Motor system

Question 1

What are the 3 basic movement types?

Answer 1

Reflexive responses
Rhythmic motor patterns
Voluntary movements

Question 2

What is the highest level of motor control?

Answer 2

Programming in cerebellum and basal nuclei

Question 3

What is the middle level of motor control?

Answer 3

Motor cortex - projection areas

Question 4

What is the lowest level of motor control?

Answer 4

Segmental motor controls in spinal cord

Question 5

What is a UMN?

Answer 5

Located within brain or brainstem
Axon travel downs spinal cord
Innervates alpha and gamma motor neurons in ventral horn of spinal cord

Question 6

What is a LMN?

Answer 6

Alpha and gamma motor neurons located in ventral horn of spinal cord

Question 7

What layer of the cerebral cortex is almost absent in Brodmann’s areas 4 and 6?

Answer 7

Layer 4 - inner granular

Question 8

What layer of the cerebral cortex are the cell bodies of the corticospinal tract located?

Answer 8

Layer 5

Question 9

What will electrical stimulation of Brodmann’s area 4 cause?

Answer 9

Movement of an individual or a few muscles
Lowest threshold of movement
Short latency of movment

Question 10

The cortical region supplying the lower limb is supplied by what artery?

Answer 10

ACA

Question 11

The cortical region supplying the hand and face is supplied by what artery?

Answer 11

MCA

Question 12

What occurs with a lesion to the primary motor cortex?

Answer 12

Contralateral paralysis

Question 13

What occurs with a lesion to the premotor cortex?

Answer 13

Apraxia - inability to perform voluntary movement in the absence of paralysis

Question 14

What is the 3 complex process of voluntary movements?

Answer 14

Posterior parietal cortex (areas 5 And 7) - identification of target
Supplementary motor cortex (area 6) - plan movement
Primary motor cortex (area 4) - execute movement

Question 15

Efferents from the motor cortex form what tract?

Answer 15

Corticospinal tract

Question 16

What parts of the internal capsule do the corticospinal fibers pass through?

Answer 16

Face near genu
Upper limb, trunk, and lower limb in posterior limb

Question 17

Occlusion of what arteries can cause internal capsule lesions?

Answer 17

Deep branches of MCA
Anterior choroidal A

Question 18

What part of the midbrain do the corticospinal fibers pass through?

Answer 18

Cerebral peduncle/crus cerebri

Question 19

What happens to corticospinal fibers in the pons?

Answer 19

The separate into fascicles in ventral pons

Question 20

What happens to the corticospinal fibers in the medulla?

Answer 20

Forms pyramids of anterior medulla
Most fibers decussate

Question 21

What forms the lateral corticospinal tract in the spinal cord?

Answer 21

Crossed corticospinal fibers from medulla

Question 22

What forms the anterior corticospinal tract in the spinal cord?

Answer 22

Uncrossed corticospinal fibers from medulla

Question 23

What tract acts on the lateral motor nuclei of ventral horn of spinal cord?

Answer 23

Lateral corticospinal tract

Question 24

What tract acts on the medial motor nuclei of the ventral horn of the spinal cord?

Answer 24

Anterior corticospinal tract

Question 25

What can corticospinal axons synapse with in the spinal cord?

Answer 25

Alpha motor neurons - extrafusal muscle fibers Gamma motor neurons - intrafusal muscle fibers to muscle spindles Intrasegmental interneurons - project within same segment Intersegmental interneurons - ascend and descend to different segmental levels

Question 26

What is the effect of the corticospinal tract on flexor motor neurons?

Answer 26

Facilitatory/excitatory

Question 27

What is the effect of the corticospinal tract on extensor motor neurons?

Answer 27

Inhibitory

Question 28

What are the major UMN tracts?

Answer 28

Corticospinal tract Corticobulbar tract Rubrospinal tract Tectospinal tract Anti-gravity reflex Lateral vestibulospinal tract Pontine reticulospinal tract Medullary reticulospinal tract

Question 29

What tracts are part of the anti-gravity reflex?

Answer 29

Lateral vestibulospinal tract Pontine reticulospinal tract Medullary reticulospinal tract

Question 30

Where does the rubrospinal tract terminate?

Answer 30

Anterior gray column of spinal cord

Question 31

Where is the rubrospinal tract located in the spinal cord?

Answer 31

Lateral white column

Question 32

What is the function of the rubrospinal tract?

Answer 32

Facilitates the activity of the flexor muscles and inhibits the activity of the extensor muscles Allows for proximal limb flexion

Question 33

Where is the tectospinal tract located in the spinal cord?

Answer 33

Anterior white column, close to anterior median fissure

Question 34

What nuclei in the brainstem are related to the anti-gravity reflex?

Answer 34

Lateral vestibular nucleus Reticularis pontis oralis Reticularis pontis caudalis Reticularis gigantocellularis

Question 35

Where do fibers of the corticobulbar pathway terminate?

Answer 35

Directly onto neurons of CN V, VII, and XII Both contralateral and bilateral

Question 36

When will the eyes go to the side of paralysis?

Answer 36

If lesion is in the FEF and CS

Question 37

When will eyes go to the opposite side of lesion

Question 38

When will eyes go to the opposite side of paralysis?

Answer 38

If lesion is in the PPRF and CS

Question 39

What is decorticate regidity?

Answer 39

Lesion above the red nucleus, possibly from bleeding in internal capsule Pt is paralyzed Responds to stimulus by flexion of UL and extension of LL

Question 40

What is decerebrate rigidity?

Answer 40

Site of lesion in superior and inferior colliculi, below red nucleus Extensive extensor posture of all extremities