Bodily self recognition and autonomic correlates during social interaction: implications for Restrictive Anorexia

It is widely known that among others, the most pervasive symptoms characterizing Anorexia nervosa (AN) concern their body-image overestimation, a wide range of autonomic system disturbances, and the difficulty to discriminate their emotional states and visceral sensations. Since these pervasive symptoms largely contribute to the onset and maintenance of Eating Disorders, we investigated the nature of the body image distortion in AN (restrictive subtype), and its possible relation with Interoceptive Sensitivity (IS, the sensitivity to stimuli originating inside the body). Furthermore, since previous studies found that IS seems to contribute to the autonomic regulation of social behavior, as measured by Respiratory Sinus Arrhythmia (RSA), here we aimed at assessing the possible relation between IS and autonomic regulation both in resting state and during social interactions in AN patients, whose ability to perceive their bodily signal is impaired. For these purposes, we recorded reaction times of both healthy controls (HC) and AN patients during two tasks requiring an implicit or explicit recognition of self/other hands stimuli, in which the perceived size of the stimuli was manipulated. To assess IS, we used a widely used Heartbeat perception task. Finally, we measured participants’ autonomic reactivity, recording their RSA responses during both the resting state and a social task (Physiological proxemics task). Our results showed not only that the perceived size of hands stimuli could modulate the implicit self-recognition in HC, but also the body image distortion of AN patients, beside stemming from a disturbed body image (i.e. explicit perceptual, semantic, aesthetic and emotional representation of the body) reflects – at least partly – abnormal neural processing of the implicit and pre-reflective motor experience of the bodily self. Furthermore, we found that IS predicts the ability to execute a hand mental rotation (Implicit task: higher IS, faster RTs) but not the ability to perform a task (explicit task) in which more cognitive and/or perceptually-based mechanisms are likely involved. More importantly this relationship was lacking in AN patients, whose IS, was also significantly lower than HC. In addition, we found that IS, might be strictly related to social disposition (as measured by RSA responses at rest) since the higher was IS, the higher were RSA responses at rest. This relation was lack in AN patients, who showed significantly lower RSA at rest, and a flattened autonomic regulation during the social task compared to HC. In the light of our results, we conclude AN patients’ blunted IS might play a pivotal role in the lack of the implicit, pre-reflective sense of self as power for action leading to a less efficient self/other distinction. The lack of contact with the inner body might also account for the affected social disposition of AN patients and their autonomic regulation in social contexts

Interoception Sensitivity and Autonomic Regulation During Social Interaction in Schizophrenia

Introduction The awareness of one's body constitutes a basic experience of Self which modulates the individual engagement in social interactions. Indeed, Interoception Sensitivity (IS), an index of individual ability to represent one's own internal body states, is implicated in the autonomic regulation in interpersonal context. Schizophrenia deficits in Self-experience and awareness, which frequently entail anomalies in self-other relationship, capture the ever-growing attention of researchers. Nevertheless, IS and autonomic regulation of schizophrenic patients in social context are completely new and not yet investigated aspects of Schizophrenia. Aim To investigate whether Schizophrenia could be associated with lower IS and with a dysfunctional autonomic regulation during social interaction. Methods 24 chronic schizophrenia patients, and a matched group of healthy controls, performed a Social and a Non-social task while respiratory sinus arrhythmia (an index of autonomic regulation) was measured. In the Social task participants viewed an experimenter performing a caress-like movement at different distances from their hand. In the Non-social task a metal stick was moved at the same distances from the participants' hand. As measure of IS, a cardiac Mental Tacking Task was performed. Results Comparing to controls, Schizophrenia patients presented lower IS, absence of relation between IS and autonomic regulation, and an anomalous autonomic regulation in social and non-social contexts. Conclusions Deficits in Self-experience, associated with Schizophrenia, could be extended to patients' sensitivity to internal bodily signals. Moreover, the observed altered autonomic regulation will be part of interpersonal interaction deficit frequently associated to Schizophrenia

Pain mirrors: Neural correlates of observing self or others' facial expressions of pain

