Commentary on “Autism, oxytocin and interoception”: Alexithymia, not Autism Spectrum Disorders, is the consequence of interoceptive failure

Oxytocin Modulates Attention Switching Between Interoceptive Signals and External Social Cues

Emotional experience involves an integrated interplay between processing of external emotional cues and interoceptive feedback, and this is impaired in a number of emotional disorders. The neuropeptide oxytocin (OT) enhances the salience of external social cues but its influence on interoception is unknown. The present pharmaco-fMRI study therefore investigated whether OT enhances interoceptive awareness and if it influences the interplay between interoceptive and salience processing. In a randomized, double-blind, between-subject, design study 83 subjects received either intranasal OT or placebo. In Experiment 1, subjects performed a heartbeat detection task alone, while in Experiment 2 they did so while viewing both neutral and emotional face stimuli. Interoceptive accuracy and neural responses in interoceptive and salience networks were measured. In Experiment 1, OT had no significant influence on interoceptive accuracy or associated activity in the right anterior insula (AI) and dorsal anterior cingulate cortex. However, in Experiment 2 when face stimuli were also presented, OT decreased interoceptive accuracy and increased right AI activation and its functional connectivity with the left posterior insula (PI), with the latter both being negatively correlated with accuracy scores. The present study provides the first evidence that while OT does not influence processing of interoceptive cues per se it may switch attention away from them towards external salient social cues by enhancing right AI responses and its control over the PI. Thus OT may help regulate the interplay between interoceptive and external salience processing within the insula and could be of potential therapeutic benefit for emotional disorders.

The specificity of the link between alexithymia, interoception, and imitation

Alexithymia is a subclinical condition traditionally characterized by difficulties identifying and describing one's own emotions. Recent formulations of alexithymia, however, suggest that the condition may result from a generalized impairment in the perception of all bodily signals ("interoception"). Interoceptive accuracy has been associated with a variety of deficits in social cognition, but recently with an improved ability to inhibit the automatic tendency to imitate the actions of others. The current study tested the consequences for social cognition of the hypothesized association between alexithymia and impaired interoception by examining the relationship between alexithymia and the ability to inhibit imitation. If alexithymia is best characterized as a general interoceptive impairment, then one would predict that alexithymia would have the same relationship with the ability to control imitation as does interoceptive accuracy. Forty-three healthy adults completed measures of alexithymia, imitation-inhibition, and as a control, inhibition of nonimitative spatial compatibility. Results revealed the predicted relationship, such that increasing alexithymia was associated with an improved ability to inhibit imitation, and that this relationship was specific to imitation-inhibition. These results support the characterization of alexithymia as a general interoceptive impairment and shed light on the social ability of alexithymic individuals-with implications for the multitude of psychiatric, neurological, and neurodevelopmental disorders associated with high rates of alexithymia. (PsycINFO Database Record

Alexithymia is associated with a multidomain, multidimensional failure of interoception: Evidence from novel tests

Interoception, the perception of the body’s internal state, contributes to numerous aspects of higher-order cognition. Several theories suggest a causal role for atypical interoception in specific psychiatric disorders, including a recent claim that atypical interoception represents a transdiagnostic impairment across disorders characterized by reduced perception of one’s own emotion (alexithymia). Such theories are supported predominantly by evidence from only one interoceptive domain (cardiac); however, evidence of domain-specific interoceptive ability highlights the need to assess interoception in noncardiac domains. Using novel interoceptive tasks, we demonstrate that individuals high in alexithymic traits show a reduced propensity to utilize interoceptive cues to gauge respiratory output (Experiment 1), reduced accuracy on tasks of muscular effort (Experiment 2), and taste sensitivity (Experiment 3), unrelated to any co-occurring autism, depression, or anxiety. Results suggest that alexithymia reflects a multidomain, multidimensional failure of interoception, which is consistent with theories suggesting that atypical interoception may underpin both symptom commonalities between psychiatric disorders and heterogeneity within disorders.

