scores and heartbeat counting accuracy. In conclusion, this study suggests that individual differences in thermosensory perception in different areas of the body are associated with self-reported anxiety and depression.

Sensory spinal interoceptive pathways and energy balance regulation

Interoception plays an important role in homeostatic regulation of energy intake and metabolism. Major interoceptive pathways include gut-to-brain and adipose tissue-to brain signaling via vagal sensory nerves and hormones, such as leptin. However, signaling via spinal sensory neurons is rapidly emerging as an additional important signaling pathway. Here we provide an in-depth review of the known anatomy and functions of spinal sensory pathways and discuss potential mechanisms relevant for energy balance homeostasis in health and disease. Because sensory innervation by dorsal root ganglia (DRG) neurons goes far beyond vagally innervated viscera and includes adipose tissue, skeletal muscle, and skin, it is in a position to provide much more complete metabolic information to the brain. Molecular and anatomical identification of function specific DRG neurons will be important steps in designing pharmacological and neuromodulation approaches to affect energy balance regulation in disease states such as obesity, diabetes, and cancer.

The self and our perception of its synchrony - Beyond internal and external cognition

The self is the core of our mental life which connects one's inner mental life with the external perception. Since synchrony is a key feature of the biological world and its various species, what role does it play for humans? We conducted a large-scale psychological study (n = 1072) combining newly developed visual analogue scales (VAS) for the perception of synchrony and internal and external cognition complemented by several psychological questionnaires. Overall, our findings showed close connection of the perception of synchrony of the self with both internal (i.e., body and cognition) and external (i.e., others, environment/nature) synchrony being associated positively with adaptive and negatively with maladaptive traits of self. Moreover, we have demonstrated how external (i.e., life events like the COVID-19 pandemic) variables modulate the perception of the self's internal-external synchrony. These findings suggest how synchrony with self plays a central role during times of uncertainty.

Depth and hierarchies in the predictive brain: From reaction to action

The human brain is a prediction device, a view widely accepted in neuroscience. Prediction is a rational and efficient response that relies on the brain's ability to create and employ generative models to optimize actions over unpredictable time horizons. We argue that extant predictive frameworks while compelling, have not explicitly accounted for the following: (a) The brain's generative models must incorporate predictive depth (i.e., rely on degrees of abstraction to enable predictions over different time horizons); (b) The brain's implementation scheme to account for varying predictive depth relies on dynamic predictive hierarchies formed using the brain's functional networks. We show that these hierarchies incorporate the ascending processes (driven by reaction), and the descending processes (related to prediction), eventually driving action. Because they are dynamically formed, predictive hierarchies allow the brain to address predictive challenges in virtually any domain. By way of application, we explain how this framework can be applied to heretofore poorly understood processes of human behavioral thermoregulation. Although mammalian thermoregulation has been closely tied to deep brain structures engaged in autonomic control such as the hypothalamus, this narrow conception does not translate well to humans. In addition to profound differences in evolutionary history, the human brain is bestowed with substantially increased functional complexity (that itself emerged from evolutionary differences). We argue that behavioral thermoregulation in humans is possible because, (a) ascending signals shaped by homeostatic sub-networks, interject with (b) descending signals related to prediction (implemented in interoceptive and executive sub-networks) and action (implemented in executive sub-networks). These sub-networks cumulatively form a predictive hierarchy for human thermoregulation, potentiating a range of viable responses to known and unknown thermoregulatory challenges. We suggest that our proposed extensions to the predictive framework provide a set of generalizable principles that can further illuminate the many facets of the predictive brain. This article is categorized under: Neuroscience > Behavior Philosophy > Action Psychology > Prediction.

I Feel! Therefore, I Am from Pain to Consciousness in DOC Patients

Pain assessment and management in patients with disorders of consciousness (DOC) is a challenging and important aspect of care, with implications for detecting consciousness and promoting recovery. This narrative review explores the role of pain in consciousness, the challenges of pain assessment, pharmacological treatment in DOC, and the implications of pain assessment when detecting changes in consciousness. The review discusses the Nociception Coma Scale and its revised version, which are behavioral scales used to assess pain in DOC patients, and the challenges and controversies surrounding the appropriate pharmacological treatment of pain in these patients. Moreover, we highlight recent evidence suggesting that an accurate pain assessment may predict changes in the level of consciousness in unresponsive wakefulness syndrome/vegetative state patients, underscoring the importance of ongoing pain management in these patients.

