L15: Motor Control 1

Question 1

What are the 3 principles of sensorimotor function?

Answer 1

• It is hierarchically organised
• Motor output is guided by sensory input
• Learning changes the nature and locus of sensorimotor control.

Question 2

What is apraxia?

Answer 2

Refers to an inability to properly execute a learned skilled movement following brain damage.

Question 3

What is limb apraxia?

Answer 3

Involves movement of the wrong portion of the limb, incorrect movement of the correct limb part or an incorrect sequence of movements.

Question 4

What is constructional apraxia?

Answer 4

Results in difficulty with drawing pictures or assembling objects.

Question 5

How many neurons is there in the cerebellum?

Answer 5

50 billion (10% volume, 50% neurons)

Question 6

Where does the cerebellum input from?

Answer 6

Inputs from primary motor cortex (PMC), supplementary motor area (SMC) and descending motor signals from brain stem nuclei.

Question 7

Where does the cerebellum feedback from?

Answer 7

Somatosensory and vestibular systems.

Question 8

What can the cerebellum cause disturbances in?

Answer 8

Posture and balance.

Question 9

What can damage to the posterior parietal association cortex cause?

Answer 9

Limb apraxia, constructional apraxia and contralateral neglect.

Question 10

What did the single cell recording from macaque monkeys suggest?

Answer 10

Existence of mirror neurons (supported by neuroimaging studies in humans).

Question 11

What does the cerebellum and basal ganglia do?

Answer 11

They interact with different levels of the hierarchy and coordinate/modulate it’s activities.

Question 12

What can damage in the cerebellum cause?

Answer 12

• Disturbances in posture and balance
• Limb rigidity
• Weakness and decomposition of movement
  (separate movement of joints rather than
  simultaneous).
• Impaired timing of rapid ballistic movements.