The cerebellum and event timing.

Damage to the cerebellum disrupts performance on a range of tasks that require precise timing including the production of skilled movements, eyeblink conditioning, and perceptual tasks such as duration discrimination. We hypothesize that such tasks involve event timing, a form of representation in which the temporal goals are explicitly represented. For example, during finger tapping, the goal to produce evenly paced intervals invokes an explicit temporal representation of the time between successive contact points with the tapping surface. In contrast, timing can be an emergent property in other actions, reflecting temporal consistencies that arise through the control of other movement parameters. One example is continuous circle drawing, a task in which temporal consistency can be achieved by maintaining a constant angular velocity or minimizing higher-order derivatives (e.g., jerk). Temporal consistency on event and emergent timing tasks is not correlated and patients with cerebellar damage show no increase in temporal variability during continuous circle drawing. While the cerebellum likely contributes to performance of a wide range of skilled behaviors, it appears to be especially important when the tasks entail event timing.