Atypical Social Rank Recognition in Autism Spectrum Disorder

Reading the room: Autistic traits, gaze behaviour, and the ability to infer social relationships

Individuals high in autistic traits can have difficulty understanding verbal and non-verbal cues, and may display atypical gaze behaviour during social interactions. The aim of this study was to examine differences among neurotypical individuals with high and low levels of autistic traits with regard to their gaze behaviour and their ability to assess peers' social status accurately. Fifty-four university students who completed the 10-item Autism Quotient (AQ-10) were eye-tracked as they watched six 20-second video clips of people ("targets") involved in a group decision-making task. Simulating natural, everyday social interactions, the video clips included moments of debate, humour, interruptions, and cross talk. Results showed that high-scorers on the AQ-10 (i.e., those with more autistic traits) did not differ from the low-scorers in either gaze behaviour or assessing the targets' relative social status. The results based on this neurotypical group of participants suggest that the ability of individuals high in autistic traits to read social cues may be preserved in certain tasks crucial to navigating day-to-day social relationships. These findings are discussed in terms of their implications for theory of mind, weak central coherence, and social motivation theories of autism.

Role of Brain Modulators in Neurodevelopment: Focus on Autism Spectrum Disorder and Associated Comorbidities

Autism spectrum disorder (ASD) and associated neurodevelopmental disorders share similar pathogenesis and clinical features. Pathophysiological changes in these diseases are rooted in early neuronal stem cells in the uterus. Several genetic and environmental factors potentially perturb neurogenesis and synaptogenesis processes causing incomplete or altered maturation of the brain that precedes the symptomology later in life. In this review, the impact of several endogenous neuromodulators and pharmacological agents on the foetus during pregnancy, manifested on numerous aspects of neurodevelopment is discussed. Within this context, some possible insults that may alter these modulators and therefore alter their role in neurodevelopment are high-lighted. Sometimes, a particular insult could influence several neuromodulator systems as is supported by recent research in the field of ASD and associated disorders. Dopaminergic hy-pothesis prevailed on the table for discussion of the pathogenesis of schizophrenia (SCH), atten-tion-deficit hyperactivity disorder (ADHD) and ASD for a long time. However, recent cumulative evidence suggests otherwise. Indeed, the neuromodulators that are dysregulated in ASD and comorbid disorders are as diverse as the causes and symptoms of this disease. Additionally, these neuromodulators have roles in brain development, further complicating their involvement in comorbidity. This review will survey the current understanding of the neuromodulating systems to serve the pharmacological field during pregnancy and to minimize drug-related insults in pa-tients with ASD and associated comorbidity disorders, e.g., SCH or ADHD.

Altered Processing of Social Emotions in Individuals With Autistic Traits

Social impairment is a defining phenotypic feature of autism. The present study investigated whether individuals with autistic traits exhibit altered perceptions of social emotions. Two groups of participants (High-AQ and Low-AQ) were recruited based on their scores on the autism-spectrum quotient (AQ). Their behavioral responses and event-related potentials (ERPs) elicited by social and non-social stimuli with positive, negative, and neutral emotional valence were compared in two experiments. In Experiment 1, participants were instructed to view social-emotional and non-social emotional pictures. In Experiment 2, participants were instructed to listen to social-emotional and non-social emotional audio recordings. More negative emotional reactions and smaller amplitudes of late ERP components (the late positive potential in Experiment 1 and the late negative component in Experiment 2) were found in the High-AQ group than in the Low-AQ group in response to the social-negative stimuli. In addition, amplitudes of these late ERP components in both experiments elicited in response to social-negative stimuli were correlated with the AQ scores of the High-AQ group. These results suggest that individuals with autistic traits have altered emotional processing of social-negative emotions.

Cognitive and Affective Processes Associated with Social Biases

BACKGROUND

Our social activities are quite often erroneous and irrational, based on biased judgements and decision-making, known as social biases. However, the cognitive and affective processes that produce such biases remain largely unknown. In this study, we investigated associations between social schemas, such as social judgment and conformity, entailing social biases and psychological measurements relevant to cognitive and affective functions.

METHOD

This study recruited 42 healthy adult subjects. A psychological test and a questionnaire were administered to assess biased social judgements by superficial attributes and social conformity by adherence to social norms, respectively, along with additional questionnaires and psychological tests for cognitive and affective measurements, including negative affects, autistic traits, and Theory of Mind (ToM). Associations of social judgment and conformity with cognitive and affective functions were examined using a multiple regression analysis and structural equation modeling.

RESULTS

Anxiety and the cognitive realm of ToM were mutually associated with both social judgments and conformity, although social judgements and conformity were still independent processes. Social judgements were also associated with autistic traits and the affective realm of ToM, whereas social conformity was associated with negative affects other than anxiety and an intuitive decision-making style.

