Motor Control and Learning

Motor Control

Theories of Motor Control 

MOTOR CONTROL THEORY	AUTHOR	DATE	PREMISE	CLINICAL IMPLICATIONS
Reflex Theory	Sherrington	1906	Movement is controlled by stimulus-response.  Reflexes are basis for movement - Reflexes are combined into actions that create behavior.	Use sensory input to control motor output  Stimulate good reflexes  Inhibit undesirable (primitive) reflexes  Rely heavily on Feedback
Dynamical Systems Theory	Bernstein  Turvey  Kelso & Tuller  Thelen	1967  1977  1984  1987	Movement emerges to control degrees of freedom.  Patterns of movements self-organize within the characteristics of environmental conditions and the existing body systems of the individual.  Functional synergies are developed naturally through practice and experience and help solve the problem of coordinating multiple muscles and joint movements at once.  De-emphasize commands from CNS in controlling movement and emphasize physical explanations for movement.	Movement is an emergent property from the interaction of multiple elements.  Understand the physical & dynamic properties of the body - i.e. Velocity- important for dynamics of movement. May be good to encourage faster movement in patients to produce momentum and therefore help weak patients move with greater ease.
Hierarchical Theories	Adams	1971	Cortical centers control movement in a top-down manner throughout the nervous system.  Closed-loop Mode: Sensory feedback is needed and used to control the movement.  Voluntary movementts initiated by “Will” (higher levels). Reflexive movements dominate only after CNS damage.	Identify & prevent primitive reflexes  Reduce hyperactive stretch  Normalize tone  Facilitate “normal” movement patterns  Developmental Sequence  Recapitulation
Motor Program Theory	Schmidt	1976	Adaptive, exible motor programs (MPs) and generalized motor programs (GMPs) exist to control actions that have common characteristics.  Higher-level Motor Programs - Store rules for generating movements.	Abnormal Movement - Not just reflexive, also including abnormalities in central pattern generators or higher level motor programs.  Help patients relearn the correct rules for action  Retrain movements important to functional task  Do not just reeducate muscles in isolation
Ecological Theories	Gibson & Pick	2000	The person, the task, and the environment interact to in uence motor behavior and learning. The interaction of the person with any given environment provides perceptual information used to control movement.  The motivation to solve problems to accomplish a desired movement task goal facilitates learning.	Help patient explore multiple ways in achieving functional task → Discovering best solution for patient, given the set of limitations
Systems Model	Shumway-Cook	2007	Multiple body systems overlap to activate synergies for the production of movements that are organized around functional goals.  Considers interaction of the person with the environment.  Goal-directed Behavior - Task Orientated	Identifiable, functional tasks  Practice under a variety of conditions  Modify environmental contexts

Motor Learning

Theories of Motor Learning 

MOTOR LEARNING THEORY	AUTHOR	DATE	PREMISE	CLINICAL IMPLICATIONS
Adams Closed Loop Theory	Adams	1971	Closed Loop - Sensory feedback is used for the ongoing production of skilled movement  Slow movements  Relies on sensory feedback (Sherrington)  Blocked Practice  Errors = Bad! Needs to be accurate!  Memory Trace - Initiation of movement  Perceptual Trace - Built up over a period of practice & is the reference of correctness.   Improvements = Increased capability of performer to use the reference in closed loop	Perform same exact mvmt repeatedly to one accurate end point  Increase Practice → Increase Learning  Errors produced during learning → Increase strength of incorrect perceptual trace
Schmidt's Schema Theory	Schmidt	1975	Open Loop  Schema - Abstract memory representation for events → RULE  Generalized Motor Program - Rules that allow for the generation of novel movements  Rapid, ballistic movements = recall memory withmotor programs and parameters to carry out movement without peripheral feedback  Variability of Practice → Improve Motor Learning	Optimal Learning → Task practiced under many different conditions  Positive benefits for error production (learn from own mistakes)  Schema has rules for all stored elements, not just correct elements
Ecological Theory	Newell	1991	Based on Systems & Ecological Motor Control Theories  Motor Learnining = Increases coordination between perception and action thru task & environmental constraints.  Perceptual-motor workspace - Identifies mvmts and perceptual cues most relevant to performance of task  Optimal task-relevant mapping of perception & action → NO Rules!	Patient learns to distinguish relevant perceptual cues important to action.

Resources

Presentations

• Motor Learning. Presentation by Dr. Duane "Spike" Millslagle, Associate Professor Exercise Science, University of Minnesota
  http://www.d.umn.edu/~dmillsla/courses/motorlearning/documents/Chapter04.pdf
  

Podcasts