Where there is a goal, there is a way: what, why and how the parieto-frontal mirror network can mediate imitative behaviours

Impact of imitation abilities on social communication in autistic children: evidence from an Early Start Denver Model intervention study

Imitation is foundational to early social learning, yet autistic children often exhibit significant impairments in imitation, potentially impacting their social communication skills. This study examined the relationship between imitation abilities and social communication in autistic children and evaluated the effectiveness of the Early Start Denver Model (ESDM) intervention. The study included 52 autistic children aged 2-5, divided into an experimental group receiving ESDM intervention and a control group undergoing standard rehabilitation. We assessed the children's imitation and social communication skills before and after the intervention. Results indicated a significant positive correlation between imitation and social communication skills both before and after the intervention. Specifically, various forms of imitation (e.g., vocal, gestural, object-related) were closely linked to different domains of social communication (e.g., expressive communication, joint attention, social skills). Baseline imitation levels and improvements in imitation were significant predictors of enhanced social communication, jointly accounting for over half of the observed improvements in social communication, with imitation improvement being the strongest predictor. Age positively moderated the relationship between imitation and social communication, with older children showing a stronger impact of imitation on social communication. Although these effects were evident across groups, the ESDM group showed greater gains in imitation skills compared to the control group. However, we did not find evidence of an intervention effect on social communication skills. This study underscores the critical role of imitation in the social communication development of autistic children. These findings support the enhancement of imitation skills in early interventions for autistic children, highlighting the effectiveness of ESDM in fostering imitation abilities.

From neural noise to co-adaptability: Rethinking the multifaceted architecture of motor variability

In the last decade, the source and the functional meaning of motor variability have attracted considerable attention in behavioral and brain sciences. This construct classically combined different levels of description, variable internal robustness or coherence, and multifaceted operational meanings. We provide here a comprehensive review of the literature with the primary aim of building a precise lexicon that goes beyond the generic and monolithic use of motor variability. In the pars destruens of the work, we model three domains of motor variability related to peculiar computational elements that influence fluctuations in motor outputs. Each domain is in turn characterized by multiple sub-domains. We begin with the domains of noise and differentiation. However, the main contribution of our model concerns the domain of adaptability, which refers to variation within the same exact motor representation. In particular, we use the terms learning and (social)fitting to specify the portions of motor variability that depend on our propensity to learn and on our largely constitutive propensity to be influenced by external factors. A particular focus is on motor variability in the context of the sub-domain named co-adaptability. Further groundbreaking challenges arise in the modeling of motor variability. Therefore, in a separate pars construens, we attempt to characterize these challenges, addressing both theoretical and experimental aspects as well as potential clinical implications for neurorehabilitation. All in all, our work suggests that motor variability is neither simply detrimental nor beneficial, and that studying its fluctuations can provide meaningful insights for future research.

Action Understanding Promoted by Interoception in Children: A Developmental Model

Action understanding of children develops from simple associative learning to mentalizing. With the rise of embodied cognition, the role of interoception in action observation and action understanding has received more attention. From a developmental perspective, this study proposes a novel developmental model that explores how interoception promotes action understanding of children across ages. In early infancy, most actions observed in infants come from interactions with their caregivers. Babies learn about action effects through automatic interoceptive processing and interoceptive feedback. Interoception in early infancy is not fully developed, such as the not fully developed gastrointestinal tract and intestinal nervous system. Therefore, in early infancy, action understanding is based on low-level and original interoceptive information. At this stage, after observing the actions of others, infants can create mental representations or even imitate actions without external visual feedback, which requires interoception to provide internal reference information. By early childhood, children begin to infer action intentions of other people by integrating various types of information to reach the mentalizing level. Interoception processing requires the integration of multiple internal signals, which promotes the information integration ability of children. Interoception also provides inner information for reasoning about action intention. This review also discussed the neural mechanisms of interoception and possible ways by which it could promote action understanding of children. In early infancy, the central autonomic neural network (CAN) automatically processes and responds to the actions of caregivers on infants, providing interoceptive information for action understanding of infants. In infancy, the growth of the somatomotor system provides important internal reference information for observing and imitating the actions of infants. In early childhood, the development of interoception of children facilitates the integration of internal and external information, which promotes the mentalization of action understanding of children. According to the proposed developmental model of action understanding of children promoted by interoception, there are multilevel and stage-dependent characteristics that impact the role of interoception in action understanding of children.

