January 15, 2021

Autism Spectrum Disorder (ASD), which impacts communication and interaction abilities, affects 1 in every 54 children in the United States. In order to understand the biological basis of these types of human disorders, scientists must turn to translational animal models—research with animals that closely reflects the same processes in humans.    

Until now, there hasn’t been an effective way to identify which animals were ideal candidates for ASD research. But Kate Talbot, PhD, and her colleagues in the Neuroscience and Behavior Unit at the California National Primate Research Center (CNPRC) have optimized a screening tool—based on an ASD diagnostic tool used in humans—to do just that.  

ASD is classified by the National Institute of Mental Health as a developmental disorder that affects communication and behavior. It is a spectrum disorder, which means autism can present differently in symptoms and severity across individuals. This variability is part of what makes treatment of ASD more complicated. Rather than a primary treatment for ASD, doctors and patients have to work together to develop specific treatment programs.  

Talbot pointed out that studying disease biology directly in ASD patients is difficult in other animal models because they fundamentally lack the complex social cognitive abilities that are impaired in people with autism. But there is a subset of rhesus monkeys within the natural population illustrating low-social behavior similar to what is observed in humans with ASD. The difficult part is identifying enough of these animals early in their development to conduct the necessary translational research. 

Talbot and her team made a breakthrough in that area. The original macaque social responsiveness scale (mSRS) was a 36-item observation-based instrument similar to the Social Responsiveness Scale originally developed for human children. The mSRS was developed using a relatively small sample mostly composed of females, but due to the sample size and the fact that ASD is a particularly male-biased disorder (four males for every one female), the mSRS was difficult to translate to the human screening tool.  

Talbot and colleagues refined the mSRS by applying it to hundreds of male rhesus macaques across their development. They could then compare experimenter responses to the questionnaire directly to behavioral data collected on the animals throughout their lives. Now, the revised tool can determine with 96% accuracy which monkeys qualify as particularly low-social animals compared to their peers.   

“This instrument will be indispensable for advancing the field’s understanding of the developmental trajectory of core autistic symptomology in rhesus and other macaque monkeys, and it can be used as a primary outcome measure in fast-fail preclinical therapeutic testing efforts,” Talbot explained. 

Understanding autism and other neurological conditions is a primary goal of NPRC research. Find out more about our ASD-related studies by visiting this link.  

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