Sustained visual signals in the primate cerebellar dentate nucleus drive associative learning

A number of studies have suggested that the cerebellum has cognitive functions; however, the underlying neuronal mechanisms remain unclear. In this study, we demonstrated that sustained visual signals in the cerebellar dentate nucleus represent the visuomotor associative information. We recorded neuronal activity from the dentate nucleus when monkeys performed a learning task involving the association between visual objects and saccade directions. We found that sustained visual activity was greater during learning than during memory retrieval. This enhancement disappeared under the uncertain reward condition, in which the monkeys did not engage in learning behavior. Furthermore, sustained visual signals changed the response to visual objects depending on the associated saccade direction. This direction selectivity was positively correlated with modulation during learning. These results suggest that sustained visual signals in the dentate nucleus reflect learning related motivation and drive learning by increasing the strength of discrimination among visual objects.