Roby Jacobs is working on some really cool work on motor control.

He described an experiment in which subjects had to control a joystick under differerent noise regimes: no noise, signal proportional noise, signal inverse proportional noise. The optimal trajectories are very different in these 3 cases and humans seem to be quite good at learning these trajectories. Here is a link to the paper
He talked about an experiment by Julia something from Germany were the task is reaching under different pay off regimes.
He talked about experiments on combination of visual and proprioceptive information. Cited the work by a person at UCSF.
He talked about some computational work he is doing in which optimal trajectories are computed as linear combinations of a library of trajectories. This approach may simplify the optimization problem so it becomes a standard gradient descent like problem as opposed to a variational problem.
Here is a link to Roby’s work