Chapter_5_Motor_Control_Theori.ppt

7/23/2019 Chapter_5_Motor_Control_Theori.ppt

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Chapter 5Chapter 5

Motor Control TheoriesMotor Control Theories

Concept:Theories about how we control coordinatedmovement differ in terms of the roles of central and

environmental features of a control system


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Theory and Professional PracticeTheory and Professional Practice

What is a theory?What is a theory?

Accurately describes a large class of observationsAccurately describes a large class of observations

Make definite predictions about results of future observationsMake definite predictions about results of future observations

(a!king" #$$%&(a!king" #$$%&

Theories of 'otor learning and control focus onTheories of 'otor learning and control focus on

)*plaining hu'an 'ove'ent behavior)*plaining hu'an 'ove'ent behavior

Providing e*planations about !hy people perfor' skills as theyProviding e*planations about !hy people perfor' skills as they

dodo

+oes a theory have relevance to professional practice?+oes a theory have relevance to professional practice?

Provides the ,!hy- basis for !hat practitioners doProvides the ,!hy- basis for !hat practitioners do

[[.ee /igure 50#.ee /igure 50#]]


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Motor Control TheoryMotor Control Theory

+escribes and e*plains ho! the nervous+escribes and e*plains ho! the nervous

syste' produces coordinated 'ove'entsyste' produces coordinated 'ove'ent

of 'otor skill in a variety of environ'entsof 'otor skill in a variety of environ'ents

T!o i'portant ter'sT!o i'portant ter's

CoordinationCoordination

The degrees of freedo' proble'The degrees of freedo' proble'


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CoordinationCoordination

Patterning of body and li'b 'otions relative toPatterning of body and li'b 'otions relative to

the patterning of environ'ental ob1ects andthe patterning of environ'ental ob1ects and

events (Turvey" #$$2&events (Turvey" #$$2&

T!o parts to considerT!o parts to considerMove'ent pattern of a skill in relation to a specificMove'ent pattern of a skill in relation to a specific

point of ti'epoint of ti'e

Conte*t of the environ'ent of the head" body"Conte*t of the environ'ent of the head" body"

and3or li'b 'ove'ents so the actions can beand3or li'b 'ove'ents so the actions can beacco'plishedacco'plished


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+egrees of /reedo' Proble'+egrees of /reedo' Proble'

+egrees of freedo' (df& 4+egrees of freedo' (df& 4u'ber of independentu'ber of independent

ele'ents in a syste' and the !ays each ele'ent canele'ents in a syste' and the !ays each ele'ent can

actact

+egrees of freedo' proble' 4+egrees of freedo' proble' 4o! to control the df too! to control the df to'ake a co'ple* syste' act in a specific !ay'ake a co'ple* syste' act in a specific !ay

e0g0 The control of a helicopter6s flight (described ine0g0 The control of a helicopter6s flight (described in

the te*tbook&the te*tbook&

+egree of freedo' proble' for the control of 'ove'ent+egree of freedo' proble' for the control of 'ove'ento! does the nervous syste' control the 'any df of 'uscles"o! does the nervous syste' control the 'any df of 'uscles"

li'bs" and 1oints to enable a person to perfor' an action asli'bs" and 1oints to enable a person to perfor' an action as

intended?intended?


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T!o 7eneral Types ofT!o 7eneral Types of

Control .yste'sControl .yste's

Open- and Closed-Loop Control SystemsOpen- and Closed-Loop Control Systems

88See Figure 5.3See Figure 5.399

:ncorporated into all theories of 'otor control:ncorporated into all theories of 'otor control

Models of basic descriptions to sho! different !aysModels of basic descriptions to sho! different !aysthe C. and P. initiate and control actionthe C. and P. initiate and control action

)ach has a central control center (e*ecutive&)ach has a central control center (e*ecutive&/unction to generate and for!ard 'ove'ent/unction to generate and for!ard 'ove'ent

instructions to effectors (i0e0" 'uscles&instructions to effectors (i0e0" 'uscles&

)ach includes 'ove'ent instructions fro' control)ach includes 'ove'ent instructions fro' controlcenter to effectorscenter to effectors

Content of the instructions differs bet!een syste'sContent of the instructions differs bet!een syste's


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+ifferences ;et!een the .yste's+ifferences ;et!een the .yste'sOpen-LoopOpen-Loop

+oes not use feedback+oes not use feedback

Control center provides all the infor'ation for effectors toControl center provides all the infor'ation for effectors tocarry out 'ove'entcarry out 'ove'ent

