Circuits in the cerebellar control of movement.

Abstract

Neuroanatomists have generally recognized that the cerebellum provides the greatest challenge in our initial efforts to discern functional meaning in neuronal patterns because there is a stereotyped and simple geometrical arrangement of its unique neuronal constituents.Presumably, it is for this reason that there is the most refined knowledge of microstructure that is available in the central nervous system.The pioneer investigations of Ram6n y Cajall have led in recent times to fascinating developments concerning microstructure, geometrical arrangements, and numerical assessment.2As shown in Figure 1,3 there are only two kinds of afferent fibers conveying information to the cerebellum, the climbing fibers (cf) and the mossy fibers (mf);and there is only one type of efferent fiber from the cerebellum, the axons of the Purkinje cells (Pc), which terminate in the cerebellar nuclei (cn) and otherwise largely in Deiters' nucleus.The climbing fiber is uniquely distributed to a single FIG.1.-Perspective drawing by Fox3 of a part of a folium of the cerebellar cortex.The principal components are shown in diagrammatic form, and are described in the text.