Facial expressions of pain are able to elicit empathy and adaptive behavioral responses in the observer. An influential theory posits that empathy relies on an affective mirror mechanism, according to which emotion recognition relies upon the internal simulation of motor and interoceptive states triggered by emotional stimuli. We tested this hypothesis comparing representations of self or others' expressions of pain in nineteen young healthy female volunteers by means of functional magnetic resonance imaging (fMRI). We hypothesized that one's own facial expressions are more likely to elicit the internal simulation of emotions, being more strictly related to self. Video-clips of the facial expressions of each volunteer receiving either painful or non-painful mechanical stimulations to their right hand dorsum were recorded and used as stimuli in a 2 × 2 (Self/Other; Pain/No-Pain) within-subject design. During each trial, a 2 s video clip was presented, displaying either the subject's own neutral or painful facial expressions (Self No-Pain, SNP; Self Pain, SP), or the expressions of other unfamiliar volunteers (Others' No-Pain, ONP; Others' Pain, OP), displaying a comparable emotional intensity. Participants were asked to indicate whether each video displayed a pain expression. fMRI signals were higher while viewing Pain than No-Pain stimuli in a large bilateral array of cortical areas including middle and superior temporal, supramarginal, superior mesial and inferior frontal (IFG) gyri, anterior insula (AI), anterior cingulate (ACC), and anterior mid-cingulate (aMCC) cortex, as well as right fusiform gyrus. Bilateral activations were also detected in thalamus and basal ganglia. The Self vs. Other contrast showed signal changes in ACC and aMCC, IFG, AI, and parietal cortex. A significant interaction between Self and Pain [(SP vs. SNP) > (OP vs. ONP)] was found in a pre-defined region of aMCC known to be also active during noxious stimulation. These findings demonstrate that the observation of one's own and others' facial expressions share a largely common neural network, but self-related stimuli induce generally higher activations. In line with our hypothesis, selectively greater activity for self pain-related stimuli was found in aMCC, a medial-wall region critical for pain perception and recognition

Interoception and Positive Symptoms in Schizophrenia

The present study focuses on the multifaceted concept of self-disturbance in schizophrenia, adding knowledge about a not yet investigated aspect, which is the interoceptive accuracy. Starting from the assumption that interoceptive accuracy requires an intact sense of self, which otherwise was proved to be altered in schizophrenia, the aim of the present study was to explore interoceptive accuracy in a group of schizophrenia patients, compared to healthy controls. Furthermore, the possible association between interoceptive accuracy and patients' positive and negative symptomatology was assessed. To pursue these goals, a group of 23 schizophrenia patients and a group of 23 healthy controls performed a heartbeat perception task. Patients' symptomatology was assessed by means of the Positive and Negative Syndrome Scale (PANSS). Results demonstrated significantly lower interoceptive accuracy in schizophrenia patients compared to healthy controls. This difference was not accounted for participants' age, BMI, anxiety levels, and heart rate. Furthermore, patients' illness severity, attention and pharmacological treatment did not influence their interoceptive accuracy levels. Interestingly, a strong positive relation between interoceptive accuracy and positive symptoms severity, especially Grandiosity, was found. The present results demonstrate for the first time that interoceptive accuracy is altered in schizophrenia. Furthermore, they prove a specific association between interoceptive accuracy and positive symptomatology, suggesting that the symptom Grandiosity might be protective against an altered basic sense of self in patients characterized by higher sensibility to their inner bodily sensations

Pain Mirrors: Neural Correlates of Observing Self or Others’ Facial Expressions of Pain

Facial expressions of pain are able to elicit empathy and adaptive behavioral responses in the observer. An influential theory posits that empathy relies on an affective mirror mechanism, according to which emotion recognition relies upon the internal simulation of motor and interoceptive states triggered by emotional stimuli. We tested this hypothesis comparing representations of self or others’ expressions of pain in nineteen young healthy female volunteers by means of functional magnetic resonance imaging (fMRI). We hypothesized that one’s own facial expressions are more likely to elicit the internal simulation of emotions, being more strictly related to self. Video-clips of the facial expressions of each volunteer receiving either painful or non-painful mechanical stimulations to their right hand dorsum were recorded and used as stimuli in a 2 × 2 (Self/Other; Pain/No-Pain) within-subject design. During each trial, a 2 s video clip was presented, displaying either the subject’s own neutral or painful facial expressions (Self No-Pain, SNP; Self Pain, SP), or the expressions of other unfamiliar volunteers (Others’ No-Pain, ONP; Others’ Pain, OP), displaying a comparable emotional intensity. Participants were asked to indicate whether each video displayed a pain expression. fMRI signals were higher while viewing Pain than No-Pain stimuli in a large bilateral array of cortical areas including middle and superior temporal, supramarginal, superior mesial and inferior frontal (IFG) gyri, anterior insula (AI), anterior cingulate (ACC), and anterior mid-cingulate (aMCC) cortex, as well as right fusiform gyrus. Bilateral activations were also detected in thalamus and basal ganglia. The Self vs. Other contrast showed signal changes in ACC and aMCC, IFG, AI, and parietal cortex. A significant interaction between Self and Pain [(SP vs. SNP) >(OP vs. ONP)] was found in a pre-defined region of aMCC known to be also active during noxious stimulation. These findings demonstrate that the observation of one’s own and others’ facial expressions share a largely common neural network, but self-related stimuli induce generally higher activations. In line with our hypothesis, selectively greater activity for self pain-related stimuli was found in aMCC, a medial-wall region critical for pain perception and recognition

