Neuroanatomy of Developmental Disorders
The underlying brain anatomy of neurodevelopmental disorders can be studied using several neuroimaging methods that allow us to probe different aspects of brain structure. These various methods can be used in isolation or together in multimodal studies to answer different kinds of questions about the brain and its development over the lifespan.
Morphological features, those having to do with the shape and size of the brain like volume, cortical thickness, and surface area, can be extracted from Anatomical MRI (aMRI). Advanced 3D modeling techniques can be used to generate more complex morphological measurements, such as local gyrification index, which can be used to examine patterns of cortical folding in different brain regions. These different aspects of brain structure may be related to very early developmental processes in autism and related disorders that diverge from typical development. Different kinds of aMRI scans can also be used in combination to highlight structural abnormalities that may not be visible in one modality alone, or to explore the myeloarchitectonic organization of the brain. One goal of this type of research is to aid in earlier diagnosis based on biological measurements, rather than relying on behavioral indices that can only be used later in development.
Kohli, J. S., Kinnear, M. K., Martindale, I. A., Carper, R. A., & Müller, R. A. (2019). Regionally decreased gyrification in middle-aged adults with autism spectrum disorders. Neurology, 93(20), e1900-e1905. PDF
Kohli, J. S., Kinnear, M. K., Fong, C. H., Fishman, I., Carper, R. A., & Müller, R. A. (2019). Local cortical gyrification is increased in children with autism spectrum disorders, but decreases rapidly in adolescents. Cerebral Cortex, 29(6), 2412-2423. PDF
Diffusion-weighted MRI (DWI) allows us to explore brain tissue structure through the diffusion of water molecules, which can reflect patterns of white matter connectivity, along with gray matter microstructure. This type of MRI is the basis of many striking brain images that make their way into popular media. It's easy to see why DWI is so aesthetically pleasing, but it's also an important tool that facilitates research that could previously only be done in post-mortem tissue. In white matter, DWI based tractography can examine the structure of bundles of nerve fibers that travel between different parts of the brain and highlight differences that may underly unique brain network organization in developmental disorders. In gray matter, it may aid in localizing cytoarchitectonic abnormalities that contribute to functional and behavioral differences.
Carper, R. A., Treiber, J. M., White, N. S., Kohli, J. S., & Müller, R. A. (2017). Restriction spectrum imaging as a potential measure of cortical neurite density in autism. Frontiers in neuroscience, 10, 610. PDF
Hau, J., Kohli, J.S., Shryock, I., Kinnear, M.K., Schadler, A., Müller, R.A., & Carper, R.A. (2021). Supplementary and premotor aspects of the corticospinal tract show links with symptomatology in middle-aged adults with autism spectrum disorder. Cerebral Cortex. PDF
Predoctoral Fellowship Grant
Age-related changes in myeloarchitectonics across adulthood in Autism Spectrum Disorder
In vivo myeloarchitectonic mapping based on Magnetic Resonance Imaging (MRI) provides a unique view of gray matter structure and has shown promise for the identification of biomarkers of pathogenesis in clinical studies. With the risk of demyelination associated with aging, older adults with ASD are an important population to examine, as they may show increased vulnerability to abnormalities of cortical myelination. This project investigates the age-related trajectory of intracortical myelin in middle aged to older adults with ASD to establish the spatial distribution of any such abnormalities, and aims to relate these measures to cognitive skills and neuropsychological functions that are also at risk in aging.