+oes not use feedback to continue and ter'inate 'ove'ent+oes not use feedback to continue and ter'inate 'ove'ent

Closed-LoopClosed-Loop


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T!o Theories of Motor ControlT!o Theories of Motor Control

1.1. Motor Program-based theor!Motor Program-based theor!Me'ory>basedMe'ory>based

'echanis' that controls coordinated'echanis' that controls coordinated

'ove'ent'ove'ent

".". #nami$ Pattern theor %a.&.a. #nami$al#nami$ Pattern theor %a.&.a. #nami$alSstems'!Sstems'!+escribes and e*plains coordinated+escribes and e*plains coordinated

'ove'ent control by e'phasiing the role of'ove'ent control by e'phasiing the role of

infor'ation in the environ'ent andinfor'ation in the environ'ent and

'echanical properties of the body and li'bs'echanical properties of the body and li'bs


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Motor Progra'>;ased TheoryMotor Progra'>;ased Theory

;est e*a'ple co'es fro' ,.che'a Theory- by;est e*a'ple co'es fro' ,.che'a Theory- by

.ch'idt (#$@@&.ch'idt (#$@@&

7eneralied 'otor progra' (7MP&7eneralied 'otor progra' (7MP&

ypothesied 'e'ory>based 'echanis'ypothesied 'e'ory>based 'echanis'responsible for adaptive and fle*ible ualities ofresponsible for adaptive and fle*ible ualities of

hu'an 'ove'enthu'an 'ove'ent

Proposed that each 7MP controls aProposed that each 7MP controls a

class ofclass of

actionsactionsthat have co''onthat have co''on invariantinvariant

characteristicscharacteristics


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Motor Progra'>;ased Theory"Motor Progra'>;ased Theory"

cont6dcont6dGMP FunctionGMP FunctionTo serve as the basis for generating 'ove'ent instructionsTo serve as the basis for generating 'ove'ent instructions

prior toprior toandandduringduringthe perfor'ance of an actionthe perfor'ance of an action

GMP CharacteristicsGMP Characteristics:nvariant features:nvariant features

Characteristics of the 7MP that do not vary across perfor'ancesCharacteristics of the 7MP that do not vary across perfor'ances

of a skill !ithin class of actionsof a skill !ithin class of actions

The identifying signature of a 7MPThe identifying signature of a 7MP

Para'etersPara'eters.pecific 'ove'ent features added to the invariant features to.pecific 'ove'ent features added to the invariant features to

enable the perfor'ance of a skill in a specific situationenable the perfor'ance of a skill in a specific situation

Characteristics can vary fro' one perfor'ance of a skill to anotherCharacteristics can vary fro' one perfor'ance of a skill to another


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Motor Progra'>;ased Theory"Motor Progra'>;ased Theory"

cont6dcont6dInvariant features and parametersInvariant features and parameters)*a'ple of an invariant feature)*a'ple of an invariant feature

=elative ti'e of the co'ponents of an action (i0e0 B of=elative ti'e of the co'ponents of an action (i0e0 B oftotal ti'e each co'ponent uses during perfor'ance&total ti'e each co'ponent uses during perfor'ance&

)*a'ple of a para'eter)*a'ple of a para'eterverall ti'e (i0e0& for perfor'ing a skillverall ti'e (i0e0& for perfor'ing a skill

An Analogy from Music and Dance

Relative time = Rhythm (beat) of the music, e.g. The 3

beats to a measure for a waltz

Overall time = Tempo (The speed at which you waltz)Regardless of how fast or slow you waltz, the

rhythm remains the same i.e. in!ariant)


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7MP for Walking7MP for Walking

:nvariant:nvariant

=elative ti'e for gait cycle phases >=elative ti'e for gait cycle phases >

Para'eterPara'eter

Walking speedWalking speed


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Motor Progra'>;ased TheoryMotor Progra'>;ased Theory

Testing =elative Ti'e :nvarianceTesting =elative Ti'e :nvarianceEperiment !y Shapiro et al" #$%&$'Eperiment !y Shapiro et al" #$%&$'


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+yna'ic Pattern Theory+yna'ic Pattern Theory

