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Flashcards in Corticomotor system Deck (63):
1

What is the first event of the three that preceded voluntary motor movement?

Perceptual mechanisms generate a sensory model of the external world and a person’s position in the environment

2

What is the second event of the three that preceded voluntary motor movement?

Cognitive processes use the internally generated model to decide on a course of action

3

What is the third event of the three that preceded voluntary motor movement?

The selected motor plan is conveyed to the neural areas responsible for implementation of the plan

4

What are the areas of the motor cortex?

1. Primary motor cortex
2. Supplementary/motor cortex
3. Cingulate motor cortex
4. Frontal eye fields

5

What is the function of the reticulospinal tract?

are medial system motor pathways for control of axial and proximal muscles

6

What is the function of the rubrospinal tract?

part of lateral system motor pathways to control mainly distal and proximal muscles of the upper extremity. (monkeys)

7

Where does the red nucleus receives most of its innervation from?

cerebellum and primary motor cortex

8

The rubrospinal tract go where?

Flexors of the hands

9

Which lobe is the frontal eye field located in?

Frontal lobe

10

Neurons in the frontal eye field will collaborate with cells where to control eye movement?

Superior colliculus to PPRF

OR

straight to PPRF (horizontal gaze centers)

11

What is the route of the motor system innervation?

Parietal, premotor/supplementary cortex

Primary motor cortex

Brainstem

Spinal cord

12

Corticobulbar tract = what tract?

Corticonuclear (same thing, different name)

13

What is significant about the way the upper and lower parts of the facial nucleus is innervated by UMNs?

Upper part get bilateral projections

Lower part only contralateral

14

True or false: Corticorubral fibers and corticoreticular fibers are also part of the corticonuclear tracts

True

15

Corticonuclear fibers pass through what part of the internal capsule on their way to the brainstem? What is the next part?

Genu, then crus cerebri

16

Motor control of the extraocular eye muscles is partially via a projection from what two cortical areas?

the frontal and parietal motor eye fields of the cortex

17

the frontal and parietal motor eye fields of the cortex send projections where to innervate the eyes?

the horizontal and vertical gaze centers of the reticular formation

18

What are the two ways of smiling?

Pyramidal system
RF

19

What is the pathway for the pyramidal smiling?

Cortex to pyramids to facial nucleus

20

What is the non-pyramidal pathway for smiling?

Forebrain/hypothalamus to the facial nucleus

21

Where does the corticospinal tract cross?

Lateral crosses in the medulla

Anterior crosses at the spinal cord level

22

What percent of fibers of the corticospinal tract cross in the medulla, to form the lateral corticospinal tract?

90%

23

Where do the fibers of the lateral corticospinal tract synapse (on what neurons)?

Anterior horn nuclei to distal limbs for fractionated movements

24

What percent of fibers of the corticospinal tract do not cross in the medulla, but instead stay anteriorly to form the lateral corticospinal tract?

10%

25

What is the function of the anterior corticospinal tract?

Motor innervation to the trunk, neck, and shoulder

26

True or false: the corticospinal tract is only involved in motor functions

False--has sensory, to emphasize movement

27

What is the origin of the lateral corticospinal tract?

Frontal cortex, and somatosensory cortex

28

What is the origin of the anterior corticospinal tract?

only the motor cortex

29

What type of movement is the lateral corticospinal tract necessary for?

Fractionated movements of the hand and fingers

30

Why can we not (physically) perform experiments on humans to cut the corticospinal tract?

Intermingles with the rubrospinal tract, thus no way to isolate it

31

How is the motor cortex fibers organized?

According to a given task, rather than a specific muscle

32

Can somatotopic organization of the motor cortex change?

yes

33

What artery gets the leg area of the primary motor cortex?

anterior cerebral

34

What artery supplies the trunk, hand, and face area of the primary motor cortex?

Middle cerebral

35

Lesions restricted to the primary motor cortex can cause what?

Persistent hypotonia or spasticity if other cortical areas involved

36

What are the arteries that supply the internal capsule (branches of the middle cerebral)?

Lenticulostriate

37

What is paresis?

Weakness of voluntary muscle

38

What is the role of the premotor area?

Goal directed movement that requires sensory information about the environment

39

What a mirror neurons?

Neurons in the premotor area that might encode the intentions and actions of others and participate in imitation learning

40

What are the functions of the premotor cortex compared to the supplementary motor cortex?

PM more important for movements activated or guided by external stimuli

41

What is the role of the supplementary motor cortex? (2)

Planning or preparing for sequential motor acts.

Coordinating movements from each side of the body

(especially those initiated or controlled by internal, remembered or self-determined stimuli)

42

What area of the brain has been implicated in the inability to **start** activities like walking parkinsons?

Putamen

43

Do lesions of the SMC produce paralysis?

No, but do cause problems in initiating or suppressing movement

44

What is the function of the frontal eye field?

INfluences eye movements through projections to the brainstem vertical and horizontal gaze centers and the superior colliculus

45

What is the input to the frontal eye field?

visual association cortex and basal ganglia and thalamic relays about the location of a visual target

46

What are the three projections that the frontal eye field sends off to help eye movement?

projections to the brainstem vertical and horizontal gaze centers and the superior colliculus.

47

What is the input to the FEF?

from visual association cortex and basal ganglia and thalamic relays

48

What is the effect of a lesion in the FEF?

Permanent deficit in the ability to make saccades that are not guided by an external target

Cannot voluntarily direct their eyes away from a stimulus in the visual field

49

Where do the cortical influence over eye movements go (which nucleus) to have an effect on the eyes?

Pontine RF

50

What are saccades?

Small movements of the eye

51

What part of the brain is involved in the reflexive saccades?

Superior colliculus

52

What is Brown-sequard syndrome?

Hemisection of the spinal cord

53

Fasciculations and fibrillations are characteristics of UMNs or LMN lesions?

LMNs

54

If there is a brainstem lesion to the UMN in the spinal cord which side will be affected?

Contralateral

55

If there is a brainstem lesion to the LMN in the spinal cord which side will be affected?

Ipsilateral

56

What are the deficits of Brown-Sequard syndrome ipsilateral to the lesion?

Loss of fine touch, UMN symptoms below lesion, LMN signs at level of lesion

57

What are the deficits of Brown-Sequard syndrome contralateral to the lesion?

Loss of pain and temp sensation

58

UMN lesion will produce what symptoms in the Babinski response?

Upgoing response (extension of the great toe, and flaring of the other toes)

59

A lesion to the corticospinal tract / corticonuclear tract origin will produce weakness where?

Facial weakness ipsilateral

Limb paralysis contralateral

60

What is alternating hemiplegia?

is caused by pontine lesions which involve corticospinal tract fibers and fibers from the abducens nucleus.

61

What type of lesion will affect one entire half of the body?

Hemispheric lesion

62

What type of lesion will affect ipsilateral face and contralateral side of the body?

Brainstem lesion

63

Lesions restricted to the primary motor cortex cause what symptoms?

Persistent hypotonia