Singing training predicts increased insula connectivity with speech and respiratory sensorimotor areas at rest

The insula contributes to the detection of salient events during goal-directed behavior and participates in the coordination of motor, multisensory, and cognitive systems. Recent task-fMRI studies with trained singers suggest that singing experience can enhance the access to these resources. However, the long-term effects of vocal training on insula-based networks are still unknown. In this study, we employed resting-state fMRI to assess experience-dependent differences in insula co-activation patterns between conservatory-trained singers and non-singers. Results indicate enhanced bilateral anterior insula connectivity in singers relative to non-singers with constituents of the speech sensorimotor network. Specifically, with the cerebellum (lobule V-VI) and the superior parietal lobes. The reversed comparison showed no effects. The amount of accumulated singing training predicted enhanced bilateral insula co-activation with primary sensorimotor areas representing the diaphragm and the larynx/phonation area-crucial regions for cortico-motor control of complex vocalizations-as well as the bilateral thalamus and the left putamen. Together, these findings highlight the neuroplastic effect of expert singing training on insula-based networks, as evidenced by the association between enhanced insula co-activation profiles in singers and the brain's speech motor system components.

Neurophysiological and Psychosocial Mechanisms of Fibromyalgia: A Comprehensive Review and Call for An Integrative Model

Research into the neurobiological and psychosocial mechanisms involved in fibromyalgia has progressed remarkably in recent years. Despite this, current accounts of fibromyalgia fail to capture the complex, dynamic, and mutual crosstalk between neurophysiological and psychosocial domains. We conducted a comprehensive review of the existing literature in order to: a) synthesize current knowledge on fibromyalgia; b) explore and highlight multi-level links and pathways between different systems; and c) build bridges connecting disparate perspectives. An extensive panel of international experts in neurophysiological and psychosocial aspects of fibromyalgia discussed the collected evidence and progressively refined and conceptualized its interpretation. This work constitutes an essential step towards the development of a model capable of integrating the main factors implicated in fibromyalgia into a single, unified construct which appears indispensable to foster the understanding, assessment, and intervention for fibromyalgia.

Me, Myself and My Insula: An Oasis in the Forefront of Self-Consciousness

The insula is a multiconnected brain region that centralizes a wide range of information, from the most internal bodily states, such as interoception, to high-order processes, such as knowledge about oneself. Therefore, the insula would be a core region involved in the self networks. Over the past decades, the question of the self has been extensively explored, highlighting differences in the descriptions of the various components but also similarities in the global structure of the self. Indeed, most of the researchers consider that the self comprises a phenomenological part and a conceptual part, in the present moment or extending over time. However, the anatomical substrates of the self, and more specifically the link between the insula and the self, remain unclear. We conducted a narrative review to better understand the relationship between the insula and the self and how anatomical and functional damages to the insular cortex can impact the self in various conditions. Our work revealed that the insula is involved in the most primitive levels of the present self and could consequently impact the self extended in time, namely autobiographical memory. Across different pathologies, we propose that insular damage could engender a global collapse of the self.

Microstates imbalance is associated with a functional dysregulation of the resting-state networks in obsessive-compulsive disorder: a high-density electrical neuroimaging study using the TESS method

The dysfunctional patterns of microstates dynamics in obsessive-compulsive disorder (OCD) remain uncertain. Using high-density electrical neuroimaging (EEG) at rest, we explored microstates deterioration in OCD and whether abnormal microstates patterns are associated with a dysregulation of the resting-state networks interplay. We used EEG microstates analyses, TESS method for sources reconstruction, and General Linear Models to test for the effect of disease severity on neural responses. OCD patients exhibited an increased contribution and decreased duration of microstates C and D, respectively. Activity was decreased in the Salience Network (SN), associated with microstate C, but increased in the Default Mode Network (DMN) and Executive Control Network (ECN), respectively, associated with microstates E and D. The hyperactivity of the right angular gyrus in the ECN correlated with the symptoms severity. The imbalance between microstates C and D invalidates the hypothesis that this electrophysiological pattern is specific to psychosis. Demonstrating that the SN-ECN dysregulation manifests as abnormalities in microstates C and D, we confirm that the SN deterioration in OCD is accompanied by a failure of the DMN to deactivate and aberrant compensatory activation mechanisms in the ECN. These abnormalities explain typical OCD clinical features but also detachment from reality, shared with psychosis.

