Autistic traits affect interpersonal motor coordination by modulating strategic use of role-based behavior

Social-Motor Coordination Between Peers: Joint Action Developmental Trajectories in ASD and TD

Coordinating a physical movement in time and space with social and nonsocial partners to achieve a shared goal - "joint action" (JA) - characterizes many peer-engagement situations that pose challenges for individuals with autism spectrum disorder (ASD). This cross-sectional study examined development of JA capabilities comparing ASD versus typically developing (TD) groups in early childhood, preadolescence, and adolescence while performing mirroring and complementing JA tasks with social (peer) and nonsocial (computer) partners. Results indicated better motor coordination abilities on computerized tasks than in peer dyads, with larger peer-dyad deficits shown by the ASD group. Developmental growth in JA abilities emerged, but the ASD group lagged behind same-age peers with TD. Socio-motor interventions may offer new channels to facilitate peer engagement in ASD.

Pain assessment in autism: updating the ethical and methodological challenges through a state-of-the-art review

Sensory features of autism include hypo- or hyper-reactivity to pain; however, previous studies on pain in autism lead to conflicting results. Here, we present the state of the art and the methodological challenges concerning pain perception in autism, focusing on studies that used standardized protocol as Quantitative Sensory Testing (QST) to measure perception. Despite there are still scant evidences found with the use of QST, they have challenged the presumed hyposensitivity to pain in autisms, which emerged from parents' reports. Both, peripheral and central mechanisms, have been found involved in typical features of perception in autism. Nonetheless, evidences with controlled protocols are still scarce, and even scarcer are studies focused on children. Overall, complex ethical challenges have to be overcome in order to collect subjective and objective measures from autistic children. With heterogeneous neurodevelopmental features, or intellectual disability, novel or modified protocols are needed.

Neuromodulation of the Left Inferior Frontal Cortex Affects Social Monitoring during Motor Interactions

Motor interactions require observing and monitoring a partner's performance as the interaction unfolds. Studies in monkeys suggest that this form of social monitoring might be mediated by the activity of the ventral premotor cortex (vPMc), a critical brain region in action observation and motor planning. Our previous fMRI studies in humans showed that the left vPMc is indeed recruited during social monitoring, but its causal role is unexplored. In three experiments, we applied online anodal or cathodal transcranial direct current stimulation over the left lateral frontal cortex during a music-like interactive task to test the hypothesis that neuromodulation of the left vPMc affects participants' performance when a partner violates the agent's expectations. Participants played short musical sequences together with a virtual partner by playing one note each in turn-taking. In 50% of the trials, the partner violated the participant's expectations by generating the correct note through an unexpected movement. During sham stimulation, the partner's unexpected behavior led to a slowdown in the participant's performance (observation-induced posterror slowing). A significant interaction with the stimulation type showed that cathodal and anodal transcranial direct current stimulation induced modulation of the observation-induced posterror slowing in opposite directions by reducing or enhancing it, respectively. Cathodal stimulation significantly reduced the effect compared to sham stimulation. No effect of neuromodulation was found when the partner behaved as expected or when the observed violation occurred within a context that was perceptually matched but noninteractive in nature. These results provide evidence for the critical causal role that the left vPMc might play in social monitoring during motor interactions, possibly through the interplay with other brain regions in the posterior medial frontal cortex.

Social Synchronization of Conditioned Fear in Mice Requires Ventral Hippocampus Input to the Amygdala

BACKGROUND

Social organisms synchronize behaviors as an evolutionary-conserved means of thriving. Synchronization under threat, in particular, benefits survival and occurs across species, including humans, but the underlying mechanisms remain unknown because of the scarcity of relevant animal models. Here, we developed a rodent paradigm in which mice synchronized a classically conditioned fear response and identified an underlying neuronal circuit.

METHODS

Male and female mice were trained individually using auditory fear conditioning and then tested 24 hours later as dyads while allowing unrestricted social interaction during exposure to the conditioned stimulus under visible or infrared illumination to eliminate visual cues. The synchronization of the immobility or freezing bouts was quantified by calculating the effect size Cohen's d for the difference between the actual freezing time overlap and the overlap by chance. The inactivation of the dorsomedial prefrontal cortex, dorsal hippocampus, or ventral hippocampus was achieved by local infusions of muscimol. The chemogenetic disconnection of the hippocampus-amygdala pathway was performed by expressing hM4D(Gi) in the ventral hippocampal neurons and infusing clozapine N-oxide in the amygdala.

RESULTS

Mice synchronized cued but not contextual fear. It was higher in males than in females and attenuated in the absence of visible light. Inactivation of the ventral but not dorsal hippocampus or dorsomedial prefrontal cortex abolished fear synchronization. Finally, the disconnection of the hippocampus-amygdala pathway diminished fear synchronization.

CONCLUSIONS

Mice synchronize expression of conditioned fear relying on the ventral hippocampus-amygdala pathway, suggesting that the hippocampus transmits social information to the amygdala to synchronize threat response.