Risk of Substance Use Disorder and Its Associations With Comorbidities and Psychotropic Agents in Patients With Autism

IMPORTANCE

The risk of substance use disorder (SUD) in patients with autism spectrum disorder (ASD) remains unclear.

OBJECTIVE

To investigate the risk of SUD in patients with ASD and its associations with comorbidities, psychotropic agents (PAs), and mortality.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, population-based, cohort study of 1 936 512 participants used data from the Taiwan National Health Insurance Research Database and was conducted from January 1, 2000, to December 31, 2015. Included participants attended at least 3 outpatient visits within the 1-year study period for symptomatic ASD as determined by the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic codes. Individuals diagnosed with ASD before 2000, those diagnosed with SUD before the first visit for ASD, and those with missing data were excluded from the analysis. Patients with ASD and non-ASD controls were matched 1:4 by age, sex, and index date.

EXPOSURES

Symptomatic ASD evaluated for at least 3 outpatient visits within the 1-year study period.

MAIN OUTCOMES AND MEASURES

Adjusted hazard ratios (aHRs) with 95% CIs for SUD, including alcohol use disorder (AUD) and drug use disorder (DUD), and the risk of mortality were calculated. Data were analyzed from March 1 to July 13, 2020.

RESULTS

A total of 6599 individuals with ASD (mean [SD] age, 11.9 [5.1] years; 5094 boys [77.2%]; mean [SD] follow-up period, 8.1 [8.3] years; median follow-up period, 4.3 [interquartile range [IQR], 2.3-5.3] years) and 26 396 controls (mean [SD] age, 12.1 [5.8] years; 20 376 boys [77.2%]; mean [SD] follow-up period, 8.6 [8.9] years; median follow-up period, 4.4 [IQR, 2.4-5.4] years) were enrolled in the study. According to multivariable-adjusted analysis, the aHRs for SUD (2.33; 95% CI, 1.89-2.87), AUD (2.07; 95% CI, 1.60-2.63), and DUD (3.00; 95% CI, 2.15-4.58) were significantly higher in the ASD group than in the non-ASD controls. The aHRs for SUD in the ASD subgroups with 1 PA (0.60; 95% CI, 0.43-0.66) and with multiple PAs (0.37; 95% CI, 0.28-0.49) were significantly lower than those in the ASD subgroup with no PAs. Comparisons between patients with ASD and non-ASD controls with the same comorbidities showed higher aHRs for SUD among patients with ASD (range, 1.17-2.55); moreover, the ASD subgroup not receiving any PAs had an aHR of 6.39 (95% CI, 5.11-7.87) for SUD when they had comorbid tic disorder and aHRs of 5.48 (95% CI, 5.12-5.70) for AUD and 5.42 (95% CI, 5.12-5.80) for DUD when they had comorbid impulse control disorder. The mortality risk was significantly higher in patients with ASD and concomitant SUD than in non-ASD controls without SUD (aHR, 3.17; 95% CI, 2.69-3.89).

CONCLUSIONS AND RELEVANCE

These findings suggest that patients with ASD are vulnerable to the development of SUD. Comorbid ASD and SUD were associated with an increase in mortality risk.

