A challenging, unpredictable world for people with autism spectrum disorder.

Autism is a pervasive neurodevelopmental disorder characterized by impairment of communication and social interaction, as well as by high levels of repetitive and ritualistic behaviours. This last dimension results in major difficulties in daily life: clinical reports of individuals with Autism Spectrum Disorder (ASD) show that they present tantrums as a response to change, or restricted interests and repetitive behaviours in order to prevent or minimize change. Such a crucial need to maintain sameness suggests substantial differences in how the ASD brain predicts the environment, and this might have a fundamental role in the deficit revealed in the highly unpredictable social world. Several lines of evidence indicating difficulties in generating or using predictions in ASD due to atypical information processing will be presented in this review. For instance, several studies have revealed that people with ASD demonstrate a unique profile of cognitive abilities, with strategies that depend to an abnormally large extent on sensory systems, at the expense of more integrative processing requiring an awareness of contextual subtleties necessary for prediction. At a more elementary level, patients with autism manifest unusual processing of unpredictable events, which might be rooted in a basic difference in how the brain orients to changing, novel sensory stimuli. This review presents results from ERPs and fMRI studies illustrating the psychophysiological mechanisms and neural bases underlying such phenomena in ASD. We propose that such dysfunction in the ability to build flexible prediction in ASD may originate from impaired top-down influence over a variety of sensory and higher level information processing, a physiopathological hypothesis which dovetails with the cortical under connectivity current theory.