Scientists believe that children with autism spectrum disorder (ASD) have difficulties in social interactions at least partly due to an inability to understand other people’s thoughts and feelings through a process called “theory of mind,” or ToM.
A new innovative brain imaging study has uncovered new evidence explaining why ToM deficiencies are present in ASD children. The researchers found disruptions in the brain’s circuitry involved in ToM at multiple levels compared to typical brain functioning. The findings provide valuable insight into an important neural network tied to the social symptoms in children with ASD.
“Reduced brain activity in ToM-related brain regions and reduced connectivity among these regions in children with autism suggest how deficits in the neurobiological mechanisms can lead to difficulties in cognitive and behavioral functioning, such as theory of mind,” said Marcel Just, the D.O. Hebb University Professor of Psychology at Carnegie Mellon University.
“Weaker coordination and communication among core brain areas during social thinking tasks in autism provides evidence for how different brain areas in autism struggle to work together as a team.”
The researchers used an approach first developed by Fulvia Castelli and her colleagues in the U.K. that created animation videos showing two geometric shapes moving around the screen. The shapes, such as a large red triangle and a small blue triangle, moved in ways that could be perceived as an interaction between them, such as coaxing or dancing.
The team demonstrated that “seeing” the interactions was in the mind of the beholder, or to be more specific, in the ToM circuitry of the viewer’s brain. Without ToM, it just looked like geometric shapes moving around the screen.
To better understand the the neural mechanisms involved with ToM, the scientists asked 13 high-functioning children with ASD between the ages of 10 and 16 as well as 13 similarly aged children without ASD to watch these short animated films. The children were asked to identify the thoughts and feelings, or mental states, of those triangles while having their brains scanned by an fMRI scanner.
The ASD children showed significantly reduced activation compared to the control group children in the brain regions considered to be part of the ToM network, such as the medial frontal cortex and temporo-parietal junction. Furthermore, the synchronization between such pairs of regions was lower in the autism group.
The findings support Just’s previous research in 2004 which discovered this lower synchronization. In later studies, Just continued to show how this theory accounted for many brain imaging and behavioral findings during tasks that are heavily linked to the frontal cortex.
“One reason this finding is so interesting is that the ‘actors’ in the films have no faces, facial expressions or body posture on which to base a judgment of an emotion or attitude,” said Rajesh Kana, associate professor of psychology at the University of Alabama at Birmingham.
“The neurotypical children managed to identify a social interaction without social cues, such as interpreting the large triangle nudging the smaller one as a parent’s attempt to encourage a child, but the ASD children were unable to make the connection.”
Until now, most research focused on the connectivity among core brain regions in ASD has focused on adults, limiting knowledge about how the disorder affects younger people.
“By studying children, we were able to show that it is possible to characterize the altered brain circuitry earlier in development, which could lead to designing earlier effective intervention programs that could train children to infer the intentions and thoughts that underlie physical interactions between people,” Just said. “For example, children could be trained to distinguish between a helpful nudge and a hostile poke.”
The findings are published in the journal Molecular Autism.