Neurotypical individuals fail to understand action vitality form in children with autism spectrum disorder

Action vitality forms are highly pervasive aspects of daily life and have been widely assumed to be critical for basic social interactions. Previous evidence indicates that ASD children express their own vitality forms in a way that is motorically dissimilar to TD children. Here we demonstrate that this motor dissimilarity prevents neurotypical adults from recognizing vitality forms, when observing ASD children acting gently or rudely. Although ASD children differentiate these vitality forms, neurotypical adults were remarkably inaccurate in identifying them. This indicates that difficulty in social interaction for ASD individuals should not be entirely ascribed to their lack of understanding others, as standardly assumed. The failure of neurotypical individuals to understand them plays a critical role too.

Any defects of sociality in individuals diagnosed with autism spectrum disorder (ASD) are standardly explained in terms of those individuals’ putative impairments in a variety of cognitive functions. Recently, however, the need for a bidirectional approach to social interaction has been emphasized. Such an approach highlights differences in basic ways of acting between ASD and neurotypical individuals which would prevent them from understanding each other. Here we pursue this approach by focusing on basic action features reflecting the agent’s mood and affective states. These are action features Stern named “vitality forms,” and which are widely assumed to substantiate core social interactions [D. N. Stern, The Interpersonal World of the Infant (1985); D. N. Stern, Forms of Vitality Exploring Dynamic Experience in Psychology, Arts, Psychotherapy, and Development (2010)]. Previously we demonstrated that, although ASD and typically developing (TD) children alike differentiate vitality forms when performing actions, ASD children express them in a way that is motorically dissimilar to TD children. To assess whether this motor dissimilarity may have consequences for vitality form recognition, we asked neurotypical participants to identify the vitality form of different types of action performed by ASD or TD children. We found that participants exhibited remarkable inaccuracy in identifying ASD children’s vitality forms. Interestingly, their performance did not benefit from information feedback. This indicates that how people act matters for understanding others and for being understood by them. Because vitality forms pervade every aspect of daily life, our findings promise to open the way to a deeper comprehension of the bidirectional difficulties for both ASD and neurotypical individuals in interacting with one another.

A look at actions: direct gaze modulates functional connectivity of the right TPJ with an action control network

Social signals such as eye contact and motor actions are essential elements of social interactions. However, our knowledge about the interplay of gaze signals and the control of actions remains limited. In a group of 30 healthy participants, we investigated the effect of gaze (direct gaze vs averted) on behavioral and neural measures of action control as assessed by a spatial congruency task (spatially congruent vs incongruent button presses in response to gaze shifts). Behavioral results demonstrate that inter-individual differences in condition-specific incongruency costs were associated with autistic traits. While there was no interaction effect of gaze and action control on brain activation, in a context of incongruent responses to direct gaze shifts, a psychophysiological interaction analysis showed increased functional coupling between the right temporoparietal junction, a key region in gaze processing, and the inferior frontal gyri, which have been related to both social cognition and motor inhibition. Conversely, incongruency costs to averted gaze were reflected in increased connectivity with action control areas implicated in top-down attentional processes. Our findings indicate that direct gaze perception inter-individually modulates motor actions and enforces the functional integration of gaze-related social cognition and action control processes, thereby connecting functional elements of social interactions.

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.

Insights from perceptual, sensory, and motor functioning in autism and cerebellar primary disturbances: Are there reliable markers for these disorders?

The contribution of cerebellar circuitry alterations in the pathophysiology of Autism Spectrum Disorder (ASD) has been widely investigated in the last decades. Yet, experimental studies on neurocognitive markers of ASD have not been attentively compared with similar studies in patients with cerebellar primary disturbances (e.g., malformations, agenesis, degeneration, etc). Addressing this neglected issue could be useful to underline unexpected areas of overlap and/or underestimated differences between these sets of conditions. In fact, ASD and cerebellar primary disturbances (notably, Cerebellar Cognitive Affective Syndrome, CCAS) can share atypical manifestations in perceptual, sensory, and motor functions, but neural subcircuits involved in these anomalies/difficulties could be distinct. Here, we specifically deal with this issue focusing on four paradigmatic neurocognitive functions: visual and biological motion perception, multisensory integration, and high stages of the motor hierarchy. From a research perspective, this represents an essential challenge to more deeply understand neurocognitive markers of ASD and of cerebellar primary disturbances/CCAS. Although we cannot assume definitive conclusions, and beyond phenotypical similarities between ASD and CCAS, clinical and experimental evidence described in this work argues that ASD and CCAS are distinct phenomena. ASD and CCAS seem to be characterized by different pathophysiological mechanisms and mediated by distinct neural nodes. In parallel, from a clinical perspective, this characterization may furnish insights to tackle the distinction between autistic functioning/autistic phenotype (in ASD) and dysmetria of thought/autistic-like phenotype (in CCAS).

