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Questions and Answers
What primarily dictates the need for correction in movement performance?
What primarily dictates the need for correction in movement performance?
What is anticipated feedback also known as in the context of feedforward control?
What is anticipated feedback also known as in the context of feedforward control?
Which of the following best describes a limitation of closed-loop control models?
Which of the following best describes a limitation of closed-loop control models?
What characterizes movements that are too rapid for closed-loop processing?
What characterizes movements that are too rapid for closed-loop processing?
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In terms of motor behavior, how are closed-loop and open-loop controls characterized?
In terms of motor behavior, how are closed-loop and open-loop controls characterized?
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What is the primary role of open-loop organizations in movement control?
What is the primary role of open-loop organizations in movement control?
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Which of the following best describes closed-loop control systems?
Which of the following best describes closed-loop control systems?
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In a closed-loop control system, what occurs after a difference is detected as an error?
In a closed-loop control system, what occurs after a difference is detected as an error?
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What example illustrates the concept of closed-loop control in human performance?
What example illustrates the concept of closed-loop control in human performance?
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What is the main difference between open-loop and closed-loop control systems?
What is the main difference between open-loop and closed-loop control systems?
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Explain how open-loop organizations determine muscle contractions during movement.
Explain how open-loop organizations determine muscle contractions during movement.
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Describe the role of postural adjustments in open-loop motor control.
Describe the role of postural adjustments in open-loop motor control.
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How does the feedback process work in a closed-loop control system?
How does the feedback process work in a closed-loop control system?
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What is the significance of error correction in closed-loop control of human motor performance?
What is the significance of error correction in closed-loop control of human motor performance?
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Contrast the functioning of open-loop and closed-loop control systems in terms of feedback utilization.
Contrast the functioning of open-loop and closed-loop control systems in terms of feedback utilization.
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How do exteroceptive and proprioceptive feedback contribute to movement accuracy?
How do exteroceptive and proprioceptive feedback contribute to movement accuracy?
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What role does the executive play in the closed-loop control model?
What role does the executive play in the closed-loop control model?
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Explain why rapid, discrete tasks cannot rely on closed-loop control alone.
Explain why rapid, discrete tasks cannot rely on closed-loop control alone.
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In what ways does movement programming differ between slow and fast tasks according to the motor program theory?
In what ways does movement programming differ between slow and fast tasks according to the motor program theory?
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Describe how the inability to tickle oneself illustrates anticipated feedback in feedforward control.
Describe how the inability to tickle oneself illustrates anticipated feedback in feedforward control.
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Match the major roles of open-loop organizations with their descriptions:
Match the major roles of open-loop organizations with their descriptions:
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Match the components of a closed-loop control system with their functions:
Match the components of a closed-loop control system with their functions:
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Match the types of control systems with their characteristics:
Match the types of control systems with their characteristics:
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Match the examples of closed-loop control with their functions:
Match the examples of closed-loop control with their functions:
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Match the roles of feedback in closed-loop control systems:
Match the roles of feedback in closed-loop control systems:
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Match the following types of feedback with their descriptions:
Match the following types of feedback with their descriptions:
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Match the following components of closed-loop control with their functions:
Match the following components of closed-loop control with their functions:
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Match the following examples with their relevance to movement control:
Match the following examples with their relevance to movement control:
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Match the following concepts with their respective classifications:
Match the following concepts with their respective classifications:
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Match the following limitations to their respective closed-loop control issues:
Match the following limitations to their respective closed-loop control issues:
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Match the types of feedback with their descriptions:
Match the types of feedback with their descriptions:
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Match the concepts of movement control to their characteristics:
Match the concepts of movement control to their characteristics:
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Match the elements of a closed-loop control system with their function:
Match the elements of a closed-loop control system with their function:
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Match the limitations of closed-loop control with their implications:
Match the limitations of closed-loop control with their implications:
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Match the examples of movement tasks with their control theory description:
Match the examples of movement tasks with their control theory description:
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Match the elements involved in motor programming with their relevance:
Match the elements involved in motor programming with their relevance:
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Match the types of movements with their feedback characteristics:
Match the types of movements with their feedback characteristics:
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Match the feedback types with their sources:
Match the feedback types with their sources:
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Match the following terms with their definitions:
Match the following terms with their definitions:
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Match the scenarios with their relevance to anticipated feedback:
Match the scenarios with their relevance to anticipated feedback:
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Match the components of closed-loop control with their functions:
Match the components of closed-loop control with their functions:
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Match the concepts with their respective classifications:
Match the concepts with their respective classifications:
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Match the limitations to their respective closed-loop control issues:
Match the limitations to their respective closed-loop control issues:
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Study Notes
Open-Loop Control Systems
- Open-loop control is a system where instructions for the effector system are pre-determined and executed without feedback.
- This system is preprogrammed and doesn't rely on corrections during the action.
- Example roles of open-loop control in the body involve determining muscle contractions, organizing multiple degrees of freedom in muscles and joints, and regulating postural adjustments in preparation for actions. Modulation of reflex pathways for movement achievement is also managed by open loop means.
