Development of brain structure supporting face learning in infants at risk for autism

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Project Summary Autism is a pervasive developmental disorder that is characterized by impaired social cognition, with global differences in brain structure that emerge as early as 6 months of age, years before symptoms are typically detected and can lead to a diagnosis. Among the brain regions that exhibit these early changes is the fusiform gyrus, part of the ventral visual pathway that contains the fusiform face area (FFA). The FFA is important for recognizing faces and undergoes changes in its structure in response to experience-dependent learning of faces, which is ubiquitous in the first year when infants are exposed to caregivers’ faces. This early learning of faces constitutes a foundational proto-social skill upon which social cognition builds. The FFA is defined by its functional response to faces using functional MRI (fMRI), making its study in young infants challenging as they usually cannot be scanned while awake. However, a reliable anatomical landmark, the mid-fusiform sulcus (MFS), specifies the location of FFA in over 80% of brains studied to date. The average and peak depth of cortical sulci, as well as the thickness of cortex in their banks, have been shown in other studies to predict functional properties of the cortex. Thus, we will use a rich publicly available resource, the IBIS dataset, which comprises structural MRI scans at 6, 12, and 24 months from infants at high and low risk of developing autism, to investigate the structure of the MFS and surrounding cortex. In Aim I, we will characterize its typical longitudinal development, and in Aim II, we will test for group differences in its structure and the developmental trajectory of its growth and predictive association of its structure with clinical measures of social communication and socialization. The outcome of this project will shed light on the developmental timing of early visual experience related to social skills development, and has the potential to lead to a novel biomarker reflecting early face learning ability that could provide a new target for early intervention approaches.