Description:

Abstract

Human actions are always performed under unpredictable changes in the external forces and intrinsic states of the body. This makes dynamic stability of natural movements involving large (abundant) groups of elements crucial for any meaningful behavior. Over the past years, the framework of the uncontrolled manifold (UCM) hypothesis has been used to address the problem of task-specific stabilization of salient performance variables in spaces of kinetic, kinematic, and electromyographic elemental variables. Recently, we have developed a method of UCM-based analysis of action stability in spaces of control variables associated with referent coordinates for the effectors. I will review briefly the theoretical framework of this approach, and some of the recent findings that link stability-related phenomena in different abundant spaces of elemental variables and in task-related performance. These will include the concepts of ascending and descending synergies, anticipatory synergy adjustments, and causes of unintentional drifts in performance. I will also share a few examples of applications of this approach to movements of patients with various neurological disorders such as Parkinson’s disease, stroke, and multiple sclerosis.

Speaker info

Mark Latash is a Distinguished Professor of Kinesiology and Director of the Motor Control Laboratory at the Pennsylvania State University. He was trained in Physics, Physics of Living Systems, and Physiology. His research is focused on the control and coordination of human voluntary movements in healthy persons and in patients with movement disorders. He has been developing and applying such theoretical concepts as motor abundance, synergic control, the uncontrolled manifold hypothesis, and control with referent coordinates to a variety of tasks and effector systems. Overall, he views the main goal of motor control research as discovery of laws of nature that define characteristics of biological movement.