MC: Lecture 1 (section 2)

a theory of motor control is

a group of abstract ideas about the control of movement that describe unobservable structures or processes

Reflex theory

Complex behavior can be explained by individual reflexes chained together

reflex theory says that reflexes are the

building blocks of complex behavior

A reflex has 3 parts

Receptor, conductor and effector (response)

example of a reflex with 3 parts

muscle spindle, alpha motor neuron (or synapse) and contraction is the response

where does reflex theory break down

1. Can't explain spontaneous and voluntary movement

2. Movement without sensation (rhythmic movement)

3. Fast movements (typing)

4. One stimulus, different responses (example of your child being in a fire overriding hot reflex)

5. novel movement (cello example)

If chained or compounded reflexes really are the basis of functional movement,

three clinical consequences follow directly

Three clinical consequences of reflex theory

Examination, Interpretation, and Intervention

Examination (3 implications of Reflex)

Testing reflexes should let you predict function

Interpretation (3 Implications of Reflex)

a patient's movement behavior is read in terms of the presence or absence of controlling reflexes

Intervention (3 Implications of Reflex)

retraining focuses on enhancing or reducing the effect of various reflexes during motor tasks

Hierarchal theory

Builds off reflex theory. When higher level reflexes are damaged, lower levels suffer. If there is an issue with primitive reflexes then a higher level issue is present

in hierarchal theory, upper centers

supercede the lower centers, this is what makes it apart from the other theories. (if there is a problem with the upper center, we will see a problem the lower center is actually responsible for)

example in hierarchal theory of problem in lower center

tonic neck movement in infants

hierarchy is an old theory, what survived and what did not?

Some hierarchal organization is real and has been confirmed, however the strict hierarchal top down is not always true, bottom up can occur

Motor Programming Theory

When the stimulus of a reflex is removed, you still have a patterned motor response (different than reflex because we can still complete tasks in the absence of sensation)

wired pattern

writing your name with your left vs your right hand. connection responsible for a particular movement

program/rules for a particular program

carrying out the task even without the environment changes (if you don't have your hands, you can still complete the task) You can easily train another body part for a task because you already have the program in your nervous system

rhythmic movements and repetitive movements are part of

motor programming theories, they arise out of a pattern you've completed before

In motor programming theory, abstract motor programs lead to

synergies which come together and complete a motor task

what is a synergy?

A group of muscles coming together to complete a motor task

Dynamical Systems theory

higher levels activate lower levels, activating synergies, which work as a unit, and the whole synergy scales up together (called dynamical after it was improved

Degrees of freedom

body as a mechanical system with many degrees of freedom. Systems theory stresses the importance of the whole body as a mechanical system with many degrees of freedom. Coordination of movement is the process of mastering the redundant degrees of freedom of the moving organism

one muscle can belong to different

synergies in the dynamic system theory

Synergies

Proposed as a solution to the degrees of freedom problem. concept of synergies modified to reflect the flexible, adaptive nature of synergies rather than fixed stereotypical patterns of activity

Self organization of dynamic systems theory

cloud formations, one neural command can lead to many tasks. Things come together without needing commands, the system will organize itself

Nonlinear behavior

input does not necessarily equal output, doubling the control parameter does not equal 2x the behavior. Example of going from walking at 6 m/s to 12 m/s, you're not walking, you're jogging. velocity is a control parameter

Our movement systems are not

linear (with running all that changes is the speed, not the posture)

Variability

indicates adaptability, is good because it means an individual is able to change up a movement to complete it a different way. there is a cutoff limit to variability, outside preferred movement pattern

motor programming theory sees variable as

error. (theories product is the same everytime) BUT the systems theory sees it as adaptability, a good thing.

definition of attractor well

stable pattern of behavior

deep and shallow attractor wells

shallow well indicates high variability and low retention on a movement. Deep well indicates a result of extensive practice and low variability

when do you want a deep attractor well

free throw, attractive movements

when do you want a shallow attractor well

movements like gait

limitations of the dynamical systems theory

analysis can be difficult to translate into clinical practice

Ecological Theory

emphasizes environment, physiology of human movement working with environment.

All other theories propose some passive nervous system waiting for a sensation...

Ecological theory says we don't need the sensation just perception to support action

Implications of ecological theory

patient is active explorer, helps patients explore several routes to the same goal

limitations of ecological theory

Tends to give less emphasis on organization and function of the nervous system. Does not take into account the nervous system.

Integrated Theory

a combination of any of the 5 theories