Exercise during development induces an increase in Purkinje cell dendritic tree size.

Mice allowed to exercise during the late postnatal period had Purkinje cells with larger dendritic trees and greater numbers of spines than littermates whose physical activity was severly restricted. These changes in Purkinje cells were accompanied by a selective reduction in the thickness of the cerebellar molecular layer. The data provide evidence for cerebellar plasticity during late development and demonstrate that physical activity can modify the development of Purkinje cell dendrites.