Lateralized Response Timing Deficits in Autism

Background: Procedural learning is an implicit process in which a behavioral response is refined through repeated performance. Neural systems supporting this cognitive process include specific frontostriatal systems responsible for the preparation and timing of planned motor responses. Evaluating performance on procedural learning tasks can provide unique information about neurodevelopmental disorders in which frontostriatal disturbances have been reported, such as autism. Methods: Fifty-two individuals with autism and 54 age-, IQ-, and gender-matched healthy individuals performed an oculomotor serial reaction time task and a sensorimotor control task. Results: Whereas the rate of procedural learning and the precision of planned motor responses were unimpaired in autism, a lateralized alteration in the ability to time predictive responses was observed. Rightward saccadic responses were speeded in individuals with autism relative to healthy control subjects. Conclusions: Speeded rightward predictive saccades suggest atypical functioning of left hemisphere striatal chronometric systems in autism.