Motor Control Theories Flashcards
How do motor control theories differ
how we control coordinated movement differ in terms of roles of central and environmental features of a control system
Theory
Provides large class of observations
- provides why for basis of everything we do
What do theories enable the practitioner to do
- evaluate effectiveness of intervention strategies
- create new intervention strategies
- identify performance problems
- develop approach to help person increase skill performance
Motor control theory
Describes and explains how the nervous system produces coordinated movement of motor skills in a variety of environments
Two important terms of motor control theory
- Coordination
- Degrees of freedom
Coordination
Patterning of body and limb motions relative to the patterning of environmental objects and events
Two parts to consider in coordination
- movement pattern of a skill in relationship at the specific point in time
- context of the environment of the head, body and/or limb movements so actions can be accomplished
Degrees of freedom
Number of independent elements in a system and the ways each element can act
Degrees of freedom problem
How to control the degrees of freedom to make a complex system act in a specific way
- getting muscles, bones, joints to move coordinated and achieve goal
- ie. control helicopter’s flight
Degree of freedom problem for the control of movement
How does NS control the many degrees of freedom of muscles, limbs, and joints to enable a person to perform an action as intended (=experience)
Two theories of motor control
- Motor program based theory
- Dynamic pattern theory
Motor program based theory
Memory based mechanism that controls coordinated movement
Dynamic pattern theory
Emphasizes the role of info in the environment and mechanical properties of the body and limbs
2 general types of control systems
Open and closed loop control systems
What is incorporated in all theories of motor control
Open and closed loop control systems
What are control systems
Models of basic descriptions to show different ways the CNS and PNS initiate and control action
What is order of open loop control system
Movement control center (CNS) - instructions - movement effectors (muscles)
What is not needed in an open loop to continue skill
Feedback
Order for closed loop control system
Movement control center (CNS) - instructions - movement effectors (muscles) -feedback - back to movement control center
When we first learn or relearn a motor skilll what system do all performers operate in
Closed loop
As we become better at motor skill what system do we switch to
Open loop control
What is open loop system
- Does not use feedback
- Control center provides all info for the effectors to carry out movement
(Does not use feedback to continue or terminate movement)
Closed loop system
- Uses feedback
- Control center issues info to effectors sufficient only to initiate movement
(Relies on feedback to continue and terminate)
What are instructions influenced by in dynamic patter theory
By environment and interactions of the body, limb and nervous system
What are instructions specified by for motor program based theory
CNS
What is the control process managed by in motor program based theory
Motor programs
What do motor programs do in motor program based theory
Organizes, initiates, and carries out intended actions
What type of theory is the motor program based theory
Hierarchical orientation theory (top down)
What does motor program based theory solve
The degrees of freedom problem through the motor program
What is generalized motor program (GMP)
Hypothesized memory based mechanism responsible for adaptive and flexibility of coordinated movement behaviour
What is it proposed that each GMP controls
A class of actions that have common invariant characteristics
What are examples of class of actions
Sending (throwing, striking) vs receiving (using hands, feet, stick)
GMP function
Basis for generating movement instruction prior to and during the performance of an action
What are the 2 characteristics of GMPS
Invariant features (unchanging)
Parameters (flexible)
Invariant features
Characteristics that do not change across performances of a skill within a class of actions
Ex) backhand in tennis is always shoulder internally then externally rotated
Parameters
Movement features added to the invariant feature to enable performance of a skill in specific situations
Can vary from one performance to another
Parameters that can change
Time can increase or decrease (overall time)
Size of movement s can increase or decrease (overall force)
Specifications of muscles and limbs used (how you use them)
Examples of invariant features
Relative time or sequence of the components of a skill
Spatial components
Examples of parameters
Overal duration, force generated
Muscles used to perform the skill
What are 3 invariant features of handwriting
- Relative timing
- Relative force used
- Sequence
4 phases of gait cycle
Flexion phase (toe off to start of knee extension)
Extension phase 1 (start of knee extension to heel strike)
Extension phase 2 (heel strike to max knee flexion
Extension phase 3 (max knee flexion to toe off)
What is an invariant feature of walking and running gait
Relative timing
What are walking and running
Two different motor programs
- relative time in each phase is different between them
- difference in percentage of step cycle for 4 phases between them
Walking and running are controlled by different
Generalized motor programs
What is the running and walking study an example of
The motor program based theory
Schema
Rule or set of rules that serves to provide the basis for a decision
Motor response schema
Explains how movements can be adapted to new situation or environments (remodeling schema)
When performing a skill what 4 pieces of info do you subconsciously subtract
- Initial conditions (start of movement)
- Response specifications (parameter used in execution)
- Sensory consequences of movement
- Response outcome (end result)
What happens to the subconscious 4 pieces of info and what used for
Stored in memory following a movement attempt
Schema begins to develop
With each movement attempt schema becomes stronger
2 relationships between motor response and schema
Recall schema
Recognition schema
Recall schema
Responsible for organizing the motor program capable of initiating and controlling the movement
Recognition schema
Responsible for evaluating the last executed movement attempt based on the initial conditions, past actual outcomes and sensory info
What happens to schema with every attempt
Recall schema updates the instruction to muscles based on recognition schema which leads to more accurate response
How does a learner decide what movement to execute in a given situation
By subconsciously retrieving the GMP from memory based on existing schema and parameters
How is the desired movement organized
In advance by the motor program (need to establish properly)
If motor program contains all info needed to carry out the action how does movement operate
Under open loop
- doesnt need to revise, motor program complete
If continually registering and evaluating accuracy of movement how is movement controlled
Through closed loop
- still updating what doing
In coordination the invariant features of GMP control
Patterns of movement
In coordination, parameter of GMP control
Movement in context (allow for adaptation)
In degrees of freedom what are motor response schema used for
To release GMPS at appropriate time
- modifies parameters
What are 4 criticisms of motor program based theory
- can brain store all necessary GMPs
- how does controller continually make very quick decisions on correct GMP to release
- are invariant feature never variant
- how is sensory feedback used to adapt movements
