Disrupted action perception in autism: behavioral evidence, neuroendophenotypes, and diagnostic utility

Segregated Dynamical Networks for Biological Motion Perception in the Mu and Beta Range Underlie Social Deficits in Autism

OBJECTIVE

Biological motion perception (BMP) correlating with a mirror neuron system (MNS) is attenuated in underage individuals with autism spectrum disorder (ASD). While BMP in typically-developing controls (TDCs) encompasses interconnected MNS structures, ASD data hint at segregated form and motion processing. This coincides with less fewer long-range connections in ASD than TDC. Using BMP and electroencephalography (EEG) in ASD, we characterized directionality and coherence (mu and beta frequencies). Deficient BMP may stem from desynchronization thereof in MNS and may predict social-communicative deficits in ASD. Clinical considerations thus profit from brain-behavior associations.

METHODS

Point-like walkers elicited BMP using 15 white dots (walker vs. scramble in 21 ASD (mean: 11.3 ± 2.3 years) vs. 23 TDC (mean: 11.9 ± 2.5 years). Dynamic Imaging of Coherent Sources (DICS) characterized the underlying EEG time-frequency causality through time-resolved Partial Directed Coherence (tPDC). Support Vector Machine (SVM) classification validated the group effects (ASD vs. TDC).

RESULTS

TDC showed MNS sources and long-distance paths (both feedback and bidirectional); ASD demonstrated distinct from and motion sources, predominantly local feedforward connectivity, and weaker coherence. Brain-behavior correlations point towards dysfunctional networks. SVM successfully classified ASD regarding EEG and performance.

CONCLUSION

ASD participants showed segregated local networks for BMP potentially underlying thwarted complex social interactions. Alternative explanations include selective attention and global-local processing deficits.

SIGNIFICANCE

This is the first study applying source-based connectivity to reveal segregated BMP networks in ASD regarding structure, cognition, frequencies, and temporal dynamics that may explain socio-communicative aberrancies.

Autism and intention attribution test: a non-verbal evaluation with comic strips

BACKGROUND

Despite autism spectrum disorder (ASD) and mentalization being two words often associated in the literature, the assessment of this ability in individuals with ASD in the clinical setting is still limited. Indeed, there are no standardized Theory of Mind (ToM) tests that are adaptable to different cognitive profiles, such as individuals with language poverty, and intellectual or memory impairments. This study proposes a non-verbal test (Intentions Attribution-Comic Strip Test; IA-CST) to evaluate the ability to infer the intentions of others, a basic component of ToM, in the clinical setting.

METHOD

In Study 1, the test was administered to 261 healthy individuals and we performed structural validation using Exploratory Graph Analysis. In Study 2, the final version of the test was administered to 32 individuals with ASD to assess the known group validity of the measure by comparing their scores with a sample of IQ-matched controls. Moreover, we performed logistic regression and ROC curve to preliminarily assess the diagnostic performance of the IA-CST.

RESULTS

The IA-CST resulted in a 3-dimension measure with good structural stability. Group comparison indicated that the ASD group shows significantly lower performance in intention attribution but not in inferring causal consequences. The test demonstrated known group validity and that, preliminarily, it is suitable for implementation within the clinical practice.

CONCLUSIONS

The results support the IA-CST as a valid non-verbal task for evaluating intentions attribution in the clinical setting. Difficulties in ToM are early and relevant in ASD, so assessing these aspects is valuable for structuring individualized and evidence-based interventions.

Autistic Adults Show Similar Performance and Sensitivity to Social Cues on a Visual Perspective Taking Task as Non-autistic Adults

Autistic and non-autistic adults completed a visual perspective taking (VPT) task, reporting an object’s location from an actor’s perspective, or their own. On half the trials the actor looked at and reached for the object, and on half did not. Accuracy and reaction time were measured. In Experiment 1, both groups (N = 34, mean age = 24 years) responded slower when reporting the actor’s perspective, with no group differences in this effect. Experiment 2 included “other” VPT trials only. Both groups (N = 30, mean age = 25 years) showed sensitivity to the actor’s behaviour, more accurately reporting his perspective when he acted upon the object. No group differences were observed. In contrast to developmental studies, these experiments suggest similar VPT abilities in autistic and non-autistic adults.

Distinct cerebellar regions for body motion discrimination

Visual processing of human movements is critical for adaptive social behavior. Cerebellar activations have been observed during biological motion discrimination in prior neuroimaging studies, and cerebellar lesions may be detrimental for this task. However, whether the cerebellum plays a causal role in biological motion discrimination has never been tested. Here, we addressed this issue in three different experiments by interfering with the posterior cerebellar lobe using transcranial magnetic stimulation (TMS) during a biological discrimination task. In Experiments 1 and 2, we found that TMS delivered at onset of the visual stimuli over the vermis (vermal lobule VI), but not over the left cerebellar hemisphere (left lobule VI/Crus I), interfered with participants' ability to distinguish biological from scrambled motion compared to stimulation of a control site (vertex). Interestingly, when stimulation was delivered at a later time point (300 ms after stimulus onset), participants performed worse when TMS was delivered over the left cerebellar hemisphere compared to the vermis and the vertex (Experiment 3). Our data show that the posterior cerebellum is causally involved in biological motion discrimination and suggest that different sectors of the posterior cerebellar lobe may contribute to the task at different time points.

Difficulties in Recognising Dynamic but not Static Emotional Body Movements in Autism Spectrum Disorder

In this study, we investigated whether the difficulties in body motion (BM) perception may led to deficit in emotion recognition in Autism spectrum disorder (ASD). To this aim, individuals with high-functioning ASD were asked to recognise fearful, happy, and neutral BM depicted as static images or dynamic point-light and full-light displays. Results showed slower response times in participants with ASD only in recognising dynamic stimuli, but no group differences in accuracy. This suggests that i) a deficit in action chaining mechanism in ASD may prevent the recognition of dynamic BM automatically and rapidly, ii) individuals with ASD and high cognitive resources can develop alternative—but equally successful—strategies to recognise emotional body expressions. Implications for treatment are discussed

Explaining Variance in Social Symptoms of Children with Autism Spectrum Disorder

The social symptoms of autism spectrum disorder are likely influenced by multiple psychological processes, yet most previous studies have focused on a single social domain. In school-aged autistic children (n = 49), we compared the amount of variance in social symptoms uniquely explained by theory of mind (ToM), biological motion perception, empathy, social reward, and social anxiety. Parent-reported emotional contagion-the aspect of empathy in which one shares another's emotion-emerged as the most important predictor, explaining 11-14% of the variance in social symptoms, with higher levels of emotional contagion predicting lower social symptom severity. Our findings highlight the role of mutual emotional experiences in social-interactive success, as well as the limitations of standard measures of ToM and social processing in general.