Analysis of group behavior based on sharing heterogeneous roles in a triad using a coordinated drawing task

Humans often share roles and aim to achieve a group goal based on sociality, which is the tendency to spontaneously involve oneself with others. Cognitive science, psychology, and neuroscience studies suggest that in such planned coordination, adjusting one’s own actions based on other roles is crucial for high task performance. However, the mechanisms of complex and dynamically planned coordination, such as non-verbal group behavior with three or more members, remain to be fully investigated. This study introduced a coordinated drawing task in a triad, quantitatively analyzed non-verbal group behavior based on sharing heterogeneous roles, and investigated an important role. Participant triads engaged in the task repeatedly by operating reels to change thread tensions and moving a pen connected to the three threads to draw an equilateral triangle. Then, the three roles (pulling, relaxing, and adjusting) had to be shared. The pulling and relaxing roles served to move the pen as if an operator pulled it closer to the hand and to support the pen’s movement, respectively. However, these roles alone could not draw a side considering the task specification. The adjusting role needed to change the tension flexibly and maintain an overall balance. In the experiment, we measured the pen positions and tensions, and established statistical models to fit the analyzed data. The results estimated that the action in the adjusting role was related to the improved performance of faster drawing on a side. This role may moderately intervene in the actions by the other roles and fine-tune without disturbing the pen’s smooth movement while avoiding great pen deviation. Our findings may suggest the crucial role as a facilitator that handles resiliently in non-verbal coordinated behavior of a triad, and contribute to our understanding of social interactions.

Impaired Biological Motion Processing and Motor Skills in Adults with Autistic Traits

The present study explored the relationship between biological motion (BioM) processing, motor skills, and autistic traits within a non-clinical sample of 621 adults (18-73 years, 51.8% female). Results indicated that adults with greater autistic traits also endorsed difficulties associated with developmental coordination disorder (DCD) in childhood and adulthood. Traits associated with autism spectrum disorder and DCD were predictive of BioM processing abilities. The results also revealed sex differences in DCD, autistic traits, and BioM processing. Overall, these findings suggest that adults with greater autistic traits experience both deficits in motor activities as well as underlying motor perceptual abilities.

Midfrontal Theta tACS Facilitates Motor Coordination in Dyadic Human-Avatar Interactions

Synchronous interpersonal motor interactions require moment-to-moment prediction and proactive monitoring of the partner's actions. Neurophysiologically, this is highlighted by an enhancement of midfrontal theta (4-7 Hz) oscillations. In this study, we explored the causal role of midfrontal theta for interpersonal motor interactions using transcranial alternating current stimulation (tACS). We implemented a realistic human-avatar interaction task in immersive virtual reality where participants controlled a virtual arm and hand to press a button synchronously with a virtual partner. Participants completed the task while receiving EEG-informed theta (Experiment 1) or beta (control frequency, Experiment 2) tACS over the frontal midline, as well as sham stimulation as a control. Results showed that midfrontal theta tACS significantly improved behavioral performance (i.e., reduced interpersonal asynchrony) and participants' motor strategies (i.e., increased movement times and reduced RTs), whereas beta tACS had no effect on these measures. These results suggest that theta tACS over frontal areas facilitates action monitoring and motor abilities supporting interpersonal interactions.

Examining the Use of Game-Based Assessments for Hiring Autistic Job Seekers

Although people with autism are protected under the Americans with Disabilities Act of 1990, there is little theoretical or practical effort to determine whether traditional pre-employment assessments unfairly impact autistic job seekers. Due to the lack of emphasis on social communication, game-based assessments (GBAs) may offer a way of assessing candidate ability without disadvantaging autistic candidates. A total of 263 autistic job seekers took one of two game-based assessment packages designed to measure cognitive ability. After comparing their results to 323 college-graduate job seekers in the general population, we found that performance on the GBAs was generally similar in both populations, although some small differences were detected. Implications for hiring decisions are discussed.

Taking apart what brings us together: The role of action prediction, perspective-taking, and theory of mind in joint action

The ability to act together with others to achieve common goals is crucial in life, yet there is no full consensus on the underlying cognitive skills. While influential theoretical accounts suggest that interaction requires sophisticated insights into others' minds, alternative views propose that high-level social skills might not be necessary because interactions are grounded on sensorimotor predictive mechanisms. At present, empirical evidence is insufficient to decide between the two. This study addressed this issue and explored the association between performance at joint action tasks and cognitive abilities in three domains-action prediction, perspective-taking, and theory of mind-in healthy adults (N = 58). We found that, while perspective-taking played a role in reading the behaviour of others independently of the social context, action prediction abilities specifically influenced the agents' performance in an interactive task but not in a control (social but non-interactive) task. In our study, performance at a theory of mind test did not play any role, as confirmed by Bayesian analyses. The results suggest that, in adults, sensorimotor predictive mechanisms might play a significant and specific role in supporting interpersonal coordination during motor interactions. We discuss the implications of our findings for the contrasting theoretical views described earlier and propose a way they might be partly reconciled.

Robots facilitate human language production

Despite recent developments in integrating autonomous and human-like robots into many aspects of everyday life, social interactions with robots are still a challenge. Here, we focus on a central tool for social interaction: verbal communication. We assess the extent to which humans co-represent (simulate and predict) a robot's verbal actions. During a joint picture naming task, participants took turns in naming objects together with a social robot (Pepper, Softbank Robotics). Previous findings using this task with human partners revealed internal simulations on behalf of the partner down to the level of selecting words from the mental lexicon, reflected in partner-elicited inhibitory effects on subsequent naming. Here, with the robot, the partner-elicited inhibitory effects were not observed. Instead, naming was facilitated, as revealed by faster naming of word categories co-named with the robot. This facilitation suggests that robots, unlike humans, are not simulated down to the level of lexical selection. Instead, a robot's speaking appears to be simulated at the initial level of language production where the meaning of the verbal message is generated, resulting in facilitated language production due to conceptual priming. We conclude that robots facilitate core conceptualization processes when humans transform thoughts to language during speaking.

