The core social impairments that characterize autism spectrum disorder (ASD) remain poorly understood. Improved understanding of ASD has been hindered by the inability to directly study brain tissue in ASD patients, and mice lack the complex social capabilities found in humans and other primates. These limitations have impeded the discovery of ASD biomarkers and the development of promising medications to treat social deficits seen in ASD.

Development of a monkey model of social impairments that resemble the biological and behavioral deficits of ASD would be of tremendous value. Rhesus monkeys are ideally suited for such a model because, like humans, they are a highly social species that displays stable and pronounced individual variation in both the quantity and quality of social behavior. Karen Parker and her team at Stanford University have shown that, at the behavioral extremes, low-social compared with high-social male monkeys initiate fewer affiliative interactions and display more inappropriate social behavior in their home groups. Supported by a previous grant from SFARI, Parker and her team developed a powerful behavioral screening tool to rapidly identify low-social male monkeys in this large population. They also demonstrated in two independent cohorts that low-social monkeys exhibit biomarker irregularities previously implicated in individuals with ASD, and that the greater these biological irregularities, the more severe the monkeys’ observed social deficits.

In the current project, the researchers plan to develop social tests with clinical relevance to better characterize the type and severity of impairments in low-social rhesus monkeys. They will also isolate the biomarkers that best predict performance on these behavioral tests. Finally, they will begin biomarker-informed therapeutic testing in low-social monkeys, with the ultimate aim of improving social functioning in people with ASD.