Diminished socially selective neural processing in 5-month-old infants at high familial risk of autism

Abstract

The social and communicative difficulties that characterize autism spectrum disorder (ASD) are considered the most striking fea-ture of the disorder. Research has reported that individuals with ASD show abnormalities in the brain regions associated with theprocessing of social information. Importantly, a recent study using functional near-infrared spectroscopy (fNIRS) found the firstevidence of atypicalities in the neural processing of social information in 4- to 6-month-old infants at high familial risk of ASD.These findings provide an important step in the search for early markers of ASD and highlight the potential for neuroimaging tech-niques to detect atypical patterns of neural activity prior to the manifestation of most behavioural symptoms. This study aimed toextend the findings of reduced neural sensitivity to social stimuli in an independent cohort. Twenty-nine 5-month-old infants (13low-risk infants, 16 high-risk infants) were presented with social and non-social visual stimuli, similar to the previous experiment.Importantly, a non-social dynamic motion control condition was introduced allowing the comparison between social dynamic andnon-social, static, as well as dynamic stimuli. We found that while low-risk infants showed activation to social stimuli in the rightposterior temporal cortex, this activation was reduced in infants at high risk of ASD. Although the current sample size was rela-tively small, our results replicate and extend previous work and provide evidence for a social processing difference in infants atrisk of autism. Future research will determine whether these differences relate to an eventual ASD diagnosis or may rather reflectthe broader autism phenotype