On the interaction between the central nervous system and the peripheral motor system

The problem of the control of voluntary human movements is considered from a cybernetic point of view. The human motor system is considered to be divided into a central part and a peripheral part. The peripheral part is relatively well known and may be regarded as a set of subsystems with well known input-output relations. The interaction between the peripheral part and the central part is related to the mechanisms of the peripheral motor part. With regard to the central part two different types of control mechanisms are possible, a) an intricate functioning of the central part which generates the control signals with regard to internal and extrenal dynamical factors, b) the central part has some degree of independence with respect to the dynamics of the peripheral motor part. In the latter case the central part prescribes the desired movement exactly, but the final performance of the movement is also brought about by peripheral feed-back mechanisms. As a functional form of the interaction between the central part and the peripheral part it might be that the control signals are encoded in a way that is related to the muscle lengths.