Neuroimaging study sheds light on the brain’s response to restricted interests in individuals with autism

Young boy playing with toy train

A study conducted by Vanderbilt Kennedy Center investigator Carissa Cascio, Ph.D., assistant professor of Psychiatry, sought to determine the extent to which the fusiform face area (FFA) responds to images related to restricted interests in children and adolescents with autism, compared to typically developing peers who have strong interests or hobbies.

The findings, published in April in the Journal of Neurodevelopment Disorders*, were that both groups showed response in the FFA, which is a part of the visual system in the lower part of the temporal lobe, but that the participants with autism had a measurably stronger response. Findings also contribute to a growing body of evidence that debunk previous assumptions that the FFA is used only for facial recognition and is somehow impaired in individuals with autism.

Headshot of Carissa Cascio, Ph.D.

Carissa Cascio, Ph.D.

“For a long time, we thought the FFA was specific for recognizing faces because it has such a strong response to faces in most people,” said Cascio. “The work of Isabel Gauthier [Psychology, Radiology; co-author] has suggested it may be more of a general expertise region. If you think about our daily lives, we become face experts because we look at and discriminate faces all the time. Faces become a level of expertise for most people. Gauthier’s work has shown that a lot of people who have expertise in other areas will also recruit this part of the brain when they are engaging with their preferred subject.

“So, we were curious as to whether that would be true for people with autism who have these highly specialized interests. We found the FFA was indeed engaged and working properly when viewing examples of restricted interests. This and previous findings that this area doesn’t respond as expected to faces may simply be the result of it being tuned into different types of stimuli in autism.”

Children and adolescents with and without autism who engaged with a hobby or interest for at least 1 hour a day, 7 days a week, were recruited for the study. Each participant underwent functional magnetic resonance imaging (fMRI) as they viewed images of their particular interests. To get at the research questions, each stimulus set needed to be individualized for each participant. The research team went through several stages to identify and compile the stimuli, including conducting interviews with both parents and participants to tease out the details of each individual interest or hobby.

Composite of brain scans showing differences in response of the fusiform brain area when participants with autism (A) and typically developing participants (B) viewed images of their interests; (G) shows areas of greater response in participants with autism compared to typically developing participants. Photo courtesy Cascio lab.

Composite of brain scans showing differences in response of the fusiform brain area when participants with autism (A) and typically developing participants (B) viewed images of their interests; (G) shows areas of greater response in participants with autism compared to typically developing participants. Photo courtesy Cascio lab.

“Both groups showed response in this visual expertise region of the brain while viewing pictures of their own interests, which we expected,” said Cascio. “The cool part is the group of participants with autism had a measurably stronger response in that region, which has exciting implications for intervention. For example, pairing stimuli of particular interest and expertise with social input or interactions such as a smile or eye contact, may serve to shape these regions toward responding more robustly to social input as well.”

*Foss-Feig, J. H., McGugin, R. W., Gauthier, I., Mash, L. E., Ventola, P., & Cascio. C. J. (2016). A functional neuroimaging study of fusiform response to restricted interests in children and adolescents with autism spectrum disorder. Journal of neurodevelopmental Disorders8:15.

Courtney Taylor is VKC associate director of Communications and Dissemination.

Pictured top of page: photo by Kent Creative.

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