Sense of agency during and following recovery from anorexia nervosa.

The need to feel in control is central to anorexia nervosa (AN). The sense of control in AN has only been studied through self-report. This study investigated whether implicit sense of control (sense of agency; SoA) differs across AN patients, recovered AN (RAN) patients and healthy controls (HC). Furthermore, we assessed whether state anxiety is influenced by negative emotional states. SoA was measured with the intentional binding task (IB) and state-anxiety levels through a questionnaire. We did not find any evidence of differences in SoA between groups. Furthermore, state anxiety was not a significant predictor of SoA. Further research into SoA in AN should focus on other features of the SoA that are not targeted by the IB task.

How do we relate to our heart? Neurobehavioral differences across three types of engagement with cardiac interoception.

Standard measures of interoception are typically limited to the conscious perception of heartbeats. However, the fundamental purpose of interoceptive signaling, is to regulate the body. We present a novel biofeedback paradigm to explore the neurobehavioral consequences of three different types of engagement with cardiac interoception (Attend, Feel, Regulate) while participants perform a 'cardiac recognition' task. For both the Feel and Regulate conditions, participants displayed enhanced recognition of their own heartbeat, accompanied by larger heartbeat-evoked potentials (HEPs), suggesting that these approaches could be used interchangeably. Importantly, meta-cognitive interoceptive insight was highest in the Regulate condition, indicative of stronger engagement with interoceptive signals in addition to greater ecological validity. Only in the passive interoception condition (Feel) was a significant association found between accuracy in recognising one's own heartbeat and the amplitude of HEPs. Overall, our results imply that active conditions have an important role to play in future investigation of interoception.

Interoceptive Awareness Is Negatively Related to the Exteroceptive Manipulation of Bodily Self-Location.

The perception of being located within one's body (i.e., bodily self-location) is an essential feature of everyday self-experience. However, by manipulating exteroceptive input, healthy participants can easily be induced to perceive themselves as being spatially dislocated from their physical bodies. It has previously been suggested that interoception, i.e., the processing of inner physiological signals, contributes to the stability of body representations; however, this relationship has not previously been tested for different dimensions of interoception and bodily self-location. In the present study, using an advanced automatized setup, we systematically manipulated participants' perspective of their own body (first- vs third-person perspective) as well as the synchrony of visuotactile stimulation (synchronous vs asynchronous). The malleability of bodily self-location was assessed using a questionnaire targeting in-body and out-of-body experiences. Participants also performed a heartbeat discrimination task to assess their interoceptive accuracy (behavioral performance), interoceptive sensibility (confidence in their interoceptive abilities), and interoceptive awareness (meta-cognitive representation of interoceptive signals). Bodily self-location was significantly influenced by perspective, with third-person perspective being associated with stronger out-of-body experiences compared to first-person perspective. Furthermore, there was a significant perspective × stimulation interaction, with subsequent analyses showing that participants reported out-of-body experiences particularly under third-person perspective combined with synchronous visuotactile stimulation. Correlation and regression analyses revealed that meta-cognitive interoceptive awareness was specifically and negatively related to the exteroceptively mediated malleability of body experiences. These results indicate that the perception of the self being located within one's body relies on the interaction of exteroceptive input and higher-order interoceptive abilities. This has implications for theoretical considerations about the bodily self in health as well as for the understanding of disturbed bodily self-processing in clinical contexts.

Altered Interoceptive Perception and the Effects of Interoceptive Analgesia in Musculoskeletal, Primary, and Neuropathic Chronic Pain Conditions.

