Theories of Motor Control

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Assumptions

Theories of Motor Control

Clinical Implications Limitations

Reflex Theory

Motor Programming

Theory

Dynamical Action

Theory

Ecological Theory

- Sherrington

- “Peripheralist”

- Reflexes are basis for all mvmt

- External stimulus leads to mvmt

- Nervous System – triggers, coordinates, & activates muscles

Hierarchical Theory

- JH Jackson

- “Centralist”

- “Top-Down” unidirectional flow

- Voluntary mvmts initiated by “will” (higher levels)

Systems Theory

- Reflexive mvmts dominate only after CNS damage.

- Bernstein

- Goal-directed behavior ( Task Oriented )

- Synergies to master redundant degrees of freedom

- Feedback (closed loop)

- Central Motor Pattern – motor response w/o sensory stimulus/reflex

- Central pattern generators (CPGs) – spinal motor programs that can produce mvmt w/o cortical or sensory input

- Higher-level motor programs – store rules for generating mvmts.

- New mvmt emerges 2 o to change in control parameter.

- De-emphasize commands from CNS in controlling mvmt and emphasize physical explanations for mvmt

- Attractor state – preferred pattern (vice-versa)

- Deeper attractor well

more stable pattern

- Stable patterns become more variable prior to transition to new mvmt pattern.

- James Gibson

- Perception-action system

- Perception focuses on detecting information in the environment that will support the actions necessary to achieve the goal.

- Use sensory input to control motor output

- Stimulate good reflexes

- Inhibit undesirable (primitive) reflexes

- Relies heavily on feedback

- Identify & prevent primitive reflexes

- Reduce hyperactive stretch

- Normalize tone

- Facilitate “normal” mvmt patterns

- DEVELOPMENTAL SEQUENCE

- Recapitulation

- Identifiable, functional tasks

- Practice under a variety of conditions

- Modify environmental contexts

- Abnormal mvmt – not just reflexive, also including abnormalities in central pattern generators or higher level motor programs.

- Help pts relearn the correct rules for action

- Retrain mvmts important to fxn’al task

- Do not just reeducate muscles in isolation

- Mvmt 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 mvmt. May be good to encourage faster mvmt in pts to produce momentum and therefore help weak pts move w/ greater ease.

- Help pt explore multiple ways in achieving fxn’al task 

discovering best solution for pt, given the set of limitations

-

- Reflex can’t be basic unit of behavior

- Doesn’t explain fast mvmts

- Doesn’t explain how single stimulus results in varying responses.

- Doesn’t explain voluntary mvmts.

- Doesn’t explain dominance of reflexive behaviors in normal adults

- Everyone’s developmental pattern is diff.

- Hands-on approach

pt may become very passive

- Very broad – many diff. systems

- Doesn’t focus as heavily on the interaction of the organism w/ the environment.

- Not intended to replace importance of sensory input in controlling mvmt

- Central motor program can’t be sole determinant of action

- Doesn’t explain nervous sys. dealing w/ both musculoskeletal & environment variables

- Nervous sys. has unimportant role

- Presumption that the relationship b/w the physical sys. & environment determines behavior.

- Gives less emphasis on nervous sys.

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