Preserved action recognition in children with autism spectrum disorders: Evidence from an EEG and eye-tracking study

Individuals with Autism Spectrum Disorder (ASD) have difficulties recognizing and understanding others' actions. The goal of the present study was to determine whether children with and without ASD show differences in the way they process stimuli depicting Biological Motion (BM). Thirty-two children aged 7-16 (16 ASD and 16 typically developing (TD) controls) participated in two experiments. In the first experiment, electroencephalography (EEG) was used to record low (8-10 Hz) and high (10-13 Hz) mu and beta (15-25 Hz) bands during the observation three different Point Light Displays (PLD) of action. In the second experiment, participants answered to action-recognition tests and their accuracy and response time were recorded, together with their eye-movements. There were no group differences in EEG data (first experiment), indicating that children with and without ASD do not differ in their mu suppression (8-13 Hz) and beta activity (15-25 Hz). However, behavioral data from second experiment revealed that children with ASD were less accurate and slower than TD children in their responses to an action recognition task. In addition, eye-tracking data indicated that children with ASD paid less attention to the body compared to the background when watching PLD stimuli. Our results indicate that the more the participants focused on the PLDs, the more they displayed mu suppressions. These results could challenge the results of previous studies that had not controlled for visual attention and found a possible deficit in MNS functions of individuals with ASD. We discuss possible mechanisms and interpretations.

Social endophenotypes in autism spectrum disorder: A scoping review

Endophenotypes are measurable markers of genetic vulnerability to current or future disorder. Autism spectrum disorder (ASD) is well-suited to be examined within an endophenotype framework given past and current emphases on the broader autism phenotype and early detection. We conducted a scoping review to identify potential socially-related endophenotypes of ASD. We focused on paradigms related to sociality (e.g., theory of mind (TOM), social attention), which comprise most of this literature. We integrated findings from traditional behavioral paradigms with brain-based measures (e.g., electroencephalography, functional magnetic resonance imaging). Broadly, infant research regarding social attention and responsivity (Research Domain Criteria (RDoC) domain of affiliation) and attention to faces and voices (social communication) finds consistent abnormality in vulnerable infant siblings. Several additional paradigms that have shown differences in vulnerable infants and young children include animacy perception tasks (perception and understanding of others), measures of recognition and response to familiar faces (attachment), and joint attention and false-belief tasks (understanding mental states). Research areas such as alexithymia (the perception and understanding of self), empathic responding, and vocal prosody may hold interest; however, challenges in measurement across populations and age ranges is a limiting factor. Future work should address sex differences and age dependencies, specificity to ASD, and heterogeneous genetic pathways to disorder within samples individuals with ASD and relatives.

Visual Perception in Autism Spectrum Disorder: A Review of Neuroimaging Studies

Although autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social impairments, patients with ASD frequently manifest atypical sensory behaviors. Recently, atypical sensory perception in ASD has received much attention, yet little is known about its cause or neurobiology. Herein, we review the findings from neuroimaging studies related to visual perception in ASD. Specifically, we examined the neural underpinnings of visual detection, motion perception, and face processing in ASD. Results from neuroimaging studies indicate that atypical visual perception in ASD may be influenced by attention or higher order cognitive mechanisms, and atypical face perception may be affected by disrupted social brain network. However, there is considerable evidence for atypical early visual processing in ASD. It is likely that visual perceptual abnormalities are independent of deficits of social functions or cognition. Importantly, atypical visual perception in ASD may enhance difficulties in dealing with complex and subtle social stimuli, or improve outstanding abilities in certain fields in individuals with Savant syndrome. Thus, future research is required to elucidate the characteristics and neurobiology of autistic visual perception to effectively apply these findings in the interventions of ASD.

"Motion or Emotion? Recognition of Emotional Bodily Expressions in Children With Autism Spectrum Disorder With and Without Intellectual Disability"

The recognition of emotional body movement (BM) is impaired in individuals with Autistic Spectrum Disorder ASD, yet it is not clear whether the difficulty is related to the encoding of body motion, emotions, or both. Besides, BM recognition has been traditionally studied using point-light displays stimuli (PLDs) and is still underexplored in individuals with ASD and intellectual disability (ID). In the present study, we investigated the recognition of happy, fearful, and neutral BM in children with ASD with and without ID. In a non-verbal recognition task, participants were asked to recognize pure-body-motion and visible-body-form stimuli (by means of point-light displays-PLDs and full-light displays-FLDs, respectively). We found that the children with ASD were less accurate than TD children in recognizing both the emotional and neutral BM, either when presented as FLDs or PLDs. These results suggest that the difficulty in understanding the observed BM may rely on atypical processing of BM information rather than emotion. Moreover, we found that the accuracy improved with age and IQ only in children with ASD without ID, suggesting that high level of cognitive resources can mediate the acquisition of compensatory mechanisms which develop with age.

Anomalous Perception of Biological Motion in Autism: A Conceptual Review and Meta-Analysis

Despite its popularity, the construct of biological motion (BM) and its putative anomalies in autism spectrum disorder (ASD) are not completely clarified. In this article, we present a meta-analysis investigating the putative anomalies of BM perception in ASD. Through a systematic literature search, we found 30 studies that investigated BM perception in both ASD and typical developing peers by using point-light display stimuli. A general meta-analysis including all these studies showed a moderate deficit of individuals with ASD in BM processing, but also a high heterogeneity. This heterogeneity was explored in different additional meta-analyses where studies were grouped according to levels of complexity of the BM task employed (first-order, direct and instrumental), and according to the manipulation of low-level perceptual features (spatial vs. temporal) of the control stimuli. Results suggest that the most severe deficit in ASD is evident when perception of BM is serving a secondary purpose (e.g., inferring intentionality/action/emotion) and, interestingly, that temporal dynamics of stimuli are an important factor in determining BM processing anomalies in ASD. Our results question the traditional understanding of BM anomalies in ASD as a monolithic deficit and suggest a paradigm shift that deconstructs BM into distinct levels of processing and specific spatio-temporal subcomponents.

Biological motion perception in autism spectrum disorder: a meta-analysis

Background

Biological motion, namely the movement of others, conveys information that allows the identification of affective states and intentions. This makes it an important avenue of research in autism spectrum disorder where social functioning is one of the main areas of difficulty. We aimed to create a quantitative summary of previous findings and investigate potential factors, which could explain the variable results found in the literature investigating biological motion perception in autism.

Methods

A search from five electronic databases yielded 52 papers eligible for a quantitative summarisation, including behavioural, eye-tracking, electroencephalography and functional magnetic resonance imaging studies.

Results

Using a three-level random effects meta-analytic approach, we found that individuals with autism generally showed decreased performance in perception and interpretation of biological motion. Results additionally suggest decreased performance when higher order information, such as emotion, is required. Moreover, with the increase of age, the difference between autistic and neurotypical individuals decreases, with children showing the largest effect size overall.

Conclusion

We highlight the need for methodological standards and clear distinctions between the age groups and paradigms utilised when trying to interpret differences between the two populations.