Motor Intention/Intentionality and Associationism - A conceptual review

Motor intention/intentionality (MI) has been investigated from many different angles. Some researchers focus on the purely physical and mechanical aspects of the human motor system, while others emphasize the subjectivity involved in intentionality. While bridging this seemingly dualistic gap between the two concepts ought to be the researcher's' main task, different schools of thought have instead specialized in stressing one (objective) or the other (subjective) part of this construct. Thus, we find everything from neuroscientific to phenomenologically inspired approaches to MI. The purpose of this article is to review the literature regarding these different approaches to the MI construct. In reviewing the literature, we introduce a broadened conception of associationism. In organizing our data in relation to the laws of association, a lack of methodology clearly manifests itself. Hence, 123 articles out of 143 meet the criteria of our definition of associationism. It seems that this old doctrine sneaks in to a big part of the research rather implicitly through a lack of methodology. To shed light on how this happens in the 123 articles, we develop a continuum to show to which extend associationism operates on a transcendent or substantial level in each article. We find only very few articles that seem to try to gap the bridge between motor and intention/intentionality, and thus we suggest that future MI research reintroduce methodological debates concerning the conceptual character of this construct.

Are We "Motorically" Wired to Others? High-Level Motor Computations and Their Role in Autism

High-level motor computations reflect abstract components far apart from the mere motor performance. Neural correlates of these computations have been explored both in nonhuman and human primates, supporting the idea that our brain recruits complex nodes for motor representations. Of note, these computations have exciting implications for social cognition, and they also entail important challenges in the context of autism. Here, we focus on these challenges benefiting from recent studies addressing motor interference, motor resonance, and high-level motor planning. In addition, we suggest new ideas about how one maps and shares the (motor) space with others. Taken together, these issues inspire intriguing and fascinating questions about the social tendency of our high-level motor computations, and this tendency may indicate that we are "motorically" wired to others. Thus, after furnishing preliminary insights on putative neural nodes involved in these computations, we focus on how the hypothesized social nature of high-level motor computations may be anomalous or limited in autism, and why this represents a critical challenge for the future.

The functional and developmental role of imitation in the (a)typical brain

Keven & Akins (K&A) propose a biologically plausible view of neonatal imitation based on the analysis of sensorimotor development. Here, we consider imitation in the general context of motor cognition, taking examples from both typical and atypical development. Specifically, we will discuss the functional role of imitation, its multi-level nature, and its anomalous features in autism.

Neural Activity while Imitating Emotional Faces is Related to Both Lower and Higher-Level Social Cognitive Performance

Imitation and observation of actions and facial emotional expressions activates the human fronto-parietal mirror network. There is skepticism regarding the role of this low-level network in more complex high-level social behaviour. We sought to test whether neural activation during an observation/imitation task was related to both lower and higher level social cognition. We employed an established observe/imitate task of emotional faces during functional MRI in 28 healthy adults, with final analyses based on 20 individuals following extensive quality control. Partial least squares (PLS) identified patterns of relationships between spatial activation and a battery of objective out-of-scanner assessments that index lower and higher-level social cognitive performance, including the Penn emotion recognition task, reading the mind in the eyes, the awareness of social inference test (TASIT) parts 1, 2, and 3, and the relationships across domains (RAD) test. Strikingly, activity in limbic, right inferior frontal, and inferior parietal areas during imitation of emotional faces correlated with performance on emotion evaluation (TASIT1), social inference - minimal (TASIT2), social inference - enriched (TASIT3), and the RAD tests. These results show a role for this network in both lower-level and higher-level social cognitive processes which are collectively critical for social functioning in everyday life.

