theories of motor control kmc

THEORIES OF THEORIES OF MOTOR MOTOR

CONTROLCONTROL

OUTLINEOUTLINE

What is motor control?What is motor control? Theories of motor control- Theories of motor control-

limitations and clinical implicationslimitations and clinical implications Motor LearningMotor Learning Theories related to skilled learningTheories related to skilled learning Factors contributing to motor Factors contributing to motor

learninglearning CONCLUSIONCONCLUSION

WHAT IS MOTOR WHAT IS MOTOR CONTROL?CONTROL?

The study of the The study of the nature and causes nature and causes of movementof movement

2 issues- postural 2 issues- postural and balance controland balance control

movementmovement

Interaction of Interaction of individual, task and individual, task and the environmentthe environment

III

I

13 THEORIES13 THEORIES

Reflex theoryReflex theory Hierarchical theoryHierarchical theory Neuromaturational theoryNeuromaturational theory Spatiotemporal adaptation theorySpatiotemporal adaptation theory Servo mechanistic theories (Loop Servo mechanistic theories (Loop

theories)theories) Cognitive theoriesCognitive theories ““Motor-genre” theoryMotor-genre” theory

Motor programming theoryMotor programming theory Systems theorySystems theory Dynamical action theoryDynamical action theory Parallel distributed processing Parallel distributed processing

theory theory Task oriented theoriesTask oriented theories Ecological theoryEcological theory

REFLEX THEORYREFLEX THEORY

Sir Charles Sherrington in 1906 wrote Sir Charles Sherrington in 1906 wrote book The Interactive Action of the book The Interactive Action of the Nervous SystemNervous System

reflexes were the building blocks of reflexes were the building blocks of complex behaviourcomplex behaviour

a reflex requires a stimulus and results in a reflex requires a stimulus and results in a responsea response

He also saw ‘chaining’ of simple reflexesHe also saw ‘chaining’ of simple reflexes Theorists suggest that one reflex becomes Theorists suggest that one reflex becomes

the stimulus for anotherthe stimulus for another

Movements result from the activation of the Movements result from the activation of the muscle groups in characteristic spatial-muscle groups in characteristic spatial-temporal relationships. temporal relationships.

“ “A simple reflex is probably a purely abstract A simple reflex is probably a purely abstract conception, because all parts of the nervous conception, because all parts of the nervous system are connected together and no part of it system are connected together and no part of it is probably ever capable of reaction without is probably ever capable of reaction without affecting and being affected by various other affecting and being affected by various other parts, and it is a system certainly never parts, and it is a system certainly never absolutely at rest”(1906).absolutely at rest”(1906).

LIMITATIONSLIMITATIONS Reflexes cannot be considered the basic unit Reflexes cannot be considered the basic unit

of behaviourof behaviour It does not adequately explain and predict It does not adequately explain and predict

movement that occurs in the absence of a movement that occurs in the absence of a sensory stimulus. sensory stimulus.

It does not explain fast movements It does not explain fast movements Chaining model fails to explain the fact that Chaining model fails to explain the fact that

a single stimulus can result in varying a single stimulus can result in varying responses depending on context and responses depending on context and descending commandsdescending commands

Chaining also does not explain the ability to Chaining also does not explain the ability to produce novel or new movements produce novel or new movements

CLINICAL CLINICAL IMPLICATIONSIMPLICATIONS

Clinical testing of reflexes can allow Clinical testing of reflexes can allow therapists to predict functiontherapists to predict function

Functional skills by retraining motor Functional skills by retraining motor control would emphasize on control would emphasize on enhancing or reducing the effect of enhancing or reducing the effect of various reflexes during motor task.various reflexes during motor task.

HIERARCHICAL THEORYHIERARCHICAL THEORY The term ‘hierarchy’ means a series of The term ‘hierarchy’ means a series of

levels of control with each succeeding levels of control with each succeeding level controlling all the previous levels.level controlling all the previous levels.

Dominated by the cerebral cortexDominated by the cerebral cortex It is defined as an organizational structure It is defined as an organizational structure

that is that is top down.top down. Rudolf Magnus(1920)Rudolf Magnus(1920) Georg SchaltenbrandGeorg Schaltenbrand Stephan WeiszStephan Weisz (1938) (1938) Hughlings Jackson Hughlings Jackson

The hierarchical control structure is The hierarchical control structure is characterized characterized

by a top downby a top down

structure.structure.

