Lecture 11 - Voluntary Movements and the Hierarchical control of Motor behaviour Flashcards
What kind of reflexes do muscle receptors produce?
Stretch reflexes
What kind of reflexes do cutaneous receptors produce?
Withdrawal reflexes
What can studying spinal reflexes diagnose?
Integrity of afferent and efferent pathways
What is needed for voluntary movements?
- Spinal cord
- Brainstem
How do voluntary movements improve?
- With practice
- You learn to anticipate and correct for environmental obstacles
What is pychophysics?
An area of psychology that uses physics to explore the relationships between intended actions and the actual outcomes
What are the three laws of voluntary movement? [3]
- Motor Equivalence
- Processing Time scales with complexity
- Speed/Accuracy trade off
What is motor equivalence?
The brain represents the outcome of motor actions independently of the specific effectors used
What is an example of motor equivalence?
- People developing their own handwriting styles
- Their handwriting will be the same if they use their feet or hands
How are all movements stored?
- In an abstract format
- Called movement primitives
How are complex actions such as writing achieved?
Using the stored sets if movement primitives
How does the processing time scales with complexity rule work?
The time is takes to respond to a stimulus depends on the amount of information that needs to be processed to accomplish a task
What is relationship between number of possible choices and the time it takes to accomplish a task?
More choices = More time taken
What does the Speed/Accuracy trade off mean?
- To make accurate movements it takes time
- To make fast movements you lose accuracy
Why are faster movements less accurate than sower ones?
- Less time for feedback corrections
- More is fed-forward control
- More force is required to stop movement (larger margin for errors)
How are motor systems organised?
- In a hierarchy
- Sensory information is processed in different systems that operate in parallel
What is the lowest level of the motor system hierarchy?
The spinal cord
True or False? Spinal relfexes can not happen is the cord is disconnected from the brain.
- False
- Spinal reflexes can still happen
What comes after the spinal cord in the motor system hierarchy?
The brainstem
What input does the brainstem receive?
- Cerebrum
- Subcortical nuclei
What two descending control systems start in the brainstem? [2]
- Medial descending system
- Lateral descending system
What does the Medial descending system deal with?
Posture
What does the Lateral descending system deal with?
Goal directed movements
What is the highest level of the motor system hierarchy?
The cerebral cortex