CONCLUSIONS

These results suggest that ToM and negative affects may play important roles in social judgements and conformity, and the social biases connoted in these social schemas.

Assessment of autism-relevant behaviors in C57BKS/J leptin receptor deficient mice

Gestational diabetes mellitus (GDM) was associated with greater autism risk in epidemiological studies. Disrupted leptin signaling may contribute to their coincidence, as it is found in both disorders. Given this we examined leptin receptor (Lepr) deficient (BKS.Cg-Dock7^m +/+ Lepr^db/J diabetic (db)) heterozygous (db/+) mice for autism-relevant behaviors. BKS db/+ females are lean with normal blood glucose, but they develop GDM while pregnant. We hypothesized BKS db/+ offspring might exhibit physiological and behavior traits consistent with autism. Adolescent body weight, fasting blood glucose, serum corticosterone, social preferences, self-grooming, marble burying, social dominance and cognitive flexibility of BKS db/+ mice was compared to C57BLKS/J (BKS) and C57BL/6J (BL6) mice. Male db/+ weighed more and had higher blood glucose and corticosterone relative to BL6, but not BKS mice. Also, male db/+ lacked social interaction preference, explored arenas less, and buried more marbles than BL6, but not BKS males. Male and female db/+ were more dominant and made more mistakes in water T-mazes locating a sunken platform after its position was reversed than BL6, but not BKS mice. Overall BKS db/+, particularly males, exhibited some autism-like social deficits and restrictive-repetitive behaviors relative to BL6, but BKS strain contributions to BKS db/+ behaviors were evident. Since BKS db/+ and BKS behavioral and physiological phenotypes are already so similar, it will be difficult to use these models in studies designed to detect contributions of fetal GDM exposures to offspring behaviors.

Differentially altered social dominance- and cooperative-like behaviors in Shank2- and Shank3-mutant mice

BACKGROUND

Recent progress in genomics has contributed to the identification of a large number of autism spectrum disorder (ASD) risk genes, many of which encode synaptic proteins. Our understanding of ASDs has advanced rapidly, partly owing to the development of numerous animal models. Extensive characterizations using a variety of behavioral batteries that analyze social behaviors have shown that a subset of engineered mice that model mutations in genes encoding Shanks, a family of excitatory postsynaptic scaffolding proteins, exhibit autism-like behaviors. Although these behavioral assays have been useful in identifying deficits in simple social behaviors, alterations in complex social behaviors remain largely untested.

METHODS

Two syndromic ASD mouse models-Shank2 constitutive knockout [KO] mice and Shank3 constitutive KO mice-were examined for alterations in social dominance and social cooperative behaviors using tube tests and automated cooperation tests. Upon naïve and salient behavioral experience, expression levels of c-Fos were analyzed as a proxy for neural activity across diverse brain areas, including the medial prefrontal cortex (mPFC) and a number of subcortical structures.

FINDINGS

As previously reported, Shank2 KO mice showed deficits in sociability, with intact social recognition memory, whereas Shank3 KO mice displayed no overt phenotypes. Strikingly, the two Shank KO mouse models exhibited diametrically opposed alterations in social dominance and cooperative behaviors. After a specific social behavioral experience, Shank mutant mice exhibited distinct changes in number of c-Fos⁺ neurons in the number of cortical and subcortical brain regions.

CONCLUSIONS

Our results underscore the heterogeneity of social behavioral alterations in different ASD mouse models and highlight the utility of testing complex social behaviors in validating neurodevelopmental and neuropsychiatric disorder models. In addition, neural activities at distinct brain regions are likely collectively involved in eliciting complex social behaviors, which are differentially altered in ASD mouse models.

A mouse model of Timothy syndrome exhibits altered social competitive dominance and inhibitory neuron development

Multiple genetic factors related to autism spectrum disorder (ASD) have been identified, but the biological mechanisms remain obscure. Timothy syndrome (TS), associated with syndromic ASD, is caused by a gain-of-function mutation, G406R, in the pore-forming subunit of L-type Ca2+ channels, Cav 1.2. In this study, a mouse model of TS, TS2-neo, was used to enhance behavioral phenotyping and to identify developmental anomalies in inhibitory neurons. Using the IntelliCage, which enables sequential behavioral tasks without human handling and mouse isolation stress, high social competitive dominance was observed in TS2-neo mice. Furthermore, histological analysis demonstrated inhibitory neuronal abnormalities in the neocortex, including an excess of smaller-sized inhibitory presynaptic terminals in the somatosensory cortex of young adolescent mice and higher numbers of migrating inhibitory neurons from the medial ganglionic eminence during embryonic development. In contrast, no obvious changes in excitatory synaptic terminals were found. These novel neural abnormalities in inhibitory neurons of TS2-neo mice may result in a disturbed excitatory/inhibitory (E/I) balance, a key feature underlying ASD.