Human Trajectory Planning: Historical Perspectives and Current Research Directions

A question of fundamental importance in biological motor control is what coordinate frames are used by the brain in internally representing sensorimotor information and motor plans and how the brain performs the necessary transformations between the various coordinate frames available to it. Another focus of motor control studies during the last two decades has been on characterizing the kinematic features of human and primate movements, particularly the associated hand trajectories, and investigating the underlying trajectory planning strategies. In my first talk I shall review the main findings from both earlier and more recent behavioral studies on the spatial and temporal features of two- and three-dimensional hand trajectories. I will also discuss several computational models based on the idea that the brain selects and plans trajectories which optimize different cost functions. In addition I shall review other models which focus on the relations between path geometry, movement velocity and motor timing. Finally, I will discuss current controversies over planning and representation of desired trajectories and the topics of eye-hand coordination and trajectory modification.