Module 9 Arpin Review

Question 1

upper motor neurons in the cortex involves waht 2 tracts

Answer 1

-corticospinal tract (CST)
-corticobulbar tract

Question 2

corticospinal tract (CST) synapses with

Answer 2

neurons in the spinal cord

Question 3

corticospinal tract (CST) synapses contralateral/ispilateral

Answer 3

-90% of the CST cross over (at the level of the medulla) to control contralateral distal muscles; their axons are located in the lateral white matter of the spinal cord
-this is the lateral CST (“direct pathway” from cortex to spinal cord)

-10% remain ipsilateral – this is the ventral (anterior) CST

Question 4

what is the direct pathway from cortex to spinal cord

Answer 4

lateral CST (corticospinal tract)

Question 5

contralateral CST is lateral/ventral

Answer 5

lateral

Question 6

ipsilateral CST is lateral/ventral

Answer 6

ventral (anterior)

Question 7

how do corticobulbar axons terminate

Answer 7

bilaterally in the brainstem to coordinate lower motor neurons in the facial motor nucleus

Question 8

what controls lower facial movements

Answer 8

contralateral motor cortex only

Question 9

inferior facial muscles are more affected by a lower/upper motor neuron lesion

Answer 9

upper motor neuron lesion

Question 10

primary motor cortex (M1) neurons are a motor map of contralateral/ipsilateral muscles

Answer 10

contralateral

Question 11

primary motor cortex (M1) neurons are associated with

Answer 11

a “muscle field”

Question 12

primary motor cortex (M1) neurons

Answer 12

-motor map of movement/behaviors
-preferred movement direction
-population coding

Question 13

premotor cortex

Answer 13

-planning of movement
-mirror motor neurons

Question 14

where are mirror motor neurons

Answer 14

premotor cortex

Question 15

upper motor neurons in the brainstem are important for

Answer 15

reactive and anticipatory balance control (feedback and feedforward posture control)

Question 16

upper motor neurons in brainstem give rise to several descending/ascending pathways

Answer 16

descending

Question 17

4 descending pathways of upper motor neurons

Answer 17

-medial vesitbulospinal tract
-lateral vestibulospinal tract
-medial/lateral vestibulospinal tracts
-reticulospinal pathway

Question 18

medial vestibulospinal tract

Answer 18

receives vestibular input from the canals and mediates the VCR

Question 19

lateral vestibulospinal tract

Answer 19

receives vestibular input from the otoliths and mediates the VSR

Question 20

medial/lateral vestibulospinal tracts

Answer 20

responsible for reactive postural responses

Question 21

reticulospinal pathway

Answer 21

receives input from upper motor neurons from the cortex

Question 22

what does the reticulospinal pathway do

Answer 22

indirect pathway from the motor cortex to the spinal cord that helps coordinate anticipatory postural response during voluntary limb movements

Question 23

lower motor neuron syndrome vs. upper motor neuron syndrome

STRENGTH

Answer 23

LMN: weakness or paralysis
UMN: weakness only

Question 24

lower motor neuron syndrome vs. upper motor neuron syndrome

MUSCLE BULK

Answer 24

LMN: severe atrophy
UMN: mild or no atrophy

Question 25

lower motor neuron syndrome vs. upper motor neuron syndrome

REFLEXES

Answer 25

LMN: hypoactive superficial and deep reflexes
UMN: hyperactive deep reflexes after initial spinal shock

Question 26

special signs and symptoms of lower motor neuron syndrome

Answer 26

-initial signs and symptoms persist
-fasciculations and fibrillations
-geographic distribution of impairment (reflecting distribution of affected spinal segments, cranial nuclei, or spinal/cranial nerves)
-impairments of reflexive and gross and/or fine voluntary movements

Question 27

special signs and symptoms of upper motor neuron syndrome

Answer 27

-initial period of spinal shock, then spasticity ensues
-babinski’s sign and clonus
-more widespread (nongeographic) distribution of impairment in body regions
-impairment of fine voluntary movements; gross movements relatively unimpaired