Role of the cerebellum in high stages of motor planning hierarchy

Motor planning is not a monolithic process, and distinct stages of motor planning are responsible for encoding different levels of abstractness. However, how these distinct components are mapped into different neural substrates remains an open question. We studied one of these high-level motor planning components, defined as second-order motor planning, in a patient (R.G.) with an extremely rare case of cerebellar agenesis but without any other cortical malformations. Second-order motor planning dictates that when two acts must be performed sequentially, planning of the second act can influence execution of the first. We used an optoelectronic system for kinematic analysis to compare R.G.'s performance with age-matched controls in a second-order motor planning task. The first act was to reach for an object, and the second was to place it into a small or large container. Our results showed that despite the expected difficulties in fine-motor skills, second-order motor planning (i.e., the ability to modulate the first act as a function of the nature of the second act) was preserved even in the patient with congenital absence of the cerebellum. These results open new intriguing speculations about the role of the cerebellum in motor planning abilities. Although prudence is imperative when suggesting conclusions made on the basis of single-case findings, this evidence suggests fascinating hypotheses about the neural circuits that support distinct stages of the motor planning hierarchy, and regarding the functional role of second-order motor planning in motor cognition and its potential dysfunction in autism.NEW & NOTEWORTHY Traditionally, the cerebellum was considered essential for motor planning. By studying an extremely rare patient with cerebellar agenesis and a group of neurotypical controls, we found that high stages of the motor planning hierarchy can be preserved even in this patient with congenital absence of the cerebellum. Our results provide interesting insights that shed light on the neural circuits supporting distinct levels of motor planning. Furthermore, the results are intriguing because of their potential clinical implications in autism.

So close yet so far: Motor anomalies impacting on social functioning in autism spectrum disorder

Difficulties in the social domain and motor anomalies have been widely investigated in Autism Spectrum Disorder (ASD). However, they have been generally considered as independent, and therefore tackled separately. Recent advances in neuroscience have hypothesized that the cortical motor system can play a role not only as a controller of elementary physical features of movement, but also in a complex domain as social cognition. Here, going beyond previous studies on ASD that described difficulties in the motor and in the social domain separately, we focus on the impact of motor mechanisms anomalies on social functioning. We consider behavioral, electrophysiological and neuroimaging findings supporting the idea that motor cognition is a critical "intermediate phenotype" for ASD. Motor cognition anomalies in ASD affect the processes of extraction, codification and subsequent translation of "external" social information into the motor system. Intriguingly, this alternative "motor" approach to the social domain difficulties in ASD may be promising to bridge the gap between recent experimental findings and clinical practice, potentially leading to refined preventive approaches and successful treatments.

Identification of neuromotor deficits common to autism spectrum disorder and attention deficit/hyperactivity disorder, and imitation deficits specific to autism spectrum disorder

Deficits in motor and imitation abilities are a core finding in autism spectrum disorders (ASD), but impaired motor functions are also found in attention deficit/hyperactivity disorder (ADHD). Given recent theorising about potential aetiological overlap between the two disorders, the present study aimed to assess difficulties in motor performance and imitation of facial movements and meaningless gestures in a sample of 24 ADHD patients, 22 patients with ASD, and 20 typically developing children, matched for age (6-13 years) and similar in IQ (>80). Furthermore, we explored the impact of comorbid ADHD symptoms on motor and imitation performance in the ASD sample and the interrelationships between the two groups of variables in the clinical groups separately. The results show motor dysfunction was common to both disorders, but imitation deficits were specific to ASD. Together with the pattern of interrelated motor and imitation abilities, which we found exclusively in the ASD group, our findings suggest complex phenotypic, and possibly aetiological, relationships between the two neurodevelopmental conditions.