Motor Control and Learning

Original Editor - Naomi O'Reilly

Top Contributors - Naomi O'Reilly, Rucha Gadgil, Kim Jackson, Lucinda hampton, Nikhil Benhur Abburi, WikiSysop, Simisola Ajeyalemi, Candace Goh, Claire Knott, Jess Bell, 127.0.0.1 and Shaimaa Eldib  

Introduction

According Roller et al (2012) the production and control of human movement is a process that varies from a simple reflex loop to a complex network of neural patterns that communicate throughout the Central Nervous System (CNS) and Peripheral Nervous System (PNS). 

New motor patterns are learned through movement, interactions with rich sensory environments, and challenging experiences that challenge a person to solve problems they encounter. The knowledge about motor control and motor learning shape our understanding of how individuals progress from novice to skilled motor performance throughout the lifespan. This page provides an overview about Motor Control and Motor Learning.

Motor Control

Definition

Motor Control is defined as the process of initiating, directing, and grading purposeful voluntary movement. Shumway-Cook has defined motor control as the ability to regulate mechanisms essential to movement.

How does it work?

The Motor Control functions in the following way:

1. The task that needs to be completed is identified→ body gathers sensory information from the environment→ perceives the information→ chooses a movement plan appropriate plan to meet the goal of the task,
2. Plan is coordinated within the CNS → executed through motor neurons in the brain stem and spinal cord → outcome communicated to the muscles in postural and limb synergies, and in the head and neck→ motor units timed to fire in a specific manner.
3. Sensory feedback supplied to the CNS by the movement → decision taken to (1) modify the plan during execution, (2) acknowledge the goal of the task to be achieved, and (3) store the information for future performance of the same task-goal combination.

Theories of Motor Control 

The organization and production of movement is a complex problem, so the study of motor control has been approached from a wide range of disciplines, including psychology, cognitive science, biomechanics and neuroscience. The control of human movement has been described in many different ways with many different models of Motor Control put forward throughout the 19th & 20th Centuries.

Motor Control Theories include the production of reflexive, automatic, adaptive, and voluntary movements and the performance of efficient, coordinated, goal-directed movement patterns which involve multiple body systems (input, output, and central processing) and multiple levels within the nervous system. Many textbooks and researcher recommend adoption of a systems model of Motor Control incorporating neurophysiology, biomechanics and motor learning principles (learning solutions based on the interaction between the patient, the task and the environment). It is imperative to be aware of the effect this relationship between the task and environment when planning our interventions so as to enable our patients to achieve their goals.  

Motor Control Theories are:

MOTOR CONTROL THEORIES	AUTHOR	DATE	PREMISE	CLINICAL IMPLICATIONS
Reflex Theory	Sherrington	1906	Movement is controlled by stimulus-response.  Reflexes are the 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

The motor control theories given above are developed to assist the therapist in:

1. identifying issues in motor performance,
2. developing treatment strategies to help patients remediate performance problems, and
3. evaluating the effectiveness of intervention strategies employed in the clinic.

Systems Involved in Motor Control

Sensory/ Perceptual System	Action Systems
Somatosensory	Motor Cortex
Visual	Basal Ganglia
Vestibular	Cerebellum
	Central Pattern generators

Motor Learning

Definition

1. " The process of acquiring a skill by which the learner, through practice and assimilation, refines and makes automatic the desired movement".
2. "An internal neurologic process that results in the ability to produce a new motor task". 
3. “A set of internal processes associated with practice or experience leading to relatively permanent changes in the capability for skilled behavior”

Theories of Motor Learning 

Motor learning is a complex process occurring in the brain in response to practice or experience of a certain skill resulting in changes in the central nervous system. It allows for the production of a new motor skill. It often involves improving the smoothness and accuracy of movements and is necessary for developing controlled movement and calibrating simple movements like reflexes.

Motor learning research considers variables that contribute to motor program formation (i.e., underlying skilled motor behaviour), the sensitivity of error-detection processes, and strength of movement schemas. Motor learning requires practice, feedback and knowledge of results .

The Motor learning theories are:

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 movement 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.

Stages of Motor Learning

Stages of Learning	Characteristics	Attention Demands	Activities	Description
Cognitive	Movements are slow, inconsistent and inefficient. Considerable cognitive activity is required.	Attention to understand what must move to produce a specific result. Large parts of the movement are controlled consciously	Practise sessions are: performance focused less variable incorporate a clear mental image (technical & visual).	Early Cognitive; Essential Elements were not observed or not present
				Late Cognitive; Essential elements are starting to appear
Associative	Movements are more fluid, reliable and efficient Less cognitive activity is required	Some parts of the movements are controlled consciously, some automatically.	Practise sessions link performance and results, conditions can be varied. Clear Mental Image = Accurate Performance	Early Associative; Essential elements appear, but not with consistency.
				Late Associative; Essential elements appear regulalry at a satisfactory level.
Autonomous	Movements are accurate, consistent and efficient. Little or no cognitive activity is required.	Movement is largely controlled automatically Attention can be focused on tactical choices	Practise sessions are more results orientated Focus is on greater range of movement, speed, acceleration and use of skill in a novel situation.	Early Autonomous; Essential elements appear frequently avove required level.
				Late Autonomous; Essential elements appear continuously at a superior level.

The end result of motor learning is the acquisition of a new movement, or the reacquisition and/or modification of movement in a manner that is efficient, consistent and transferrable (ability to perform movement under different environments and conditions).

Resources 

Presentations 

• Essential Concepts of Motor Control & Learning: Presentation by DM McKeough.
  

Podcasts

• Motor Learning Strategies Applied to Neurorehabilitation. Dr. Joe Hidler, CEO of Aretech and inventor of the ZeroG Gait and Balance Training System discusses the research he and colleagues have done which has served as the catalyst as to why ZeroG was developed.
  

• Making Sense of Sensory and Motor Control of Human Movement. Dr. Kristen Pickett is an Assistant Professor in the Occupational Therapy Program within the Department of Kinesiology at the University of Wisconsin, Madison. She received her Masters in Kinesiology and her PhD in Kinesiology, Biomechanics, and Neural Control from the University of Minnesota, Twin Cities.