Regional cerebellar choline acetyltransferase activity following peduncular lesions

The activity of choline acetyltransferase (ChAT) in the cerebellar lobules of the rat was determined after bilateral destruction of either the superior, middle, or inferior cerebellar peduncles. A significant, 40-60% decrease in ChAT activity occurred in all subdivisions of the cerebellum (anterior lobe, posterior lobe hemisphere, posterior lobe vermis/nodulus and flocculus/paraflocculus) following bilateral inferior peduncle lesions. In contrast, bilateral lesions of the superior or middle peduncles did not result in significant reductions of enzyme activity. These findings indicate that the cholinergic afferents to the cerebellum are contained predominantly in the inferior peduncle, from which they emerge to innervate all of the gross subdivisions of the cerebellum.