Bridging the gap between emotion and joint action

Our daily human life is filled with a myriad of joint action moments, be it children playing, adults working together (i.e., team sports), or strangers navigating through a crowd. Joint action brings individuals (and embodiment of their emotions) together, in space and in time. Yet little is known about how individual emotions propagate through embodied presence in a group, and how joint action changes individual emotion. In fact, the multi-agent component is largely missing from neuroscience-based approaches to emotion, and reversely joint action research has not found a way yet to include emotion as one of the key parameters to model socio-motor interaction. In this review, we first identify the gap and then stockpile evidence showing strong entanglement between emotion and acting together from various branches of sciences. We propose an integrative approach to bridge the gap, highlight five research avenues to do so in behavioral neuroscience and digital sciences, and address some of the key challenges in the area faced by modern societies.

Brain and motor synchrony in children and adolescents with ASD-a fNIRS hyperscanning study

Brain-to-brain synchrony has been proposed as an important mechanism underlying social interaction. While first findings indicate that it may be modulated in children with autism spectrum disorder (ASD), no study to date has investigated the influence of different interaction partners and task characteristics. Using functional near-infrared spectroscopy hyperscanning, we assessed brain-to-brain synchrony in 41 male typically developing (TD) children (8–18 years; control sample), as well as 18 children with ASD and age-matched TD children (matched sample), while performing cooperative and competitive tasks with their parents and an adult stranger. Dyads were instructed either to respond jointly in response to a target (cooperation) or to respond faster than the other player (competition). Wavelet coherence was calculated for oxy- and deoxyhemoglobin brain signals. In the control sample, a widespread enhanced coherence was observed for parent–child competition, and a more localized coherence for parent–child cooperation in the frontopolar cortex. While behaviorally, children with ASD showed a lower motor synchrony than children in the TD group, no significant group differences were observed on the neural level. In order to identify biomarkers for typical and atypical social interactions in the long run, more research is needed to investigate the neurobiological underpinnings of reduced synchrony in ASD.

Inhibitory Theta Burst Stimulation Highlights the Role of Left aIPS and Right TPJ during Complementary and Imitative Human-Avatar Interactions in Cooperative and Competitive Scenarios

Competitive and cooperative interactions are based on anticipation or synchronization with the partner's actions. Both forms of interaction may either require performing imitative or complementary movements with respect to those performed by our partner. We explored how parietal regions involved in the control of imitative behavior (temporo-parietal junction, TPJ), goal coding and visuo-motor integration (anterior intraparietal sulcus, aIPS) contribute to the execution of imitative and complementary movements during cooperative and competitive interactions. To this aim, we delivered off-line non-invasive inhibitory brain stimulation to healthy individuals' left aIPS and right TPJ before they were asked to reach and grasp an object together with a virtual partner by either performing imitative or complementary interactions. In different blocks, participants were asked to compete or cooperate with the virtual partner that varied its behavior according to cooperative or competitive contexts. Left aIPS and right TPJ inhibition impaired individuals' performance (i.e., synchrony in cooperative task and anticipation in competition) during complementary and imitative interactions, respectively, in both cooperative and competitive contexts, indicating that aIPS and TPJ inhibition affects own-other action integration and action imitation (that are different in complementary vs imitative interactions) more than action synchronization or anticipation (that are different in cooperative vs competitive contexts).

The Association among Autistic Traits, Interactional Synchrony and Typical Pattern of Motor Planning and Execution in Neurotypical Individuals

Autism spectrum disorder (ASD) is characterized by deficits in interactional synchrony and motor performance, but little is known about the association between them. The current study investigated the association among aberrant interactional synchrony (as measured by interactors’ symmetry in the form of the hand at each time-point along movement’s execution), motor functioning and the level of Autistic traits. In this study, autistic traits were evaluated by the Autistic Spectrum Quotient (AQ). Two tasks were used: (1) an interactional synchrony task where participants and the research assistant were instructed to move their hands together; and (2) a motor planning task which allows for continuous monitoring of natural hand movements. Pearson correlation analysis indicated a significant association between lower communication skills (i.e., higher AQ communication scores) and lower intentional synchrony rates. In addition, lower communication skills were found associated with typical patterns of motor planning and execution characterized by shorter time to start the movement and higher value of max speed. Mediator analyses supported the notion that aberrant intentional synchrony in individuals with low communication skills is partially mediated through typical patterns of motor planning and execution. These results suggest typical patterns of motor functions may account for intentional synchrony difficulties.

Introducing Social Breathing: A Model of Engaging in Relational Systems

We address what it means to "engage in a relationship" and suggest Social Breathing as a model of immersing ourselves in the metaphorical social air around us, which is necessary for shared intention and joint action. We emphasize how emergent properties of social systems arise, such as the shared culture of groups, which cannot be reduced to the individuals involved. We argue that the processes involved in Social Breathing are: (1) automatic, (2) implicit, (3) temporal, (4) in the form of mutual bi-directional interwoven exchanges between social partners and (5) embodied in the coordination of the brains and behaviors of social partners. We summarize cross-disciplinary evidence suggesting that these processes involve a multi-person whole-brain-body network which is critical for the development of both we-ness and relational skills. We propose that Social Breathing depends on each individual's ability to sustain multimodal interwovenness, thus providing a theoretical link between social neuroscience and relational/multi-person psychology. We discuss how the model could guide research on autism, relationships, and psychotherapy.