Learning from errors: Distinct neural networks for monitoring errors and maintaining corrects through repeated practice and feedback

How memory representations are eventually established and maintained in the brain is one of central issues in memory research. Although the hippocampus and various brain regions have been shown to be involved in learning and memory, how they coordinate to support successful memory through errors is unclear. In this study, a retrieval practice (RP) - feedback (FB) paradigm was adopted to address this issue. Fifty-six participants (27 in the behavioral group, and 29 in the fMRI group) learned 120 Swahili-Chinese words associations and underwent two RP-answer FB cycles (i.e., RP1, FB1, RP2, FB2). The responses of the fMRI group were recorded in the fMRI scanner. The trials were divided based on participant's performance (correct or incorrect, C or I) during the two RPs and the final test (i.e., trial type, CCC, ICC, IIC III). The results showed that the regions in the salience and executive control networks (S-ECN) during RP, but not during FB, was strongly predictive of final successful memory. Their activation was just before the errors were corrected (i.e., RP1 in ICC trials and RP2 in IIC trials). The anterior insula (AI) is a core region in monitoring repeated errors, and it had differential connectivity with the default mode network (DMN) regions and the hippocampus during the RP and FB phases to inhibit incorrect answers and update memory. In contrast, maintaining corrected memory representation requires repeated RP and FB, which was associated with the DMN activation. Our study clarified how different brain regions support error monitoring and memory maintenance through repeated RP and FB, and emphasized the role of the insula in learning from errors.

Cortical oscillatory changes during thermal grill illusion

OBJECTIVE

The thermal grill illusion (TGI) can cause a burning pain sensation when the skin is subjected to simultaneously harmless hot and cold stimuli, and the pain is reported to be similar to central neuropathic pain. Although electroencephalography (EEG) is commonly used in pain research, no reports have revealed EEG activity during TGI.

METHODS

One healthy subject was enrolled, and EEG activity was recorded during the experience of the TGI and a warm sensation. Independent component analysis (ICA) was applied to preprocessed EEG data, which was divided into several clusters.

RESULTS

Theta and alpha bands in the insular cortex and parietal operculum clusters were significantly more desynchronized under the TGI condition than under the warm condition ( P  < 0.05). Additionally, theta, alpha and beta bands in the frontal (middle and inferior frontal gyrus) cluster showed significantly more desynchronization under the TGI condition than under the warm condition ( P  < 0.05).

CONCLUSION

EEG oscillations in these brain areas could be useful markers of central neuropathic pain.

How distinct functional insular subdivisions mediate interacting neurocognitive systems

Recent neurocognitive models propose that the insula serves as a hub of interoceptive awareness system, modulating 2 interplaying neurocognitive systems: The posterior insula (PI) receives and integrates various interoceptive signals; these signals are then transmitted to the anterior insula for processing higher-order representations into awareness, where the dorsal anterior insula (dAI) modulates the prefrontal self-control system and the ventral anterior insula (vAI) modulates the amygdala (AMG)-striatal reward-seeking circuit. We sought to test this view using a multimodal approach. We first used a resting-state functional magnetic resonance imaging (fMRI) approach with a sample of 120 undergraduate students. Then, we unpacked the neuro-cognitive association between insular connectivity and cognitive performance during an Iowa gambling fMRI task. Lastly, an independent Open Southwest University Longitudinal Imaging Multimodal dataset was used to validate the results. Findings suggested that the dAI was predominantly connected to the prefrontal regions; the vAI was primarily connected to the AMG-ventral-striatum system; and the PI was mainly connected to the visceral-sensorimotor system. Moreover, cognitive scores were positively correlated with FC between dAI and the self-control process of ventrolateral prefrontal cortex and were negatively correlated with FC between vAI and the reward-seeking process of orbitofrontal cortex and subgenual anterior cingulate cortex. The findings highlight the roles of our theorized subinsular functionality in the overall operation of the neural cognitive systems.

