1. Control Systems: How Do We Control Movements?
(Response Programming Stage)

2. Closed-Loop Control System
Four Components
Executive--For decision making and error correction
Effector System--For carrying out decisions
Feedback about error--Information about error that executive acts on
Reference mechanism--Feedback is compared to this to define error

3. Closed-Loop Control Allows for error detection and correction
Self-regulating--All components are contained within system
Works well with slow movements
Response Produced Feedback
Information from a variety of sources about movement (from teacher, vision, proprioceptors)

4. Closed-Loop Control Examples Central heating or AC
Traffic light that takes into account the traffic patterns

5. Closed-Loop Control Advantages Used for fine motor control
Can be utilized to produce unpracticed movements
Error determination
Flexibility in movement
Not dependent on advance information
Used for fine motor control
Threading a needle

6. Closed-Loop Control Disadvantages
Execution of corrections is very attention demanding
Movement to small target vs. a large target
System is very slow
Uses Information Processing stages (Need one RT) to correct
5 to 7 corrections per second

7. Open-Loop Control Two components Self-initiating
Executive
Effector
Self-initiating
Works well with rapid actions
Planned in advance
Not under conscious control
Based on motor program idea

8. Motor Program Plan of action for movement Stored in long-term memory
Details are determined by CNS and sent to muscles for action
Practice leads to new programs
More stable or precise
Longer programs
Analogous to a computer program

9. Open-Loop Control Examples Room Air Conditioner
Traffic light that doesn't account for traffic flow

10. Open-Loop Control Advantages Disadvantages
Can produce rapid movement when feedback is absent or disrupted
Attention can be focused on other components of movement
Disadvantages
No ability to detect/correct errors
Not effective in open skills

11. Hierarchical Control Combination of open and closed loop control
Higher level is responsible for monitoring feedback
Lower level is responsible for carrying out adjustments
Control could be a result of practice or strategic decision

12. Errors in Movement Errors in Response Selection Made the wrong choice
Need a new program for movement
Requires ms to initiate a movement correction
Involve higher centers
Requires attention

13. Errors in Movement Errors in Response Execution
Made the correct choice, but performed movement wrong
Doesn't require new program
Only requires ms to initiate a correction in the movement
Mechanism for correction is reflexive closed-loop control
Attention is not needed

14. Feedforward Control Advance information to prepare system
FB prior to movement
Example
Postural Adjustments

15. Are these closed loop systems?

18. Factors Contributing to Motor Control
Mechanical Factors
Force resulting from a contraction is greatest when muscle is at optimal length
Elastic properties of muscles
Physical properties can enhance movement control
Environmental properties
Body's own properties

19. Factors Contributing to Control
Neurological-Reflex Factors
Reciprocal Inhibition
Inhibition of flexors when extensors are stimulated
Central pattern generators
In animals, rhythmic activity in flexors/extensors for walking
Synergies
Functional linkage of muscle groups across joints

20. Factors Influencing Movement Production
After-contraction Phenomenon
Contraction temporarily biases later contractions
Magnitude of contraction is related to magnitude of bias
Tonic Neck Response
When head is turned to one side, ipsilateral arm extends, contralateral arm flexes
Hand grip measures

21. Theories of Motor Learning
Adam's Closed-Loop Theory
Utlilizes feedback (KR, vision, proprioception)
Composed of two components
Perceptual Trace--memory of past movement
Memory Trace--selects and initiates response; Open-loop motor program

22. Adam's Closed-Loop Theory
Problems with theory
Slow & fast movements develop error detection differently
Predicts that variability in practice is harmful to learning

23. Schmidt's Schema Theory (1975)
Schema--rule or concept
Theory has open-loop dependency; rapid actions
Two states of memory
Recall Memory
Movement production
MP structured in advance
Recognition Memory
Response evaluation

24. Schema Theory KR and sensory consequences are important
Errors are not detrimental
Variability in practice is beneficial for rule formation
Novel movements are not a problem because of rule-based learning
Error detection in fast actions