Disrupted integration of exteroceptive and interoceptive signaling in autism spectrum disorder

In addition to deficits in social communication, individuals diagnosed with Autism Spectrum Disorder (ASD) frequently exhibit changes in sensory and multisensory function. Recent evidence has focused on changes in audiovisual temporal processing, and has sought to relate these sensory-based changes to weaknesses in social communication. These changes in audiovisual temporal function manifest as differences in the temporal epoch or "window" within which paired auditory and visual stimuli are integrated or bound, with those with ASD exhibiting expanded audiovisual temporal binding windows (TBWs). However, it is unknown whether this impairment is unique to audiovisual pairings, perhaps because of their relevance for speech processing, or whether it generalizes across pairings in different sensory modalities. In addition to the exteroceptive senses, there has been growing interest in ASD research in interoception (e.g., the monitoring of respiration, heartbeat, hunger, etc.), as these internally directed sensory processes appear to be altered as well in autism. In the current study, we sought to examine both exteroception and interoception in individuals with ASD and a group of typically developing (TD) matched controls, with an emphasis on temporal perception of audiovisual (exteroceptive) and cardiovisual (interoceptive to exteroceptive) cues. Results replicate prior findings showing expanded audiovisual TBWs in ASD in comparison to TD. In addition, strikingly, cardiovisual TBWs were fourfold larger in ASD than in TD, suggesting a putative complete lack of cardiovisual temporal acuity in ASD individuals. Results are discussed in light of recent evidence indicating a reduced tendency to rely on sensory priors in ASD. Autism Res 2018, 11: 194-205. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Studies have shown that individuals with autism have difficulty in separating auditory and visual events in time. People with autism also weight sensory evidence originating from the external world and from their body differently. We measured simultaneity judgments regarding visual and auditory events and between visual and heartbeat events. Results suggest that while individuals with autism show unusual temporal function across the senses in a general manner, this deficit is greater when pairings bridged between the external world and the internal body.

A Predictive Coding Account of Psychotic Symptoms in Autism Spectrum Disorder

The co-occurrence of psychotic and autism spectrum disorder (ASD) symptoms represents an important clinical challenge. Here we consider this problem in the context of a computational psychiatry approach that has been applied to both conditions-predictive coding. Some symptoms of schizophrenia have been explained in terms of a failure of top-down predictions or an enhanced weighting of bottom-up prediction errors. Likewise, autism has been explained in terms of similar perturbations. We suggest that this theoretical overlap may explain overlapping symptomatology. Experimental evidence highlights meaningful distinctions and consistencies between these disorders. We hypothesize individuals with ASD may experience some degree of delusions without the presence of any additional impairment, but that hallucinations are likely indicative of a distinct process.

Autonomic Reactivity to Arousing Stimuli with Social and Non-social Relevance in Alexithymia

Emotional difficulties in alexithymia and their social consequences have been linked to alterations in autonomic nervous system. However, most of previous studies did not take into account the distinction between the affective and the cognitive dimensions of the alexithymia, leading to inconsistent results. Aim: In this study, we compared the effects of both dimensions of alexithymia on the autonomic arousal to emotional and social visual stimulations. Methods: Skin conductance responses (SCRs) to items of the International Affective Pictures System characterized by emotional (unpleasant, neutral, and pleasant), social (with humans) or non-social (without humans) content were recorded in non-alexithymic (NA), affective (AA) and cognitive alexithymic (CA) participants, selected on the basis of the Toronto Alexithymia Scale and the Bermond-Vorst Alexithymia Questionnaire. All participants responded to questionnaires of empathy, social phobia, depression, and anxiety before the experiment and evaluated the arousal of the pictures after it. Results: Cognitive alexithymic group showed lower amplitudes of SCRs to pictures with social than without social relevance whereas the opposite pattern was observed for the NA group. Arousal emotional effects of the pictures on SCRs did not differ among groups. In addition, CA participants showed lower scores than NA in the Personal Taking sub-scale of the empathy questionnaire, while AA showed lower scores than NA in the fantasy sub-scale. The CA group showed higher social phobia, depression and anxiety scores, than the other two groups. Conclusion: This work has two original outcomes: first, affective alexithymics expressed lower empathic affective scores than other groups; second, alexithymia modulated the impact of the social relevance of the stimuli on the autonomic reactivity, this impact vanishing in affective alexithymics and reversing in cognitive alexithymics. Thus, though the groups could not be distinguished on the basis of emotional effect on SCRs, they clearly differed when the empathic characteristics and the autonomic impact of social relevance were considered. Finally, the described autonomic signature to social relevant information could contribute to elucidate the difficulty of alexithymics to deal with emotions during social transactions.

