Motor Systems Shai.

Question 1

what is the motor system?

Answer 1

neural activity begins with a decision made in the anterior part of the frontal lobe.. next, motor planning areas are activated and then its followed by control circuts which consist of the cerebellum and basal ganglia that regulate the activity in upper motor neuron tracts

Question 2

what do UMN do in the motor system?

Answer 2

deliver signals to spinal interneurons and LMNs

Question 3

what do LMNs do in the motor system?

Answer 3

signal directly to skeletal muscles eliciting the contraction of muscle fibers that move the upper/lower limbs and fingers

Question 4

how is voluntary movement controlled. what direction?

Answer 4

top down.. brain to spinal cord to muscle

Question 5

what is the direct motor pathway?

Answer 5

Corticospinal tracts- start in the premotor cortex to the motor cortex through the brainstem.

efferent=motor

Question 6

what is the premotor cortex?

Answer 6

frontal lobe–planning and decision making

Question 7

what is the precentral gyrus?

Answer 7

primary motor cortex && upper motor neurons with very long axons

Question 8

where are the upper motor neurons?

Answer 8

in the precentral gyrus– the axons go through the CNS in an area called the INTERNAL CAPSULE

Question 9

how does the INTERNAL CAPSULE Seperated?

Answer 9

posterior limb of internal capsule is associated with motor below neck

cranial nerves travel in the bend of the internal capsule, so motor behaviors above the neck

Question 10

where does the direct motor pathway stufff go after the internal capsule?

Answer 10

crus cerebri at the midbrain, on the ventral side of the brainstem (just the name changes, theyre the same axons)

then the pons - motor fibers arent solid structure anymore

to medulla where they recoalesces and become pyramid but its still the same axon from the cortex.

pyramidal decussation at the bottom of the medulla where it defines the border between the brainstem and the spinal cord

Question 11

what are the basal nuclei?

Answer 11

caudate nucleus, putamen, globus pallidus

Question 12

what is the lateralcorticospinal tract?

Answer 12

innervates limbs lateral to ventral horn in spinal cord.. close to where target cells are in ventral horn

Question 13

where is the medial corticospinal tract?

Answer 13

innervates the trunk, and is medial to the ventral horn in the spinal cord.. close to where the target cells are in the ventral horn.

Question 14

what is a similarity between the lateral and medial corticospinal tracts?

Answer 14

they both synapse in the ventral horn iwth LMN (alpha motor neurons); big neurons with axons go through the ventral rootlets, roots, spinal nerve(named enrves)

Question 15

what about the ventral/anterior corticospinal tract?

Answer 15

1/2 crossed and 1/2 not crossed

trunk moves as a whole

needs info from both sides of brain talking to both sides of body

Question 16

what is the motor units iwth the corticospinal tract?

Answer 16

muscle fibers innervated by one lower motor neuron (alpha motor neuron) determines how fine the control is

1 neuron=100motorfibers
1 neuron to 1000

Question 17

what is the medial corticospinal tract?

Answer 17

directo connection from cerebral cortex to the spinal cord.

descends from the cortex through the internal capsule and the anterior brainstem–same as lateral

individual medial corticospinal axons project to the ipsilateral contralateral and bilateral spinal cord

medial corticospinal neurons synapse with motor neurosn that control neck shoulder and trunk muscles.

Question 18

where to LMNs originate? aka where is their cell body?

Answer 18

ventral horn of spinal cord

Question 19

where do alpha motor neurons (LBNs) project to?

Answer 19

extrafusal skeletal muscle

Question 20

where do gamma motor neurons project to?

Answer 20

intrafusal fibers in muscle spindle

Question 21

what are motor units?

Answer 21

lower motor neurons and the muscle fibers it innervates

Question 22

where do LMNs receive input?

Answer 22

from peripheral afferents and from UMNs

Question 23

what do alpha motor neurons look like?

