7a. Introduction to Motor Control and Motor Systems Flashcards
Motor System Damage
- Motor Neurones
Flaccid paralysis
Motor System Damage
- Brainstem Pathway to Spinal Cord
Postural defects
- Difficulty maintaining posture
- Difficulty walking
Motor System Damage
- Primary Motor Cortex or Corticospinal Pathway
Spastic Paralysis
Motor System Damage
- Association Motor Cortex and Association Cortex
Apraxia, where movements can still be made using lower cortical areas, but they are not coordinated to current conditions
Motor System Damage
- Cerebellum
Ataxia, which is poor coordination of movement
Motor System Damage
- Basal ganglia
Hyperkinesia, which is too much movement
Hypokinesia, which is too little movement
Motor System Functional Hierarchy
- Idea
- Plan
- Programme
- Execution
- Movement
5 Sources of Motor System Inaccuracy
- Noise
- Redundancy
- Biological delays
- Non-linearity
- Non-stationarity
Sources of Motor System Inaccuracy
- Noise
Random variation in motor and sensory signals, rendering them imprecise
Sources of Motor System Inaccuracy
- Redundancy
Many ways to achieve a goal so a single approach from a variety must be chosen
This is called the motor equivalence problem
Sources of Motor System Inaccuracy
- Biological Delays
Conduction velocity causes delay
Sources of Motor System Inaccuracy
- Non-Linearity
Mixing individual motor commands doesn't produce predictable results. Force depends on: - Length - Load - Velocity of Shortening
Sources of Motor System Inaccuracy
- Non-Stationarity
Muscle contraction depends on history
Thixotrophy = the property of becoming less viscous when subjected to an applied tress
2 Types of Movement
- Spontaneous continuous movement
- Reactionary movement
Types of Movement
- Spontaneous Continuous Movement
Movement independent of external stimuli
Types of Movement
- Reactionary Movement
Movement in response to a stimuli, generating a specific motor response
Disadvantages of Negative Feedback
Delays:
- Signal transduction
- Signal conduction
- Excitation-contraction coupling to produce muscle contraction
Cold Shower Phenomenon
Overcorrection of negative feedback due to delays leading oscillation about the set point
Efference Copy
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