A new test of advanced theory of mind: The "Strange Stories Film Task" captures social processing differences in adults with autism spectrum disorders

Real-life social processing abilities of adults with autism spectrum disorders (ASD) can be hard to capture in lab-based experimental tasks. A novel measure of social cognition, the "Strange Stories Film task' (SSFt), was designed to overcome limitations of available measures in the field. Brief films were made based on the scenarios from the Strange Stories task (Happé) and designed to capture the subtle social-cognitive difficulties observed in ASD adults. Twenty neurotypical adults were recruited to pilot the new measure. A final test set was produced and administered to a group of 20 adults with ASD and 20 matched controls, alongside established social cognition tasks and questionnaire measures of empathy, alexithymia and ASD traits. The SSFt was more effective than existing measures at differentiating the ASD group from the control group. In the ASD group, the SSFt was associated with the Strange Stories task. The SSFt is a potentially useful tool to identify social cognitive dis/abilities in ASD, with preliminary evidence of adequate convergent validity. Future research directions are discussed. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1120-1132. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Interoception and psychopathology: A developmental neuroscience perspective

Interoception refers to the perception of the physiological condition of the body, including hunger, temperature, and heart rate. There is a growing appreciation that interoception is integral to higher-order cognition. Indeed, existing research indicates an association between low interoceptive sensitivity and alexithymia (a difficulty identifying one's own emotion), underscoring the link between bodily and emotional awareness. Despite this appreciation, the developmental trajectory of interoception across the lifespan remains under-researched, with clear gaps in our understanding. This qualitative review and opinion paper provides a brief overview of interoception, discussing its relevance for developmental psychopathology, and highlighting measurement issues, before surveying the available work on interoception across four stages of development: infancy, childhood, adolescence and late adulthood. Where gaps in the literature addressing the development of interoception exist, we draw upon the association between alexithymia and interoception, using alexithymia as a possible marker of atypical interoception. Evidence indicates that interoceptive ability varies across development, and that this variance correlates with established age-related changes in cognition and with risk periods for the development of psychopathology. We suggest a theory within which atypical interoception underlies the onset of psychopathology and risky behaviour in adolescence, and the decreased socio-emotional competence observed in late adulthood.

Associations Between Interoceptive Cognition and Age in Autism Spectrum Disorder and Typical Development

Interoceptive awareness is linked to emotional and social cognition, which are impaired in individuals with autism spectrum disorder (ASD). It is unknown how this ability is associated with age in either typical or atypical development. We used a standard test of interoceptive accuracy (IA) to investigate these questions in children and adults with and without ASD. Perceived number of heartbeats over 4 time intervals was compared with actual heart rate to determine IA. Effects of group, age, IQ, heart rate, and mental counting ability on accuracy were assessed using multiple regression. Post hoc correlations were performed to clarify significant interactions. Age was unrelated to IA in both groups when IQ ≥115. When IQ <115, this relationship was positive in typical development and negative in ASD. These results suggest that cognitive ability moderates the effect of age on IA differently in autism and typical development.

Recent progress in understanding skills and impairments in social cognition

PURPOSE OF REVIEW

Social interaction is affected in many different developmental disorders; indeed, the new Diagnostic and Statistical Manual of Mental Disorders has introduced social cognition as one of six core components of neurocognitive functioning. Social cognition is not one thing, but a wide range of putative processes, which may be differentially affected in different clinical groups. This review focuses on recent advances in one aspect of social cognition, 'theory of mind' (ToM, representing what people think), and one core clinical group, autism spectrum disorder (ASD).

RECENT FINDINGS

It is 30 years since impaired ToM was proposed as an explanation for ASD social difficulties, and recently there has been a widening of interest to other clinical groups. ToM has been found to be distinct from emotion recognition and empathy. Recent research on ASD has focused increasingly on atypical sensory responses and commonly comorbid conditions. Interventions for social deficits, including ToM training and oxytocin, have shown mixed results to date.

SUMMARY

Heterogeneity poses a major obstacle to current research. Theoretical and empirical refinements are needed to elucidate neurocognitive and aetiological underpinnings of sociocognitive processes and inform clinical advances.

The psychophysiological mechanisms of alexithymia in autism spectrum disorder

Accumulating evidence indicates that co-occurring alexithymia underlies several facets of the social-emotional difficulties common in individuals with autism spectrum disorder. The mechanisms involved, however, remain poorly understood because measuring alexithymia relies heavily on self-report. To address this issue, carefully matched groups of individuals with autism spectrum disorder and comparison participants rated 70 emotion-inducing pictures on subjectively experienced arousal while skin conductance responses were monitored objectively. The results demonstrated reliable correlations between these subjective and objective measures, and in both groups, around 25% of individual differences in this correlation (i.e. in emotion-relevant interoception) were accounted for by self-reported alexithymia. In the context of the wider literature, this suggests that alexithymia involves a disruption in how physiological arousal modulates the subjective experience of feelings in those with and without a diagnosis of autism spectrum disorder. Since mindfulness-based therapies foster greater awareness of thoughts, feelings and bodily sensations, the findings also have implications for how the symptoms and consequences of alexithymia (e.g. anxiety) might be ameliorated.