Prediction in Autism by Deep Learning Short-Time Spontaneous Hemodynamic Fluctuations

This study aims to explore the possibility of using a multilayer artificial neural network for the classification between children with autism spectrum disorder (ASD) and typically developing (TD) children based on short-time spontaneous hemodynamic fluctuations. Spontaneous hemodynamic fluctuations were collected by a functional near-infrared spectroscopy setup from bilateral inferior frontal gyrus and temporal cortex in 25 children with ASD and 22 TD children. To perform feature extraction and classification, a multilayer neural network called CGRNN was used which combined a convolution neural network (CNN) and a gate recurrent unit (GRU), since CGRNN has a strong ability in finding characteristic features and acquiring intrinsic relationship in time series. For the training and predicting, short-time (7 s) time-series raw functional near-infrared spectroscopy (fNIRS) signals were used as the input of the network. To avoid the over-fitting problem and effectively extract useful differentiation features from a sample with a very limited size (e.g., 25 ASDs and 22 TDs), a sliding window approach was utilized in which the initially recorded long-time (e.g., 480 s) time-series was divided into many partially overlapped short-time (7 s) sequences. By using this combined deep-learning network, a high accurate classification between ASD and TD could be achieved even with a single optical channel, e.g., 92.2% accuracy, 85.0% sensitivity, and 99.4% specificity. This result implies that the multilayer neural network CGRNN can identify characteristic features associated with ASD even in a short-time spontaneous hemodynamic fluctuation from a single optical channel, and second, the CGRNN can provide highly accurate prediction in ASD.

Inflexibility in Autism Spectrum Disorder: Need for certainty and atypical emotion processing share the blame

Although ASD (Autism Spectrum Disorder) diagnosis requires the co-occurrence of socio-emotional deficits and inflexible behaviors, the interaction between these two domains remains unexplored. We used an emotional Wisconsin Card Sorting Test adapted to fMRI to explore this question. ASD and control participants matched a central card (a face) with one of four surrounding cards according to one of three rules: frame color, facial identity or expression. Feedback informed participants on whether to change or maintain the current sorting rule. For each rule, we modeled feedback onsets to change, switch (confirming the newly found rule) and maintenance events. "Bias error", which measures participants' willingness to switch, was larger in ASD participants for the emotional sorting rule. Brain activity to change events showed no group differences. In response to switch events significantly larger activity was observed for ASD participants in bilateral Inferior Parietal Sulci. Inflexibility in ASD appears characterized by the unwillingness to switch toward processing socio-emotional information, rather than a major disruption in cognitive flexibility. However, a larger activity to switch events in ASD highlights the need for a higher level of certainty before setting into a stable processing stage, which may be particularly detrimental in the highly changeable socio-emotional environment.

Perception of biological motions is preserved in people with autism spectrum disorder: electrophysiological and behavioural evidences

BACKGROUND

There have been some controversies over the ability of individuals with autism spectrum disorder (ASD) to perceive biological motion. In this study, we used electroencephalography and behavioural measures (recognition test) to examine whether or not children with ASD can correctly identify biological motion.

METHOD

Twenty participants with ASD (mean = 11.3, SD = 2.1 years) and 20 typically developed (TD) participants (mean = 11.4, SD = 2.8 years) participated in the study. They watched videos and point light displays of actions, and their EEG was recorded. Then they answered action recognition test, and their accuracy and response times were recorded.

RESULTS

Our findings showed that children with ASD had the same mu suppression as a TD age-matched control group in both point light display and video presentations. Furthermore, the results showed that while TD and ASD groups did not differ in accuracy, ASD participants had a slower reaction time.

CONCLUSION

Taken together, our results indicate that the perception of non-emotional BMs is preserved in children with ASD.

Adults with autism spectrum disorder are sensitive to the kinematic features defining natural human motion

It has been hypothesized that individuals with Autism Spectrum Disorder (hereafter "autism") have problems perceiving biological motion, which contributes to their social difficulties. However, the ability to perceive the kinematic profile characteristic of biological motion has not been systematically examined in autism. To examine this basic perceptual ability we conducted two experiments comparing adults with autism with matched typical adults. In Experiment 1, participants indicated whether two movements-which differed in the quantity of formula-generated biological motion-were the same or different. In Experiment 2, they judged which of two movements was "less natural," where the stimuli varied in the degree to which they were a product of real movement data produced by autistic and typical models. There were no group differences in perceptual sensitivity in either experiment, with null effects supported by Bayesian analyses. The findings from these two experiments demonstrate that adults with autism are sensitive to the kinematic information defining biological motion to a typical degree-they are both able to detect the perceptual information in a same-different judgment, and as inclined to categorize biological motion derived from real models as natural. These findings therefore provide evidence against the hypothesis that individuals with autism exhibit low-level difficulties in perceiving the kinematics of others' actions, suggesting that atypicalities arise either when integrating this kinematic information with other perceptual input, or in the interpretation of kinematic information. Autism Res 2019, 12: 284-294 © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: It has previously been suggested that autistic children and adults have problems perceiving the detailed manner in which others move-that is, the subtle changes in speed as we move from point to point-which may impact on their ability to learn from, and about, others in a typical fashion. However, the results from the present two studies demonstrate that adults with autism can perceive this information, suggesting that atypicalities in processing others' movement may arise mainly as a consequence of atypical interpretation rather than perception.

Facilitation of biological motion processing by group-based autism specific social skills training

Abnormalities in neurophysiological correlates of social perception are a well-known feature of autism spectrum disorder (ASD). However, little is known if and how ASD specific behavioral interventions may affect neural processing in ASD. The aim of the current study was to investigate for the first time, whether the group-based social skills training SOSTA-FRA would elicit changes in neurophysiological correlates of social perception in high-functioning ASD individuals aged 8-17 years. Event-related potentials (ERPs) of a facial emotion recognition (FER) and a biological motion perception task were examined. ERPs were compared between a randomized intervention and a treatment as usual group at three time points (baseline, post-intervention, and at 3 months follow-up). A reduction of P100 amplitude in the right hemisphere and a trend toward reduced N200 latency in the biological motion task were found after the training only in the intervention group, whereas behavioral performance remained stable. Change in N200 latencies and parent-rated social responsiveness showed small but statistically nonsignificant correlations. No changes were observed regarding FER. Results indicate that the intervention changed neural correlates of social perception in ASD. Especially neural correlates of biological motion perception, which is an important prerequisite for successful social interaction, were sensitive to change. ERPs of social perception tasks that are impaired in ASD can well be used to objectively measure neural processing improvement by behavioral intervention. Autism Res 2018, 11: 1376-1387. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: It is well known that people with autism spectrum disorder (ASD) process social information differently than other people and that these differences can also be seen in their brain activity. We also know that behavioral therapies, such as group-based social skills trainings can help people with ASD improve their behavior. But it is unclear how therapy changes social processing in the brain. The aim of our study was therefore to examine how neural processing of social stimuli changed after behavioral intervention. Comparing a group of children and adolescents that received the group-based social skills training SOSTA-FRA to a control group we found that the neural processing of human motion became faster and involved less brain resources after the intervention, while behavioral performance remained stable. No changes were seen for the processing of emotional facial expressions. We recommend that future studies should also analyze changes in brain function as well as behavioral changes as a secondary therapy outcome parameter.

Transcriptional network analysis on brains reveals a potential regulatory role of PPP1R3F in autism spectrum disorders

OBJECTIVE

This study aims at identifying master regulators of transcriptional networks in autism spectrum disorders (ASDs).

