Motor Neurons 2 - Kenyon

Question 1

cell bodies located lateraly project to muscles of posture or skilled movement?

Answer 1

skilled movement

Question 2

cell bodies located medially in the spinal cord project to postural or muscles of skilled movement?

Answer 2

postural muscles

Question 3

In the lateral CST, where are the lower motor neurons located?

Answer 3

In the lateral ventral horn

Question 4

In the ventral CST, where are the lower motor neurons located?

Answer 4

in teh medial ventral horn

Question 5

Does the ventral CST decussate?

Answer 5

No

Question 6

Where are the upper motor neurons originating for the vestibulospinal and reticulospinal tracts?

Answer 6

brainstem

Question 7

dot the vestibulospinal and reticulospinal tracts decussate?

Answer 7

NO

Question 8

Is there extensive crossing over of the medial local circuit neurons controlling posture?

Answer 8

yes

Question 9

Do the local circuit neurons controlling posture control muscles independently or groups of muscles?

Answer 9

groups of muscles

Question 10

Is there extensive crossing over of the local circuit neurons controlling skilled movement?

Answer 10

no

Question 11

Do the local circuit neurons controlling skilled movement control muscles independently or groups of muscles?

Answer 11

independent muscles

Question 12

The lower motor neurons controlling muscles of the face are in the (blank). They receive input from upper motor neurons via (blank) tract

Answer 12

brainstem

corticobulbar

Question 13

Lower motor neurons controlling the muscles of the body are in the (blank) They receive input from upper motor neurons via the (blank) tract

Answer 13

spinal cord

corticospinal

Question 14

Can upper motor neurons contribute to both the corticobulbar and corticospinal tracts?

Answer 14

yes

Question 15

the corticobulbar tract would find its upper motor neurons medial or lateral on the brain somatotopy?

Answer 15

lateral

Question 16

the corticospinal tract would find its upper motor neurons medially or laterally on the brain somatotopy?

Answer 16

medial`

Question 17

At what level does the corticospinal decussate? what is the name of the decussation?

Answer 17

Caudal medulla; pyramidal decussation

Question 18

On the shared CST and corticobulbar tract, where do the corticobulbar fibers head off to in the middle medulla?

Answer 18

to the reticular formation

Question 19

In what nuclei does the CST synapse in the dorsal column?

Answer 19

Gracile and cuneate

Question 20

What body structures does the lateral CST control?

Answer 20

limbs and hands

Question 21

what body structures does the ventral CST control?

Answer 21

hip, trunk, shoulder, elbow, and neck

Question 22

Can neurons from the ventral CST send fibers to the reticular formation?

Answer 22

Yes

Question 23

Why is is that the neurons in the motor and premotor cortex branch to synapse in both the lateral and ventral CST?

Answer 23

to coordinate postural adjustments

Question 24

Lower motor neurons controlling superior and inferior facial muscles are located in the (ipsilateral/contralateral) facial nerve (VII) nucleus.

Answer 24

ispilateral

Question 25

Upper motor neurons originate in (contralaterally/ipsilaterally) that control lower motor neurons controlling inferior facial muscles

Answer 25

contralaterally

Question 26

Upper motor neurons originating in the contralateral and ipsilateral (blank) gyrus project (cortico- bulbar) to lower motor neurons controlling superior facial muscles.

Answer 26

cingulate

Question 27

Primary and premotor complex controls upper or lower face muscles?

Answer 27

lower

Question 28

Cingulate gyrus controls upper or lower face muscles?

Answer 28

upper

Question 29

Lesions in the right primary motor cortex will have what effects on facial expression? is this upper or lower motor neuron lesion?

Answer 29

Loss of LOWER muscles to LEFT face; UPPER lesion

Question 30

Lesions in the tract common to both the pimary cortex and cingulate gyrus will have what effects on facial expression? Why is it this way?

Answer 30

Upper motor neuron lesion; loss of CONTRALATERAL LOWER face. Upper face maintained by bilateral input from cingulate gyrus

Question 31

Lesions below the last synapse of either facial tract will lead to what change in facial expression

Answer 31

full loss on CONTRALATERAL side, both top and bottom

Question 32

Occlusion of the middle cerebral artery will result in what facial deficits?

Answer 32

Weakness/paralysis in inferior facial muscles

Question 33

Ispilateral neurons of the (blank) gyrus maintain superior facial expression despite anterior cerebral artery occlusion

Answer 33

cingulate

Question 34

What are the three major upper motor neuron nuclei of the brainstem?

Answer 34

Vestibular, reticular formation, and superior colliculus

Question 35

What is the main input to the vestibular nuclei?

Answer 35

semicircular canals

Question 36

What is the output for the vestibular nucleus?

Answer 36

vestibulospinal tract

Question 37

where does the vestibulospinal tract go in the cord?

Answer 37

medial (and some lateral) regions, but mostly medial

Question 38

What is the function of the vestibulospinal tract?

Answer 38

posture and VOR

Question 39

what are the primary inputs from the reticular formation?

Answer 39

pimrary motor cortex via ventral CST and corticobulbar

Question 40

what is the primary output tract of the reticular formation?

Answer 40

reticulospinal

Question 41

where does the reticulospinal tract go?

Answer 41

medial spinal cord

Question 42

What is the function of the reticulospinal tract?

Answer 42

posture

Question 43

what are the primary inputs to the superior colliculus?

Answer 43

upper body proprioceptors, retina, auditory, olfaction, corticolbular form FEF

Question 44

where do the fibers from the superior colliculus go?

Answer 44

motor nuerons innervate neural ciricuts in the reticular formation that give rise to reticulospinal projections

Question 45

What is the function of the fibers leaving the superior colliculus?

Answer 45

axial muscles in the neck that oritentate the head, SACCADES

Question 46

What is considered the indirect action of upper motor neurons?

Answer 46

postrual adjustment following instability

Question 47

Direct pathways between UMN and LMNs go straight through the cord while indirect pathways synapse in the (blank)

Answer 47

brainstem (sup colliculus and reticular formation)

Question 48

What is the function of the lateral premotor cortex

Answer 48

sets the intent to make a movements, selects appropriate movements, and responds to external cues

Question 49

what is the function of the medial premotor cortex?

Answer 49

same as the lateral premotor cortex but for internally generated movements (because I want to vs my life is in danger)

Question 50

In an UMN syndrome, is the brainstem and spinal cord intact?

Answer 50

yes

Question 51

do local circuit neurons still recieve sensory input in UMN syndrome?

Answer 51

yes

Question 52

What is spinal shock of UMN syndrome?

Answer 52

contralateral flaccidity | LOSS of reflexes, but only while the shock is present

Question 53

What are the long lasting responses of UMN syndrome?

Answer 53

``` Babinski sign Spasticity HYERREFLEXIA weak superficial reflexes (cornea, cremasteric) loss of fine movements clonus ```

Question 54

What are the symptoms of LMN syndrome?

Answer 54

``` Weakness/paralysis DECREASED superficial and deep reflexes decreased tone FASCICULATIONS and fibrillations MUSCLE ATROPHY ```