Supraspinal Motor Control

Question 1

supraspinal motor control is carried out at multiple levels of the ( ) and is conveyed to the cord via the ( )

Answer 1

• brainstem and cerebral cortex

- descending pathways

Question 2

the descending pathways can be divided into ( )

Answer 2

medial and lateral pathways

Question 3

which pathways are phylogenetically older?

Answer 3

medial pathways

Question 4

which pathways are more likely uncrossed or bilateral projecting pathways?

Answer 4

medial

Question 5

medial pathways have more to do with ( ) of posture and balance

Answer 5

extensors and axial and proximal muscle control

Question 6

which pathways include vestibulospinal, descending medial longitudinal fasciculus and reticulospinal pathways

Answer 6

medial pathways

Question 7

which pathways are largely crossed pathways that control flexors and more distal muscules for fine motor control?

Answer 7

lateral pathways

Question 8

which pathways include the rubrospinal tract and the lateral corticospinal tract?

Answer 8

lateral pathways

Question 9

which tracts are lateral systems in terms of physiology but are physically located medially in the neuroaxis?

Answer 9

tectospinal and medial corticospinal tracts

Question 10

the vestibulospinal tract originates largely in the ( ) and descends ( ) through the brainstem and ventromedial spinal cord to influence ( )

Answer 10

• lateral vestibular nucleus
• ipsilaterally
• extensor alpha motoneuron pools

Question 11

this pathways serves to connect the spinal motor system with vestibular and cerebellar input, clearly proving the cord with info regarding balance

Answer 11

vestibulospinal tract

Question 12

the descending portion of the ( ) originates in the medial vestibular nucleus and descends through the thoracic cord bilaterally

Answer 12

medial longitudinal fasciculus (MLF)

Question 13

the ( ) has cells of origin in both the pontine and medullary reticular formations

Answer 13

reticulospinal tract

Question 14

the potine reticular formation gives rise to the ( ) and is excitatory to ( )

Answer 14

• ipsilateral medial reticulospinal tract

- extensor gamma motoneurons

Question 15

the meduallary reticular formation gives rise to the ( ) and is inhibitory to ( )

Answer 15

• ipsilateral lateral reticulospinal tract

- extensor gamma motoneurons

Question 16

medullary reticular formation recieves excitatory input from the ( ) while the potine reticular formation recieves exitatory input from ( )

Answer 16

• cerebral cortex

- ascending spinoreticular sources in addition to cortical input

Question 17

the ( ) originates in the contralateral red nucleus and probably only projects through the cervical spinal cord

Answer 17

rubrospinal tract

Question 18

in ( ), the rubrospinal system carries out much of what has been taken over by the corticospinal tract in humans

Answer 18

phylogenetically lower species

Question 19

the rubrospinal tract provides excitatory input to ( ) of the upper extremity

Answer 19

flexor motoneuron pools

Question 20

the ( ) originates in the deep layers of the contralateral superior colliculus

Answer 20

tectospinal tract

Question 21

tectospinal tract projects only to ( )

Answer 21

cervical levels of the spinal cord

Question 22

as the superior colliculus receives visual input, it is thought that the ( ) allows for head and trunk positioning in response to visual stimulus

Answer 22

tectospinal tract

Question 23

while tectospinal tract is crossed, it projects medial in the ( ) and to ( )

Answer 23

cord; proximal motoneuron pools

Question 24

which tract sends projections from several areas of cerebral cortex to spinal motoneurons and brainstem nuclei (predominantly those innervating FLEXOR and DISTAL muscles involved in fine motor skills)

Answer 24

the corticospinal (and corticobulbar) tract

Question 25

lesions in the ( ) affect the execution of fine motor skills while leaving motor strength relatively more preserved

Answer 25

cerebral cortex

Question 26

the areas of cerebral cortex involved in motor planning and execution send their commands to the spinal cord directly through the ( ) and indirectly through the ( )

Answer 26

• corticospinal tract

- reticular formation and red nucleus

Question 27

between 30-40% of corticospinal fibers originate in ( ) to modulate sensorimotor function within the spinal cord

Answer 27

primary sensory cortex

Question 28

the majority of corticospinal fibers cross the midline at the level of the ( ) and descend as the ( ) but a few travel in the cord ipsilaterally as ventral corticospinal tract only to terminate bilaterally in the cord

Answer 28

• pyramidal decussation in the medulla

- lateral corticospinal tract

Question 29

what are the motor components of the cerebral cortex?

Answer 29

1) primary motor cortex
2) premotor cortex
3) supplementary motor cortex

Question 30

the motor components of the cerebral cortex represent ascending hierarchies in motor execution of what type of movements that are associated largely with primary motor cortex activation alone?

Answer 30

simple movements (like a finger)

Question 31

patterned finger movement are associated with ( )

Answer 31

primary motor and premotor activation

Question 32

complex movement sequences of fingers are associated with activation of ( )

Answer 32

primary, premotor and supplementary areas, and mental rehearsal alone of such movements

Question 33

complex movement sequences are associated with ( )

Answer 33

supplementary motor cortex activation

Question 34

in general, it is through that motor commands often proceed from ( ) to ( ) to ( )

Answer 34

supplementary area to premotor area to primary motor cortex

Question 35

the primary motor cortex was originally thought to control ( ) as reflected in the homunculus

Answer 35

individual muscles

Question 36

research findings that there were ( ) where individual muscles could be activated and these corresponded to activation of different groups of muscles led researchers to conclude that the motor cortex maps ( ) rather than ( )

Answer 36

• multiple sites
• movements
• individual muscles alone

Question 37

further work demonstrated that cells in the motor cortex also had activity related to the direction of ( )

Answer 37

limb movement

Question 38

cortical motoneurons seem to encode ( ) as opposed to activation of individual muscles

Answer 38

movements and their directions

Question 39

the activity in the reticular formation favors the ( ) over the ( ) due to the effect of ascending spinoreticular inputs

Answer 39

• excitatory pontine region

- inhibitory medullary region

Question 40

if a transection was made mor rostrally that spared the red nucleus and rubrospinal pathways, a more mixed picture of ( ) was seen

Answer 40

flexor and extensor tone

Question 41

mixture of flexor and extensor tone corresponds to the clinical picture of patients with ( ) such as those affecting the cerebral cortices

Answer 41

higher lesions

Question 42

since the rubrospinal pathway only projects to the cervical cord in humans, ( ) is only seen in the upper extremities wheras ( ) predominates in the lower extremities

Answer 42

• flexor tone

- extensor tone

Question 43

fine motor contol UMN vs LMN

Answer 43

UMN: markedly diminished; LMN: minimally diminished

Question 44

pathological reflexes UMN vs LMN

Answer 44

UMN: present; LMB: absent

Question 45

Babinski: hyper-reflexia and a resultant hypertonia because sensory info entering the cord is under less ( ) and has access to additional motoneurons and motoneuron pools than under normal conditions

Answer 45

descending control

Question 46

positive phenomena of the UMN syndrome are often referred to clinically as ( )

Answer 46

spasticity