Closed-Loop Control Systems
- Closed-loop control systems utilize feedback, error detection, and correction to maintain a desired state.
- A desired state is set (e.g., 20°C).
- Sensory information measures and compares the actual state with the desired state.
- Error (difference) is detected.
- The executive decides corrective actions (e.g., turn on furnace).
- Commands are sent to effectors (e.g., furnace turns on).
- The action adjusts the system back to the desired state.
- The process repeats to maintain the desired state.
Closed-Loop Control in Human Movement
- In movements like reaching for a cup, visual feedback (hand's position relative to the cup) provides information on the movement outcome.
- Discrepancies (errors) between the hand's position and desired position trigger corrective modifications by the executive.
- Multiple feedback sources (e.g., visual, proprioceptive) are common in human movements.
- Inputs (stimuli recognition), response selection, movement programming (action planning), and execution via a motor program are crucial parts of this process.
Closed-Loop Control: Feedforward
- Feedforward information anticipates sensory consequences of a movement.
- Inability to tickle yourself is an example; anticipated feedback matches actual feedback, thus diminishing the sensation.
- Force escalation between siblings is another example—anticipated escalation predicts the next act, thus it is a feedforward mechanism for anticipated feedback.
Limitations of Closed-Loop Control Models
- Feedback processing is slow; time required for correction processing limits the number of corrections per second (approximately 3).
- Complex rapid tasks like texting or playing guitar occur too quickly for feedback to be corrective and require preprogramming of the movement.
Motor Program Theory: Blending Open-Loop & Closed-Loop Control
- Motor control often blends open-loop preprogramming with closed-loop feedback adjustment.
- Slow movements primarily rely on feedback.
- Fast, brief movements are primarily open-loop.
Major Roles of Open-Loop Organizations
• Determine which muscles contract
when, how forcefully, and for how long
• To organize the many degrees of freedom
of the muscles and joints into a single
unit
• To determine postural adjustments
necessary to support the upcoming
action
• E.g. bicep pull experiment
• To modulate the many reflex pathways to
ensure that the movement goal is
achieved
Control of Movement:
Open-loop vs. closed loop
• Two ways in which movements could be controlled
• Open-Loop Control: A type of system control in which instructions for the
effector system are determined in advance and run off without feedback
• Closed loop Control: A type of system control involving feedback, error
detection, and error correction that is applicable to maintaining a system goal.
Closed-Loop Control Systems:
General Concept Example
• Desired state is set (20oC)
• Sensory information measured and compared
to expected temperature
• Any difference detected as error (e.g. too cold)
• Error transmitted to executive to decide what to
do to eliminate error (e.g. decide to turn on
furnace)
• Command sent to effector (furnace turns on)
• The action returns the system to the desired
state (20oC)
• This information is sent to the executive, and the
cycle continues (e.g. furnace turns on and off all
day to maintain house temperature)
Desired state: 20oC
Executive
System
Effector
System
Comparator
Actual state
Error
Sensory info
Negative feedback loop!
Closed-Loop Control in Human
Performance
• Reaching to pick up cup
• Visual info about hand’s position relative to cup represents
feedback (i.e. information about the movement outcome)
• Difference in hand location and desired location represent
errors
• Executive determines correction and modifies an effector
• Most movements have several feedback sources
Closed-Loop Control in Human
Performance
Input
Stimulus
Identification
Response
Selection
Movement
Programming
Motor Program
Spinal Cord
Movement
Comparator
Error
Exteroceptive feedback
Proprioceptive feedback
Muscles
Input
Stimulus
Identification
Response
Selection
Motor Program
Spinal Cord
Movement
Comparator
Error
Exteroceptive feedback
Proprioceptive feedbackMuscles
Closed-Loop Control: Feedforward
Anticipated feedback
Movement
Programming
Closed-Loop Control: Feedforward
• Anticipated feedback (also called
feedforward info)
• Sensory consequences that are expected
to arise
• Why can’t you tickle yourself?
• If anticipated feedback matches actual
feedback, then there is diminished
perception of sensation
• Example 2: Force escalation between
siblings
• Shergill et al., 2003
• 38% increase in force between each turn
Limitations of Closed-Loop Control
Models
• 1. Very Slow
• Feedback must be sent to executive, and
information must be processed (seen as
reaction time)
• Example: Tracking tasks (follow a moving
target)
• Only about 3 corrections per second are
possible
• E.g. bouncing football is hard to grab
Limitations of Closed-Loop Control
Models
• 2. Rapid, discrete tasks would be impossible under
this model
• E.g. texting, playing guitar
• These movements occur too quickly to process info before
the movement is complete
• Therefore, these movements must be programed in advance
Motor Program Theory:
Closed-Loop and Open Loop Control
• Closed loop = Open loop with feedback
• In most tasks, motor behavior is neither open-
nor closed-loop alone but a complex blend of
the two
• Slow movements → Control dominated by feedback
• Fast/brief movements → Open-loop dominates
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Description
This quiz covers the fundamentals of open-loop and closed-loop control systems. It explores how these systems function, their characteristics, and their applications in various settings, including biological contexts. Test your understanding of feedback mechanisms and error correction in system controls.