Cortico-cerebellar effective connectivity during adapting to vs ignoring delayed visual movement feedback

We modelled hemodynamic responses acquired during a virtual reality based hand-target matching task with conditions in which delayed visual movement feedback was behaviorally relevant (requiring visuomotor adaptation) vs irrelevant (i.e., needed to be ignored). We had observed increased hemodynamic responses in the cerebellum, V5, and intraparietal sulcus linked to delay-dependent adaptation. Here, we used dynamic causal modeling to test if these regional activity changes could be explained in terms of network interactions among those nodes. We found a strong excitatory influence of the right cerebellum on the bilateral V5, which increased during the visuomotor adaptation > no adaptation tasks. Furthermore, there was an increased mutual excitation among the cerebellar hemispheres, and an inhibition of the cerebella by the V5, during visuomotor adaptation. These results are consistent with the idea that the cerebellum implements forward models predicting the sensory consequences of actions, and communicates these predictions to other regions of the visuomotor control hierarchy.