Motor Flashcards
Types of movement
Voluntary(conscious)
Rhythmic(unconscious)
Reflex
Sensorimotor transformations
Turning sensory input into motor output
Reflexes low level voluntary movement high level
Inverse problem in movement
It is the inverse of a forward problem, which starts with the causes and then calculates the effects
Movement planning-inverse kinematics(muscle plan and path)-inverse dynamics(muscle activation)
Internal model
Brain needs to control and predict Inverse model(motor plan) + forward model(end position) Efference copy=How it will work in real life
Experiment for motor task
Ask subjects to point at remembered object in the dark
sensorimotor transformation must be good to point accurately
Computational task
This task is done easiest when based on hand position and speed
Feedfoward control
Is when there is no feedback and Is an open loop meaning it is faster
Feedback control
After motor movement if error is there it is taken into account when trying again
FB is dependent on delay
High gain means big response to small error
Delay magnifies the effect of gain
Stages of the observer model
Previous state estimate- predicted current state- Final state estimate
Role of perception in motor anticipation
size weight illusion shows that action and perception are independent
Motor plasticity
Motor plasticity is defined as the ability of motor neurones and their respective effector muscles to physically and functionally change as a result of failure
Anticipation
Plays an important role in movement
Top down structure for movement
Starts of with conscious processing from motor cortex and brain stem to motor neurones that drive muscles
Cerebellum
Stores coordinated movement
Where are Lower motor neurones
Found at the ventral horn
What does lower motor neurones do?
Innervates fibres in a specific muscle
LMN pool
Each muscle has a LMN pool which is when all the motor neurons innervating a single muscle
Motor unit
muscle fibres+1 motor neurone= motor unit
1 fibre only receives input from 1 motor neurone
fatiguability
susceptibility to fatigue
Marathon runners have a slow fatiguability compared to a sprinter
Muscle tension
This is spike rate dependent and motor units have different threshold so you don’t use all the power in a muscle
What happens when 2 motor neurones receive identical inputs with different sizes
Smaller motor neurones have fewer ion channels and are more excitable
Motor plasticity
Motor neurones when fired can adapt and change there appearance of fibres
What are spindle fibres?
Muscle spindles are stretch receptors within the body of a skeletal muscle that primarily detect changes in the length of the muscle.
Tendon organ
The Golgi tendon organ responds to a tendon stretch, or a muscle contraction, by sending action potentials so that the muscle tension increases