Neural substrates of interoceptive sensibility: An integrated study in normal and pathological functioning

In early studies interoception strictly referred to the awareness of visceral sensations, but recent theories have expanded this concept to denote the ongoing status of the body, including somatosensory feelings. Here, we integrated data from normal and pathological functioning to disclose neural underpinnings of interoceptive sensibility, taking into account the crucial distinction between visceral and somatosensory feelings. Twenty-seven healthy young individuals underwent structural MRI (including T1w images and DTI). Voxel-wise analyses of the gyrification index (GI) and fractional anisotropy (FA) data were performed to assess the relation between interoceptive sensibility and surface morphometry and anatomical connectivity. Thirty-three unilateral brain-damaged patients took part in this study for Voxel-Based Lesion-Symptom Mapping (VLSM) and track-wise hodological lesion-deficit analysis (TWH). All participants completed the Self-Awareness Questionnaire (SAQ), a self-report tool assessing interoceptive sensibility of visceral (F1) and somatosensory feelings (F2). Tract-Based Spatial Statistics showed that F2 was positively associated with FA in the bilateral anterior thalamic radiation, corticospinal tract, cingulum, forceps, inferior longitudinal, fronto-occipital, superior longitudinal, and uncinate fasciculi; no significant association was detected for F1. However, F1 was positively associated with GI in the left anterior cingulate cortex. VLSM showed that F1 mainly relies on the right posterior insula, whereas F2 is related mostly to subcortical nuclei and surrounding white matter in the right hemisphere. Accordingly, patients with disconnection of the anterior thalamic projection, corticospinal tract, inferior fronto-occipital, inferior longitudinal, uncinate and superior longitudinal fasciculus III showed lower scores on F2. Overall, results support the dissociation between interoceptive sensibility of visceral and somatosensory feelings.

Integration of structural MRI and epigenetic analyses hint at linked cellular defects of the subventricular zone and insular cortex in autism: Findings from a case study

Introduction

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction, communication and repetitive, restrictive behaviors, features supported by cortical activity. Given the importance of the subventricular zone (SVZ) of the lateral ventrical to cortical development, we compared molecular, cellular, and structural differences in the SVZ and linked cortical regions in specimens of ASD cases and sex and age-matched unaffected brain.

Methods

We used magnetic resonance imaging (MRI) and diffusion tractography on ex vivo postmortem brain samples, which we further analyzed by Whole Genome Bisulfite Sequencing (WGBS), Flow Cytometry, and RT qPCR.

Results

Through MRI, we observed decreased tractography pathways from the dorsal SVZ, increased pathways from the posterior ventral SVZ to the insular cortex, and variable cortical thickness within the insular cortex in ASD diagnosed case relative to unaffected controls. Long-range tractography pathways from and to the insula were also reduced in the ASD case. FACS-based cell sorting revealed an increased population of proliferating cells in the SVZ of ASD case relative to the unaffected control. Targeted qPCR assays of SVZ tissue demonstrated significantly reduced expression levels of genes involved in differentiation and migration of neurons in ASD relative to the control counterpart. Finally, using genome-wide DNA methylation analyses, we identified 19 genes relevant to neurological development, function, and disease, 7 of which have not previously been described in ASD, that were significantly differentially methylated in autistic SVZ and insula specimens.

Conclusion

These findings suggest a hypothesis that epigenetic changes during neurodevelopment alter the trajectory of proliferation, migration, and differentiation in the SVZ, impacting cortical structure and function and resulting in ASD phenotypes.

A neurophenomenological approach to non-ordinary states of consciousness: hypnosis, meditation, and psychedelics

No contemporary unifying framework has been provided for the study of non-ordinary states of consciousness (NSCs) despite increased interest in hypnosis, meditation, and psychedelics. NSCs induce shifts in experiential contents (what appears to the experiencer) and/or structure (how it appears). This can allow the investigation of the plastic and dynamic nature of experience from a multiscale perspective that includes mind, brain, body, and context. We propose a neurophenomenological (NP) approach to the study of NSCs which highlights their role as catalysts of transformation in clinical practice by refining our understanding of the relationships between experiential (subjective) and neural dynamics. We outline the ethical implications of the NP approach for standard conceptions of health and pathology as well as the crucial role of experience-based know-how in NSC-related research and application.

The influence of high worry on static and dynamic insular functional connectivity

Worry is a form of repetitive negative thought. High worry-proneness is one risk factor leading to anxiety disorder. Several types of research indicated that anxiety disorder was highly associated with disrupted interoception. The insula is consistently considered to play a key role in interoception. However, the relationship between worry and the interoception network is poorly investigated in worry-prone individuals. Thus, it is essential to identify the neural characteristic of high worry-proneness subjects. A total of 32 high worry-proneness (HWP) subjects and 25 low worry-proneness (LWP) subjects were recruited and underwent magnetic resonance imaging scanning. Six subregions of insula were chosen as regions of interest. Then, seed-based static and dynamic functional connectivity were calculated. Increased static functional connectivity was observed between the ventral anterior insula and inferior parietal lobule in HWP compared to LWP. Decreased static functional connectivity was found between the left ventral anterior insula and the pregenual anterior cingulate cortex. Decreased dynamic functional connectivity was also shown between the right posterior insula and the inferior parietal lobule in HWP. Moreover, a post-hoc test exploring the effect of changed function within the insular region confirmed that a significant positive relationship between static functional connectivity (ventral anterior insula-inferior parietal lobule) and dynamic functional connectivity (posterior insula-inferior parietal lobule) in LWP but not in HWP. Our results might suggest that deficient insular function may be an essential factor related to high worry in healthy subjects.

