Abstract des Autors

This paper addresses the question what level of detail is required in internal representations used in control of multi-joint movements, focusing on contact control tasks. Following Bernstein, we define the central problem to be which strategies are used in the nervous system in order to control the vastly redundant musculoskeletal system. Simplifications based on equilibrium point theories are rejected on the basis that when they are simple they do not lead to adequate behaviour, whereas when they are complex they implicitly introduce the detailed internal representations that they were meant to dispense with. Based on both experimental data and on simulation results, it is argued that timing of muscle activation needs to be precisely tuned to the task at hand and the environmental conditions. It is argued that it is impossible to achieve this without detailed internal representations of the properties of the effector system in relation to the environment. It is attempted to link Bernstein's notion of a hierarchical organization of the nervous system in which tasks are delegated to subsystems as low as possible in the hierarchical structure of the central nervous system, to recent advances in neuroscience. Verf.-Referat