(a0k0a0" +yna'ical .yste's&(a0k0a0" +yna'ical .yste's&+escribes the control of coordinated 'ove'ent that+escribes the control of coordinated 'ove'ent that

e'phasies the role of infor'ation in the environ'ente'phasies the role of infor'ation in the environ'ent

and dyna'ic properties of the body3li'bsand dyna'ic properties of the body3li'bs

;egan to influence vie!s about 'otor control in early;egan to influence vie!s about 'otor control in early#$@26s#$@26s

Gie!s the process of hu'an 'otor control as aGie!s the process of hu'an 'otor control as a

complex systemcomplex systemthat behaves like any co'ple*that behaves like any co'ple*

biological or physical syste'biological or physical syste'Concerned !ith identifyingConcerned !ith identifying lawslaws(natural and physical&(natural and physical&

that govern changes in hu'an coordination patternsthat govern changes in hu'an coordination patterns


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+yna'ic Pattern Theory Concepts+yna'ic Pattern Theory Concepts

Motor control syste' operates on the basisMotor control syste' operates on the basis

of non>linear dyna'icsof non>linear dyna'ics

;ehavioral changes;ehavioral changesare not al!ays continuous"are not al!ays continuous"

linear progressions butlinear progressions butoften 'ake sudden andoften 'ake sudden and

abrupt changesabrupt changes

;ehaviors specified by environ'ental and task;ehaviors specified by environ'ental and task

characteristics3conditionscharacteristics3conditions;ehaviors are self>organied;ehaviors are self>organied


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AttractorsAttractors(ttractor (ttractor A stable state of the 'otor controlA stable state of the 'otor controlsyste' that leads to behavior according tosyste' that leads to behavior according to

preferred coordination patterns (preferred coordination patterns (e.g. *al&inge.g. *al&ing&&

Characteristics of an attractorCharacteristics of an attractor..

:dentified by order para'eters:dentified by order para'eters ##e.ge.g0" relative phase&0" relative phase&

Control para'eters (Control para'eters (e.ge.g0" speed& influence order0" speed& influence order

para'eterspara'eters

Mini'u' trial>to>trial perfor'ance variabilityMini'u' trial>to>trial perfor'ance variability

.tability .tability (etains present state despite perturbation(etains present state despite perturbation

)nergy efficient)nergy efficient


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rder and Control Para'etersrder and Control Para'etersOrder parametersOrder parametersAlso called collective variablesAlso called collective variables

/unctionally specific and abstract variables/unctionally specific and abstract variables

that define the overall behavior of the syste'that define the overall behavior of the syste')nable a coordinated pattern of 'ove'ent)nable a coordinated pattern of 'ove'ent

that can be reproduced and distinguished fro'that can be reproduced and distinguished fro'other patternsother patterns

=elative phase=elativephaseis the 'ost pro'inent ofis the 'ost pro'inent oforder para'eters !hich represents theorder para'eters !hich represents the'ove'ent relationship bet!een t!o 'ove'ent'ove'ent relationship bet!een t!o 'ove'entseg'ents (see chapter F&seg'ents (see chapter F&


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rder and Control Para'eters"rder and Control Para'eters"

cont6dcont6dControl parameterControl parameter

A variable" !hen increased or decreased"A variable" !hen increased or decreased"!ill influence the stability and character of the!ill influence the stability and character of the

order para'eterorder para'eter:s i'portant to identify since it beco'es:s i'portant to identify since it beco'es

the variable to 'anipulate in order to assessthe variable to 'anipulate in order to assessthe stability of the order para'eterthe stability of the order para'eter

Provides the basis for deter'iningProvides the basis for deter'iningattractor states for patterns of li'b 'ove'entattractor states for patterns of li'b 'ove'ent


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.elf>rganiation.elf>rganiation

.elf>rganiation.elf>rganiation

When certain conditions characterie aWhen certain conditions characterie a

situation" a specific pattern of li'b 'ove'entsituation" a specific pattern of li'b 'ove'ente'ergese'erges

This pattern of 'ove'ent self>organiesThis pattern of 'ove'ent self>organies

!ithin the characteristic of environ'ental!ithin the characteristic of environ'ental

conditions and li'b dyna'icsconditions and li'b dyna'ics


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Attractors and .elf>rganiation forAttractors and .elf>rganiation for

Move'ent CoordinationMove'ent Coordination7ait Transitions7ait Transitions

=esearch (=esearch (to be dis$ussedto be dis$ussedmore in $h. ,more in $h. ,& sho!s that if& sho!s that ifa person begins !alking ona person begins !alking on

tread'ill at slo! speedtread'ill at slo! speedTread'ill speed increasesTread'ill speed increasesevery fe! 'inutesevery fe! 'inutes

