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Social motivation is critical to the development of typical social functioning. The root of the social challenges characteristic of autism is hypothesized to be a deficit in social motivation, specifically in one or more subcomponents (e.g. social reward seeking or social orienting). We developed a social operant conditioning task to quantify effort to access a social partner and concurrent social orienting in mice. We established that mice will work for access to a social partner, identified sex differences, and observed high test-retest reliability. We then benchmarked the method with two test-case manipulations. Shank3B mutants exhibited reduced social orienting and failed to show social reward seeking. Oxytocin receptor antagonism decreased social motivation, consistent with its role in social reward circuitry. Overall, we believe this method provides a valuable addition to the assessment of social phenotypes in rodent models of autism and the mapping of potentially sex-specific social motivation neural circuits. This repository includes the detailed protocols for assembly and operation of equipment, parts lists, and annotated scripts for data processing and analysis.

Motor deficits such as abnormal gait are an underappreciated yet characteristic phenotype of many neurodevelopmental disorders (NDDs), including Williams Syndrome (WS) and Neurofibromatosis Type 1 (NF1). Compared to cognitive phenotypes, gait phenotypes are readily and comparably assessed in both humans and model organisms, and are controlled by well-defined CNS circuits. Discovery of a common gait phenotype between NDDs might suggest shared cellular and molecular deficits and highlight simple outcome variables to potentially quantify longitudinal treatment efficacy in NDDs. We therefore characterized gait using the DigiGait assay in two different NDD models: the complete deletion (CD) mouse, which models hemizygous loss of the complete WS locus, and the Nf1+/R681X mouse, which models a patient-derived heterozygous germline NF1 mutation. We collected longitudinal data across five developmental time points (postnatal days 21-30) and one early adulthood time point. Compared to wild type littermate controls, both models displayed markedly similar spatial, temporal, and postural gait abnormalities during development. Developing CD mice also displayed significant decreases in variability metrics. Multiple gait abnormalities observed across Nf1+/R681X mouse development persisted into early adulthood, including increased stride length and decreased stride frequency, while developmental abnormalities in CD mice largely resolved by adulthood. These findings suggest that gait subcomponents affected in NDDs show overlap between disorders as well as some disorder-specific features, which may change over the course of development. Our incorporation of spatial, temporal, and postural gait measures also provides a template for gait characterization in other NDD models, and a platform to examining circuits or longitudinal therapeutics.Lay SummaryGait changes have been reported in Williams Syndrome and Neurofibromatosis Type 1, but how these changes develop over time has not been explored. We therefore studied gait in mouse models of these two disorders across time. We found multiple shared differences in gait as compared to healthy controls at the younger ages in both models. However, those differences were resolved in the Williams Syndrome model by adulthood, yet persisted in the Neurofibromatosis Type 1 model.

Social motivation is critical to the development of healthy social functioning. Autism spectrum condition (ASC) is characterized in part by challenges with social communication and social interaction. The root of these challenges is hypothesized to be a deficit in social motivation, specifically in one or more subcomponents (e.g. social reward reward seeking or social orienting). Current social behavior assays lack the ability to quantitatively measure both social reward seeking and social orienting simultaneously. We have developed an automated socially-rewarded operant conditioning task coupled with video tracking, to quantify effort to achieve access to a social partner and concurrent social orienting behavior in mice. We established that adult wildtype mice will work for access to a social partner, that male mice exhibit greater social motivation compared to females, and there is high test-retest reliability in the task across multiple days. We then benchmarked the method with two test-case manipulations. We first tested a mouse model of Phelan-McDermid syndrome, a neurodevelopmental disorder associated with ASC. These Shank3B mutants failed to show social reward seeking and exhibited reduced social orienting. Next, we demonstrated that oxytocin receptor antagonism decreased social motivation in wildtype mice, consistent with its role in social reward circuitry. Intriguingly, only male mice were vulnerable to Shank3B mutation, while females were more vulnerable to oxytocin blockade, a double dissociation suggesting separate circuits for social motivation in male and female brain. Overall, we believe this method provides a valuable addition to the assessment of social phenotypes in rodent models of ASC and the mapping of potentially sex-specific social motivation circuits in the brain.

Racism continues to be a significant problem in much of the world. Understanding how racism happens in the brain may help us find ways to overcome it. Our brains often categorize people as similar to, or different from, ourselves. A part of the brain called the amygdala becomes active when we see someone who we think is different, and this can lead to treating that person unfairly. But another part of the brain called the prefrontal cortex is able to calm the amygdala, and we can boost its power using a thinking strategy called cognitive reappraisal. Even better, we may be able to prevent people from becoming racist by teaching kids to appreciate differences, so their amygdala does not get activated by people different from themselves. Combined with fixing unfair rules and systems around us, these brain strategies may help us to defeat racism.

