Motor Functions

Question 1

proximal

Answer 1

muscles in face

Question 2

distal

Answer 2

arms and legs

Question 3

muscle signals

Answer 3

Paired agonist and antagonist –> one muscles is always going inward and one extending at the
same time

Question 4

Stretch spindles (somatosensory cells)

Answer 4

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

Question 5

knee reflex

Answer 5

Reflexes are on the lowest part of the hierarchy → Reflexes have no involvement of the brain (cortex)

Question 6

sherrington

Answer 6

• 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

Question 7

brown

Answer 7

• sensory is not necessary
• central pattern generators

Question 8

central pattern generators

Answer 8

• 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

Question 9

population vector

Answer 9

Summed activity over all neurons

Question 10

SMA (supplementary motor area)

Answer 10

internal (based on what we already know)

Question 11

PMC (pre-motor cortex)

Answer 11

external, visually guided

Question 12

In order to make a movement

Answer 12

• M1 needs to make a plan
• M1 preferences → the direction of the movement

Question 13

simple movement

Answer 13

Primary and somatosensory activated

Question 14

complex movement

Answer 14

supplementary motor (SMA) and prefrontal

Question 15

Imagining movements

Answer 15

only SMA
(SMA is the planning function –> sends info to M1 to create movement)

Question 16

Hemiplegia

Answer 16

• Loss of voluntary movement (voluntary = movement due to motor cortex)
• Reflexes are exaggerated
• Muscles are overly active (like always flexing your muscles)

Question 17

Apraxia

Answer 17

• 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)

Question 18

Cerebellum

Answer 18

• Fine tunes motor plans so the timing is perfect (like a conductor of an orchestra)
• smooth movements

Question 19

Vestibulocerebellum

Answer 19

Function: keeping you balanced, VOR, etc.
Lesions: affect balance

Question 20

Spinocerebellum

Answer 20

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)

Question 21

Neocerebellum

Answer 21

• 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

Question 22

basal ganglia

Answer 22

receives multiple inputs but only allows the accurate one to process –> inhibit unwanted movements and to
facilitate wanted movements

Question 23

Parkinson’s (damage in the substantia niagra)

Answer 23

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

Question 24

Huntington’s chorea (striatum)

Answer 24

Clumsiness, balance problems, increase in involuntary movements