Chronic pain (CP) severely disrupts the daily life of millions. Interoception (i.e., sensing the physiological condition of the body) plays a pivotal role in the aetiology and maintenance of CP. As pain is inherently an interoceptive signal, interoceptive frameworks provide important, but underutilized, approaches to this condition. Here we first investigated three facets of interoceptive perception in CP, compared with pain-free controls. We then introduce a novel interoceptive treatment and demonstrate its capacity to reduce pain severity in CP, potentially providing complementary analgesic treatments. Study 1 measured interoceptive accuracy, confidence and sensibility in patients (N = 60) with primary, secondary musculoskeletal, and neuropathic CP. Compared with matched controls, CP participants exhibited significantly lower interoceptive accuracy and interoceptive confidence. Pain severity was predicted positively by interoceptive accuracy, anxiety and depression, and negatively by interoceptive confidence. Study 2 tested a promising new interoceptive treatment for CP, in a single-blind between-subjects design (N = 51) with primary, secondary musculoskeletal, and neuropathic CP patients. The treatment specifically activates the C-Tactile system, by means of controlled stimulation of interoceptive unmyelinated afferents, at 3 cm/s with a force of 2.5 mN. This treatment led to significant pain reduction (mean 23%) in the CP treatment group after only 11 min, while CP controls who received comparable but non-interoceptive stimulation reported no change in pain intensity. These studies highlight the importance of interoceptive approaches to CP and demonstrate the potential of this novel method of C-Tactile stimulation to provide complementary analgesic treatments.

Comment on "Zamariola et al. (2018), Interoceptive Accuracy Scores are Problematic: Evidence from Simple Bivariate Correlations"-The empirical data base, the conceptual reasoning and the analysis behind this statement are misconceived and do not support the authors' conclusions.

A recent paper by Zamariola and colleagues is widely cited as an authority on the invalidity of the Heartbeat Counting Task as a measure of interoceptive accuracy. Given the widespread interest in this field, it is essential that papers about methods are conceptually sound. However, only one of the authors' four criticisms appears substantiated - that people count too few heartbeats. Their arguments about "simple bivariate correlations" and their finding that interoceptive accuracy and heart rate correlate, depend on 'spurious correlations' arising from the overlooked point that interoceptive accuracy is a ratio. Moreover, scrutiny of the authors' data shows that their fourth criticism (that interoceptive accuracy is lower on longer trials) is confounded by differences in mean heart rate between trials. We present data from our own labs to refute it. We draw the authors' and editors' attention to these issues and trust that they will reconsider these erroneous conclusions.

Working With the Predictable Life of Patients: The Importance of "Mentalizing Interoception" to Meaningful Change in Psychotherapy.

To understand our patients and optimize their treatment, psychotherapists of all theoretical orientations may benefit from considering current scientific evidence alongside psychodynamic constructs. There is recent neuroscientific evidence that subjective awareness, feelings and emotions depend upon "interoception," defined as the neural signaling to the brain from all tissues of the body. Interoception is the obvious basis of homeostasis (in the brainstem) but some interoceptive signals rise above this level and contribute to inferential processes that substantiate intrapersonal and interpersonal experience. The focus of this paper is on the essential role that their "interoception" plays in our patients' emotional experience and subjective awareness, and how the process referred to as "mentalizing interoception" may be harnessed in therapy. This can best be understood in terms of "predictive processing," which describes how subjective states, and particularly emotion, are inferred from sensory inputs - both interoceptive and exteroceptive. Predictive processing assumes that the brain infers (probabilistically) the likely cause of sensation experienced through the sense organs, by testing this sensory data against its innate and learned "priors." This implies that any effort at changing heavily over-learned prior beliefs will require action upon the system that has generated that set of prior beliefs. This involves, quite literally, acting upon the world to alter inferential processes, or in the case of interoceptive priors, acting on the patient's body to alter habitual autonomic nervous system (ANS) reflexes. Focused attention to bodily sensations/reactions, in the safety of the therapeutic relationship, provides a route to "mentalizing interoception," by means of the bodily cues that may be the only conscious element of deeply hidden priors and thus the clearest way to access them. This can: update patients' characteristic, dysfunctional responses to emotion and feelings; increase emotional insight; decrease cognitive distortions; and engender a more acute awareness of the present moment. These important ideas are outlined below from the perspective of psychodynamic psychotherapeutic practice, in order to discuss how relevant information from neuroscientific theory and current research can best be applied in clinical treatment. A clinical case will be presented to illustrate how this argument or treatment relates directly to clinical practice.