Understanding joint action: Current theoretical and empirical approaches

Joint actions are omnipresent, ranging from a handshake between two people to the coordination of groups of people playing in an orchestra. We are highly skilled at coordinating our actions with those of others to reach common goals and rely on this ability throughout our daily lives. What are the social, cognitive and neural processes underlying this ability? How do others around us influence our task representations? How does joint action influence interpersonal interactions? How do language and gesture support joint action? What differentiates joint action from individual action? This article forms an introductory editorial to the field of joint action. It accompanies contributions to the special issue entitled "Current Issues in Joint Action Research". The issue brings together conceptual and empirical approaches on different topics, ranging from lower-level issues such as the link between perception and joint action, to higher-level issues such as language as a form of joint action.

Competence-based social status and implicit preference modulate the ability to coordinate during a joint grasping task

Studies indicate that social status influences people's social perceptions. Less information is available about whether induced social status influences dyadic coordination during motor interactions. To explore this issue, we designed a study in which two confederates obtained high or low competence-based status by playing a game together with the participant, while the participant always occupied the middle position of the hierarchy. Following this status-inducing phase, participants were engaged in a joint grasping task with the high- and low-status confederates in different sessions while behavioural (i.e., interpersonal asynchrony and movement start time) indexes were measured. Participants' performance in the task (i.e., level of interpersonal asynchrony) when interacting with the low-status partner was modulated by their preference for him. The lower participants' preference for a low- relative to a high-status confederate, the worse participants' performance when interacting with the low-status confederate. Our results show that participants' performance during motor interactions changes according to the social status of the interaction partner.

Interpersonal Motor Interactions Shape Multisensory Representations of the Peripersonal Space

This perspective review focuses on the proposal that predictive multisensory integration occurring in one's peripersonal space (PPS) supports individuals' ability to efficiently interact with others, and that integrating sensorimotor signals from the interacting partners leads to the emergence of a shared representation of the PPS. To support this proposal, we first introduce the features of body and PPS representations that are relevant for interpersonal motor interactions. Then, we highlight the role of action planning and execution on the dynamic expansion of the PPS. We continue by presenting evidence of PPS modulations after tool use and review studies suggesting that PPS expansions may be accounted for by Bayesian sensory filtering through predictive coding. In the central section, we describe how this conceptual framework can be used to explain the mechanisms through which the PPS may be modulated by the actions of our interaction partner, in order to facilitate interpersonal coordination. Last, we discuss how this proposal may support recent evidence concerning PPS rigidity in Autism Spectrum Disorder (ASD) and its possible relationship with ASD individuals' difficulties during interpersonal coordination. Future studies will need to clarify the mechanisms and neural underpinning of these dynamic, interpersonal modulations of the PPS.

Acting with shared intentions: A systematic review on joint action coordination in Autism Spectrum Disorder

BACKGROUND

Joint actions, described as a form of social interaction in which individuals coordinate their actions in space and time to bring about a change in the environment, rely on sensory-motor processes that play a role in the development of social skills. Two brain networks, associated with "mirroring" and "mentalizing", are engaged during these actions: the mirror neuron and the theory of mind systems. People with autism spectrum disorder (ASD) showed impairment in interpersonal coordination during joint actions. Studying joint action coordination in ASD will contribute to clarify the interplay between sensory-motor and social processes throughout development and the interactions between the brain and the behavior.

METHOD

This review focused on empirical studies that reported behavioral and kinematic findings related to joint action coordination in people with ASD.

RESULTS

Literature on mechanisms involved in the joint action coordination impairment in ASD is still limited. Data are controversial. Different key-components of joint action coordination may be impaired, such as cooperative behavior, temporal coordination, and motor planning.

CONCLUSIONS

Interpersonal coordination during joint actions relies on early sensory-motor processes that have a key role in guiding social development. Early intervention targeting the sensory-motor processes involved in the development of joint action coordination could positively support social skills.

Haptic communication optimises joint decisions and affords implicit confidence sharing

Group decisions can outperform the choices of the best individual group members. Previous research suggested that optimal group decisions require individuals to communicate explicitly (e.g., verbally) their confidence levels. Our study addresses the untested hypothesis that implicit communication using a sensorimotor channel—haptic coupling—may afford optimal group decisions, too. We report that haptically coupled dyads solve a perceptual discrimination task more accurately than their best individual members; and five times faster than dyads using explicit communication. Furthermore, our computational analyses indicate that the haptic channel affords implicit confidence sharing. We found that dyads take leadership over the choice and communicate their confidence in it by modulating both the timing and the force of their movements. Our findings may pave the way to negotiation technologies using fast sensorimotor communication to solve problems in groups.

Brief Report: Classification of Autistic Traits According to Brain Activity Recoded by fNIRS Using ε-Complexity Coefficients

Individuals with ASD have been shown to have different pattern of functional connectivity. In this study, brain activity of participants with many and few autistic traits, was recorded using an fNIRS device, as participants preformed an interpersonal synchronization task. This type of task involves synchronization and functional connectivity of different brain regions. A novel method for assessing signal complexity, using ε-complexity coefficients, applied for the first i.e. on fNIRS recording, was used to classify brain recording of participants with many/few autistic traits. Successful classification was achieved implying that this method may be useful for classification of fNIRS recordings and that there is a difference in brain activity between participants with low and high autistic traits as they perform an interpersonal synchronization task.