RESULTS

With two sets of independent RNA-Seq data generated on cerebellum from patients with ASDs and control subjects (N = 39 and 45 for set 1, N = 24 and 38 for set 2, respectively), we carried out a network deconvolution of transcriptomic data, followed by virtual protein activity analysis. We identified PPP1R3F (Protein Phosphatase 1 Regulatory Subunit 3F) as a candidate master regulator affecting a large body of downstream genes that are associated with the disease phenotype. Pathway analysis on the identified targets of PPP1R3F in both datasets indicated alteration of endocytosis pathway. Despite a limited sample size, our study represents one of the first applications of network deconvolution approach to brain transcriptomic data to generate hypotheses that may be further validated by large-scale studies.

Behavioral Own-Body-Transformations in Children and Adolescents With Typical Development, Autism Spectrum Disorder, and Developmental Coordination Disorder

Background: In motor imitation, taking a partner's perspective often involves a mental body transformation from an embodied, ego-centered viewpoint to a disembodied, hetero-centered viewpoint. Impairments of both own-body-transformation (OBT) and abnormalities in visual-spatial processing have been reported in patients with neurodevelopmental disorders including autism spectrum disorder (ASD). In the context of a visual-motor interactive task, studying OBT impairments while disentangling the contribution of visual-spatial impairments associated with motor coordination problems has not been investigated. Methods: 85 children and adolescents (39 controls with typical development, TD; 29 patients with ASD; 17 patients with developmental coordination disorder, DCD), aged 6-19 years, participated in a behavioral paradigm in which participants interacted with a virtual tightrope walker (TW) standing and moving with him. The protocol enables to distinguish ego-centered and hetero-centered perspectives. Results: We show that (1) OBT was possible but difficult for children with neurodevelopmental disorders, as well as for TD children, when the task required the participant to perform a mental rotation in order to adopt a hetero-centered perspective. (2) Using multivariate models, hetero-centered perspective score was significantly associated with age, TW orientation, latency, and diagnosis. ASD and TD groups' performances were close and significantly correlated with age. However, it was not the case for DCD, since this group was specifically handicapped by visual-spatial impairments. (3) ASD and DCD did not perform similarly: motor performance as shown by movement amplitude was better in DCD than ASD. ASD motor response was more ambiguous and hardly readable. Conclusion: Changing perspective in a spatial environment is possible for patients with ASD although delayed compared with TD children. In patients with DCD, their visual-spatial impairments negatively modulated their performances in the experiment.

Brain Responses Underlying Anthropomorphism, Agency, and Social Attribution in Autism Spectrum Disorder

Background:

Theory of Mind (ToM), the ability to attribute mental states to oneself and others, is frequently impaired in Autism Spectrum Disorder (ASD) and may result from altered activation of social brain regions. Conversely, Typically Developing (TD) individuals overextend ToM and show a strong tendency to anthropomorphize and interpret biological motion in the environment. Less is known about how the degree of anthropomorphism influences intentional attribution and engagement of the social brain in ASD.

Objective:

This fMRI study examines the extent of anthropomorphism, its role in social attribution, and the underlying neural responses in ASD and TD using a series of human stick figures and geometrical shapes.

Methods:

14 ASD and 14 TD adults watched videos of stick figures and triangles interacting in random or socially meaningful ways while in an fMRI scanner. In addition, they completed out-of-scanner measures of ToM skill and real-world social deficits. Whole brain statistical analysis was performed for regression and within and between group comparisons of all conditions using SPM12’s implementation of the general linear model.

Results:

ToM network regions were activated in response to social movement and human-like characters in ASD and TD. In addition, greater ToM ability was associated with increased TPJ and MPFC activity while watching stick figures; whereas more severe social symptoms were associated with reduced right TPJ activation in response to social movement.

Conclusion:

These results suggest that degree of anthropomorphism does not differentially affect social attribution in ASD and highlights the importance of TPJ in ToM and social attribution.

Seeing More Than Human: Autism and Anthropomorphic Theory of Mind

Theory of mind (ToM) is defined as the process of taking another's perspective. Anthropomorphism can be seen as the extension of ToM to non-human entities. This review examines the literature concerning ToM and anthropomorphism in relation to individuals with Autism Spectrum Disorder (ASD), specifically addressing the questions of how and why those on the spectrum both show an increased interest for anthropomorphism and may even show improved ToM abilities when judging the mental states of anthropomorphic characters. This review highlights that while individuals with ASD traditionally show deficits on a wide range of ToM tests, such as recognizing facial emotions, such ToM deficits may be ameliorated if the stimuli presented is cartoon or animal-like rather than in human form. Individuals with ASD show a greater interest in anthropomorphic characters and process the features of these characters using methods typically reserved for human stimuli. Personal accounts of individuals with ASD also suggest they may identify more closely with animals than other humans. It is shown how the social motivations hypothesized to underlie the anthropomorphizing of non-human targets may lead those on the spectrum to seek social connections and therefore gain ToM experience and expertise amongst unlikely sources.

Diminished socially selective neural processing in 5-month-old infants at high familial risk of autism

The social and communicative difficulties that characterize autism spectrum disorder (ASD) are considered the most striking feature of the disorder. Research has reported that individuals with ASD show abnormalities in the brain regions associated with the processing of social information. Importantly, a recent study using functional near-infrared spectroscopy (fNIRS) found the first evidence of atypicalities in the neural processing of social information in 4- to 6-month-old infants at high familial risk of ASD. These findings provide an important step in the search for early markers of ASD and highlight the potential for neuroimaging techniques to detect atypical patterns of neural activity prior to the manifestation of most behavioural symptoms. This study aimed to extend the findings of reduced neural sensitivity to social stimuli in an independent cohort. Twenty-nine 5-month-old infants (13 low-risk infants, 16 high-risk infants) were presented with social and non-social visual stimuli, similar to the previous experiment. Importantly, a non-social dynamic motion control condition was introduced allowing the comparison between social dynamic and non-social, static, as well as dynamic stimuli. We found that while low-risk infants showed activation to social stimuli in the right posterior temporal cortex, this activation was reduced in infants at high risk of ASD. Although the current sample size was relatively small, our results replicate and extend previous work and provide evidence for a social processing difference in infants at risk of autism. Future research will determine whether these differences relate to an eventual ASD diagnosis or may rather reflect the broader autism phenotype.

The impact of atypical sensory processing on social impairments in autism spectrum disorder

Altered sensory processing has been an important feature of the clinical descriptions of autism spectrum disorder (ASD). There is evidence that sensory dysregulation arises early in the progression of ASD and impacts social functioning. This paper reviews behavioral and neurobiological evidence that describes how sensory deficits across multiple modalities (vision, hearing, touch, olfaction, gustation, and multisensory integration) could impact social functions in ASD. Theoretical models of ASD and their implications for the relationship between sensory and social functioning are discussed. Furthermore, neural differences in anatomy, function, and connectivity of different regions underlying sensory and social processing are also discussed. We conclude that there are multiple mechanisms through which early sensory dysregulation in ASD could cascade into social deficits across development. Future research is needed to clarify these mechanisms, and specific focus should be given to distinguish between deficits in primary sensory processing and altered top-down attentional and cognitive processes.

