The Cerebellum

Abstract

The role of the cerebellum in movement coordination is experimentally well established. The appearance of this structure in evolution was the natural consequence of the necessity for the nervous system to solve the coordination problem. It is obvious that motor control requires the interaction of different OCSs, each of which controls its own body part. An examination of the possible interactions between simple OCSs that are included in a more complex OCS shows that there are two major mechanisms available to the system for solving coordination problems. The first is the anatomical arrangement that results in mutual interconnections between all possible pairs of OCSs. In this case, each OCS creates an internal model of inflow from other OCSs, because this inflow is a source of its afferent flow. Obviously, such an awkward construction can be relatively efficient in simple systems consisting of small numbers of OCSs. The second mechanism is the creation of one coordinating central dispatcher which receives information from all OCSs and other sources, processes it, and sends corresponding commands back to each OCS. This dispatcher accumulates knowledge regarding spatiotemporal correlations between afferent signals and the optimal control signals that should be sent to each OCS in a particular situation. In previous articles (Baev and Shimansky 1992; Baev 1994), the cerebellum was proposed as the central dispatcher created by nature and elaborated in the evolution of vertebrates.