Face individual identity recognition: a potential endophenotype in autism

BACKGROUND

Face individual identity recognition skill is heritable and independent of intellectual ability. Difficulties in face individual identity recognition are present in autistic individuals and their family members and are possibly linked to oxytocin polymorphisms in families with an autistic child. While it is reported that developmental prosopagnosia (i.e., impaired face identity recognition) occurs in 2-3% of the general population, no prosopagnosia prevalence estimate is available for autism. Furthermore, an autism within-group approach has not been reported towards characterizing impaired face memory and to investigate its possible links to social and communication difficulties.

METHODS

The present study estimated the prevalence of prosopagnosia in 80 autistic adults with no intellectual disability, investigated its cognitive characteristics and links to autism symptoms' severity, personality traits, and mental state understanding from the eye region by using standardized tests and questionnaires.

RESULTS

More than one third of autistic participants showed prosopagnosia. Their face memory skill was not associated with their symptom's severity, empathy, alexithymia, or general intelligence. Face identity recognition was instead linked to mental state recognition from the eye region only in autistic individuals who had prosopagnosia, and this relationship did not depend on participants' basic face perception skills. Importantly, we found that autistic participants were not aware of their face memory skills.

LIMITATIONS

We did not test an epidemiological sample, and additional work is necessary to establish whether these results generalize to the entire autism spectrum.

CONCLUSIONS

Impaired face individual identity recognition meets the criteria to be a potential endophenotype in autism. In the future, testing for face memory could be used to stratify autistic individuals into genetically meaningful subgroups and be translatable to autism animal models.

Midline frontal and occipito-temporal activity during error monitoring in dyadic motor interactions

Discrepancies between sensory predictions and action outcome are at the base of error coding. However, these phenomena have mainly been studied focussing on individual performance. Here, we explored EEG responses to motor prediction errors during a human-avatar interaction and show that Theta/Alpha activity of the frontal error-monitoring system works in phase with activity of the occipito-temporal node of the action observation network. Our motor interaction paradigm required healthy individuals to synchronize their reach-to-grasp movements with those of a virtual partner in conditions that did (Interactive) or did not require (Cued) movement prediction and adaptation to the partner's actions. Crucially, in 30% of the trials the virtual partner suddenly and unpredictably changed its movement trajectory thereby violating the human participant's expectation. These changes elicited error-related neuromarkers (ERN/Pe - Theta/Alpha modulations) over fronto-central electrodes during the Interactive condition. Source localization and connectivity analyses showed that the frontal Theta/Alpha activity induced by violations of the expected interactive movements was in phase with occipito-temporal Theta/Alpha activity. These results expand current knowledge about the neural correlates of on-line interpersonal motor interactions linking the frontal error-monitoring system to visual, body motion-related, responses.

Two-Person Approaches to Studying Social Interaction in Psychiatry: Uses and Clinical Relevance

Social interaction is ubiquitous in human society. The two-person approach-a new, powerful tool to study information exchange and social behaviors-aims to characterize the behavioral dynamics and neural mechanisms of real-time social interactions. In this review, we discuss the benefits of two-person approaches compared to those for conventional, single-person approaches. We describe measures and paradigms that model social interaction in three dimensions (3-D), including eye-to-eye, body-to-body, and brain-to-brain relationships. We then discuss how these two-person measures and paradigms are used in psychiatric conditions (e.g., autism, mood disorders, schizophrenia, borderline personality disorder, and psychotherapy). Furthermore, the advantages of a two-person approach (e.g., dual brain stimulation, multi-person neurofeedback) in clinical interventions are described. Finally, we discuss the methodological and translational challenges surrounding the application of two-person approaches in psychiatry, as well as prospects for future two-/multi-person studies. We conclude that two-person approaches serve as useful additions to the range of behavioral and neuroscientific methods available to assess social interaction in psychiatric settings, for both diagnostic techniques and complementary interventions.

This is for you: Social modulations of proximal vs. distal space in collaborative interaction

Human spatial representations are shaped by affordances for action offered by the environment. A prototypical example is the organization of space into peripersonal (within reach) and extrapersonal (outside reach) regions, mirrored by proximal (this/here) and distal (that/there) linguistic expressions. The peri-/extrapersonal distinction has been widely investigated in individual contexts, but little is known about how spatial representations are modulated by interaction with other people. Is near/far coding of space dynamically adapted to the position of a partner when space, objects, and action goals are shared? Over two preregistered experiments based on a novel interactive paradigm, we show that, in individual and social contexts involving no direct collaboration, linguistic coding of locations as proximal or distal depends on their distance from the speaker's hand. In contrast, in the context of collaborative interactions involving turn-taking and role reversal, proximal space is shifted towards the partner, and linguistic coding of near space ('this' / 'here') is remapped onto the partner's action space.

How Task Interactivity Shapes Action Observation

Action observation triggers imitation, a powerful mechanism permitting interpersonal coordination. Coordination, however, also occurs when the partners’ actions are nonimitative and physically incongruent. One influential theory postulates that this is achieved via top-down modulation of imitation exerted by prefrontal regions. Here, we rather argue that coordination depends on sharing a goal with the interacting partner: this shapes action observation, overriding involuntary imitation, through the predictive activity of the left ventral premotor cortex (lvPMc). During functional magnetic resonance imaging (fMRI), participants played music in turn with a virtual partner in interactive and noninteractive conditions requiring 50% of imitative/nonimitative responses. In a full-factorial design, both perceptual features and low-level motor requirements were kept constant throughout the experiment. Behaviorally, the interactive context minimized visuomotor interference due to the involuntary imitation of physically incongruent movements. This was paralleled by modulation of neural activity in the lvPMc, which was specifically recruited during the interactive task independently of the imitative/nonimitative nature of the social exchange. This lvPMc activity reflected the predictive decoding of the partner’s actions, as revealed by multivariate pattern analysis. This demonstrates that, during interactions, we process our partners’ behavior to prospectively infer their contribution to the shared goal achievement, generating motor predictions for cooperation beyond low-level imitation.

