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Flashcards in motor control part 1 Deck (49)
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1

greater than 1/2 of the primary motor cortex controls what?

hands and speech

2

what area is anterior to the lateral portions of primary motor cortex below supplemental area?

premotor area

3

the premotor area projects to?

1 degree motor cortex and basal ganglia

4

what area is superior to premotor area lying mainly in the longitudinal fissure?

supplemental motor area

5

what movements do the premotor and supplemental motor areas provide?

attitudinal movements
fixation movements
positional movements of head and eyes
background for finer control of arms/hands

6

what percentage of the corticospinal tract originates in the primary motor cortex?

30%

7

what percentage of the corticospinal tract originates in the premotor and supplemental areas?

30%

8

what percentage of the corticospinal tract originates in the somatic sensory areas?

40%

9

where does the corticospinal tract descend?

via the posterior limb of the internal capsule (btw caudate and putamen)

10

what does the corticospinal tract form?

pyramids of the medulla

11

when corticospinal tract fibers cross midline they form?

lateral corticospinal tract

12

when corticospinal fibers stay ipsilateral they form?

ventral corticospinal tract

13

when all tracts are cut and the cord is completely isolated from the brain its called? Low

spinal preparation

flaccidity!

14

when you have a transection at the mid collicular level mid brainstem its called?

decerebrate preparation

rigidity!

15

destruction of the cerebral cortex/ high brain stem is called?

decorticate preparation

different type of rigidity- spasticity

16

which brainstem area that receives stimulation from the vestibular nuclei and transmits excitatory signals to stimulate the axial trunk and extensor muscles that support the body against gravity?

pontine reticular nuclei

17

which brainstem area that receives strong input from the cortex, red nucleus, and other motor pathways and transmits inhibitory signals to the same antigravity muscles via the medullary (lateral) reticulospinal tract

medullary reticular nuclei

18

with regard to postural control, if DESCENDING cortical signals are blocked, what is the expected result?

increased extensor tone, flexors repressed- decerebrate rigidity

19

what is the function of a dynamic signal from pyramidal cells to alpha motor neurons?

initiation of muscle contraction

20

what is the function of static signal from pyramidal cells to alpha motor neurons?

fires at a slower rate to maintain contraction after initiation has occurred

21

what some important characteristics of postural reflexes?

-impossible to separate from voluntary movements
-they maintain body in an upright position
-maintain stable postural background for voluntary movement

22

extension of the neck facilitates extensors of?

arms and legs

23

flexion of the neck facilitates flexors of?

arms and legs

24

rotation of the neck facilitates extensors ______ and inhibits flexors ______

ipsilateral; ipsilateral

25

rotation of the neck facilitates flexors ______ and inhibits extensors _________

contralateral; contralateral

26

at the onset of clockwise rotation (to the right) what would you expect happens in the VIII cranial nerve on the left side?

decrease in firing rate

27

stimulation of semicircular canals is associated with?

increased extensor tone
nystagmus

28

slow component- tracking nystagmus is initiated by

semicircular canals

29

fast component- jumping ahead nystagmus is initiated by

brain stem nuclei

30

after 20 clockwise rotations with eyes closed on a revolving stool, the subject is abruptly stopped and the eyes are opened. what is observed?

lateral nystagmus with slow component clockwise

31

what are 3 disorders involved with the basal ganglia?

tremor and other involuntary movements
changes in posture and muscle tone
poverty and slowness of movement

32

motor functions of the basal ganglia are mediated by the?

motor areas of the cortex

33

what are the 2 circuits of the basal ganglia?

caudate
putamen

34

caudate + putanem =

striatum

35

what is a lesion in the globus pallidus?

athetosis- spontaneous and continuous writhing movements

36

what is a lesion in the subthalamus?

hemiballismus- sudden violent and flailing movements

37

what is multiple small lesions in putamen?

chorea- flicking movements in hands and feet

38

rigidity, akinesia and resting tremors happen in?

substantia nigra- Parkinsons

39

in backward sway, what is the distal to proximal sequence of muscles?

tibialis- quad- abdominal

40

in forward sway, what is the distal to proximal sequence of muscles?

gastrocnemius- hamstring- paraspinals

41

what would happen to a repetitive simple stretch reflex, if when a muscle contracts it destabilizes posture?

it would be inhibited

42

what would happen to a repetitive simple stretch reflex, if when a muscle contracts it stabilizes posture?

it would be facilitated

43

ones sense of upright is generally a combination of cues that include both visual and vestibular information, true or false?

true- CN VIII connected to CN III, IV, VI

44

what effect does the striatum have on the substantia nigra?

inhibitory GABA projections

45

a stroke that lesions the posterior limb of the internal capsule (between putamen and caudate) would be associated with?

loss of voluntary movement

46

when supine, head tilt is best detected by what?

saccule

47

what plays an important role in determining orientation of the head when person is upright?

utricle

48

what plays an important role in determining orientation of the head when person is lying down?

saccule

49

signals from neck proprioceptors typically OPPOSE signals from the vestibular apparatus as the head and neck are rotated and have similar effects on limb flexion and extension. true or false?

true