Motor-descending Pathways

Question 1

What does the medial motor tracts control?

Answer 1

Postural and girdle control (unconscious)

Question 2

What are the 4 medial motor tracts that regulate posture/gross movement?

Answer 2

Reticulospinal

Medial vestibulospinal

Lateral vestibulospinal

Medial corticospinal

Question 3

What do the LMN in the reticulospinal tract do?

Answer 3

Postural and gross limb movement (bilaterally)

Question 4

What are the actions of the Reticulospinal tract?

Answer 4

Active during walking

Anticipatory postural adjustments

Reaching movements

Neck reflexes (turning head to see something)

Question 5

What do the LMN control in the medial vestibulospinal tract?

Answer 5

Neck and upper back muscles

Question 6

What are the actions that occur in the medial vestibulospinal tract?

Answer 6

Medial information about head movement and position

Help maintain an erect posture

Question 7

What do the LMN do in the lateral vestibulospinal tract?

Answer 7

Activate extensors and inhibit flexors

Question 8

What are the actions of the lateral vestibulospinal tract?

Answer 8

Lateral info about gravity

Center of gravity

Response to destabilization

Help maintain an erect posture

Question 9

What do the LMN control in the medial corticospinal tract (anterior corticospinal)?

Answer 9

Neck, shoulders, and trunk

Question 10

Why is the medial corticospinal (anterior corticospinal) tract considered a pyramidal tract?

Answer 10

Because it descends through the pyramidal sections of the medulla

Question 11

What do lateral motor tracts do?

Answer 11

Fractionated movement of face, neck, and distal limbs

Question 12

What are the tracts associated with the lateral motor tracts?

Answer 12

Rubrospinal tract

Lateral corticospinal tract

Question 13

What does the rubrospinal tract do?

Answer 13

Minor contribution to control of upper limb distal extensor muscles

Question 14

What is the most clinically important descending motor pathway?

Answer 14

Lateral corticospinal tract

Question 15

What does the lateral corticospinal tract do?

Answer 15

Controls movement of the extremities (pyramidal tract)

Question 16

How do lesions work in the lateral corticospinal tract?

Answer 16

Lesion above pyramidal decussation = contralateral weakness

Lesion below the pyramidal decussation = ipsilateral weakness

Question 17

What do the corticospinal brainstem tracts (corticobulbar) control?

Answer 17

LMN of the face, tongue, pharynx, SCM, and upper trap

Question 18

What are the LMN of the lower portion of the face controlled by on the corticospinal brainstem tracts?

Answer 18

Contralateral neurons

Question 19

What are the LMN of the upper portion of the face controlled by on the corticospinal brainstem tracts?

Answer 19

Bilaterally

Question 20

What do the non specific motor tracts do?

Answer 20

Involved in excessive limbic activity in the emotional motor system (performance anxiety)

Question 21

Where do the non specific UMN descend from?

Answer 21

Locus coeruleus and raphe nuclei

Question 22

What do non specific UMN enhance?

Answer 22

Activity of interneurons and LMN

Question 23

What are the two non specific motor tracts?

Answer 23

Ceruleospinal

Raphespinal

Question 24

What is the function of the ceruleospinal tract?

Answer 24

Tonic facilitation of LMN

Releases norepinephrine

Question 25

What is the function of the raphespinal tract?

Answer 25

Releases serotonin