Observing and participating in social interactions: Action perception and action control across the autistic spectrum

Autism is a developmental condition, characterized by difficulties of social interaction and communication, as well as restricted interests and repetitive behaviors. Although several important conceptions have shed light on specific facets, there is still no consensus about a universal yet specific theory in terms of its underlying mechanisms. While some theories have exclusively focused on sensory aspects, others have emphasized social difficulties. However, sensory and social processes in autism might be interconnected to a higher degree than what has been traditionally thought. We propose that a mismatch in sensory abilities across individuals can lead to difficulties on a social, i.e. interpersonal level and vice versa. In this article, we, therefore, selectively review evidence indicating an interrelationship between perceptual and social difficulties in autism. Additionally, we link this body of research with studies, which investigate the mechanisms of action control in social contexts. By doing so, we highlight that autistic traits are also crucially related to differences in integration, anticipation and automatic responding to social cues, rather than a mere inability to register and learn from social cues. Importantly, such differences may only manifest themselves in sufficiently complex situations, such as real-life social interactions, where such processes are inextricably linked.

Brain network dynamics in high-functioning individuals with autism

Theoretically, autism should be underpinned by aberrant brain dynamics. However, how brain activity changes over time in individuals with autism spectrum disorder (ASD) remains unknown. Here we characterize brain dynamics in autism using an energy-landscape analysis applied to resting-state fMRI data. Whereas neurotypical brain activity frequently transits between two major brain states via an intermediate state, high-functioning adults with ASD show fewer neural transitions due to an unstable intermediate state, and these infrequent transitions predict the severity of autism. Moreover, in contrast to the controls whose IQ is correlated with the neural transition frequency, IQ scores of individuals with ASD are instead predicted by the stability of their brain dynamics. Finally, such brain–behaviour associations are related to functional segregation between brain networks. These findings suggest that atypical functional coordination in the brains of adults with ASD underpins overly stable neural dynamics, which supports both their ASD symptoms and cognitive abilities.

Though individuals with autism spectrum disorder (ASD) show a number of neural abnormalities, the relationship between global dynamic neural patterns and ASD symptoms remains unclear. Here, authors describe such global brain dynamics, relate these to cognitive abilities, ASD symptoms, and predict ASD diagnosis.

Disrupted development and imbalanced function in the global neuronal workspace: a positive-feedback mechanism for the emergence of ASD in early infancy

Autism spectrum disorder (ASD) is increasingly being conceptualized as a spectrum disorder of connectome development. We review evidence suggesting that ASD is characterized by a positive feedback loop that amplifies small functional variations in early-developing sensory-processing pathways into structural and functional imbalances in the global neuronal workspace. Using vision as an example, we discuss how early functional variants in visual processing may be feedback-amplified to produce variant object categories and disrupted top-down expectations, atypically large expectation-to-perception mismatches, problems re-identifying individual people and objects, socially inappropriate, generally aversive emotional responses and disrupted sensory-motor coordination. Viewing ASD in terms of feedback amplification of small functional variants allows a number of recent models of ASD to be integrated with neuroanatomical, neurofunctional and genetic data.

Influence of oxytocin on emotion recognition from body language: A randomized placebo-controlled trial

The neuropeptide 'oxytocin' (OT) is known to play a pivotal role in a variety of complex social behaviors by promoting a prosocial attitude and interpersonal bonding. One mechanism by which OT is hypothesized to promote prosocial behavior is by enhancing the processing of socially relevant information from the environment. With the present study, we explored to what extent OT can alter the 'reading' of emotional body language as presented by impoverished biological motion point light displays (PLDs). To do so, a double-blind between-subjects randomized placebo-controlled trial was conducted, assessing performance on a bodily emotion recognition task in healthy adult males before and after a single-dose of intranasal OT (24 IU). Overall, a single-dose of OT administration had a significant effect of medium size on emotion recognition from body language. OT-induced improvements in emotion recognition were not differentially modulated by the emotional valence of the presented stimuli (positive versus negative) and also, the overall tendency to label an observed emotional state as 'happy' (positive) or 'angry' (negative) was not modified by the administration of OT. Albeit moderate, the present findings of OT-induced improvements in bodily emotion recognition from whole-body PLD provide further support for a link between OT and the processing of socio-communicative cues originating from the body of others.

Anatomical imbalance between cortical networks in autism

Influential psychological models of autism spectrum disorder (ASD) have proposed that this prevalent developmental disorder results from impairment of global (integrative) information processing and overload of local (sensory) information. However, little neuroanatomical evidence consistent with this account has been reported. Here, we examined relative grey matter volumes (rGMVs) between three cortical networks, how they changed with age, and their relationship with core symptomatology. Using public neuroimaging data of high-functioning ASD males and age-/sex-/IQ-matched controls, we first identified age-associated atypical increases in rGMVs of the regions of two sensory systems (auditory and visual networks), and an age-related aberrant decrease in rGMV of a task-control system (fronto-parietal network, FPN) in ASD children. While the enlarged rGMV of the auditory network in ASD adults was associated with the severity of autistic socio-communicational core symptom, that of the visual network was instead correlated with the severity of restricted and repetitive behaviours in ASD. Notably, the atypically decreased rGMV of FPN predicted both of the two core symptoms. These findings suggest that disproportionate undergrowth of a task-control system (FPN) may be a common anatomical basis for the two ASD core symptoms, and relative overgrowth of the two different sensory systems selectively compounds the distinct symptoms.

Evaluation of Quantified Social Perception Circuit Activity as a Neurobiological Marker of Autism Spectrum Disorder

IMPORTANCE

Autism spectrum disorder (ASD) is marked by social disability and is associated with dysfunction in brain circuits supporting social cue perception. The degree to which neural functioning reflects individual-level behavioral phenotype is unclear, slowing the search for functional neuroimaging biomarkers of ASD.

OBJECTIVE

To examine whether quantified neural function in social perception circuits may serve as an individual-level marker of ASD in children and adolescents.

DESIGN, SETTING, AND PARTICIPANTS

The cohort study was conducted at the Yale Child Study Center and involved children and adolescents diagnosed as having ASD and typically developing participants. Participants included a discovery cohort and a larger replication cohort. Individual-level social perception circuit functioning was assessed as functional magnetic resonance imaging brain responses to point-light displays of coherent vs scrambled human motion.

MAIN OUTCOMES AND MEASURES

Outcome measures included performance of quantified brain responses in affected male and female participants in terms of area under the receiver operating characteristic curve (AUC), sensitivity and specificity, and correlations between brain responses and social behavior.

RESULTS

Of the 39 participants in the discovery cohort aged 4 to 17 years, 22 had ASD and 30 were boys. Of the 75 participants in the replication cohort aged 7 to 20 years, 37 had ASD and 52 were boys. A relative reduction in social perception circuit responses was identified in discovery cohort boys with ASD at an AUC of 0.75 (95% CI, 0.52-0.89; P = .01); however, typically developing girls and girls with ASD could not be distinguished (P = .54). The results were confirmed in the replication cohort, where brain responses were identified in boys with ASD at an AUC of 0.79 (95% CI, 0.64-0.91; P < .001) and failed to distinguish affected and unaffected girls (P = .82). Across both cohorts, boys were identified at an AUC of 0.77 (95% CI, 0.64-0.86) with corresponding sensitivity and specificity of 76% each. Additionally, brain responses were associated with social behavior in boys but not in girls.

