Acquisition of internal models of motor tasks in children with autism. Brain 131(Pt

Children with autism exhibit a host of motor disorders including poor coordination, poor tool use and delayed learning of complex motor skills like riding a tricycle. Theory suggests that one of the crucial steps in motor learning is the ability to form internal models: to predict the sensory consequences of motor commands and learn from errors to improve performance on the next attempt. The cerebellum appears to be an important site for acquisition of internal models, and indeed the development of the cerebellum is abnormal in autism. Here, we examined autistic children on a range of tasks that required a change in the motor output in response to a change in the environment.We first considered a prism adaptation task in which the visualmap of the envi-ronment was shifted.The children were asked to throw balls to visual targets with and without the prism gog-gles.We next considered a reaching task that requiredmoving the handle of a novel tool (a robotic arm).The tool either imposed forces on the hand or displaced the cursor associated with the handle position. In all tasks, the children with autism adapted their motor output by forming a predictive internal model, as exhibited through after-effects. Surprisingly, the rates of acquisition and washout were indistinguishable from normally developing children. Therefore, the mechanisms of acquisition and adaptation of internal models in self-generated move-ments appeared normal in autism. Sparing of adaptation suggests that alternative mechanisms contribute to impairedmotor skill development in autism. Furthermore, the findingsmay have therapeutic implications, high