Class Test 1 Flashcards
what 2 things are involved in making an action?
- Plan a goal
2. Guide the action to achieve the goal
what does sensory information during action allow for?
movement guidance and correction
How is an action goal achieved through the sensory feedback loop?
Goal –> Reference Mechanism –> Effectors/executive –> Environment. (environment then gives feedback to the reference mechanism)
What does feedback for correction of a movement depend on?
capacity and time
what are the problems with closed loop control?
- we can execute some movements without sensory feedback
- the sensory feedback loop may be too long to control fast movements
Define a motor programme
a prestructured set of central commands capable of carrying out the movement open-loop
What is an open loop system?
When there is no sensory feedback
Learning and improving and open-loop movement is done through a reference which is compared to movement feedback…
If it is right and perfect then it is stored in memory. if not, it is improved.
What are the 2 problems with open and closed loop motor control?
- The storage problem –> questions whether there are set programmes that we learn and execute for every single movement - we wont have the capacity for all of this
- The novelty problem –> questions how we adapt the set programs we have to make new responses.
Explain the role of the generalised motor programme
it is a memory structure that governs a class of movements possessing a common movement pattern
It consists of invariant characteristics and adjusted parameters
Main invariants = Relative duration, relative force, order of events
Main Parametes = overall duration overall force
what are the two types of movement errors that may require correction?
- Programme selection - incorrect action selected
2. Programme execution - incorrect execution
How long does a selection error take to correct to form a new plan?
120-200 ms
Execution errors require modifying the ongoing plan. How long after error detection does this take?
30-50 ms
What is the main difference between open-loop and closed-loop systems
closed loop systems contain feedback between the movement effectors and the movement control centre.
what is an internal model and what are the two types?
= neural mechanisms that can mimic the input/output characteristics or their inverses, of the motor apparatus
- internal forward model
- internal inverse model
Describe what a forward model does?
their goal is to predict ‘what would be the sensory consequences of the movement’
- you begin with ‘ what is the goal?’
Describe what an inverse model does?
A series of motor commands that decide on the necessary motor commands from the desired goal.
It acts as a motor controller
Desired trajectory –> Inverse model –> Controlled object –> Realised trajectory
How do the internal models work together in a pair?
we set a feed forward model of what we want to achieve and then the inverse model is used to decide how we get there
Describe where motor control happens in the brain
In the cerebellum cortex
Motor cortex –> plans and executes the movement
Basal Ganglia –> Initiates movement
Cerebellum –> Integrates and refines the movment
What is the effect of cerebellar damage on motor control?
loss of coordination
some effects to muscle tone and posture
no effect on muscle strength, sensory perception or higher order
How does the cerebellum affect motor coordination?
- corrects ongoing movements when they deviate from the intended course + modifies descending output + central motor programs
Each motor programme of complex action can be called a what? and what can the separation between these be based around
unit of action
The separation between these units can be based around the relative timing of the movement. A change in timing represents a change in the movement unit
Explain the dynamic pattern theory
the theory suggests that continuous action coordinates on the basis of stability. this is defined by the relationship between movement variability and efficiency. (increased variability means a decrease in motor efficiency) –> to improve this, the dynamic pattern of the movement changes.
A change in dynamic serves to provide a ‘self-organised process’ that establishes more of a process. What is the evidence for this?
- Actions in asymmetry are known as anti-phase (left finger flexion, right finger extension thing)
- Actions made together in symmetry are known as in-phase (flexion of both fingers)
in-phase movements are more stable. When anti-phase movements are made quicker and quicker, they will switch to the in-phase pattern to ‘self organise itself