Comparing Intersubject Correlation (ISC) Between Autism Spectrum Disorder and Typically Developed Groups to Better Understand Biological Motion Processing

In this study, we addressed significant neurological differences between autistic and typically developed individuals, specifically when processing biological motion, using Intersubject correlation (ISC) analysis methods. ISC is a tool used to analyze functional magnetic resonance imaging (fMRI) data acquired under naturalistic stimuli. Using ISC, it is possible to pinpoint common brain responses within a group of individuals as they react to a specific stimulus. ISC is also used to highlight the different brain responses two different groups might have while experiencing the same stimulus. In this experiment, we used two subject groups, one group of autism spectrum disorder (ASD) individuals and one typically developed (TD) group of individuals. The participants in each group watched a ninety second clip of romantic ballet. A short clip of ballet dance was chosen as the stimulus because it had been used in past studies to specify brain responses associated with biological motion processing. Using a standard subject-wise permutation statistical test in the ISC Toolbox for analysis, we computed ISC difference maps between the ASD and TD groups. The findings suggested that during biological motion processing, lateralization of brain responses between the two groups differed; TD individuals had greater ISC in the right hemisphere while ASD individuals had greater ISC in the left hemisphere. Greater ISC in typically developed individuals was concentrated in the culmen of the cerebellum which is responsible for kinesthesia and coordination of movement and is also a component of the mirror neuron network that allows individuals to anticipate movement. These results were consistent with data from prior research that found that TD groups share more synchronized brain responses in the cerebellum, which characterizes higher prediction and anticipation of biological movement in TD groups than ASD groups. ISC within the autistic group was found in the temporal gyrus, which plays a neurological role in motion processing and has been seen to be activated in past comparative studies