The Role of the Skin in Interoception: A Neglected Organ?

In the past 2 decades, interoception has received increasing attention in the fields of psychology and cognitive science, as well as neuroscience and physiology. A plethora of studies adopted the perception of cardiac signals as a proxy for interoception. However, recent findings have cast doubt on the methodological and intrinsic validity of the tasks used thus far. Therefore, there is an ongoing effort to improve the existing cardiac interoceptive tasks and to identify novel channels to target the perception of the physiological state of the body. Amid such scientific abundancy, one could question whether the field has been partially neglecting one of our widest organs in terms of dimensions and functions: the skin. According to some views grounded on anatomical and physiological evidence, skin-mediated signals such as affective touch, pain, and temperature have been redefined as interoceptive. However, there is no agreement in this regard. Here, we discuss some of the anatomical, physiological, and experimental arguments supporting the scientific study of interoception by means of skin-mediated signals. We argue that more attention should be paid to the skin as a sensory organ that monitors the bodily physiological state and further propose thermosensation as a particularly attractive model of skin-mediated interoception.

Imitation encourages empathic capacity toward other individuals with physical disabilities

Many people have difficulty empathizing with others who have dissimilar characteristics, such as physical disabilities. We hypothesized that people with no disabilities imitating the movements of individuals with disabilities could improve the empathic capacity toward their difficulties. To evaluate this hypothesis, we used functional magnetic resonance imaging to measure the neural activity patterns of 26 healthy participants while they felt the difficulties of individuals with hemiplegia by adopting their perspective. The participants initially either imitated or observed hemiplegic hand movements shown in video clips. Subsequently, the videos were rewatched and their difficulties were rated. Analysis of the subjective rating scores indicated that after imitating the hemiplegic movements, the participants felt into the difficulties of hemiplegia better than if they simply observed them. The cross-validation approach of multivoxel pattern analyses demonstrated that the information regarding the effect of imitation on empathizing with the difficulties was represented in specific activation patterns of brain regions involved in the mirror neuron system and cognitive empathy by comparing to other conditions that did not contain the information. The cross-classification approach detected distinct activation patterns in the brain regions involved in affective and cognitive empathy, commonly while imitating the hemiplegic movements and subsequently feeling them. This indicated that the common representation related to these two types of empathy existed between imitating and feeling the hemiplegic movements. Furthermore, representational similarity analysis revealed that activity patterns in the anterior cingulate cortex linked to affective empathy tuned to the subjective assessment of hemiplegic movements. Our findings indicate that imitating the movements of individuals with hemiplegia triggered the affective empathic response and improved the cognitive empathic response toward them. The affective empathic response also linked the subjective assessment to the difficulties of hemiplegia, which was especially modulated by the experience of imitation. Imitating the movements of individuals with disabilities likely encourages empathic capacity from both affective and cognitive aspects, resulting in people with no disabilities precisely feeling what they are feeling.

Motor awareness: a model based on neurological syndromes

Motor awareness is a complex, multifaceted construct involving the awareness of both (i) one's motor state while executing a movement or remaining still and (ii) one's motor abilities. The analysis of neurological syndromes associated with motor disorders suggests the existence of various different components which are, however, integrated into a model of motor awareness. These components are: (i) motor intention, namely, a conscious desire to perform an action; (ii) motor monitoring and error recognition, that is, the capacity to check the execution of the action and identify motor errors; and (iii) a general awareness of one's own motor abilities and deficits, that is, the capacity to recognize the general state of one's motor abilities about the performance of specific actions and the potential consequences of motor impairment. Neuroanatomical correlates involving the parietal and insular cortices, the medial and lateral frontal regions, and subcortical structures (basal ganglia and limbic system) support this multi-component model. Specific damage (or disconnections) to these structures results in a number of different disorders in motor awareness, such as anosognosia for hemiplegia and apraxia, and a number of symptoms which are specific to motor intention disorders (e.g., the Anarchic Hand Syndrome and Tourette's Syndrome) or motor monitoring (e.g., Parkinson's and Huntington's diseases). All of these clinical conditions are discussed in the light of a motor awareness model.