BRAIN

Brain stem

Spinal cord

Muscle

NEUROMATURATIONAL NEUROMATURATIONAL THEORY OF THEORY OF

DEVELOPMENTDEVELOPMENT Arnold Gesell and Myrtle McGrawArnold Gesell and Myrtle McGraw CNS corticalization results in higher CNS corticalization results in higher

levels of control over lower levels of levels of control over lower levels of reflexes.reflexes.

primitive movements become voluntary primitive movements become voluntary movementsmovements

Motor development progresses in a Motor development progresses in a cephalo-caudal mannercephalo-caudal manner

Sequence and rate of motor development Sequence and rate of motor development among infants is consistent.among infants is consistent.

Motor Motor development is development is achieved by neural achieved by neural process maturation process maturation including the including the progressive progressive appearance and appearance and disappearance of disappearance of reflexes.reflexes.

NeuroNeuronatominatomical cal structustructuresres

PosturPostural al reflex reflex develodevelopmentpment

Motor Motor develodevelopmentpment

CortexCortex EquilibEquilibrium rium reactioreactionsns

BipedaBipedal l functiofunctionn

MidbraMidbrainin

RightinRighting g reactioreactionsns

QuadriQuadripedal pedal functiofunctionn

BrainstBrainstem & em & spinal spinal cordcord

PrimitiPrimitive ve reflexreflex

Apedal Apedal functiofunctionn

LIMITATIONSLIMITATIONS

Does not explain dominance of lower Does not explain dominance of lower level reflexes with increased level reflexes with increased environmental demands.environmental demands.

Does not consider other factors like Does not consider other factors like musculoskeletal changes that affect musculoskeletal changes that affect motor control.motor control.

Does not provide a foundation for Does not provide a foundation for altering the environment as apart of altering the environment as apart of its intervention theory base.its intervention theory base.

(Bobath 1971; Fiorentino 1973) a (Bobath 1971; Fiorentino 1973) a major problem with respect to the major problem with respect to the integration centresintegration centres for these reflexes for these reflexes existexist

Does not always bring improvements Does not always bring improvements in functional skillsin functional skills


Therapist using a complete Therapist using a complete understanding of this and reflexes understanding of this and reflexes could determine the could determine the neural age neural age of a of a child or a patient and maturity of child or a patient and maturity of CNS.CNS.

Positioning and handling techniques Positioning and handling techniques to treat child with atypical motor to treat child with atypical motor development. development.

SPATIOTEMPORAL SPATIOTEMPORAL PHYSICAL THEORYPHYSICAL THEORY

Proposed by Gilfoyle, Grady, and Moore Proposed by Gilfoyle, Grady, and Moore (1990)(1990)

Mc Cormack & Perrin(1997)Mc Cormack & Perrin(1997) Developmental-------------------AcquisitionalDevelopmental-------------------Acquisitional(Hierarchical--------Motor genre------(Hierarchical--------Motor genre------

SystemsSystems STP theorySTP theory

What is adaptation?What is adaptation? Adaptation involves 4 processesAdaptation involves 4 processes


complex theoretical concepts and complex theoretical concepts and assumptions assumptions

Misinterpret dynamic nature of Misinterpret dynamic nature of nervous systemnervous system

Reflex and reaction analysis is Reflex and reaction analysis is approximation of developmental approximation of developmental continuumcontinuum


EVALUATION- High risk infantsEVALUATION- High risk infants INTERVENTIONINTERVENTION

NON-VOLITIONALNON-VOLITIONAL

MOVEMENTSMOVEMENTSPHYSICALPHYSICAL

MS. MS. FUNCTIOFUNCTIONN

SPATIAL SPATIAL

PLANE PLANE MOVTS.MOVTS.

TEMPORTEMPORAL AGE AL AGE SPANSPAN

VOLIVOLITIONTIONAL AL

MOVMOVT.T.

SERVOMECHANISTIC SERVOMECHANISTIC THEORIES (“Loop THEORIES (“Loop

Theories”)Theories”) OPEN LOOPOPEN LOOP CLOSED LOOPCLOSED LOOP 3-4 differences between them3-4 differences between them Serves as a explanation of motor Serves as a explanation of motor

controlcontrol

Ref:Crutchfield Ref:Crutchfield

COGNITIVE THEORIESCOGNITIVE THEORIES

Relate in particular to highly skilled Relate in particular to highly skilled and rapid movementsand rapid movements

2 major components-decision and 2 major components-decision and actionaction

Keele (1982)Keele (1982) Clinical significanceClinical significance Do not equate average everyday Do not equate average everyday

activities with highly skilled athletic activities with highly skilled athletic activities.activities.