'Bodily precision': a predictive coding account of individual differences in interoceptive accuracy.

Individuals differ in their awareness of afferent information from within their bodies, which is typically assessed by a heartbeat perception measure of 'interoceptive accuracy' (IAcc). Neural and behavioural correlates of this trait have been investigated, but a theoretical explanation has yet to be presented. Building on recent models that describe interoception within the free energy/predictive coding framework, this paper applies similar principles to IAcc, proposing that individual differences in IAcc depend on 'precision' in interoceptive systems, i.e. the relative weight accorded to 'prior' representations and 'prediction errors' (that part of incoming interoceptive sensation not accounted for by priors), at various levels within the cortical hierarchy and between modalities. Attention has the effect of optimizing precision both within and between sensory modalities. Our central assumption is that people with high IAcc are able, with attention, to prioritize interoception over other sensory modalities and can thus adjust the relative precision of their interoceptive priors and prediction errors, where appropriate, given their personal history. This characterization explains key findings within the interoception literature; links results previously seen as unrelated or contradictory; and may have important implications for understanding cognitive, behavioural and psychopathological consequences of both high and low interoceptive awareness.This article is part of the themed issue 'Interoception beyond homeostasis: affect, cognition and mental health'.

Cardio-visual integration modulates the subjective perception of affectively neutral stimuli.

Interoception, which refers to the perception of internal body signals, has been consistently associated with emotional processing and with the sense of self. However, its influence on the subjective appraisal of affectively neutral and body-unrelated stimuli is still largely unknown. Across two experiments we sought to investigate this issue by asking participants to detect changes in the flashing rhythm of a simple stimulus (a circle) that could either be pulsing synchronously with their own heartbeats or following the pattern of another person's heart. While overall task performance did not vary as a function of cardio-visual synchrony, participants were better at identifying trials in which no change occurred when the flashes were synchronous with their own heartbeats. This study adds to the growing body of research indicating that we use our body as a reference point when perceiving the world; and extends this view by focusing on the role that signals coming from inside the body, such as heartbeats, may play in this referencing process. Specifically we show that private interoceptive sensations can be combined with affectively neutral information unrelated to the self to influence the processing of a multisensory percept. Results are discussed in terms of both standard multisensory integration processes and predictive coding theories.

Heartfelt empathy? No association between interoceptive awareness, questionnaire measures of empathy, reading the mind in the eyes task or the director task.

Interoception, defined as afferent information arising from within the body, is the basis of all emotional experience and underpins the 'self.' However, people vary in the extent to which interoceptive signals reach awareness. This trait modulates both their experience of emotion and their ability to distinguish 'self' from 'other' in multisensory contexts. The experience of emotion and the degree of self/other distinction or overlap are similarly fundamental to empathy, which is an umbrella term comprising affect sharing, empathic concern and perspective-taking (PT). A link has therefore often been assumed between interoceptive awareness (IA) and empathy despite a lack of clear evidence. To test the hypothesis that individual differences in both traits should correlate, we measured IA in four experiments, using a well-validated heartbeat perception task, and compared this with scores on several tests that relate to various aspects of empathy. We firstly measured scores on the Index of Interpersonal Reactivity and secondly on the Questionnaire of Cognitive and Affective Empathy. Thirdly, because the 'simulationist' account assumes that affect sharing is involved in recognizing emotion, we employed the 'Reading the Mind in the Eyes Task' for the recognition of facial expressions. Contrary to expectation, we found no significant relationships between IA and any aspect of these measures. This striking lack of direct links has important consequences for hypotheses about the extent to which empathy is necessarily embodied. Finally, to assess cognitive PT ability, which specifically requires self/other distinction, we used the 'Director Task' but found no relationship. We conclude that the abilities that make up empathy are potentially related to IA in a variety of conflicting ways, such that a direct association between IA and various components of empathy has yet to be established.

Heartfelt imitation: high interoceptive awareness is linked to greater automatic imitation.

