Understanding the structure of stability: theory of the uncontrolled manifold
John P Scholz
Department of Physical Therapy, University of Delaware
Last modified: April 28, 2007
Presentation date: 08/11/2007 8:05 AM in MCC
The concept of the uncontrolled manifold captures how the degrees of freedom problem is solved by the Central Nervous System. A theoretical account based on dynamical systems thinking proposes four sources of the task specific structure of variance that has been observed in many different motor systems and task settings: (a) the coupling structure among joint virtual trajectories, (b) back-coupling of real joint trajectories into the planning system, (c) propagation of joint configurations from trial to trial, (d) and the structuring of joint variability by the direction of movement in joint space. The account provides an estimate of the relative contributions of muscle and neural noise and leads to a new view of motor equivalence. Theoretical ideas will be illustrated in reference to a wide range of experimental data sets.