MRI study questions links between autism and brain connectivity
A new MRI study prompts questions about the validity of claims that individuals with autism spectrum disorder have altered connectivity patterns in certain brain regions.
Prior studies have hypothesized that reduced functional connectivity in the amygdala—an area of the brain associated with emotional processing—was more common among people on the autism spectrum. This latest study, however, refutes those claims, and suggests that prior findings might have been influenced by "small sample sizes, unquantified data quality and analytic flexibility.”
This latest work compared hundreds of functional MRI exams of individuals diagnosed with ASD to a group of neurotypical participants. When comparing the scans, researchers led by Dorit Kliemann, PhD, an assistant professor of psychological and brain sciences with the University of Iowa, found “no consistent evidence” of significant connectivity variability between the groups.
The team analyzed neural connections in two anatomically defined amygdala subdivisions while participants were in a resting state, paying close attention to connectivity pattern similarity and variability between the two groups.
The results showed that, on average, varied connectivity between individuals was normal and not exclusive to individuals with ASD. This finding was consistent in different subregions of the amygdala as well, the group noted.
They also observed that the results “strongly depended on analytic choices,” such as the preprocessing pipeline for the neuroimaging data, anatomical specificity and subject exclusions.
The group suggested that future work could provide more detailed insight into the role of functional connectivity in ASD by utilizing multiple processing pipelines, collecting more detailed data on participants and including a more diverse group of individuals to increase study generalizability.
"It is important to note that we do not conclude that amygdala [connectivity] is generally typical in autism,” the team clarified. “Instead, we conclude that the evidence for atypical [connectivity] of the amygdala in autism is weak at best, and unreliable.”
The study abstract is available in the American Journal of Psychiatry.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.