The nested hierarchy of self and its trauma: In search for a synchronic dynamic and topographical re-organization

The sense of self has always been a topic of high interest in both psychoanalysis and most recently in neuroscience. Nowadays, there is an agreement in psychoanalysis that the self emerges from the relationship with the other (e.g., the caregiver) in terms of his/her capacity to attune, regulate, and synchronize with the emergent self of the infant. The outcome of this relational/intersubjective synchronization is the development of the sense of self and its regulatory processes both in dynamic psychology and neuroscience. In this work, we propose that synchrony is a fundamental biobehavioral factor in these dialectical processes between self and others which shapes the brain-body-mind system of the individuals, including their sense of self. Recently in neuroscience, it has been proposed by the research group around Northoff that the self is constituted by a brain-based nested hierarchical three-layer structure, including interoceptive, proprio-exteroceptive, and mental layers of self. This may be disrupted, though, when traumatic experiences occur. Following the three levels of trauma theorized by Mucci, we here suggest how different levels of traumatic experiences might have an enduring effect in yielding a trauma-based topographic and dynamic re-organization of the nested model of self featured by dissociation. In conclusion, we propose that different levels and degrees of traumatic experience are related to corresponding disruptions in the topography and dynamic of the brain-based three-layer hierarchical structure of the self.

Spatial-topographic nestedness of interoceptive regions within the networks of decision making and emotion regulation: Combining ALE meta-analysis and MACM analysis

Prominent theories propose that interoception modulates our behavioral and emotional responses involving decision-making and emotion regulation. Are the regions implicated in interoception also spatially related to and possibly nested within the networks of decision making and emotion regulation? Addressing this question, we performed three meta-analyses of functional magnetic resonance imaging studies to identify the regions that are commonly activated by the three domains using activation likelihood estimation (ALE). Additionally, we assessed the coactivation pattern of identified common regions using meta-analytic connectivity modeling (MACM). The results showed major overlaps of interoception with both decision making and emotion regulation in specifically the right dorsal anterior insula. The pairwise contrast analyses confirmed this finding and revealed conjunction-based activities in decision making and emotion regulation in the dorsal anterior cingulate cortex (dACC). MACM based on the identified insula revealed a widespread convergent coactivation pattern with the left anterior insula, dACC, and bilateral thalamus which, together, constitute the salience network. Among these co-activated regions, bilateral insula and the dACC were shared among all three domains. These results suggest that the regions mediating interoception including intero-exteroceptive integration and salience attribution are contained and thus spatially nested within the more extensive networks recruited during decision making and emotion regulation.

Memory retrieval brain-behavior disconnection in mild traumatic brain injury: A magnetoencephalography and diffusion tensor imaging study

Mild traumatic brain (mTBI) injury is often associated with long-term cognitive and behavioral complications, including an increased risk of memory impairment. Current research challenges include a lack of cross-modal convergence regarding the underlying neural-behavioral mechanisms of mTBI, which hinders therapeutics and outcome management for this frequently under-treated and vulnerable population. We used multi-modality imaging methods including magnetoencephalography (MEG) and diffusion tensor imaging (DTI) to investigate brain-behavior impairment in mTBI related to working memory. A total of 41 participants were recruited, including 23 patients with a first-time mTBI imaged within 3 months of injury (all male, age = 29.9, SD = 6.9), and 18 control participants (all male, age = 27.3, SD = 5.3). Whole-brain statistics revealed spatially concomitant functional-structural disruptions in brain-behavior interactions in working memory in the mTBI group compared with the control group. These disruptions are located in the hippocampal-prefrontal region and, additionally, in the amygdala (measured by MEG neural activation and DTI measures of fractional anisotropy in relation to working memory performance; p < .05, two-way ANCOVA, nonparametric permutations, corrected). Impaired brain-behavior connections found in the hippocampal-prefrontal and amygdala circuits indicate brain dysregulation of memory, which may leave mTBI patients vulnerable to increased environmental demands exerting memory resources, leading to related cognitive and emotional psychopathologies. The findings yield clinical implications and highlight a need for early rehabilitation after mTBI, including attention- and sensory-based behavioral exercises.