Evaluation of the inverse dynamic model in cerebellum during visual-vestibular interactions at different VOR gains in squirrel monkeys

Generality of the cerebellar inverse dynamic model (IDM) theory was evaluated in oculomotor control in squirrel monkeys. Flocculus Purkinje cell firing patterns recorded during visual, vestibular, and their interaction paradigms at various vestibuloocular reflex (VOR) gains were reconstructed by the IDM consisting of the linear combination of eye position, velocity, and acceleration. The IDM could successfully reconstruct more than 72% of the firing patterns of 138 cells, but with different sets of parameters for different paradigms and different VOR gains. This result suggests that the output of the flocculus relates to motor output, but not the motor command per se.