Research of motor response
For unconstrained hand movements, there is a very large set of possible trajectories determined both by the path as well as by the time at which each point on the path is reached. Accessing such trajectories requires special tools like a 2D manipulandum. The TREC manipulandum is made of a 2D planar base plate with an arm that can be moved by the subject without resistance. The movement of the manipulandum is measured continuously and the current position of the ball shaped knob, representing the hand position of the subject, is displayed in real time on a pc screen.
 Kruse W., Dannenberg S., Kleiser R., Hoffmann K.-P. Temporal Relation of Population Activity in Visual Areas MT/MST and in Primary Motor Cortex during Visually Guided Tracking Movements. Oxford Journals, Life Science, Cerebral Cortex, Volume 12, Number 5, Pp. 466-476