MOTOR-GENRE THEORYMOTOR-GENRE THEORY

McDonnell,Corkum &WilsonMcDonnell,Corkum &Wilson Reflexes and volitional and Reflexes and volitional and

nonvolitional movementsnonvolitional movements

Some 8 theoretical assumptionsSome 8 theoretical assumptions


limited explanation of the limited explanation of the relationship of non-volitional and relationship of non-volitional and volitional movements volitional movements

Musculoskeletal changes during Musculoskeletal changes during infancy infancy


Involuntary movement and volitional Involuntary movement and volitional skillsskills

Treat effects of primitive reflexesTreat effects of primitive reflexes

MOTOR PROGRAMMING MOTOR PROGRAMMING THEORIESTHEORIES

Wilson (1961),Frosberg, Grillner and Wilson (1961),Frosberg, Grillner and Rossignol (1975), Grillner (1981)Rossignol (1975), Grillner (1981)

CPGs and complex movementsCPGs and complex movements The term ‘The term ‘motor programmotor program’ is used to identify ’ is used to identify

CPG – a stereotypic and hardwired neural CPG – a stereotypic and hardwired neural circuit.circuit.

Pattern Generators- Brooks(1986)Pattern Generators- Brooks(1986)

Nashner Nashner &Woollacot(1979)&Woollacot(1979)

Milani- Comparetti(1981)Milani- Comparetti(1981)


Central motor program cannot be Central motor program cannot be considered as the sole determinant considered as the sole determinant of motor action.of motor action.

Does not provide a developmental Does not provide a developmental guideline for normal motor skill guideline for normal motor skill acquisition.acquisition.


help in assessing abnormal or help in assessing abnormal or disordered motor controldisordered motor control

relearn correct rules for movement relearn correct rules for movement and functional taskand functional task

SYSTEMS OR SYSTEMS OR DISTRIBUTED CONTROL DISTRIBUTED CONTROL

MODELS OF MOTOR MODELS OF MOTOR CONTROLCONTROL Nicolai Bernstein (1967)Nicolai Bernstein (1967)

A A heterarchical system heterarchical system Biomechanical aspectsBiomechanical aspects Coordinative structures or SynergiesCoordinative structures or Synergies Self-regulatory SystemsSelf-regulatory Systems Sensory ComponentsSensory Components Neurological Aspects- sensoryNeurological Aspects- sensory && motormotor Self-Organizing aspectsSelf-Organizing aspects

BIOMECHANICAL BIOMECHANICAL ASPECTSASPECTS

DEGREES OF FREEDOMDEGREES OF FREEDOM control combined degrees of freedomcontrol combined degrees of freedom size principle & pattern generator size principle & pattern generator

(synergy) (synergy) 3 SOURCES OF VARIABILITY3 SOURCES OF VARIABILITY anatomicalanatomical mechanicalmechanical physiologicalphysiological Skill requires controlling of Skill requires controlling of degrees of degrees of

freedomfreedom

FUNCTIONAL SYNERGYFUNCTIONAL SYNERGY

Systematically regulates many Systematically regulates many degrees of freedomdegrees of freedom

Coordinative structureCoordinative structure- a group of - a group of muscles constrained to act as a muscles constrained to act as a single functional unitsingle functional unit

E.g. 4 wheels of carE.g. 4 wheels of car Muscles do not work in isolation e.g.Muscles do not work in isolation e.g. Kelso(1982),Fitts LawKelso(1982),Fitts Law

SELF-REGULATORY SELF-REGULATORY SYSTEMSSYSTEMS

Independent muscles constrained Independent muscles constrained togethertogether

Walk, trot,rack,gallop of a horseWalk, trot,rack,gallop of a horse EQUILIBRIUM POINT MODEL OF EQUILIBRIUM POINT MODEL OF

MOTOR CONTROLMOTOR CONTROL Fel’dman (1986)Fel’dman (1986) joint stiffness and position are regulated joint stiffness and position are regulated

by the length-tension characteristics of by the length-tension characteristics of the agonist and antagonist musclesthe agonist and antagonist muscles

SENSORY COMPONENTSSENSORY COMPONENTS

Sensory perceptual processes Sensory perceptual processes required for motor output.required for motor output.

Nervous system “sets” the desired Nervous system “sets” the desired position by adjusting length-tension position by adjusting length-tension relationships of the muscles relationships of the muscles involved.involved.

