Control of Movement (1)

Question 1

Define motor learning

Answer 1

Neuronal changes allowing completion of new task of faster/better/more accurate completion of task

Question 2

What are methods of studying movement control?

Answer 2

Healthy humans
Animals
Human development
Human movement disorders

Question 3

What is the role of feedback and feedforward in motor control?

Answer 3

CNS predicts movement needed to achieve goal - creates plan - sends out motor command - feedforward
Plan updated after movement with sensory input - feedback

Question 4

What is online learning?

Answer 4

Temporary changes in movement whilst performing it

Question 5

What is offline learning?

Answer 5

Changes in movement that stay beyond training

Question 6

What are the traditional categories of movements and what are their characteristics?

Answer 6

Reflex - involuntary, automatic, reproducible
Rhythmical - e.g. pattern generators
Voluntary - goal-directed, mainly automatic

Question 7

What are the 2 basic types of motor activity?

Answer 7

Ballistic

Guided by feedback

Question 8

What are the characteristics of ballistic movements?

Answer 8

Goal set - movement cannot be changed during execution
Forward model
Open-loop - no feedback
Low accuracy
Fast
Useful for well-known tasks
Updated by learning

Question 9

What are the characteristics of movements guided by feedback?

Answer 9

Can be adjusted during execution
Feedback model
Closed-loop - feedback
Accurate
Slow
Useful for novel tasks
Enables learning

Question 10

How long is required for sensory feedback to adjust motor output?

Answer 10

~50ms

Question 11

What are the two models of motor control?

Answer 11

Servo model

Optimal feedback control

Question 12

What is the servo model of motor control?

Answer 12

Desired goal
Motor command from CNS based on goal
Muscle movement
Muscle afferent stimulation - feedback to CNS

Question 13

What is the optimal feedback control model of motor control?

Answer 13

Desired goal
Motor command from CNS based on goal - to optimal feedback control law
Output from optimal feedback control law to muscle - movement
Copy of efferent command from optimal feedback control law to optimal state estimator - estimates body position
Sensory feedback from muscle to optimal state estimator
Optimal state estimator feeds back changes in system state (e.g. positions, velocities, forces) to optimal feedback control law