The cerebellum and learning processes in animals.

In theories of motor learning, the cerebellum is assumed to be the storage site of the engram. Recent evidence is presented that the cerebellum, in addition to its mediation of learning of simple motor responses, has a role in cognitive behaviors. For this type of learning, it is possible that the storage site is not the cerebellum, but cerebellar target areas. The possible role of the cerebellum in spatial learning and discrimination learning is emphasized. Ascending cerebellar afferents to fronto-parietal association cortex, the limbic system and the superior colliculus and feedback loops from these areas may be the anatomical basis underlying cerebellar modulation of spatial learning. In regard to discrimination learning, the possible significance of pathways arising from the visual cortex to pontine nuclei projecting to the cerebellar hemispheres must be evaluated. Although much remains to be resolved, the cerebellum seems to contribute to various emotions such as fear, the neural basis of which being cerebellar contributions to the reticular activating system, the limbic system and two-way hypothalamo-cerebellar connections.