Diversity of the nature of input and output signals in the cerebellum suggests a diversity of function

Cerebellar research has been guided by the idea that it subserves a single computational function — the ‘universal cerebellar transform’ — across different tasks. This idea is motivated by the uniform cerebellar circuit and our understanding of how it supports simple motor learning tasks. In this review, we examine findings for three motor domains (eyeblink conditioning, saccades, and reaching arm movements) that highlight inconsistencies in the nature of input and output signals across tasks and show that the cerebellum may even contribute in multiple different ways to a single task, challenging this classical view. Even though this review cannot offer a coherent picture of cerebellar function across tasks, we stress the importance of considering the possibility that the cerebellar circuit subserves multiple computational, rather than one universal, function.