Descending Motor Pathways Part II

Question 1

What part of the internal capsule does motor go through

Answer 1

The posterior limb

Question 2

What does genu mean

Answer 2

Bend

Question 3

What limb of the internal capsule is the corticospinal tract in

Answer 3

Posterior limb

Question 4

Where does the lateral corticospinal tract travel

Answer 4

Posterior limb of internal capsule to cerebral peduncles through the pons to the pyramids

Question 5

Where does the lateral corticospinal tract decussate/cross

Answer 5

Cervicomedullary junction

Question 6

What percent of the corticospinal tract decussate at the cervicomedullary junction

Answer 6

85%

Question 7

True or False:

The lateral corticospinal tract decussates while the anterior corticospinal tract does not decussate in the medulla

Answer 7

True

Question 8

Where does the rubrospinal tract originate

Answer 8

Red nucleus of the midbrain

Question 9

What does the rubrospinal tract receive afferent input from (2)

Answer 9

1. Ipsilateral cortical motor areas (corticorubral pathway)

2. Contralateral side of the cerebellum

Question 10

True or False:

The fibers of the rubrospinal tract decussate immediately after they emerge

Answer 10

True

Question 11

Where does the rubrospinal tract decussate

Answer 11

Ventral tegmental decussation

Question 12

True or False:

The rubrospinal tract fibers descend with the corticospinal tract after they decussate

Answer 12

True

Question 13

Where does the rubrospinal tract terminate in humans

Answer 13

Cervical enlargement

Question 14

True or False:

In monkeys the rubrospinal tract can compensate for corticospinal lesions

Answer 14

True

Question 15

What happened to the monkey when you severed the lateral corticospinal tract

Answer 15

Function of fingers was lost but recovered rather quickly

Question 16

What recovered the ability to use the fingers again

Answer 16

The rubrospinal tract compensated

Question 17

Was the rubrospinal tract able to recover the ability to use individual fingers

Answer 17

Nope

Question 18

If the rubrospinal tract was also severed could the monkey recover use of hands and fingers

Answer 18

Negative

Question 19

What does the anterior corticospinal tract consist of

Answer 19

The corticospinal fibers that did not decussate in the rostral medulla

Question 20

Where do the anterior corticospinal tract fibers decussate

Answer 20

In the spinal cord near the synapse of the LMN in the central gray

Question 21

What does the anterior corticospinal tract supply (3)

Answer 21

1. Neck
2. Bilateral upper girdle
3. Axial muscles

Question 22

What does the vestibular system provide

Answer 22

Rapid sensory indication of the rotation and linear movement of the head

Question 23

Where does the vestibular apparatus send signals

Answer 23

To the vestibular nuclei in the dorsal surface of the medulla via cranial nerve VIII

Question 24

What are the 4 vestibular nuclei that receive distinct but overlapping info

Answer 24

1. Superior
2. Medial
3. Lateral
4. Inferior

Question 25

Where do axons of the vestibular nuclei terminate on or near

Answer 25

Motor neurons for muscles of the legs, eyes, and neck

Question 26

Where does the medial vestibulospinal tract originate

Answer 26

Medial vestibular nucleus

Question 27

Where does the medial vestibulospinal tract descend

Answer 27

Bilaterally to cervical levels of the cord

Question 28

Where does the lateral vestibulospinal tract originate

Answer 28

Lateral, inferior, and superior to vestibular nuclei

Question 29

Where does the lateral vestibulospinal tract receive input from

Answer 29

Vestibulocerebellum

Question 30

What does the vestibulocerebellum modulae

Answer 30

Postural adjustments

Question 31

Where does the lateral vestibulospinal tract descend

Answer 31

Ipsilaterally to all levels of the cord

Question 32

What do both the medial and lateral vestibulospinal tracts control

Answer 32

Proximal muscles

Question 33

What does the lateral vestibulospinal tract cause to happen when you tip forward in raft

Answer 33

Stimulates extensor motor neurons in LE to adjust limbs and trunk musculature

Question 34

Where does the reticulospinal tract terminate

Answer 34

The entire cord

Question 35

What is the reticulospinal tract involved in

Answer 35

Automatic and anticipatory posturing and gait movements

Question 36

What are the 2 tracts of the reticulospinal tract

Answer 36

1. Medullary (lateral) | 2. Pontine (medial)

Question 37

What does the medullary tract off the reticulospinal tract do (3)

Answer 37

1. Inhibits extensors and excites flexors 2. Inhibits voluntary movements 3. Reduces tone

Question 38

What does the pontine tract of the reticulospinal tract do (3)

Answer 38

1. Excites extensors and inhibits flexors 2. Facilitates voluntary movements 3. Increases tone

Question 39

True or False: Since we have feed forward processing we are able to predict changes in posture and generate an appropriate stabilizing response

Answer 39

True

Question 40

What is an example of the stabilizing response

Answer 40

The gastrocnemius fires when doing a biceps curl to prevent you from pulling yourself into the machine.

Question 41

What happened to cats if you inhibited the reticulospinal tract

Answer 41

Paw still moved but other legs do not

Question 42

Where does the tectospinal tract originate

Answer 42

Superior colliculus

Question 43

Where is the superior colliculus located

Answer 43

Tectum of the midbrain

Question 44

Where does the tectospinal tract decussate

Answer 44

Immediately in the midbrain

Question 45

Where does the tectospinal tract terminate

Answer 45

Largely in the upper cervical cord

Question 46

What does the tectospinal tract do

Answer 46

Coordinates head movements in response to rapid eye movements

Question 47

What does the tectospinal tract receive input from (2)

Answer 47

1. Hearing | 2. Eyes

Question 48

Is the tectum anterior or posterior on the midbrain

Answer 48

Posterior

Question 49

Is the tegmentum anterior or posterior on the midbrain

Answer 49

Anterior

Question 50

True or False: | The function of the tectospinal tract is very well understood in humans

Answer 50

False