Differences in Brain Wiring Associated With Changes in Autism Symptoms Across Childhood, Finds UC Davis

July 18, 2022

Colleagues at California's IDDRC at UC Davis recently published a study that helps to explain differences in the development of the brain’s wiring in autism, and how these differences are associated with changes in autism symptoms across childhood.  

Within the brain, white matter serves as connective tissue, “wiring” different parts of the brain together (like bundles of wires). These structural connections provide critical pathways for different brain regions to communicate with each other to produce a desired behavior. It is widely theorized that autistic characteristics, including social communication challenges and restricted repetitive behaviors arise from alterations in brain connectivity. A type of magnetic resonance imaging (MRI) scan called diffusion weighted MRI is particularly well suited to investigate the white matter pathways in the brain and has been utilized by several previous studies of autism. These studies have consistently found alterations in white matter structure in autism; however, little is known about when these differences develop 

This recent study leveraged diffusion weighted MRI scans from the UC Davis Autism Phenome Project, which was first initiated in 2006 by Professors David Amaral and Christine Wu Nordahl. This project continues to follow children at multiple points across childhood starting from around three years of age, near the time when an autism diagnosis is first possible. By acquiring multiple brain scans longitudinally across childhood, we were able to chart the developmental course of white matter pathways in autism compared to typical development. We found that in autism, white matter differences in these pathways emerge over early childhood due to slower white matter development and might not be present, or even have differences in the opposite direction closer to three years of age. Importantly, slower white matter development was found to be associated with a trajectory of increasing autism characteristics. This provides new evidence that white matter development may serve as an important indicator of the progression of autism.  

We hope in the near future that measurements such as this can both identify children who would benefit from more intensive intervention and serve as a marker to determine the effectiveness of interventions. Accomplishing this would allow us to better tailor interventions for individual children and hopefully improve the quality of their lives