Motor Functions Flashcards
proximal
muscles in face
distal
arms and legs
muscle signals
Paired agonist and antagonist –> one muscles is always going inward and one extending at the
same time
Stretch spindles (somatosensory cells)
Cells that sit in your muscles and if the muscle is stretched than the spindle is
stretched and causes a neural reaction that initiates an action potential
knee reflex
Reflexes are on the lowest part of the hierarchy → Reflexes have no involvement of the brain (cortex)
sherrington
- found that dogs still have reflexes when the input is cut but the reflexes were exaggerated when the output from the cortex was cut
- Input coming from muscles is inhibitory from the cortex
- Reflexes need one motor neuron + one sensory neuron
brown
- sensory is not necessary
- central pattern generators
central pattern generators
- Cortex is not necessary for movement
- Central pattern generator are the cells in the spinal cord which just remember the
movement pattern - In order to engage and use consistent reflex → cortex needs to be activated then the pattern generator keeps the reflex consistent
population vector
Summed activity over all neurons
SMA (supplementary motor area)
internal (based on what we already know)
PMC (pre-motor cortex)
external, visually guided
In order to make a movement
- M1 needs to make a plan
- M1 preferences → the direction of the movement
simple movement
Primary and somatosensory activated
complex movement
supplementary motor (SMA) and prefrontal
Imagining movements
only SMA
(SMA is the planning function –> sends info to M1 to create movement)
Hemiplegia
- Loss of voluntary movement (voluntary = movement due to motor cortex)
- Reflexes are exaggerated
- Muscles are overly active (like always flexing your muscles)
Apraxia
- Loss of motor skill (not muscle related)
- Understand and describe the motor plan → but not able to succeed in doing the motor skill (concept not movement)
Cerebellum
- Fine tunes motor plans so the timing is perfect (like a conductor of an orchestra)
- smooth movements
Vestibulocerebellum
Function: keeping you balanced, VOR, etc.
Lesions: affect balance
Spinocerebellum
Function: Sensory info from spinal cord, auditory/visual
–> Output to spinal cord and motor cortex
Lesions: function affected – can still perform movement, but can no longer execute accurately
and precisely (e.g. when drunk from alcohol)
Hypermetria – good initiation, but clumsy, irregular, erratic movement (e.g. guy pointing at the finger but overestimating it)
Neocerebellum
- Has inputs from everything the Spinocerebellum has inputs from but goes back via the
thalamus - Thalamus then gives the information back into the cortex
lesions: prolonged initiation – difficult to start movements
basal ganglia
receives multiple inputs but only allows the accurate one to process –> inhibit unwanted movements and to
facilitate wanted movements
Parkinson’s (damage in the substantia niagra)
Because of the cell death in the substantia niage, the inhibition in the basal ganglia is
increased, so you can no longer let the cells go initiation of a movement becomes
extremely slow
Huntington’s chorea (striatum)
Clumsiness, balance problems, increase in involuntary movements
