| Todorov, E., Jordan, M.I. Optimal feedback control as a theory of motor coordination Nature Neuroscience 2002 (5):11 [pdf] |
| Motor coordination the marshalling of redundant actuators in the service of a desired behavioral outcome is among the most important and least understood facets of motor function. Models that focus on mechanisms for achieving behavioral goals often fail to account for experimental data on movement variability and the exploitation of redundancy. Models that focus on variability and redundancy often fail to explain how goals are achieved in the first place. Here we show that not only are variability and goal achievement compatible, but indeed that allowing variability in redundant dimensions is the optimal strategy in the face of uncertainty. Our approach is based on stochastic optimal control theory, which provides, for a given task, the feedback control law that maximizes expected performance. This control law does not enforce a "desired trajectory" an approach that we show to be suboptimal but instead corrects only those deviations that interfere with the task goals. We find that the resulting behavior exhibits goal-directed adjustments, synergies, controlled parameters , simplifying rules , and discrete coordination modes none of which are built in a priori. Experimentally, we investigate a range of motor tasks and report patterns of variability in close agreement with the model. |
| |
|
|