INTRApersonal Synchrony as Constituent of INTERpersonal Synchrony and Its Relevance for Autism Spectrum Disorder

INTERpersonal synchrony leads to increased empathy, rapport and understanding, enabling successful human-human interactions and reciprocal bonding. Research shows that individuals with Autism Spectrum Disorder (ASD) exhibit difficulties to INTERpersonally synchronize but underlying causes are yet unknown. In order to successfully synchronize with others, INTRApersonal synchronization of communicative signals appears to be a necessary prerequisite. We understand INTRApersonal synchrony as an implicit factor of INTERpersonal synchrony and therefore hypothesize that atypicalities of INTRApersonal synchrony may add to INTERpersonal synchrony problems in ASD and their interaction partners. In this perspective article, we first review evidence for INTERpersonal dissynchrony in ASD, with respect to different approaches and assessment methods. Second, we draft a theoretical conceptualization of INTRApersonal dissynchrony in ASD based on a temporal model of human interaction. We will outline literature indicating INTRApersonal dissynchrony in ASD, therefore highlighting findings of atypical timing functions and findings from clinical and behavioral studies that indicate peculiar motion patterns and communicative signal production in ASD. Third, we hypothesize that findings from these domains suggest an assessment and investigation of temporal parameters of social behavior in individuals with ASD. We will further propose specific goals of empirical approaches on INTRApersonal dissynchrony. Finally we present implications of research on INTRApersonal timing in ASD for diagnostic and therapeutic purposes, what in our opinion warrants the increase of research efforts in this domain.

Interactor's body shape does not affect visuo-motor interference effects during motor coordination

The biological-tuning of the Action Observation Network is highly debated. A current open question relates to whether the morphological appearance (body shape) and/or the biological motion of the observed agent triggers action simulation processes. Motor simulation of the partner's action is critical for motor interactions, where two partners coordinate their actions in space and time. It supports interpersonal alignment and facilitates online coordination. However, motor simulation also leads to visuo-motor interference effects when people are required to coordinate with complementary actions, i.e. incongruent movements as compared to the observed ones. Movement kinematics of interactive partners allows us to capture their automatic tendency to simulate and imitate the partner's complementary movements. In an online reach-to-grasp task, we investigated whether visuo-motor interference effects, visible in the kinematics of complementary movements, are modulated by the visual presence of the interactor's body shape. We asked participants to interact with 1) a humanoid agent with a human-like body shape and with real human, biological, movement kinematics, or 2) a non-humanoid agent, which did not resemble the human body-shape but moved with the same real kinematics. Through the combination of inferential and Bayesian statistics, the results show no effect of interactor's body shape on visuo-motor interference in reaching and grasping kinematics during online motor coordination. We discuss the results and propose that the kinematics of the observed movements, during motor interactions, might be the key factor for visuo-motor interference to take place independently from the morphological appearance of the partner. This is particularly relevant in a technological society that constantly asks humans to interact with artificial agents.

Inhibition of left anterior intraparietal sulcus shows that mutual adjustment marks dyadic joint-actions in humans

Creating real-life dynamic contexts to study interactive behaviors is a fundamental challenge for the social neuroscience of interpersonal relations. Real synchronic interpersonal motor interactions involve online, inter-individual mutual adaptation (the ability to adapt one’s movements to those of another in order to achieve a shared goal). In order to study the contribution of the left anterior Intra Parietal Sulcus (aIPS) (i.e. a region supporting motor functions) to mutual adaptation, here, we combined a behavioral grasping task where pairs of participants synchronized their actions when performing mutually adaptive imitative and complementary movements, with the inhibition of activity of aIPS via non-invasive brain stimulation. This approach allowed us to investigate whether aIPS supports online complementary and imitative interactions. Behavioral results showed that inhibition of aIPS selectively impairs pair performance during complementary compared to imitative interactions. Notably, this effect depended on pairs’ mutual adaptation skills and was higher for pairs composed of participants who were less capable of adapting to each other. Thus, we provide the first causative evidence for a role of the left aIPS in supporting mutually adaptive interactions and show that the inhibition of the neural resources of one individual of a pair is compensated at the dyadic level.

