Cognitive signals processed by the cerebro-cerebellar circuit

Brisbane Convention & Exhibition Centre 

Although several lines of evidence establish the involvement of the medial and vestibular parts of the cerebellum in adaptive motor control, the role of the lateral cerebellum in motor control remains unclear. Ascending projections from the lateral cerebellum to the frontal and parietal association cortices are consistent with the role of these pathways in higher-order behavioral control. Consistent with this, we found that the dentate nucleus, the output structure of the lateral cerebellum, is involved in cognitive functions such as action strategy and movement timing (Kunimatsu et al., 2016, 2018). Especially, the sustained activity in the dentate nucleus before movement onset proactively regulates these behaviors. Recently, we found that these sustained activities are also involved in associative learning. In this study, we recorded the activity of neurons in the dentate nucleus while monkeys performed the object-motor association task in two conditions: a learning condition in which novel objects were used and an over-trained condition in which well-learned objects were used. Many neurons in the dentate nucleus showed sustained activity for the delay period after the objects were presented, and it was greater in the learning condition than in the over-trained condition. Interestingly, the enhancement of sustained activity was diminished when the correct direction was randomly determined, even though the correct rate was equivalent to the early phase of the learning condition. Thus, these sustained activities were only observed when the monkey was aware of the need to learn the visuomotor association. The sustained activity in the dentate nucleus may work as proactive signals to the learning, and the signal may interact with the cerebral cortex.