CONCLUSIONS AND RELEVANCE

Quantified social perception circuit activity is a promising individual-level candidate neural marker of the male ASD behavioral phenotype. Our findings highlight the need to better understand effects of sex on social perception processing in relation to ASD phenotype manifestations.

Neural adaptation in pSTS correlates with perceptual aftereffects to biological motion and with autistic traits

The adaptive nature of biological motion perception has been documented in behavioral studies, with research showing that prolonged viewing of an action can bias judgments of subsequent actions towards the opposite of its attributes. However, the neural mechanisms underlying action adaptation aftereffects remain unknown. We examined adaptation-induced changes in brain responses to an ambiguous action after adapting to walking or running actions within two bilateral regions of interest: 1) human middle temporal area (hMT+), a lower-level motion-sensitive region of cortex, and 2) posterior superior temporal sulcus (pSTS), a higher-level action-selective area. We found a significant correlation between neural adaptation strength in right pSTS and perceptual aftereffects to biological motion measured behaviorally, but not in hMT+. The magnitude of neural adaptation in right pSTS was also strongly correlated with individual differences in the degree of autistic traits. Participants with more autistic traits exhibited less adaptation-induced modulations of brain responses in right pSTS and correspondingly weaker perceptual aftereffects. These results suggest a direct link between perceptual aftereffects and adaptation of neural populations in right pSTS after prolonged viewing of a biological motion stimulus, and highlight the potential importance of this brain region for understanding differences in social-cognitive processing along the autistic spectrum.

[Slowing down the flow of facial information enhances facial scanning in children with autism spectrum disorders: A pilot eye tracking study]

OBJECTIVE

Face and gaze avoidance are among the most characteristic and salient symptoms of autism spectrum disorders (ASD). Studies using eye tracking highlighted early and lifelong ASD-specific abnormalities in attention to face such as decreased attention to internal facial features. These specificities could be partly explained by disorders in the perception and integration of rapid and complex information such as that conveyed by facial movements and more broadly by biological and physical environment. Therefore, we wish to test whether slowing down facial dynamics may improve the way children with ASD attend to a face.

METHODS

We used an eye tracking method to examine gaze patterns of children with ASD aged 3 to 8 (n=23) and TD controls (n=29) while viewing the face of a speaker telling a story. The story was divided into 6 sequences that were randomly displayed at 3 different speeds, i.e. a real-time speed (RT), a slow speed (S70=70% of RT speed), a very slow speed (S50=50% of RT speed). S70 and S50 were displayed thanks to software called Logiral™, aimed at slowing down visual and auditory stimuli simultaneously and without tone distortion. The visual scene was divided into four regions of interest (ROI): eyes region; mouth region; whole face region; outside the face region. The total time, number and mean duration of visual fixations on the whole visual scene and the four ROI were measured between and within the two groups.

RESULTS

Compared to TD children, children with ASD spent significantly less time attending to the visual scenes and, when they looked at the scene, they spent less time scanning the speaker's face in general and her mouth in particular, and more time looking outside facial area. Within the ASD group mean duration of fixation increased on the whole scene and particularly on the mouth area, in R50 compared to RT. Children with mild autism spent more time looking at the face than the two other groups of ASD children, and spent more time attending to the face and mouth as well as longer mean duration of visual fixation on mouth and eyes, at slow speeds (S50 and/or S70) than at RT one.

CONCLUSIONS

Slowing down facial dynamics enhances looking time on face, and particularly on mouth and/or eyes, in a group of 23 children with ASD and particularly in a small subgroup with mild autism. Given the crucial role of reading the eyes for emotional processing and that of lip-reading for language processing, our present result and other converging ones could pave the way for novel socio-emotional and verbal rehabilitation methods for autistic population. Further studies should investigate whether increased attention to face and particularly eyes and mouth is correlated to emotional/social and/or verbal/language improvements.

Intact recognition, but attenuated adaptation, for biological motion in youth with autism spectrum disorder

Given the ecological importance of biological motion and its relevance to social cognition, considerable effort has been devoted over the past decade to studying biological motion perception in autism. However, previous studies have asked observers to detect or recognize briefly presented human actions placed in isolation, without spatial or temporal context. Research on typical populations has shown the influence of temporal context in biological motion perception: prolonged exposure to one action gives rise to an aftereffect that biases perception of a subsequently displayed action. Whether people with autism spectrum disorders (ASD) show such adaptation effects for biological motion stimuli remains unknown. To address this question, this study examined how well youth with ASD recognize ambiguous actions and adapt to recently-observed actions. Compared to typically-developing (TD) controls, youth with ASD showed no differences in perceptual boundaries between actions categories, indicating intact ability in recognizing actions. However, children with ASD showed weakened adaptation to biological motion. It is unlikely that the reduced action adaptability in autism was due to delayed developmental trajectory, as older children with ASD showed weaker adaptation to actions than younger children with ASD. Our results further suggest that high-level (i.e., action) processing weakens with age for children with ASD, but this change may be accompanied by a potentially compensatory mechanism based on more involvement of low-level (i.e., motion) processing. Autism Res 2016, 9: 1103-1113. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Functional Organization of the Action Observation Network in Autism: A Graph Theory Approach

BACKGROUND

The ability to recognize, understand and interpret other's actions and emotions has been linked to the mirror system or action-observation-network (AON). Although variations in these abilities are prevalent in the neuro-typical population, persons diagnosed with autism spectrum disorders (ASD) have deficits in the social domain and exhibit alterations in this neural network.

METHOD

Here, we examined functional network properties of the AON using graph theory measures and region-to-region functional connectivity analyses of resting-state fMRI-data from adolescents and young adults with ASD and typical controls (TC).

RESULTS

Overall, our graph theory analyses provided convergent evidence that the network integrity of the AON is altered in ASD, and that reductions in network efficiency relate to reductions in overall network density (i.e., decreased overall connection strength). Compared to TC, individuals with ASD showed significant reductions in network efficiency and increased shortest path lengths and centrality. Importantly, when adjusting for overall differences in network density between ASD and TC groups, participants with ASD continued to display reductions in network integrity, suggesting that also network-level organizational properties of the AON are altered in ASD.

CONCLUSION

While differences in empirical connectivity contributed to reductions in network integrity, graph theoretical analyses provided indications that also changes in the high-level network organization reduced integrity of the AON.