Older Adolescents and Young Adults With Autism Spectrum Disorder Have Difficulty Chaining Motor Acts When Performing Prehension Movements Compared to Typically Developing Peers

It is known that motor actions performed by individuals with autism spectrum disorders (ASD) are clumsy and a previous study revealed that children with ASD of around 8 years old showed less smooth movement and dysfunction of appropriate usage of online vision for grip aperture control. The present study investigates whether and how the kinematic properties of reach-to-grasp movements in older adolescents and adults with ASD [mean (±SD) age: 18.3 ± 2.1] differ from those in typically developing (TD) peers [mean (±SD) age: 19.1 ± 2.2]. Revealing the kinematic properties of reach-to-grasp movements in older adolescents and adults with ASD is indispensable in determining the developmental trajectory of this motor behavior in individuals with ASD. While wearing liquid crystal shutter goggles, participants reached for and grasped a cylinder with a diameter of either 4 or 6 cm. Two visual conditions were tested: a full vision (FV) condition (the goggles remained transparent during the movement) and a no vision (NV) condition (the goggles were closed immediately after the movement was initiated). These two visual conditions were either alternated with each trial in a single experimental session (alternated condition) or blocked within the session (blocked condition). We found that the reaching movement smoothness calculated as a normalized jerk score (i.e., index of skilled, coordinated human movements) of ASD participants did not differ significantly from that of TD peers although ASD participants showed smoother reaching in the alternated condition than in the blocked condition. The influence of online vision and its visual condition schedule on grip aperture during the in-flight phase was remarkably similar between the ASD and TD groups. Furthermore, we found that ASD group experienced a significant longer transition period from grasping end (i.e., stable holding when touching the surface of the object) to uplift initiation than the TD group. The results suggest that (1) deficits in movement smoothness and the use of online vision for motor control are rectified by the time individuals with ASD reach late adolescence and (2) older adolescents and adults with ASD still have difficulties chaining motor acts.

The Effect of Pairing Individuals With Different Social Skills on Interpersonal Motor Coordination

Previous studies have demonstrated that combining individuals with different social skills affects performance in rhythmic interpersonal motor coordination, with individuals with lower social skills, such as individuals with autism spectrum disorder or schizophrenia, being found to follow the actions of partners with higher social skills. In this study, we investigated whether this finding could be generalized among pairs of individuals without disability. To perform this, we applied an interpersonal motor coordination task that required participants to perform rhythmic movements featuring an interpersonal relative phase pattern of 90°. We did not assign the two roles (i.e., the preceding and following roles) to the participants, meaning they were forced to determine which roles to adopt by observing each other’s movements, without verbal communication. Individual social skills were measured using the autism-spectrum quotient (AQ). We found that pairs of participants with widely differing AQ scores performed better than did pairs with similar AQ scores. Most notably, the participants with higher AQ scores tended to precede their partners in the present task, which is the opposite result to that reported in previous studies. Our findings suggest that paring individuals without disability according to their social skills influences their interpersonal coordination performance in tasks wherein they must determine the preceding and following roles themselves.

Individual preferences in motor coordination seen across the two hands: relations to movement stability and optimality

The framework of the uncontrolled manifold (UCM) hypothesis was used to explore variables related to stability of task performance in the two hands of young healthy individuals. Fourteen young adults performed four-finger accurate constant force production tasks interrupted by a voluntary quick force pulse production and by an externally imposed displacement of all fingers. Three groups of variables were used to quantify stability of steady force production: (1) indices of the inter-trial variance were computed within the UCM and orthogonal to the UCM; (2) indices of motor equivalence were computed between steady-state intervals separated by the force pulse and by the finger-lifting episode; and (3) referent coordinate and apparent stiffness were computed using the data during the ascending phase of the finger-lifting episode. In another task, the subjects performed accurate constant force production with visual feedback removal after the 8th second, and the drop in the total force after the removal was computed. There were differences between the right and left hand in some outcome variables such as variance within the UCM, and the timing of anticipatory synergy adjustments prior to the force pulse, consistent with the dynamic dominance hypothesis. There were significant correlations between the two hands for indices that were unrelated to accuracy of performance: variance within the UCM, index of motor equivalence, referent coordinate, apparent stiffness, and the drop of total force after visual feedback removal. We interpret these findings within the concept of stability-optimality trade-off. In particular, we conclude that individual subjects select particular, person-specific solutions within the spectrum allowed by the explicit task constraints, and this choice is consistent between the two hands. We conclude with a hypothesis that selecting specific solutions within the stability-optimality trade-off may represent an individual's personal preference consistent between the two hands.

Visuo-motor interference with a virtual partner is equally present in cooperative and competitive interactions

Automatic imitation of observed actions is thought to be a powerful mechanism, one that may mediate the reward value of interpersonal interactions, but that could also generate visuo-motor interference when interactions involve complementary movements. Since interpersonal coordination seems to be crucial both when cooperating and competing with others, the questions arises as to whether imitation-and thus visuo-motor interference-occurs in both scenarios. To address this issue, we asked human participants to engage in high- or low-interactive (Interactive or Cued condition, respectively), cooperative or competitive, joint reach-to-grasps with a virtual partner. More specifically, interactions occurred in: (i) a Cued condition, where participants simply adapted their movement timing to synchronize with (during cooperation) or anticipate (during competition) the virtual partner's grasp; (ii) an Interactive condition requiring the same adaptation, as well as a real-time selection of their action according to the virtual character's movement. To simulate a realistic human-human interaction, the virtual character would change its movement speed in consecutive trials according to participants' behaviour. Results demonstrate that visuo-motor interference-as indexed by movement kinematics (higher maximum wrist height during complementary compared to imitative power grips)-emerge in both cooperative and competitive motor interactions only when predictions about the partner's movements are needed to perform one's own action (interactive condition). These results support the idea that simulative imitation is heavily present when individuals need to match their behaviours closely.

