Motivation: Task-driven BOLD signal nonlinearities in visuomotor areas have been reported both during execution and observation of tasks. Goal(s): We aim to study how cerebral and cerebellar regions of a visuomotor network influence each other and drive nonlinear BOLD responses. Approach: Dynamic Causal Modeling was used to estimate causal influences as effective connectivity to assess how the activity of each region modulated BOLD signal nonlinearities in a visuomotor task. Results: Execution and observation networks showed the same fixed (0th order) effective connectivity, while BOLD signal nonlinearities were modulated in the motor planning loop during execution only and were driven by the cerebellum. Impact: Dynamic causal modeling elucidates the central role of the cerebellum as a forward controller in regulating input-driven modulation differentially in execution and observation. These mechanisms may be affected by pathologies and could have an important role in visuomotor disability.

Differential control of nonlinear functional dynamics by cerebro-cerebellar interactions during action execution and observation