Effects of Transcranial Direct Current Stimulation on the Recognition of Bodily Emotions from Point-Light Displays

Perceiving human motion, recognizing actions, and interpreting emotional body language are tasks we perform daily and which are supported by a network of brain areas including the human posterior superior temporal sulcus (pSTS). Here, we applied transcranial direct current stimulation (tDCS) with anodal (excitatory) or cathodal (inhibitory) electrodes mounted over right pSTS (target) and orbito-frontal cortex (reference) while healthy participants performed a bodily emotion recognition task using biological motion point-light displays (PLDs). Performance (accuracy and reaction times) was also assessed on a control task which was matched to the emotion recognition task in terms of cognitive and motor demands. Each subject participated in two experimental sessions, receiving either anodal or cathodal stimulation, which were separated by one week to avoid residual effects of previous stimulations. Overall, tDCS brain stimulation did not affect the recognition of emotional states from PLDs. However, when emotions with a negative or positive-neutral emotional valence were analyzed separately, effects of stimulation were shown for recognizing emotions with a negative emotional valence (sadness and anger), indicating increased recognition performance when receiving anodal (excitatory) stimulation compared to cathodal (inhibitory) stimulation over pSTS. No stimulation effects were shown for the recognition of emotions with positive-neutral emotional valences. These findings extend previous studies showing structure-function relationships between STS and biological motion processing from PLDs and provide indications that stimulation effects may be modulated by the emotional valence of the stimuli.

Oxytocin: parallel processing in the social brain?

Early studies attempting to disentangle the network complexity of the brain exploited the accessibility of sensory receptive fields to reveal circuits made up of synapses connected both in series and in parallel. More recently, extension of this organisational principle beyond the sensory systems has been made possible by the advent of modern molecular, viral and optogenetic approaches. Here, evidence supporting parallel processing of social behaviours mediated by oxytocin is reviewed. Understanding oxytocinergic signalling from this perspective has significant implications for the design of oxytocin-based therapeutic interventions aimed at disorders such as autism, where disrupted social function is a core clinical feature. Moreover, identification of opportunities for novel technology development will require a better appreciation of the complexity of the circuit-level organisation of the social brain.

Understanding the brain-behaviour relationship in persons with ASD: implications for PECS as a treatment choice

INTRODUCTION

This article presents emerging neurological findings in Autism Spectrum Disorders (ASD) with particular attention to how this information might inform treatment practices addressing communication impairments.

METHODS

The article begins with a general discussion of the brain-behaviour relationship and moves to the presentation of recent research findings related to ASD. There is particular attention to individuals with autism who are either non-verbal or present emergent verbal abilities.

RESULTS/DISCUSSION

A specific communication treatment, the Picture Exchange Communication System (PECS), is presented as an example of an intervention that addresses the learner needs of many individuals with ASD. The success of PECS is discussed within the context of its fit with brain-based learner characteristics.

Age-related changes in intrinsic function of the superior temporal sulcus in autism spectrum disorders

Currently, the developmental trajectories of neural circuits implicated in autism spectrum disorders (ASD) are largely unknown. Here, we specifically focused on age-related changes in the functional circuitry of the posterior superior temporal sulcus (pSTS), a key hub underlying social-cognitive processes known to be impaired in ASD. Using a cross-sectional approach, we analysed resting-state functional magnetic resonance imaging (fMRI) data collected from children, adolescents and adults available through the autism brain imaging data exchange repository [n = 106 with ASD and n = 109 typical controls (TC), ages 7-30 years]. The observed age-related changes of pSTS intrinsic functional connectivity (iFC) suggest that no single developmental pattern characterizes ASD. Instead, pSTS circuitry displayed a complex developmental picture, with some functional circuits showing patterns consistent with atypical development in ASD relative to TC (pSTS-iFC with fusiform gyrus and angular gyrus) and others showing delayed maturation (pSTS-iFC with regions of the action perception network). Distinct developmental trajectories in different functional circuits in ASD likely reflect differential age-related changes in the socio-cognitive processes they underlie. Increasing insight on these mechanisms is a critical step in the development of age-specific interventions in ASD.

Multimodal neuroimaging based classification of autism spectrum disorder using anatomical, neurochemical, and white matter correlates

Neuroimaging techniques, such as fMRI, structural MRI, diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (1H-MRS) have uncovered evidence for widespread functional and anatomical brain abnormalities in autism spectrum disorder (ASD) suggesting it to be a system-wide neural systems disorder. Nevertheless, most previous studies have focused on examining one index of neuropathology through a single neuroimaging modality, and seldom using multiple modalities to examine the same cohort of individuals. The current study aims to bring together multiple brain imaging modalities (structural MRI, DTI, and 1H-MRS) to investigate the neural architecture in the same set of individuals (19 high-functioning adults with ASD and 18 typically developing (TD) peers). Morphometry analysis revealed increased cortical thickness in ASD participants, relative to typical controls, across the left cingulate, left pars opercularis of the inferior frontal gyrus, left inferior temporal cortex, and right precuneus, and reduced cortical thickness in right cuneus and right precentral gyrus. ASD adults also had reduced fractional anisotropy (FA) and increased radial diffusivity (RD) for two clusters on the forceps minor of the corpus callosum, revealed by DTI analyses. 1H-MRS results showed a reduction in the N-acetylaspartate/Creatine ratio in dorsal anterior cingulate cortex (dACC) in ASD participants. A decision tree classification analysis across the three modalities resulted in classification accuracy of 91.9% with FA, RD, and cortical thickness as key predictors. Examining the same cohort of adults with ASD and their TD peers, this study found alterations in cortical thickness, white matter (WM) connectivity, and neurochemical concentration in ASD. These findings underscore the potential for multimodal imaging to better inform on the neural characteristics most relevant to the disorder.

Autism, oxytocin and interoception

Autism is a pervasive developmental disorder characterized by profound social and verbal communication deficits, stereotypical motor behaviors, restricted interests, and cognitive abnormalities. Autism affects approximately 1% of children in developing countries. Given this prevalence, identifying risk factors and therapeutic interventions are pressing objectives—objectives that rest on neurobiologically grounded and psychologically informed theories about the underlying pathophysiology. In this article, we review the evidence that autism could result from a dysfunctional oxytocin system early in life. As a mediator of successful procreation, not only in the reproductive system, but also in the brain, oxytocin plays a crucial role in sculpting socio-sexual behavior. Formulated within a (Bayesian) predictive coding framework, we propose that oxytocin encodes the saliency or precision of interoceptive signals and enables the neuronal plasticity necessary for acquiring a generative model of the emotional and social 'self.' An aberrant oxytocin system in infancy could therefore help explain the marked deficits in language and social communication—as well as the sensory, autonomic, motor, behavioral, and cognitive abnormalities—seen in autism.

Schematic and realistic biological motion identification in children with high-functioning autism spectrum disorder

Research investigating biological motion perception in children with ASD has revealed conflicting findings concerning whether impairments in biological motion perception exist. The current study investigated how children with high-functioning ASD (HF-ASD) performed on two tasks of biological motion identification: a novel schematic motion identification task and a point-light biological motion identification task. Twenty-two HFASD children were matched with 21 TD children on gender, non-verbal mental, and chronological, age (M years = 6.72). On both tasks, HF-ASD children performed with similar accuracy as TD children. Across groups, children performed better on animate than on inanimate trials of both tasks. These findings suggest that HF-ASD children's identification of both realistic and schematic biological motion identification is unimpaired.

