Atypical visual-auditory predictive coding in Autism Spectrum Disorder: Electrophysiological evidence from stimulus omissions

Autism Spectrum Disorder (ASD) is a pervasive neurodevelopmental disorder characterized by impairments in social communication and social interaction, and restricted, repetitive patterns of behavior, interests or activities. ASD has been linked to a range of perceptual processing alterations, including hypo- and hyperresponsiveness to sensory stimulation. A recently proposed theory that attempts to account for these symptoms, states that individuals with ASD have a decreased ability to anticipate upcoming sensory stimulation due to overly precise internal prediction models. Here, we tested this hypothesis by comparing the electrophysiological markers of prediction errors in auditory prediction by vision between a group of individuals with ASD and a group of age-matched individuals with typical development (TD). Between group differences in visual-auditory predictive coding were assessed by comparing ERPs evoked by unexpected auditory omissions in a sequence of audiovisual recordings of a handclap, in which the visual motion reliably predicted the onset and content of the sound. The results showed clear group differences in the early electrophysiological indicators of visual-auditory predictive coding. Unexpected auditory omissions induced an increased early negative omission response (oN1) in the ASD group, indicating that violations of the visual-auditory predictive model produced larger prediction errors in the ASD group compared to the TD group. Importantly, this increased prediction error signaling could not be explained by differences in the processing of physical stimulus characteristics. The current results show that individuals with ASD have alterations in visual-auditory predictive coding, and support the notion of impaired predictive coding as a core deficit underlying atypical sensory perception in ASD.