Changes in mental state and behaviour in Huntington's disease

Changes in mental state and behaviour have been acknowledged in Huntington's disease since the original monograph in 1872 provided evidence of disinhibition and impaired social cognition. Behavioural problems can manifest before obvious motor symptoms and are frequently the most disabling part of the illness. Although pharmacological treatments are used routinely for psychiatric difficulties in Huntington's disease, the scientific evidence base for their use is somewhat sparse. Moreover, effective treatments for apathy and cognitive decline do not currently exist. Understanding the social cognitive impairments associated with Huntington's disease can assist management, but related therapeutic interventions are needed. Future research should aim to design rating scales for behaviour and mental state in Huntington's disease that can detect change in clinical trials. Generally, communication and understanding of behaviour and mental state in Huntington's would be enhanced by a clear conceptual framework that unifies ideas around movement, cognition, emotion, behaviour, and mental state, reflecting both the experience of the patient and their underlying neuropathology.

Emotional decision-making in autism spectrum disorder: the roles of interoception and alexithymia

The way choices are framed influences decision-making. These “framing effects” emerge through the integration of emotional responses into decision-making under uncertainty. It was previously reported that susceptibility to the framing effect was reduced in individuals with autism spectrum disorder (ASD) due to a reduced tendency to incorporate emotional information into the decision-making process. However, recent research indicates that, where observed, emotional processing impairments in ASD may be due to co-occurring alexithymia. Alexithymia is thought to arise due to impaired interoception (the ability to perceive the internal state of one’s body), raising the possibility that emotional signals are not perceived and thus not integrated into decision-making in those with alexithymia and that therefore reduced framing effects in ASD are a product of co-occurring alexithymia rather than ASD per se. Accordingly, the present study compared framing effects in autistic individuals with neurotypical controls matched for alexithymia. Results showed a marked deviation between groups. The framing effect was, in line with previous data, significantly smaller in autistic individuals, and there was no relationship between alexithymia or interoception and decision-making in the ASD group. In the neurotypical group, however, the size of the framing effect was associated with alexithymia and interoception, even after controlling for autistic traits. These results demonstrate that although framing effects are associated with interoception and alexithymia in the neurotypical population, emotional and interoceptive signals have less impact upon the decision-making process in ASD.

Alexithymia, not autism, is associated with impaired interoception

It has been proposed that Autism Spectrum Disorder (ASD) is associated with difficulties perceiving the internal state of one's body (i.e., impaired interoception), causing the socio-emotional deficits which are a diagnostic feature of the condition. However, research indicates that alexithymia - characterized by difficulties in recognizing emotions from internal bodily sensations - is also linked to atypical interoception. Elevated rates of alexithymia in the autistic population have been shown to underpin several socio-emotional impairments thought to be symptomatic of ASD, raising the possibility that interoceptive difficulties in ASD are also due to co-occurring alexithymia. Following this line of inquiry, the present study examined the relative impact of alexithymia and autism on interoceptive accuracy (IA). Across two experiments, it was found that alexithymia, not autism, was associated with atypical interoception. Results indicate that interoceptive impairments should not be considered a feature of ASD, but instead due to co-occurring alexithymia.

Acquired alexithymia following damage to the anterior insula

Alexithymia is a subclinical condition characterized by impaired awareness of one's emotional states, which has profound effects on mental health and social interaction. Despite the clinical significance of this condition, the neurocognitive impairment(s) that lead to alexithymia remain unclear. Recent theoretical models suggest that impaired anterior insula (AI) functioning might be involved in alexithymia, but conclusive evidence for this hypothesis is lacking. We measured alexithymia levels in a large sample of brain-injured patients (N=129) and non-brain-injured control participants (N=33), to determine whether alexithymia can be acquired after pronounced damage to the AI. Alexithymia levels were first analysed as a function of group, with patients separated into four groups based on AI damage: patients with >15% damage to AI, patients with <15% damage to AI, patients with no damage to AI, and healthy controls. An ANOVA revealed that alexithymia levels varied across groups (p=0.009), with >15% AI damage causing higher alexithymia relative to all other groups (all p<0.01). Next, a multiple linear regression model was fit with the degree of damage to AI, the degree of damage to a related region (the anterior cingulate cortex, ACC), and the degree of damage to the whole brain as predictor variables, and alexithymia as the dependent variable. Critically, increased AI damage predicted increased alexithymia after controlling for the other two regressors (ACC damage; total lesion volume). Collectively, our results suggest that pronounced AI damage causes increased levels of alexithymia, providing critical evidence that this region supports emotional awareness.