The Role of the Cerebellum in Preparing Responses to Predictable Sensory Events

Despite numerous studies on the effects of lesions of the mammalian cerebellum on coordination, adaptation and learning, the precise nature of this structure's contribution to motor control remains controversial. This paper reviews the results of a series of behavioural studies with monkeys trained to make rapid, accurate sequences of responses to visual targets. The effects of discrete cerebellar lesions on the performance of these animals is discussed in the light of recent theories about how the cerebellum might be concerned with learning to anticipate certain kinds of sensory events. Additional studies are considered that advocate sensory prediction as a fundamental cerebellar function that could contribute to many of the behavioural processes with which the cerebellum has been implicated. In particular, it is demonstrated how such information could be employed in the augmentation of motor learning by the formation of expectations about the sensory feedback arising from movements and interactions with the environment. Whilst it is argued that the cerebellum may not be unique in being able to perform such functions, comparative anatomical studies suggest that it may operate with an unequalled degree of temporal precision. Such precision forms the signature of skilled motor acts.