PHYSIOLOGY - UMNs and control of movement

Question 1

what is the essential feature for a simple spinal central pattern generator to command rhythmic alternating activity that moves a limb

Answer 1

an excitatory interneurone to display oscillatory or pacemaker activity

Question 2

what are the 3 levels of motor control

Answer 2

high middle and low

Question 3

what is forms the highest level of motor control

Answer 3

neocortical association areas and basal ganglia

- strategy

Question 4

what forms the middle tier of motor control

Answer 4

motor cortex and cerebellum

- tactics

Question 5

what forms the lowest tier of motor control

Answer 5

brain stem and spinal cord

- execution

Question 6

what are the 2 pathways of the descending tracts

Answer 6

lateral and ventromedial pathways

Question 7

the lateral pathways are under control of from the

Answer 7

cerebral cortex

Question 8

the ventromedial pathways are under the control from the

Answer 8

brainstem

Question 9

what is brown sequard syndrome

Answer 9

hemisection of the cord

• ipsilateral paralysis
• ipsilateral hyperreflexia and extensor plantar reflex
• ipsilateral loss of DCML
• contralateral loss of spinothalamic

Question 10

what is the major lateral pathway

Answer 10

corticospinal tract

Question 11

why is the corticospinal tract considered pyramidal

Answer 11

passes through the medullary pyramids

Question 12

where are the cell bodies of the corticospinal tract located

Answer 12

BA4 and BA6 of motor cortex and somatosensory areas of the parietal cortex

Question 13

where do axons of the corticospinal tract course from the cortex

Answer 13

descend through internal capsule to base of medulla

pass through crus cerebri of the midbrain, pons and medulla

Question 14

where do fibres of the corticospinal tract decussate

Answer 14

most decussate in the caudal medulla (pyramidal decussation) to form the lateral corticospinal tract
remainder stay ipsilateral to form ventral corticospinal tract and decussate segmentally more caudally

Question 15

after fibres of the lateral corticospinal tract decussate where do they go and terminate

Answer 15

descend into the spinal cord terminating in the dorsolateral region of the ventral horn at all segmental levels

Question 16

where do fibres of the ventral corticospinal tract go once they have decussated

Answer 16

decussate and terminate in the ventral horn of the cervical and upper thoracic segmental levels

Question 17

what does the corticospinal tract control

Answer 17

supplies muscles of body - fine precise movements particularly of distal musculature

Question 18

what is found in the dorsolateral region of the ventral horn and intermediate grey

Answer 18

location of LMNs and interneurons controlling distal muscles

Question 19

true/false

the left side of the brain always control right side musculature

Answer 19

true

Question 20

what are the 2 pyramidal tracts and their functions

Answer 20

corticospinal tract - supples muscles of body

corticobulbar tract - supplies muscles of head and neck

Question 21

pyramidal tracts are responsible for voluntary/involuntary movements

Answer 21

voluntary

Question 22

extra-pyramidal tracts originate where

Answer 22

brainstem

Question 23

extra-pyramidal tracts control what

Answer 23

involuntary and automatic control of all musculature such as muscle tone balance posture and locomotion

Question 24

what is the internal capsule

Answer 24

white matter pathway located between the thalamus and the basal ganglia

Question 25

what is capsular stroke

Answer 25

internal capsule is particularly susceptible to compression from haemorrhagic bleeds

Question 26

where does the corticobulbar tract arise from

Answer 26

lateral motor cortex

Question 27

where do neurones of the corticobulbar tract terminate

Answer 27

motor nuclei of the cranial nerves where they synapse with LMNs which carry motor signals to muscles of face and neck

Question 28

true/false | both right and left fibres of the corticobulbar tract innervate the motor neurones bilaterally

Answer 28

true

Question 29

what are the 2 exceptions to the bilateral innervation of the corticobulbar tract

Answer 29

UMNs for the facial nerve only have contralateral innervation of muscles below the eyes UMNs for the hypoglossal nerve only provide contralateral innervation

Question 30

name a minor lateral pathway other than the corticospinal or corticobulbar

Answer 30

rubrospinal

Question 31

is the rubrospinal tract pyramidal or extrapyramidal

Answer 31

extrapyramidal

Question 32

cell bodies of the rubrospinal tract are found where

Answer 32

red nucleus

Question 33

the red nucleus receives input from where

Answer 33

motor cortex and cerebellum

Question 34

axons of the rubrospinal tract decussate where

Answer 34

ventral tegmental decussation in the midbrain

Question 35

axons of the rubrospinal tract descend the spinal cord where in relation to the lateral corticospinal tract

