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 neural 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 in the region during learning than during memory retrieval. This enhancement disappeared under the uncertain reward condition, wherein the monkey did not perform the heuristic learning strategy. 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 motivation and drive learning by increasing the strength of discrimination among visual objects.