A reluctance to make eye contact is a hallmark of autism spectrum disorder (ASD). By simultaneously imaging the brains of people making eye contact, Yale University researchers found that eye contact between two individuals was associated with a specific area associated with social interaction, which synchronises when two people with normal neural development gaze at each other. The results, published in the journal PLOS ONE, showed that in people with ASD, there was less activity in this region when they attempted eye contact.
People with ASD have been showed to have reduced or altered neurological arousal from looking at images of faces or even robots. Although eye contact is a critically important part of social interactions, scientists have been limited in studying the neurological basis of live social interaction with eye-contact in ASD because of the inability to image the brains of two people simultaneously.
Now, using an innovative technology that enables imaging of two individuals during live and natural conditions, Yale researchers have identified specific brain areas in the dorsal parietal region of the brain associated with the social symptomatology of autism. The study finds that these neural responses to live face and eye-contact may provide a biomarker for the diagnosis of ASD as well as provide a test of the efficacy of treatments for autism.
“Our brains are hungry for information about other people, and we need to understand how these social mechanisms operate in the context of a real and interactive world in both typically developed individuals as well as individuals with ASD,” said co-corresponding author Joy Hirsch, Elizabeth Mears and House Jameson Professor of Psychiatry, Comparative Medicine, and of Neuroscience at Yale.
The Yale team, led by Hirsch and James McPartland, Harris Professor at the Yale Child Study Center, analysed brain activity during brief social interactions between pairs of adults – each including a typical participant and one with ASD – using functional near-infrared spectroscopy, a non-invasive optical neuroimaging method. Both participants were fitted with neuroimaging caps which measured brain activity during face gaze and eye-to-eye contact.
The investigators found that during eye contact, participants with ASD had significantly reduced activity in a brain region called the dorsal parietal cortex compared to those without ASD. Further, the more severe the overall social symptoms of ASD as measured by ADOS (Autism Diagnostic Observation Schedule, 2nd Edition) scores, the less activity was observed in this brain region. Neural activity in these regions was synchronous between typical participants during real eye-to-eye contact but not during gaze at a video face. This typical increase in neural coupling was not observed in ASD, and is consistent with the difficulties in social interactions.
“We now not only have a better understanding of the neurobiology of autism and social differences, but also of the underlying neural mechanisms that drive typical social connections,” Hirsch said.
Source: Yale University