Interoception and Autonomic Correlates during Social Interactions. Implications for Anorexia

The aim of this study is to investigate the bodily-self in Restrictive Anorexia, focusing on two basic aspects related to the bodily self: autonomic strategies in social behavior, in which others’ social desirability features, and social cues (e.g., gaze) are modulated, and interoception (i.e., the sensitivity to stimuli originating inside the body). Furthermore, since previous studies carried out on healthy individuals found that interoception seems to contribute to the autonomic regulation of social behavior, as measured by Respiratory Sinus Arrhythmia (RSA), we aimed to explore this link in anorexia patients, whose ability to perceive their bodily signal seems to be impaired. To this purpose, we compared a group of anorexia patients (ANg; restrictive type) with a group of Healthy Controls (HCg) for RSA responses during both a resting state and a social proxemics task, for their explicit judgments of comfort in social distances during a behavioral proxemics task, and for their Interoceptive Accuracy (IA). The results showed that ANg displayed significantly lower social disposition and a flattened autonomic reactivity during the proxemics task, irrespective of the presence of others’ socially desirable features or social cues. Moreover, unlike HCg, the autonomic arousal of ANg did not guide behavioral judgments of social distances. Finally, IA was strictly related to social disposition in both groups, but with opposite trends in ANg. We conclude that autonomic imbalance and its altered relationship with interoception might have a crucial role in anorexia disturbances

Spatial stimulus-response compatibility and affordance effects are not ruled by the same mechanisms

Stimulus position is coded even if it is task-irrelevant, leading to faster response times when the stimulus and the response locations are compatible (spatial Stimulus– Response Compatibility–spatial SRC). Faster responses are also found when the handle of a visual object and the response hand are located on the same side; this is known as affordance effect (AE). Two contrasting accounts for AE have been classically proposed. One is focused on the recruitment of appropriate grasping actions on the object handle, and the other on the asymmetry in the object shape, which in turn would cause a handle-hand correspondence effect (CE). In order to disentangle these two accounts, we investigated the possible transfer of practice in a spatial SRC task executed with a S–R incompatible mapping to a subsequent affordance task in which objects with either their intact handle or a broken one were used. The idea was that using objects with broken handles should prevent the recruitment of motor information relative to object grasping, whereas practice transfer should prevent object asymmetry in driving handle-hand CE. A total of three experiments were carried out. In Experiment 1 participants underwent an affordance task in which common graspable objects with their intact or broken handle were used. In Experiments 2 and 3, the affordance task was preceded by a spatial SRC task in which an incompatible S–R mapping was used. Inter-task delays of 5 or 30 min were employed to assess the duration of transfer effect. In Experiment 2 objects with their intact handle were presented, whereas in Experiment 3 the same objects had their handle broken. Although objects with intact and broken handles elicited a handle-hand CE in Experiment 1, practice transfer from an incompatible spatial SRC to the affordance task was found in Experiment 3 (broken-handle objects), but not in Experiment 2 (intact-handle objects). Overall, this pattern of results indicate that both object asymmetry and the activation of motor information contribute to the generation of the handle-hand CE effect, and that the handle AE cannot be reduced to a SRC effect

RSA response of High and Low interoception Groups as a function of distances in Social and Non-Social Task.

<p>(A) RSA response of the High interoception Group to each experimental condition in the Social (light gray line) and the Non-Social Task (dark gray line). (B) RSA response of the Low interoception Group to each experimental conditions in the Social (light gray line) and the Non-Social Task (dark gray line). NS =  Near-peripersonal Space; IS =  Intermediate-Peripersonal Space; FS =  Far-peripersonal Space; HG =  High interoception Group; LG =  Low interoception Group. Dashed line indicates p<0.05. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075758#pone-0075758-t002" target="_blank">Table 2</a> for standard deviations.</p

Cardiac parameters and Subjective rating of Comfort in the Social and the Non-Social Task.

<p>Mean values ± standard deviations of cardiac parameters (RSA =  Respiratory Sinus Arrhytmia and HR =  Heart Rate) and Subjective rating of Comfort for the High and the Low interoception Groups. RSA and HR are reported as changes from the resting baseline values. NS =  Near-peripersonal Space; IS =  Intermediate-Peripersonal Space; FS =  Far-peripersonal Space; bpm =  beats per minute.</p

Correlation between heartbeat perception score and RSA response to IS condition.

<p>Correlation plot between heartbeat perception scores and change in RSA response from the Touch to the IS condition in the social context. IS =  Intermediate-Peripersonal Space. * p<0.05.</p