A central challenge in preclinical research investigating the biology of autism spectrum disorder (ASD) is the translation of ASD-related social phenotypes across humans and animal models. Social orienting, an observable, evolutionarily conserved behavior, represents a promising cross-species ASD phenotype given that disrupted social orienting is an early-emerging ASD feature with evidence for predicting familial recurrence. Here, we adapt a competing-stimulus social orienting task from domesticated dogs to naturalistic play behavior in human toddlers and test whether this approach indexes decreased social orienting in ASD.Play behavior was coded from the Autism Diagnostic Observation Schedule (ADOS) in two samples of toddlers, each with and without ASD. Sample 1 (n = 16) consisted of community-ascertained research participants, while Sample 2 involved a prospective study of infants at a high or low familial liability for ASD (n = 67). Coding quantified the child's looks towards the experimenter and caregiver, a social stimulus, while playing with high-interest toys, a non-social stimulus. A competing-stimulus measure of "Social Attention During Object Engagement" (SADOE) was calculated by dividing the number of social looks by total time spent playing with toys. SADOE was compared based on ASD diagnosis and differing familial liability for ASD.In both samples, toddlers with ASD exhibited significantly lower SADOE compared to toddlers without ASD, with large effect sizes (Hedges' g ≥ 0.92) driven by a lower frequency of child-initiated spontaneous looks. Among toddlers at high familial likelihood of ASD, toddlers with ASD showed lower SADOE than toddlers without ASD, while SADOE did not differ based on presence or absence of familial ASD risk alone. SADOE correlated negatively with ADOS social affect calibrated severity scores and positively with the Communication and Symbolic Behavior Scales social subscale. In a binary logistic regression model, SADOE alone correctly classified 74.1% of cases, which rose to 85.2% when combined with cognitive development.This work suggests that a brief behavioral measure pitting a high-interest nonsocial stimulus against the innate draw of social partners can serve as a feasible cross-species measure of social orienting, with implications for genetically informative behavioral phenotyping of social deficits in ASD and other neurodevelopmental disorders.

Background Studies in psychiatric genetics have identified >100 loci associated with disease risk, yet many of these loci are distant from protein coding genes. Recent characterization of the transcriptional landscape of cell lines and whole tissues has suggested widespread transcription in both coding and noncoding regions of the genome, including differential expression from loci that produce regulatory noncoding RNAs that function within the nucleus; however, the nuclear transcriptome of specific cell types in the brain has not been previously investigated. Methods We defined the nuclear transcriptional landscape of the three major cellular divisions of the nervous system using flow sorting of genetically labeled nuclei from bacTRAP mouse lines. Next, we characterized the unique expression of coding, noncoding, and intergenic RNAs in the mature mouse brain with RNA-Seq and validation with independent methods. Results We found diverse expression across the cell types of all classes of RNAs, including long noncoding RNAs, several of which were confirmed as highly enriched in the nuclei of specific cell types using anatomic methods. We also discovered several examples of cell type–specific expression of tandem gene fusions, and we report the first cell type–specific expression of circular RNAs—a neuron-specific and nuclear-enriched RNA arising from the gene Hnrnpu . Conclusions These data provide an important resource for studies evaluating the function of various noncoding RNAs in the brain, including noncoding RNAs that may play a role in psychiatric disease.

Motor impairment is common in autism spectrum disorder (ASD) and, as such, a potential target for interventions to improve adaptive functioning. This study investigated motor skill acquisition in children with ASD (n = 15, 12 males; ages 7 – 16 years) during iCan Bike Camp, a one-week, community-based intervention (5×75-minute sessions) to teach independent bicycle riding. After completing the camp’s task-oriented, individualized training program, all participants demonstrated motor skill acquisition on the bicycle, and nine participants rode independently at least 70 feet. Exploratory analyses showed that motor coordination and social communication correlated with rates of skill acquisition. These findings indicate the feasibility and efficacy of brief, community-based motor interventions to teach bicycle riding—an important developmental skill supporting adaptive functioning—to children with ASD.

Objective Gait irregularities are prevalent in neurodevelopmental disorders (NDDs). However, there is a paucity of information on gait phenotypes in NDD experimental models. This is in part due to the lack of understanding of the normal developmental trajectory of gait maturation in the mouse. Materials and methods Using the DigiGait system, we have developed a quantitative, standardized, and reproducible assay of developmental gait metrics in commonly used mouse strains that can be added to the battery of mouse model phenotyping. With this assay, we characterized the trajectory of gait in the developing C57BL/6J and FVB/AntJ mouse lines. Results In both lines, a mature stride consisted of 40% swing and 60% stance in the forelimbs, which mirrors the mature human stride. In C57BL/6J mice, developmental trajectories were observed for stance width, paw overlap distance, braking and propulsion time, rate of stance loading, peak paw area, and metrics of intraindividual variability. In FVB/AntJ mice, developmental trajectories were observed for percent shared stance, paw overlap distance, rate of stance loading, and peak paw area, although in different directions than C57 mice. By accounting for the impact of body length on stride measurements, we demonstrate the importance of considering body length when interpreting gait metrics. Conclusion Overall, our results show that aspects of mouse gait development parallel a timeline of normal human gait development, such as the percent of stride that is stance phase and swing phase. This study may be used as a standard reference for developmental gait phenotyping of murine models, such as models of neurodevelopmental disease., To fill the gap in our understanding of the normal developmental trajectory of gait in the mouse, we characterized gait in two mouse strains across development. Our results revealed metrics that best reflect gait maturation in both strains and underscore the importance of considering body length when interpreting gait metrics. Overall, our results show that aspects of mouse gait development parallel a timeline of normal human gait development.