Mass, stiffness & desired behaviorMass, stiffness & desired behavior

NEUROLOGICAL ASPECTSNEUROLOGICAL ASPECTS

SENSORY-1) somato-sensory SENSORY-1) somato-sensory (exteroceptive & proprioceptive)(exteroceptive & proprioceptive)

2) Vestibular2) Vestibular

3)3) Vision-dominant source of Vision-dominant source of information for movementinformation for movement

Feed-forwardFeed-forward

Optical flowOptical flow

Lee and Aronson(1974) Lee and Aronson(1974) ““moving room” experimentmoving room” experiment Posture-preserving & movement systemsPosture-preserving & movement systems MOTOR: sharing of information of MOTOR: sharing of information of

systems and subsystemssystems and subsystems E.g. ATNR in normal fatigued adults E.g. ATNR in normal fatigued adults

(movement + reflex = additional strength)(movement + reflex = additional strength) Reflex and voluntary performance blend Reflex and voluntary performance blend

into one another gradually. into one another gradually.

SELF-ORGANIZING SELF-ORGANIZING ASPECTSASPECTS

Defines total system and interactions of Defines total system and interactions of the parts of the systemthe parts of the system

Change of motion in a system and flow of Change of motion in a system and flow of energy within itenergy within it

Basic laws – living systems– self-Basic laws – living systems– self-organizationorganization

Huge degrees of freedom to fewer onesHuge degrees of freedom to fewer ones Energy- no pattern decayEnergy- no pattern decay Pattern change-environment changesPattern change-environment changes

Frequency and patternFrequency and pattern Brain and self-organizing systemBrain and self-organizing system


Does not address interaction of Does not address interaction of individual with environment.individual with environment.


Musculoskeletal and neural system Musculoskeletal and neural system evaluation determines effects on evaluation determines effects on motor controlmotor control

Treatment strategies should focus Treatment strategies should focus on impairments within individual on impairments within individual motor control system and interacting motor control system and interacting systems.systems.

DYNAMICAL ACTION DYNAMICAL ACTION THEORYTHEORY

Esther Thelen and Jenson (1990)Esther Thelen and Jenson (1990) A bridge between motor control and A bridge between motor control and

motor developmentmotor development It speaks of non-linear properties of It speaks of non-linear properties of

systemsystem Real-time vs developmental timeReal-time vs developmental time Rhythmical movements in infantsRhythmical movements in infants


Appears to presume the unimportant Appears to presume the unimportant role of nervous system in acquisition role of nervous system in acquisition of motor skills.of motor skills.

No guidelines for motor No guidelines for motor developmentdevelopment


Assessment of physical and Assessment of physical and dynamical (velocity, inertia, gravity) dynamical (velocity, inertia, gravity) subsystem subsystem

Treat weak muscles by altering Treat weak muscles by altering velocityvelocity

PARALLEL DISTRIBUTED PARALLEL DISTRIBUTED PROCESSING THEORYPROCESSING THEORY

This theory shows how the nervous This theory shows how the nervous system processes information for system processes information for action.action.

parallel processingparallel processing BACK PROPAGATIONBACK PROPAGATION


Back propagation actually does not Back propagation actually does not mimic nervous system processing of mimic nervous system processing of information during performance and information during performance and learning.learning.


How injury within nervous system How injury within nervous system affects function can be predicted. It affects function can be predicted. It could predict a thresholdcould predict a threshold..

TASK-ORIENTED TASK-ORIENTED THEORIESTHEORIES

Peter GreenePeter Greene Gordan (1987) and Horak(1992)Gordan (1987) and Horak(1992) Tasks-fundamental problem-CNS-Tasks-fundamental problem-CNS-

motor tasksmotor tasks


Lack of consistent agreement about Lack of consistent agreement about what the fundamental tasks of CNS what the fundamental tasks of CNS is.is.

Scientists do not always agree on Scientists do not always agree on what the essential elements being what the essential elements being controlled within a task.controlled within a task.


understanding the role of understanding the role of perceptual, cognitive and action perceptual, cognitive and action systems in fulfilling everyday’s tasks.systems in fulfilling everyday’s tasks.

ECOLOGICAL ECOLOGICAL THEORYTHEORY

James Gibson (1960’s)James Gibson (1960’s)

how we detect information in how we detect information in our environment that is our environment that is

relevant to our actions, and relevant to our actions, and how we use this information how we use this information

to control movementto control movement


Less emphasis to the organisation Less emphasis to the organisation and function of nervous system and function of nervous system


Individual as an active explorer of Individual as an active explorer of environmentenvironment

CONCLUSIONCONCLUSION

WHICH THEORY OF MOTOR WHICH THEORY OF MOTOR CONTROL IS BEST ?CONTROL IS BEST ?

QUESTIONS ???QUESTIONS ???

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THANK YOUTHANK YOU

theories of motor control kmc

Documents

nervous system

motor control

motor development

genre theory

spinal cord

organizing

clinical implications

loop theories