Lecture 17: Control of movement 2

Question 1

What does locomotion rely upon?

Answer 1

golgi tendon organs and muscle spindles

Question 2

What happens if the leg is still supporting weight when it is meant to flex?

Answer 2

golgi tendon organs will not let the leg flex until it is not bearing any weight

Question 3

What happens when the leg is fully flexed?

Answer 3

there is no point continuing to flex the leg and, therefore, muscle spindles initiate the extension phase

Question 4

What are upper motor neurons involved in?

Answer 4

controlling the excitability of lower motor neurons

Question 5

What is the medial white matter composed of?

Answer 5

axons from brainstem

Question 6

What is the lateral white matter composed of?

Answer 6

axons from motor cortex

Question 7

What are the descending projections from the brainstem to the spinal cord related to posture?

Answer 7

lateral and medial vestibulospinal tracts
reticulospinal tract
colliculospinal tract

Question 8

How is postural adjustment maintained?

Answer 8

feedback for unanticipated postural instability and feedforward for anticipated postural instability

Question 9

What is encoded in the premotor area?

Answer 9

complex sequences of movement

Question 10

What is encoded in the primary area?

Answer 10

individual or localised movements

Question 11

Where is the hand instructed to move by prolonged stimulation of different areas of the primary motor cortex?

Answer 11

from any location to the face

from any location to the chest

Question 12

What are the signs and symptoms of upper motor neuron lesions? (more excitable)

Answer 12

weakness, spasticity, increased tone, hyperactive deep reflexes, loss of fine voluntary movements

Question 13

What are the signs and symptoms of lower motor neuron lesions?

Answer 13

weakness or paralysis, decreased superficial reflexes, hypoactive deep reflexes, decreased tone, severe muscle atrophy

Question 14

What are functions of the cerebellum?

Answer 14

coordinating the timing and sequence of muscle actions and movements
maintenance of muscle tone / motor learning
planning sequences of muscle activation for complex movements

Question 15

What does the cerebellar cortex / deep nuclei receive input from?

Answer 15

sensory inputs from inferior olive, spinal cord and vestibular nuclei
motor inputs from the pontine nuclei which receives inputs from the frontal / parietal cortex

Question 16

Why does the cerebellar cortex / deep nuclei have sensory and motor inputs?

Answer 16

allows for comparison of the intended motor result and the actual motor result so that cerebellar circuits can tweak the motor command so that the intended motor result is the actual motor result