Thalamocortical Connectivity in Children and Adolescents with ASD-A Combined fcMRI and DTI approach
San Diego State University
The Brain Development Imaging Lab (BDIL) specializes in using fcMRI, DTI and other MRI techniques to study brain network organization in autism spectrum disorders (ASD). The overarching goal of this research conducted is to identify biomarkers that distinguish children with ASD from typically developing (TD) children, and to contribute to improved diagnosis and interventions. While the causes of ASD remain unclear today, there is some consensus of genetic risk factors specifically affecting neural circuit formation. Investigations of structural and functional connectivity in ASD are therefore of utmost importance. The project seeks to understand brain networks connecting with the thalamus, which is an important subcortical relay structure through which almost all sensory information is routed. It therefore plays an important role in shaping what people see, hear, and feel. Prior neuroimaging studies in TD individuals support highly specific patterns of thalamocortical connectivity. ASD is characterized by communication and social interaction deficits, along with repetitive and restrictive behaviors. These symptoms are some of the most prominent and distressing characteristics of ASD. Sensorimotor and attentional impairments due to thalamic abnormalities may affect sociocommunicative abilities in ASD. Therefore, it is crucial to examine the role of the thalamus in regulating these functions for an improved understanding of neurodevelopmental mechanisms associated with ASD. Surprisingly little imaging research has been conducted on the thalamus in ASD. The objective of the study is to assess functional connectivity and white matter integrity between five cortical regions of interest (ROIs: prefrontal, temporal, motor, somatosensory, and parietal-occipital) and the thalamus in children and adolescents with ASD compared to TD individuals. Preliminary findings show good concordance of fcMRI findings for our TD control group with previous studies examining thalamocortical connectivity in TD adults. For the cohort of children and adolescents with ASD, which is expected to grow to a sample size of 50 within the proposed project period, the project expects to identify 1) overall reduced functional and anatomical connectivity, and 2) associations between diagnostic and neuropsychological measures and connectivity measures indicating the impact of impaired thalamocortical connectivity on general levels of functioning.