lecture 10

Question 1

what is gegenhalten seen in

Answer 1

severe dyspraxia/ apraxia `

Question 2

spasticity is a ___ disorder characterized by a ____ depended _____ in ______ stretch reflexes with exaggerated _____ ______ resulting from ____________ of the stretch reflex

Answer 2

• motor
• velcoity
• increase
• tonic
• tendon jerks
• hyper excitability

Question 3

if there is neural overactivity from an upper motor lesion and a spinal lesion happens what would be a results

Answer 3

hyperrefelxia bc alpha and gamma neurons are over stimulated

Question 4

if there is neural overactivity from an upper motor lesion and a cerebral lesion happens what would be a results

Answer 4

excessive reticulospinal drive to motor neurons leading to muscle contractions

Question 5

what is myoplasticity

Answer 5

contracture , atrophy, weak actin myosin binding

Question 6

corticospinal tract from precentral cortex control what

Answer 6

voluntary mvmt

Question 7

what are the 2 supra segmental contribution to spasticity

Answer 7

pyramidal tracts and extrapyramidal tracts

Question 8

what is thought to help with some mvmt when CST is damaged

Answer 8

venteralmedial reticulospinal tract

Question 9

what does isolated lesions of the primary motor cortex induce

Answer 9

weakness and decreased reflexes

Question 10

what does the anterior limb of the internal capsule carry

Answer 10

sensory fibers

Question 11

does the ventromedial reticulospinal tract cross

Answer 11

no

Question 12

where does the ventromedial RST come from

Answer 12

pons

Question 13

where does the dorsolateral RST come from and does it cross

Answer 13

medulla and yes it crosses (50% cross immediately and 50% does not cross)

Question 14

where is the ventromedial reticular formation

Answer 14

in the medulla and it is an inhibitory area

Question 15

what is the ventromedial reituclar formation closesly controlled by

Answer 15

premotr cortex / corticoreticular tract

Question 16

what does renshaw cells inhibit

Answer 16

homonymous and synergisitic MNs

Question 17

when renshaw cells inhibit gamma MN and la interneurosn what is it called

Answer 17

recurrent inhibition

Question 18

what excites renshaw cells and what is the neurotransmitter

Answer 18

recurrent collaterals with ACH

Question 19

what is 1a reciprocal inhibition

Answer 19

1a afferents of agonist muscle inhibits alpha MNs of its antagonist muscle via interneurons

Question 20

what does 1a reciprocal inhibiton inhibit?

Answer 20

co contraction of agnoist and antagnoist mm

Question 21

basically what is recurrent inhibition

Answer 21

allows motor neurons to inhibit themselves

Question 22

1b autogenic inhibitoin is evoked by what

Answer 22

contraction of homoymous (same muscle that is being strecthed and contracted) m

Question 23

what is fuctional reorganization within spinal circuits

Answer 23

neuroplasticity

Question 24

what is most commonly used when measuring spasticity

Answer 24

moditifed ashworth scale (0- no muscle tone & 5 - rigitidy)

Question 25

what happens when deprived of supraspinal influences

Answer 25

collateral sprouting of axons unmasking sensitivity of sensory receptors heightened sensitivity of sensory receptors enchanced cutaneous reflexes

Question 26

what contributes to the increased fusimotor drive

Answer 26

increased muscle spindle sensitivity resulting form hyperactivity of gamma MNs

Question 27

evidence from clinical observation for increased fusimotor drive is

Answer 27

"spinal shock" within 24 hours after SCI with no DTR able to be elicited during this time exaggerated DTRs after spinal shock ends

Question 28

altered fusimotor drive can be due to long term neuromuscular adaptation including changes in muscle length and receptor sensitivity also called

Answer 28

myoplasticitiy