7a. Introduction to Motor Control and Motor Systems

Question 1

Motor System Damage

- Motor Neurones

Answer 1

Flaccid paralysis

Question 2

Motor System Damage

- Brainstem Pathway to Spinal Cord

Answer 2

Postural defects

• Difficulty maintaining posture
• Difficulty walking

Question 3

Motor System Damage

- Primary Motor Cortex or Corticospinal Pathway

Answer 3

Spastic Paralysis

Question 4

Motor System Damage

- Association Motor Cortex and Association Cortex

Answer 4

Apraxia, where movements can still be made using lower cortical areas, but they are not coordinated to current conditions

Question 5

Motor System Damage

- Cerebellum

Answer 5

Ataxia, which is poor coordination of movement

Question 6

Motor System Damage

- Basal ganglia

Answer 6

Hyperkinesia, which is too much movement

Hypokinesia, which is too little movement

Question 7

Motor System Functional Hierarchy

Answer 7

1. Idea
2. Plan
3. Programme
4. Execution
5. Movement

Question 8

5 Sources of Motor System Inaccuracy

Answer 8

• Noise
• Redundancy
• Biological delays
• Non-linearity
• Non-stationarity

Question 9

Sources of Motor System Inaccuracy

- Noise

Answer 9

Random variation in motor and sensory signals, rendering them imprecise

Question 10

Sources of Motor System Inaccuracy

- Redundancy

Answer 10

Many ways to achieve a goal so a single approach from a variety must be chosen

This is called the motor equivalence problem

Question 11

Sources of Motor System Inaccuracy

- Biological Delays

Answer 11

Conduction velocity causes delay

Question 12

Sources of Motor System Inaccuracy

- Non-Linearity

Answer 12

Mixing individual motor commands doesn't produce predictable results.
Force depends on:
- Length
- Load
- Velocity of Shortening

Question 13

Sources of Motor System Inaccuracy

- Non-Stationarity

Answer 13

Muscle contraction depends on history

Thixotrophy = the property of becoming less viscous when subjected to an applied tress

Question 14

2 Types of Movement

Answer 14

• Spontaneous continuous movement

- Reactionary movement

Question 15

Types of Movement

- Spontaneous Continuous Movement

Answer 15

Movement independent of external stimuli

Question 16

Types of Movement

- Reactionary Movement

Answer 16

Movement in response to a stimuli, generating a specific motor response

Question 17

Disadvantages of Negative Feedback

Answer 17

Delays:

• Signal transduction
• Signal conduction
• Excitation-contraction coupling to produce muscle contraction

Question 18

Cold Shower Phenomenon

Answer 18

Overcorrection of negative feedback due to delays leading oscillation about the set point

Question 19

Efference Copy

Answer 19

A copy of motor commands which can be used to predict the movement outcome before it happens, and can therefore be used to generate corrective movements very rapidly