'Interoceptive awareness', defined as the individual's awareness of internal body signals, modulates self/other distinction under conditions of multisensory integration. We examined here, for the first time, the potential impact of interoceptive awareness on self/other distinction in the motor domain. In automatic imitation, inhibition of imitation is an index of an individual's success in distinguishing internally generated motor representations from those triggered by observing another person's action. This is measured by the 'congruency effect', which is the difference between mean reaction times when the observed action is 'incongruent' with the required action and when it is 'congruent'. The present study compared the congruency effect in a typical finger lifting paradigm, with interoceptive awareness measured by heartbeat perception. Contrary to expectation, interoceptive awareness was positively correlated with the congruency effect and this effect depended on mean reaction times in the incongruent condition, indicating that good heartbeat perceivers had more difficulty inhibiting the tendency to imitate. Potentially, high interoceptive awareness involves stronger interoceptive representations of the consequences of an action, implying higher empathy, greater motor reactivity in response to observed action and hence a greater tendency to imitate. Our results may also tentatively be explained within a predictive coding account of interoception.

More of myself: manipulating interoceptive awareness by heightened attention to bodily and narrative aspects of the self.

Psychology distinguishes between a bodily and a narrative self. Within neuroscience, models of the bodily self are based on exteroceptive sensorimotor processes or on the integration of interoceptive sensations. Recent research has revealed interactions between interoceptive and exteroceptive processing of self-related information, for example that mirror self-observation can improve interoceptive awareness. Using heartbeat perception, we measured the effect on interoceptive awareness of two experimental manipulations, designed to heighten attention to bodily and narrative aspects of the self. Participants gazed at a photograph of their own face or at self-relevant words. In both experimental conditions interoceptive awareness was significantly increased, compared to baseline. Results show that attention to narrative aspects of self, previously regarded as relying on higher-order processes, has an effect similar to self-face stimuli in improving interoceptive awareness. Our findings extend the previously observed interaction between the bodily self and interoception to more abstract amodal representations of the self.

Body conscious? Interoceptive awareness, measured by heartbeat perception, is negatively correlated with self-objectification.

BACKGROUND: 'Self-objectification' is the tendency to experience one's body principally as an object, to be evaluated for its appearance rather than for its effectiveness. Within objectification theory, it has been proposed that self-objectification accounts for the poorer interoceptive awareness observed in women, as measured by heartbeat perception. Our study is, we believe, the first specifically to test this relationship. METHODOLOGY/PRINCIPAL FINDINGS: Using a well-validated and reliable heartbeat perception task, we measured interoceptive awareness in women and compared this with their scores on the Self-Objectification Questionnaire, the Self-Consciousness Scale and the Body Consciousness Questionnaire. Interoceptive awareness was negatively correlated with self-objectification. Interoceptive awareness, public body consciousness and private body consciousness together explained 31% of the variance in self-objectification. However, private body consciousness was not significantly correlated with interoceptive awareness, which may explain the many nonsignificant results in self-objectification studies that have used private body consciousness as a measure of body awareness. CONCLUSIONS/SIGNIFICANCE: We propose interoceptive awareness, assessed by heartbeat perception, as a measure of body awareness in self-objectification studies. Our findings have implications for those clinical conditions, in women, which are characterised by self-objectification and low interoceptive awareness, such as eating disorders.

Looking into myself: changes in interoceptive sensitivity during mirror self-observation.

Interoceptive sensitivity is an essential component of recent models of "the self." Increased focus on the self (e.g., self-observation in a mirror) can enhance aspects of self-processing. We examined whether self-observation also enhances interoceptive sensitivity. Participants performed a heartbeat detection task while looking at their own face in a mirror or at a black screen. There was significant improvement in interoceptive sensitivity in the mirror condition for those participants with lower interoceptive sensitivity at baseline. This effect was independent of the order of conditions, gender, age, body mass index, habitual exercise, and changes in heart rate. Our results suggest that self-observation may represent a viable way of manipulating individuals' interoceptive sensitivity, in order to directly test causal relations between interoceptive sensitivity and exteroceptive self-processing.