Thalamocortical Dysconnectivity in Autism Spectrum Disorder: An Analysis of the Autism Brain Imaging Data Exchange

BACKGROUND: Individuals with autism spectrum disorder (ASD) exhibit differences in basic sensorimotor processing as well as general cortical excitability. These observations converge to implicate thalamocortical connectivity as a potential unifying neural mechanism. The goal of this study was to clarify mixed findings on thalamocortical functional connectivity in a large sample of individuals with ASD. METHODS: Using the Autism Brain Imaging Data Exchange, we examined thalamocortical functional connectivity in 228 individuals with ASD and a matched comparison group of 228 typically developing individuals. To fully characterize thalamocortical functional networks, we employed complementary seed-based approaches that examined connectivity of major cortical divisions (e.g., prefrontal cortex, temporal lobe) with the thalamus and whole-brain connectivity of specific thalamic subregions. RESULTS: The prefrontal cortex, temporal lobe, and sensorimotor cortex exhibited hyperconnectivity with the thalamus in individuals with ASD. In the whole-brain analysis, hyperconnectivity of several thalamic seeds included multiple cortical areas but tended to converge in temporal cortical areas, including the temporoparietal junction. Follow-up analyses of age effects revealed that the connectivity abnormalities in individuals with ASD were more pronounced in adolescents compared with children and adults. CONCLUSIONS: These results confirm previous findings of temporal and motor thalamocortical hyperconnectivity in ASD and extend them to include somatosensory and prefrontal cortices. Although not directly addressable with the data available in the Autism Brain Imaging Data Exchange, this widespread hyperconnectivity could theoretically account for sensorimotor symptoms and general cortical excitability in ASD. Future studies should target comprehensive clinical and behavioral characterization in combination with functional connectivity to explore this possibility.