Corticocerebellar Effective Connectivity During Adapting to vs. Ignoring Delayed Visual Movement Feedback.

Internal models in the brain may enable flexible action control by calculating estimates of the body's state and predictions of the sensory consequences that its actions will produce. These processes are thought to be implemented by interactions among cortical and subcortical brain regions including the cerebellum. During a virtual reality based hand-target matching task, in which delayed visual movement feedback was behaviorally relevant (i.e., requiring visuomotor adaptation) or irrelevant (i.e., needed to be ignored), we had observed increased hemodynamic responses in the cerebellum (left Crus I/right Lobule VI), V5, and intraparietal sulcus during the adaptation condition. These activity changes suggested processes specific to delay-dependent adaptation. Here, we used dynamic causal modeling (DCM) to test if these regional activity changes could be explained in terms of task (i.e., adaptation)-dependent between-region connectivity changes. During visuomotor adaptation, DCM revealed an increased excitatory influence of the right cerebellum (Lobule VI) on bilateral V5 (and on the IPS), and an increased mutual excitation among the right cerebellum and the left IPS. Our results support the idea that the communication of cerebellar predictions to the cortical visuomotor network underlies visuomotor adaptation.