Answer 23

have large cell bodies and alrge myelinated axons

axons of alpha motor neurons project to extrafusal skeletal muscle, branching into numerous terminals as they approach the muscle

normally the release ACh to all muscle fibers it innervates causes them to contract

Question 24

what is the neuromuscular junction

Answer 24

alpha motor neuron to the muscle. Ach

Question 25

what are gamma motor neurons like?

Answer 25

medium sized myelinated axons axons project to intrafusal fibers in the muscle spindle DO NOT CONTRIBUTE TO MUSCLE FORCE they keep muscle spindle taut and sensitive to stretch

Question 26

what does the muscle spindle do with regards to the peripheral input to motor neurons?

Answer 26

signal muscle length and velocity of contraction sensitivity adjusted by gamma motor neurons

Question 27

what do golgi tendon organs do with regards to peripheral input to motor neurons?

Answer 27

convert tension on muscle to NEURAL signals diverges to LMNs via interneurons cutaneous and joint afferents, spinal reflexes, CPGs and UMNs

Question 28

What is fractionation?

Answer 28

the ability to activate individual muscles independently of other muscles essential for normal mveoment of hands. without fractionation, fingers and thumb would act as a single unit

Question 29

what does fractionation have to do with the lateral corticospinal tract?

Answer 29

fractionates by activating inhibitory neurons to prevent unwanted muscles from contracting THIS IS THE MOST IMPORTANT PATHWAY CONTROLLING VOLUNTARY MOVEMENTS

Question 30

what is the rubrospinal tract?

Answer 30

this starts in the medulla, and terminates in the cervical spine. its smaller but involves in fine motor control and larger muscle groups

Question 31

what are the medial upper motor neuron tracts? how many are there?