Autism-related behaviors in the cyclooxygenase-2-deficient mouse model

Prostaglandin E2 (PGE2) is an endogenous lipid molecule involved in normal brain development. Cyclooxygenase-2 (COX2) is the main regulator of PGE2 synthesis. Emerging clinical and molecular research provides compelling evidence that abnormal COX2/PGE2 signaling is associated with autism spectrum disorder (ASD). We previously found that COX2 knockout mice had dysregulated expression of many ASD genes belonging to important biological pathways for neurodevelopment. The present study is the first to show the connection between irregular COX2/PGE2 signaling and autism-related behaviors in male and female COX2-deficient knockin, (COX)-2^- , mice at young (4-6 weeks) or adult (8-11 weeks) ages. Autism-related behaviors were prominent in male (COX)-2^- mice for most behavioral tests. In the open field test, (COX)-2^- mice traveled more than controls and adult male (COX)-2^- mice spent less time in the center indicating elevated hyperactive and anxiety-linked behaviors. (COX)-2^- mice also buried more marbles, with males burying more than females, suggesting increased anxiety and repetitive behaviors. Young male (COX)-2^- mice fell more frequently in the inverted screen test revealing motor deficits. The three-chamber sociability test found that adult female (COX)-2^- mice spent less time in the novel mouse chamber indicative of social abnormalities. In addition, male (COX)-2^- mice showed altered expression of several autism-linked genes: Wnt2, Glo1, Grm5 and Mmp9. Overall, our findings offer new insight into the involvement of disrupted COX2/PGE2 signaling in ASD pathology with age-related differences and greater impact on males. We propose that (COX)-2^- mice might serve as a novel model system to study specific types of autism.

Identifying others' informative intentions from movement kinematics

Previous research has demonstrated that people can reliably distinguish between actions with different instrumental intentions on the basis of the kinematic signatures of these actions (Cavallo, Koul, Ansuini, Capozzi, & Becchio, 2016). It has also been demonstrated that different informative intentions result in distinct action kinematics (McEllin, Knoblich, & Sebanz, 2017). However, it is unknown whether people can discriminate between instrumental actions and actions performed with an informative intention, and between actions performed with different informative intentions, on the basis of kinematic cues produced in these actions. We addressed these questions using a visual discrimination paradigm in which participants were presented with point light animations of an actor playing a virtual xylophone. We systematically manipulated and amplified kinematic parameters that have been shown to reflect different informative intentions. We found that participants reliably used both spatial and temporal cues in order to discriminate between instrumental actions and actions performed with an informative intention, and between actions performed with different informative intentions. Our findings indicate that the informative cues produced in joint action and teaching go beyond serving a general informative purpose and can be used to infer specific informative intentions.

Sensitivity to Social Contingency in Adults with High-Functioning Autism during Computer-Mediated Embodied Interaction

Autism Spectrum Disorder (ASD) can be understood as a social interaction disorder. This makes the emerging "second-person approach" to social cognition a more promising framework for studying ASD than classical approaches focusing on mindreading capacities in detached, observer-based arrangements. According to the second-person approach, embodied, perceptual, and embedded or interactive capabilities are also required for understanding others, and these are hypothesized to be compromised in ASD. We therefore recorded the dynamics of real-time sensorimotor interaction in pairs of control participants and participants with High-Functioning Autism (HFA), using the minimalistic human-computer interface paradigm known as "perceptual crossing" (PC). We investigated whether HFA is associated with impaired detection of social contingency, i.e., a reduced sensitivity to the other's responsiveness to one's own behavior. Surprisingly, our analysis reveals that, at least under the conditions of this highly simplified, computer-mediated, embodied form of social interaction, people with HFA perform equally well as controls. This finding supports the increasing use of virtual reality interfaces for helping people with ASD to better compensate for their social disabilities. Further dynamical analyses are necessary for a better understanding of the mechanisms that are leading to the somewhat surprising results here obtained.

Patterns of Joint Improvisation in Adults with Autism Spectrum Disorder

Recent research on autism spectrum disorders (ASDs) suggests that individuals with autism may have a basic deficit in synchronizing with others, and that this difficulty may lead to more complex social and communicative deficits. Here, we examined synchronization during an open-ended joint improvisation (JI) paradigm, called the mirror game (MG). In the MG, two players take turns leading, following, and jointly improvising motion using two handles set on parallel tracks, while their motion tracks are recorded with high temporal and spatial resolution. A series of previous studies have shown that players in the MG attain moments of highly synchronized co-confident (CC) motion, in which there is no typical kinematic pattern of leader and reactive follower. It has been suggested that during these moments players act as a coupled unit and feel high levels of connectedness. Here, we aimed to assess whether participants with ASD are capable of attaining CC, and whether their MG performance relates to broader motor and social skills. We found that participants with ASD (n = 34) can indeed attain CC moments when playing with an expert improviser, though their performance was attenuated in several ways, compared to typically developing (TD) participants (n = 35). Specifically, ASD participants had lower rates of CC, compared with TD participants, which was most pronounced during the following rounds. In addition, the duration of their CC segments was shorter, across all rounds. When controlling for participants' motor skills (both on the MG console, and more broadly) some of the variability in MG performance was explained, but group differences remained. ASD participants' alexithymia further correlated with their difficulty following another's lead; though other social skills did not relate to MG performance. Participants' subjective reports of the game suggest that other cognitive and emotional factors, such as attention, motivation, and reward-processing, which were not directly measured in the experiment, may impact their performance. Together, these results show that ASD participants can attain moments of high motor synchronization with an expert improviser, even during an open-ended task. Future studies should examine the ways in which these skills may be further harnessed in clinical settings.