Answer 35

ventrolateral

Question 36

where do axons of the rubrospinal tract terminate

Answer 36

ventral horn

Question 37

the rubrospinal tract exerts control over what muscles

Answer 37

flexors

Question 38

true / false | if the corticospinal tract is damaged the rubrospinal tract can compensate to a good degree

Answer 38

true

Question 39

what controls fine movements of hand

Answer 39

rubrospinal tract

Question 40

give 2 things lesions of the lateral columns is associated with

Answer 40

- cant move shoulders/elbow/wrist/fingers independently | - slowing and impairment of accuracy of voluntary movements

Question 41

would a lesion of the lateral column have much effect on normal posture

Answer 41

no

Question 42

what are the 3 ventromedial pathways

Answer 42

vestibulospinal tectospinal reticulospinal

Question 43

what are the 2 vestibulospinal pathways

Answer 43

medial and lateral

Question 44

where does the vestibulospinal tract arise

Answer 44

lateral and medial vestibular nuclei

Question 45

what do the vestibular nuclei receive input from

Answer 45

CN VIII - vestibulocochlear nerve which gets info from vestibular labyrinths

Question 46

does the vestibulospinal tract decussate

Answer 46

no - descends spinal cord and remains ipsilateral

Question 47

where is the lateral vestibular nucleus (Deiter's nucleus)

Answer 47

pons

Question 48

where is the medial vestibular nucleus

Answer 48

medulla

Question 49

input from where is also important for the vestibulospinal tract

Answer 49

cerebellum

Question 50

how far down does the lateral vestibulospinal tract descend

Answer 50

until the lumbar spinal cord

Question 51

what does the LVST control

Answer 51

helps to hold upright and balanced posture - extensor MNs of antigravity muscles e.g. of the leg

Question 52

how dar down does the medial VST descend

Answer 52

cervical spinal cord

Question 53

what does the MVST control

Answer 53

cervical spinal circuits that control neck and back muscles guiding the head

Question 54

which of the tracts of the VST is longer

Answer 54

lateral is longer - goes from higher up to further down

Question 55

where do cell bodies of the tectospinal tract originate

Answer 55

superior colliculus of the midbrain

Question 56

the superior colliculus receives input from what

Answer 56

retina (optic nerves) visual cortex afferents conveying somatosensory and auditory information

Question 57

where do axons of the tectospinal tract decussate

Answer 57

dorsal tegmental decussation of the midbrain

Question 58

axons of the tectospinal tract descend the spinal cord close to the midline and go to what

Answer 58

cervical spinal cord influencing muscles of the neck upper trunk and shoulders

Question 59

what does the tectospinal tract do in general

Answer 59

coordinates movement of the head and eyes in relation to visual stimuli

Question 60

what are the 2 reticulospinal tracts

Answer 60

medial (pontine) | lateral (medullary)

Question 61

where does the MRST arise

Answer 61

pons

Question 62

where does the LRST arise

Answer 62

medulla

Question 63

what does the MRST control

Answer 63

voluntary movements and increases muscle tone enhances anti-gravity reflexes of the spinal cord helps to maintain standing posture by facilitating contraction of the extensors of lower limbs

Question 64

what does the LRST control

Answer 64

opposes the action of the medial tract - releases antigravity muscles from reflex control

Question 65

which of the RST descends ipsilaterally and which descends bilaterally

Answer 65

medial - ipsilaterally | lateral - bilaterally

Question 66

what are the cardinal signs of an UMN of corticospinal tract

Answer 66

``` hypertonia hyperreflexia clonus babinski sign muscle weakness ```

Question 67

why does damage to the corticobulbar tract usually result in mild muscle weakness

Answer 67

bilateral innervation of majority from corticobulbar tract

Question 68

lesion to the UMNs of the corticobulbar supply of CN VII would result in

Answer 68

spastic paralysis of the muscles in the contralateral lower face

Question 69

lesion to UMNs of corticobulbar supply of CN XII would result in

Answer 69

spastic paralysis of contralateral genioglossus - deviation of tongue to contralateral side

Question 70

decorticate posture: (flexor/extensor) position

Answer 70

flexor | FLEX my new DECOR

Question 71

what are the hands like in decorticate

Answer 71

in decortiCate | hands are like Cs and move toward the Cord (midline)

Question 72

decorticate posture occurs due to problem with

Answer 72

cervical spinal tract or cerebral hemisphere

Question 73

decerebrate posture: (flexor/extensor) position

Answer 73

extensor | dEcErEbratE

Question 74

the arms are like what in decerebrate posture

Answer 74

like e's | and down to sides

Question 75

decerebrate posture is due to a problem with what

Answer 75

midbrain or pons