Neuroscience
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The cerebellum has been shown to be involved in temporal information processing. We recently demonstrated that neurons in the cerebellar dentate nucleus exhibited periodic activity predicting stimulus timing when monkeys attempted to detect a single omission of isochronous repetitive visual stimulus. In this study, we assessed the relative contribution of signals from Purkinje cells and mossy and climbing fibers to the periodic activity by comparing single neuronal firing before and during local infusion of GABA or glutamate receptor antagonists (gabazine or a mixture of 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide hydrate (NBQX) and (±)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP)). ⋯ We also found that the variation of baseline activity decreased during gabazine application but sometimes increased during the blockade of glutamate receptors. These changes were not observed during prolonged recording without drug administration. These results suggest that the predictive neuronal activity in the dentate nucleus may mainly attribute to the inputs from the cerebellar cortex, while the signals from both mossy fibers and Purkinje cells may play a role in setting the level and variance of baseline activity during the task.