A simple model is proposed to explain how the central nervous system (CNS) coordinates the muscles at two or more joints of a single limb, when making a voluntary pointing movement. This model has three elements: a general principle for inter-joint torque coordination, and two movement-specific rules. One rule determines the signs and magnitudes of the individual joint torques, while a second specifies the joint torque patterns. From these torques, the muscles which act as agonists and antagonists can be identified, and their patterns of activation can be approximately specified. The model also identifies regions where this agonist/antagonist pattern breaks down.
The aim of the proposed study is to test the validity of this model, in the context of two-joint arm pointing movements, and to test the limits of the model's generalizability by applying it to other limbs, to more joints, and to other classes of movements. It is suggested by the applicant that this model offers a concrete, physically meaningful approach to what """"""""coordination"""""""" is and how a lack of coordination might be measured.