Answer 31

``` 4. reticulospinal tract medial vestibulospinal tracts lateral vestibulospinal tract medial corticospinal tract ```

Question 32

what is the reticulospinal tract? (MU-MNT)

Answer 32

facilitates bilateral LMN innervating postural and gross limb movements of muscles throughout body

Question 33

what is the medial vistibulospinal tract (MU-MNT)

Answer 33

recieves info about head movement and position from the vestibular apparatus

Question 34

what is the lateral vestibulospinal tract?(MU-MNT)

Answer 34

responds to gravity informaiton from the vestibular apparatus

Question 35

what is the medial corticospinal ttract? (MU-MNT)

Answer 35

has a direct connection from cerebral cortex to the spinal cord

Question 36

what does the rediculospinal tract look like?

Answer 36

1) begins at the reticular formation in the brainstem 2) it facilitates bilateral MNs inervating gross limb and postural movement also involved in anticipatorypostural adjustemnets and reaching

Question 37

what does the medial vestibularspinal tract do/

Answer 37

head movement and position start: medial vestibular nucleus end: cervical and T spinal cord crosses? bilaterally fxn: neck and upper back muscles

Question 38

lateral vestibulospinal tract?

Answer 38

gravity info. ipsilateral travels entire spinal cord doesnt cross midline

Question 39

what does the medial motor system do?

Answer 39

controls proximal and axial muscles uses sensory info about balance body position and visual environment to maintain balance posture and locomotion includes: - vestibulospinal -reticulospinal annnnd anterior corticospinal and tectospinal

Question 40

what is the anterior corticospinal tract?

Answer 40

start: cortex end: spinal cord cervical? fxn: trunk and prox musculature crosses? yes it crosses. at the cervical spinal cord

Question 41

what the tectospinal tract look like?

Answer 41

start: midbrain at supeior colliculus end: cervical spine? function: coordiation of eye and head movement crosses? yes in midbrain

Question 42

what is the corticobulbar tracts? (aka corticonuclear tracts)

Answer 42

they go from the cerebral cortex to the cranial nerve nucleui in the brainstem. innervate contralatera muscle of face head neck geberally bilateral except VII and XII

Question 43

tracts that are very fractionated are good for?

Answer 43

functional and volitional movement

Question 44

tracts that account for subconsicous automatic control are..... more or less fractionated? and what does this mean

Answer 44

less fractionated, and less precicse.

Question 45

can less precise movements be useful?

Answer 45

yes. in addressing baseline and backgroundt runk position and to figure out what they then can do

Question 46

what are some examples of disorders in lower motor neurons?

Answer 46

trauma, infection (poliomyelitis infection that destroys LMNs denervating muscle fibers), degenerative or vascular disorders, tumors, examples: myasthenia gravis, diabetic neuropathy

Question 47

what are examples of upper motor neuron disorders?

Answer 47

stroke, spinal cord injury (complete or incomplete) cerebral palsy MS huntington's

Question 48

what is a complete spinla cord injury?

Answer 48

all descending neuronal control is lost below the level of the lesion

Question 49

what is an incomplete sci?

Answer 49

function of some ascending and or descending fibers is preserved.

Question 50

What are some signs of a motor neuron lesion

Answer 50

paresis (partial loss of voluntary contraction) paralysis (complete loss of voluntary contraction) muscle atrophy (disuse, nerogenic, denervation is the most severe) involuntary muscle contractions (cramps, fasciculations which are visible small tiny contractions) abnormal muscle tone (hypertonia - rigitity or spasticity) (hypotonia - flaccidity, LNM and initial UMN, cerebral disorders) abnormal synergies abnormal reflexes distrubances of movement efficiency and speed impaired postural control

Question 51

What is babinksi sign

Answer 51

extension of great toe and fanning of other toes. its positive in infants but shoundnt be in adults usually sign of UMN (lateral corticospinal)

Question 52

what are the three most common abnormal reflexes in those with chronic SCIs

Answer 52

muscle stretch hyperreflexia clonus clasp knife response

Question 53

in people with sci why might a muscle spasm occur?

Answer 53

in response ot cutaneous stimuli (these begin after recovery from spinal shock)

Question 54

what is muscle stretch hyperreflexia?

Answer 54

loss of inhibitory corticospinal imput (stretch receptor is hypersensitive) results in excessive LMN response to afferent input from stretch receptors

Question 55

what is clonus?

Answer 55

involuntary repeating and rhythmic muscle contractions unstrained clonus fades after a few beats, even with maintained stretch sustained clonus is always pathologic in origin and is produced when there is a lack of UMN control which allows the activation of oscillating neural networks in the spinal cord

Question 56

what is the clasp knife response?

Answer 56

occurs when a paretic muscle is slowly and passively stretch and resistance drops at a specifc point of the ROM. like the change of resistance with a pocket watch giving way at a certain point TYPE II EFFERENT ELICIT THIS

Question 57

what is myoplasticity?

Answer 57

adaptive changes within a muscle in response to changes in neuromuscular activity level and to prolonged positioning

Question 58

what is spasticity

Answer 58

neuromuscular overactivity secondary to an UMN lesion

Question 59

what is hypertonia

Answer 59

