Abnormal brain connectivity may be a major part of autism spectrum disorder (ASD). Researchers from San Diego State University evaluated the brain activity of young people with ASD using brain imaging technology. They found that, compared to typically developing children, children with ASD have denser connections between the sensorimotor centers of the brain, connecting the cerebral cortex and cerebellum. These strong connections may limit the development other types of brain connections, like higher-order cognition, that would otherwise develop in their place.
Half of the 56 children and adolescents participating in the study had ASD, the other half did not. The researchers observed the children’s brain activity using an fMRI scan. While undergoing the fMRI, the researchers asked the children to fixate on a focal point and to think of nothing in particular so that the scans would show spontaneous brain activity. It was critical to capture spontaneous brain activity to establish baseline neural patterns.
The imaging results revealed that the children with ASD had much stronger neuronal connectivity between the cerebellum and cerebral cortex’s sensorimotor regions than the children without ASD. The children with ASD had less connectivity between brain regions associated with higher-order cognitive functions like decision-making, attention, and language.
The study’s corresponding author, Ralph Axel-Müller, explains that “Our findings suggest that the early developing sensorimotor connections are highly represented in the cerebellum at the expense of higher cognitive functions in children with autism. By the time the higher cognitive functions begin to come online, many of the connections are already specialists. If a particular part of the brain is already functionally active in one domain, there may be no reason for the brain to switch it over to another domain in later life.”
The study is the first to provide a systematic look at connections between the cerebral cortex and the cerebellum. The findings may help lead to a brain-based test for identifying ASD.
This research is published in the journal Biological Psychiatry.
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