Developmental Endophenotypes to Quantify the Emergence of Autism in Infancy

Reciprocal social engagement is a fundamental platform for infant brain development, fueling the emergence and refinement of social and communicative skills and facilitating a cascade of key neurodevelopmental milestones. In particular, the immediate postnatal state is marked by neoteny and extreme neuroplasticity: because human infants enter the world in such a fragile state, their survival depends upon a parent or caregiver’s near-constant care. As a result, the fast pace of infant brain growth and specialization is typically enacted within a very specific context: reciprocal social engagement. This presentation focuses on the quantification of social visual engagement – the way in which infants visually explore, engage with, and ultimately learn from and adapt to their surrounding world. We focus on a series of experimental studies probing the first 2 years of life. Results indicate that social visual engagement is under stringent genetic control, is highly conserved across human and non-human primate species, and is pathognomonically impaired in infants later diagnosed with autism. Together, these findings implicate social visual engagement as a neurodevelopmental endophenotype for autism and also augur a new generation of human and cross-species gene-brain-behavior studies to advance understanding of the pathobiology of autism.