increased resistance to passive movement spasticity (i.e. velocity dependent hypertonia) myoplasticity (I.e. intrinsic muscle stiffness) disinhibition of brainstem and spinal circuitry

Question 60

what is velocity dependent hypertonia (spasticity?)

Answer 60

is due to the loss of descending inhibition

Question 61

what is developmental spasticity?

Answer 61

normal development: weaker synapses are eliminated and by 4yo a corticospinal axon that is previously symapsed with LMN to antagonists and synergists will only synapse with LMN to the agonist.

Question 62

what does damage to the corticospinal tracts during development cause?

Answer 62

eliminated competition for synaptic sites during a critical period, causing persistance of inappropriate connections and abnoral development of spinal motor centers.

Question 63

what is cerebral spasticity with reticulospinal overactivity?

Answer 63

brainstem UMN overactivity is the primary cause of stroke spasticity similar patters of cerebral spasticity occur with corticospinal brainstem lesions in multiple sclerosis

Question 64

what happens with a loss of fractionated movement?

Answer 64

isolated voluntary movement is imparied. lower motor systems (brainstem and spinal cord) become dominant sources of motor activity)

Question 65

what is flexion synergy (UE)

Answer 65

shoulder abduction and internal rotation elbow flexion and forearm pronation

Question 66

what is synergistic extention for lower extremity?

Answer 66

hip internal rotation, adduction and extension, knee extension, ankle plantarflexion adn inversion

Question 67

what does recurrent use of abnormal synergy cause?

Answer 67

weakness of underutilized muscles weakness of underutilized nerual substrates and strengthens the synergy and worsens chance of recovering other movement capabilities

Question 68

what is motor learning?

Answer 68

set of processes associated with practice or leading to relatively peranent changes in the capability for responding

Question 69

what is implicity learning

Answer 69

NONDECLARATIVE procedural or habituation/sensitization neocortex, striatum, amygdala, cerebellum

Question 70

what is explicit learnign

Answer 70

facts, events DECLARATIVE medial temporal diencephalic system

Question 71

what is motor learning

Answer 71

requires practice feedback and knowlege of results leads to skill as someone progresses from simple to complex taxes within controlled and open environments

Question 72

what is motor learning influenced by?

Answer 72

age, motivation, learning style, cognition

Question 73

what is learning?

Answer 73

can you do it again under different circumstances (retention) not observable

Question 74

what is performance?

Answer 74

can your patient do the task, with high quality and precision? Observable

Question 75

what are the three stages of motor learning?

Answer 75

cognitive stage associative stage autonomous stage

Question 76

what is the cognitive stage of motor learning?

Answer 76

rely on working memory, breaking down into steps declarative knowledge or integrate into movement step by step large amount of variance and error in performance

Question 77

what is the associative stage of motor learning

Answer 77

procedural process separate from working memory decreased reliance on working memory movement becomes more fluent reaching this stage is dependant on skill and may require varying amount of deliberate practice practice that is effortful and working towards improving performance

Question 78

what is the autonomous stage of motor learning?

Answer 78

minimal cognitive effort req overlearned skills improved anticipation and decision making (because they arent having to think about tasks) greater ability to detect error in skill/movement less errors and minimal variance

Question 79

what can affect the levels and success of motor learning?

Answer 79

skill level task complexity amount of pressure

Question 80

what is most important with motor learning?

Answer 80

amount, type, frequency of practice, and intensity

Question 81

what types of practice are there?

Answer 81

part, whole, physical, mental, blocked, random, random blocked

Question 82

what is the difference between massed and distributed practice?

Answer 82

massed is the amount of practice time exceeds amount of rest time distributed means the amout of rest time exceeds the amount of practice time structured vs cramming studying

Question 83

what is blocked practice?

Answer 83

all the trials of one task are blocked together (early stage of learning)

Question 84

when is random practice good?

Answer 84

later stage of learning

Question 85

whole part whole method

Answer 85

go through full, then break it down then go back to full

Question 86

what is external focus?

Answer 86

focused on the effects that movement has on the environment

Question 87

what is internal focus?

Answer 87

focus on your own motions

Question 88

external cues are better for helping with patients.. true or false?

Answer 88

true

Question 89

does mental practice help?

Answer 89

yes it may produce large positive effects for performance and learning generally not as good as physical practice

Question 90

what is intrisnisc vs extrinsic feedback?

Answer 90

intrinsic is inherent through sensory systems extrinsic is augmented feedback and supplements the intrinsic feedback

Question 91

what is the difference between knowledge of results and knowledge of performance?

Answer 91

results- terminal feedback about the outcome of the movement relative to the goal performance- movement pattern used to achieve the goal

Question 92

characterastics of effective feedback?

Answer 92

emphasis on knowledge of performance and no overloading be specific good timing frequency