The cerebellum as a developmental guidance machine

Deficits resulting from cerebellar damage vary according to the age when the insult first occurs, suggesting that it may play a role in normal development. Prenatal cerebellar damage is associated with autism spectrum disorder and is associated with reductions in the size of neocortical structures that receive input from the site of damage. In childhood, cerebellar damage leads to mutism and "extrapyramidal" movement problems. Only in adulthood are ballistic and uncontrolled movements the most prominent sequelae. Although the initial deficits shift with age, they usually last for life, suggesting that the cerebellum may play a shifting role in guiding the organization of social, cognitive, and motor capacities. At the level of neuronal circuits, models of cerebellar function focus on its role as a processor of unexpected events to adjust action. We propose that cerebellar circuits can guide social, cognitive, and motor development throughout the growing brain.