Person begins to run at aPerson begins to run at acertain speed 8certain speed 8not samenot same

speed +or all peoplespeed +or all people99.a'e effect if person begins.a'e effect if person beginsrunning on tread'ill >running on tread'ill >;egins to !alk at certain;egins to !alk at certainspeedspeed

.!i' .troke Transitions.!i' .troke Transitions

=esearch in /rance (F22D&=esearch in /rance (F22D&

#D elite 'ale s!i''ers#D elite 'ale s!i''ers

)ach trial involved a s!i')ach trial involved a s!i'

velocity increase 8began atvelocity increase 8began atpreferred velocity9preferred velocity9

Ar'>stroke analysis sho!ed FAr'>stroke analysis sho!ed Fdistinct ar' 'ove'entdistinct ar' 'ove'entcoordination 'odescoordination 'odes

;egan in one 'ode but abruptly;egan in one 'ode but abruptlybegan Fbegan Fndnd'ode at a specific'ode at a specifics!i' velocitys!i' velocity


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Attractors and .elf>rganiation forAttractors and .elf>rganiation for

Move'ent Coordination" cont6dMove'ent Coordination" cont6d/iscuss ho) the t)o research eamples on the/iscuss ho) the t)o research eamples on theprevious slide demonstrate the dynamicprevious slide demonstrate the dynamic

pattern theory concepts of.pattern theory concepts of.

Self-organi0ationSelf-organi0ation Control parameterControl parameter

(ttractors(ttractors ((i.e. stable $oordination statesi.e. stable $oordination states&&

1on-linear !ehavior change1on-linear !ehavior change


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Coordinative .tructuresCoordinative .tructures/unctional synergies (/unctional synergies (i.ei.e0 cooperative groups&0 cooperative groups&

of 'uscles and 1oints that act cooperatively toof 'uscles and 1oints that act cooperatively to

produce an actionproduce an action

:f a perturbation stops one set of 'uscles fro':f a perturbation stops one set of 'uscles fro'

!orking" another !orks in its place!orking" another !orks in its place

e0g0 !alking !ith a leg caste0g0 !alking !ith a leg cast

+evelop through practice" e*perience" or+evelop through practice" e*perience" ornaturallynaturally


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Perception and Action CouplingPerception and Action CouplingThe linking together (The linking together ( i.ei.e0 coupling& of 'ove'ent to0 coupling& of 'ove'ent toenviron'ental infor'ationenviron'ental infor'ation

The perception partThe perception part

The detection of critical invariant infor'ation in the environ'entThe detection of critical invariant infor'ation in the environ'entThe action partThe action part

The 'ove'ent that beco'es associated !ith !hat is specifiedThe 'ove'ent that beco'es associated !ith !hat is specified

by the environ'ental infor'ationby the environ'ental infor'ation

An e*a'pleAn e*a'pleWhen !alking" the ti'e to contact an ob1ect in your path!ayWhen !alking" the ti'e to contact an ob1ect in your path!ay

(specified by the perception of the changing sie of the ob1ect&(specified by the perception of the changing sie of the ob1ect&

deter'ines !hen you initiate stepping over the ob1ectdeter'ines !hen you initiate stepping over the ob1ect

i0e0 Hour stepping action is ,coupled- !ith your visual perceptioni0e0 Hour stepping action is ,coupled- !ith your visual perception

of the ob1ectof the ob1ect


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Present .tate of the ControlPresent .tate of the Control

Theory :ssueTheory :ssueCurrently" both the 'otor progra'>based theoryCurrently" both the 'otor progra'>based theoryand dyna'ic pattern theory predo'inateand dyna'ic pattern theory predo'inate

=esearch investigating each has sho!n that a=esearch investigating each has sho!n that a

theory of 'otor control cannot focus e*clusivelytheory of 'otor control cannot focus e*clusivelyon 'ove'ent infor'ation specified by the C.on 'ove'ent infor'ation specified by the C.Task and environ'ental characteristics 'ust be alsoTask and environ'ental characteristics 'ust be also

be taken into accountbe taken into account

.peculation e*ists that a hybrid of the t!o.peculation e*ists that a hybrid of the t!otheories as a co'pro'ise theory could e'ergetheories as a co'pro'ise theory could e'ergeto e*plain the control of coordinated 'ove'entto e*plain the control of coordinated 'ove'ent

Chapter_5_Motor_Control_Theori.ppt

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