Deficient local biological motion perception in migraineurs: results from a duration discrimination paradigm

Migraine ranks as the third most common disease in the world and has caused significant losses of daily life abilities. Previously, people gave more attention to the pain of migraines and usually ignored the impairments of cognitive function in migraineurs. In the present study, a duration discrimination paradigm was used to assess the global and local biological motion perception in migraineurs and healthy controls. In the experiment, biological motion sequences and inanimate motion sequences (the inverted biological motion sequences) were sequentially presented on a screen. Observers were instructed to make a two-alternative forced choice to accurately indicate which interval (the first or the second) appeared longer. The stimuli involved global biological motion sequences and local biological motion sequences. The statistical analyses were conducted on the points of subjective equality that were obtained by fitting a psychometric function to each individual observer's data. In migraineurs, global biological motion signals lengthened the perceived temporal duration (as occurs in normal people), whereas local biological motion signals did not have this temporal dilation effect. The results indicated that patients with migraine showed a deficit in local biological motion perception, whereas their global biological motion perception was comparable to that of healthy subjects.

Visual event-related potentials to biological motion stimuli in autism spectrum disorders

Atypical visual processing of biological motion contributes to social impairments in autism spectrum disorders (ASD). However, the exact temporal sequence of deficits of cortical biological motion processing in ASD has not been studied to date. We used 64-channel electroencephalography to study event-related potentials associated with human motion perception in 17 children and adolescents with ASD and 21 typical controls. A spatio-temporal source analysis was performed to assess the brain structures involved in these processes. We expected altered activity already during early stimulus processing and reduced activity during subsequent biological motion specific processes in ASD. In response to both, random and biological motion, the P100 amplitude was decreased suggesting unspecific deficits in visual processing, and the occipito-temporal N200 showed atypical lateralization in ASD suggesting altered hemispheric specialization. A slow positive deflection after 400 ms, reflecting top-down processes, and human motion-specific dipole activation differed slightly between groups, with reduced and more diffuse activation in the ASD-group. The latter could be an indicator of a disrupted neuronal network for biological motion processing in ADS. Furthermore, early visual processing (P100) seems to be correlated to biological motion-specific activation. This emphasizes the relevance of early sensory processing for higher order processing deficits in ASD.

Visual processing of biological motion in children and adolescents with attention-deficit/hyperactivity disorder: an event related potential-study

Attention-deficit/hyperactivity disorder (ADHD) is often accompanied by problems in social behaviour, which are sometimes similar to some symptoms of autism-spectrum disorders (ASD). However, neuronal mechanisms of ASD-like deficits in ADHD have rarely been studied. The processing of biological motion-recently discussed as a marker of social cognition-was found to be disrupted in ASD in several studies. Thus in the present study we tested if biological motion processing is disrupted in ADHD. We used 64-channel EEG and spatio-temporal source analysis to assess event-related potentials associated with human motion processing in 21 children and adolescents with ADHD and 21 matched typically developing controls. On the behavioural level, all subjects were able to differentiate between human and scrambled motion. But in response to both scrambled and biological motion, the N200 amplitude was decreased in subjects with ADHD. After a spatio-temporal dipole analysis, a human motion specific activation was observable in occipital-temporal regions with a reduced and more diffuse activation in ADHD subjects. These results point towards neuronal determined alterations in the processing of biological motion in ADHD.

Anthropomorphic bias found in typically developing children is not found in children with autistic spectrum disorder

The anthropomorphic bias describes the finding that the perceived naturalness of a biological motion decreases as the human-likeness of a computer-animated agent increases. To investigate the anthropomorphic bias in autistic children, human or cartoon characters were presented with biological and artificial motions side by side on a touchscreen. Children were required to touch one that would grow while the other would disappear, implicitly rewarding their choice. Only typically developing controls depicted the expected preference for biological motion when rendered with human, but not cartoon, characters. Despite performing the task to report a preference, children with autism depicted neither normal nor reversed anthropomorphic bias, suggesting that they are not sensitive to the congruence of form and motion information when observing computer-animated agents' actions.

Atypical basic movement kinematics in autism spectrum conditions

Individuals with autism spectrum conditions have difficulties in understanding and responding appropriately to others. Additionally, they demonstrate impaired perception of biological motion and problems with motor control. Here we investigated whether individuals with autism move with an atypical kinematic profile, which might help to explain perceptual and motor impairments, and in principle may contribute to some of their higher level social problems. We recorded trajectory, velocity, acceleration and jerk while adult participants with autism and a matched control group conducted horizontal sinusoidal arm movements. Additionally, participants with autism took part in a biological motion perception task in which they classified observed movements as ‘natural’ or ‘unnatural’. Results show that individuals with autism moved with atypical kinematics; they did not minimize jerk to the same extent as the matched typical control group, and moved with greater acceleration and velocity. The degree to which kinematics were atypical was correlated with a bias towards perceiving biological motion as ‘unnatural’ and with the severity of autism symptoms as measured by the Autism Diagnostic Observation Schedule. We suggest that fundamental differences in movement kinematics in autism might help to explain their problems with motor control. Additionally, developmental experience of their own atypical kinematic profiles may lead to disrupted perception of others’ actions.

Underconnectivity of the superior temporal sulcus predicts emotion recognition deficits in autism

Neurodevelopmental disconnections have been assumed to cause behavioral alterations in autism spectrum disorders (ASDs). Here, we combined measurements of intrinsic functional connectivity (iFC) from resting-state functional magnetic resonance imaging (fMRI) with task-based fMRI to explore whether altered activity and/or iFC of the right posterior superior temporal sulcus (pSTS) mediates deficits in emotion recognition in ASD. Fifteen adults with ASD and 15 matched-controls underwent resting-state and task-based fMRI, during which participants discriminated emotional states from point light displays (PLDs). Intrinsic FC of the right pSTS was further examined using 584 (278 ASD/306 controls) resting-state data of the Autism Brain Imaging Data Exchange (ABIDE). Participants with ASD were less accurate than controls in recognizing emotional states from PLDs. Analyses revealed pronounced ASD-related reductions both in task-based activity and resting-state iFC of the right pSTS with fronto-parietal areas typically encompassing the action observation network (AON). Notably, pSTS-hypo-activity was related to pSTS-hypo-connectivity, and both measures were predictive of emotion recognition performance with each measure explaining a unique part of the variance. Analyses with the large independent ABIDE dataset replicated reductions in pSTS-iFC to fronto-parietal regions. These findings provide novel evidence that pSTS hypo-activity and hypo-connectivity with the fronto-parietal AON are linked to the social deficits characteristic of ASD.

Sex differences in the development of brain mechanisms for processing biological motion

Disorders related to social functioning including autism and schizophrenia differ drastically in incidence and severity between males and females. Little is known about the neural systems underlying these sex-linked differences in risk and resiliency. Using functional magnetic resonance imaging and a task involving the visual perception of point-light displays of coherent and scrambled biological motion, we discovered sex differences in the development of neural systems for basic social perception. In adults, we identified enhanced activity during coherent biological motion perception in females relative to males in a network of brain regions previously implicated in social perception including amygdala, medial temporal gyrus, and temporal pole. These sex differences were less pronounced in our sample of school-age youth. We hypothesize that the robust neural circuitry supporting social perception in females, which diverges from males beginning in childhood, may underlie sex differences in disorders related to social processing.