cortical mechanisms of motor control

Question 1

somatic motor pathways
descending tracks deliver what from the brain the brain to the spinal cord

Answer 1

motor instructions

Question 2

somatic motor pathways (descending)
are divided into what 2 groups

Answer 2

pyramidal tracts
indirect pathways (all others)

Question 3

motor pathways contain how many neurons

Answer 3

at least 2

Question 4

give examples of UMN

Answer 4

M1
pyramidal cell

Question 5

give examples of UMN

Answer 5

M1
pyramidal cell

Question 6

give examples of LMN

Answer 6

alpha motor neuron

Question 7

basic functions of descending tracks
give 2 basic functions of the cortico-and rubrospinal descending track

Answer 7

1. transmission of commands for skilled movements
2. corrections of motor patterns generated by the spinal cord

Question 8

basic functions of descending tracks
give 2 basic functions of the reticulospinal descending track

Answer 8

1. activation of spinal motor programs for stepping and other stereotypic movement
2. control of upright body posture

Question 9

basic functions of descending tracks
give a basic function of the vestibulospinal descending tract

Answer 9

generation of tonic activity in antigravity muscles

Question 10

layer V neurons from the primary motor coretx give rise to what

Answer 10

corticospinal tract

Question 11

layer _ neurons from the primary motor cortex give rise to the corticospinal tract

Answer 11

V

Question 12

layer V neurpns from the ____ _____ _____ give rise to the corticospinal tract

Answer 12

primary motor cortex

Question 13

where does the pyramidal corticospinal pathway originate

Answer 13

in motor cortex

Question 14

Layer _ pyramidal neurons are the UMNs

Answer 14

V

Question 15

axons belonging to what form the corticospinal tract

Answer 15

Layer V

Question 16

Layer V neurons axon’s form what

Answer 16

the corticospinal tract

Question 17

UMN synapse where with LMNs

Answer 17

ventral horn

Question 18

UMNs synapse in the ventral root with what

Answer 18

LMN’s

Question 19

Where do LMNs (ventral horn motor neurons) exit

Answer 19

the spinal cord via the ventral anterior root

Question 20

what do LMN activate

Answer 20

skeletal muscles

Question 21

how do LMNs regulate fast and fine (skilled) movement

Answer 21

voluntarily

Question 22

what regulates fast and fine movements

Answer 22

LMNs

Question 23

the anterior/ventral corticospinal tract is responsible for the control of what

Answer 23

proximal musculature

Question 24

what area of the brain controls proximal musculature

Answer 24

anterior ventral/corticospinal tract

Question 25

the lateral corticospinal tract is responsible for the control of what

Answer 25

distal musculature

Question 26

what area of the brain is responsible for the control of distal musculature

Answer 26

lateral corticospinal tract

Question 27

Pyramids most of the corticospinal axons decussate to enter what

Answer 27

descending lateral corticospinal tract

Question 28

most _______ decussate to enter the descending lateral corticospinal tract

Answer 28

most of the corticospinal axons

Question 29

UMNs do not pass through what

Answer 29

pyramids

Question 30

what do extrapyramidal motor tracts regulate (3)

Answer 30

axial muscles that maintain balance and posture muscles controlling coarse movements of the proximal portions of limbs head, neck and eye movement

Question 31

where does the rubrospinal tract originate

Answer 31

red nucleus of the mid brain

Question 32

rubrospinal tract voluntary/unvoluntary choose one

Answer 32

voluntary

Question 33

the rubrospinal tract is an alternative by which voluntary commands can be sent to ___

Answer 33

spinal cord

Question 34

Rubrospinal tract major/minor pathway in animals major/minor pathway in humans

Answer 34

major in animals minor in humans

Question 35

activation of the rubrospinal tract causes excitation/inhibition of flexor muscles excitation/inhibition of extensor muscles

Answer 35

excitation of flexor muscles inhibition of extensor muscles

Question 36

medial extrapyramidal pathway the vestibulospinal tracts originate where

Answer 36

vestibular nuclei

Question 37

Medial Extrapyramidal Pathways the vestibulospinal tracts originate in the vestibular nuclei and are involved in what

Answer 37

posture, and in supporting the body against the force of gravity, mainly targeting extensors

Question 38

medial extrapyramidal pathways the tectospinal tracts originate where

Answer 38

superior colliculi

Question 39

medial extrapyramidal pathways the tectospinal tracts originate in the superior colliculi and mediate whar

Answer 39

orienting towards visual targets

Question 40

the reticulospinal tract originates in the what

Answer 40

reticular formation

Question 41

medial extrapyramidal pathway what is the reticular formation

Answer 41

a diffuse collection of neurons in the pons and medulla

Question 42

extrapyramidal pathways what is the reticulospinal tract involved in

Answer 42

balance

Question 43

what are the tracts in the medial extrapyramidal pathways

Answer 43

vestibulospinal tectospinal reticulospinal

Question 44

how many cortical layers are there

Answer 44

7

Question 45

electrical stimulation of motor cortical areas elicets what

Answer 45

movement of particular body parts

Question 46

of the three motor areas, stimulation of what cortex requires the least amount of electrical current to elicit a movement

Answer 46

primary motor cortex

Question 47

stimulation of what other 2 motor areas requires more electrical current to elicit movements

Answer 47

premotor cortex and supplementary motor area

Question 48

the primary motor cortex is ___ organised

Answer 48

somatotopically

Question 49

neuronal coding in the primary motor cortex primary motor cortex neurons fire how long before the onset of a movement

Answer 49

5-100ms

Question 50

primary motor cortex neurons can encode (4):

Answer 50

force of a movement direction of a movement extent of a movement speed of a movement

Question 51

What do M1 neurons encode

Answer 51

direction of a movement force of a movement

Question 52

what is the pre motor cortex involved in

Answer 52

motor planning

Question 53

what is the supplementary motor area involved in

Answer 53

programming complex sequences of movement and coordinating bilateral movements and selecting movements based on remembered sequences of movements

Question 54

premotor neurons can signal __

Answer 54

an intention to move

Question 55

pre motor cortex is sensitive to what

Answer 55

the behavioural context of a particular movement

Question 56

premotor cortex neurons are sensitive to what

Answer 56

the intentions behind a movement, not just the movement itself

Question 57

supplementary Motor area (SMA) responds to sequences of movement and to

Answer 57

mental rehearsal of movements

Question 58

SMA when movements are simple, such as making a repetitive movement of a single digit, what areas of the brain are activated (2)

Answer 58

contralateral primary motor cortex primary somatosensory cortex

Question 59

SMA When a subject is asked to perform a complex sequence of finger movements, the SMA is activated in what way what other brain regions are activated

Answer 59

bilaterally and contralateral primary motor somatosensory cortex

Question 60

Reaching and Grasping reaching and grasping require the transformation of visual information into what

Answer 60

a pattern of motor command

Question 61

reaching and grasping require the transformation of visual information into a pattern of motor command, and involves connections between what 3 areas

Answer 61

visual, parietal, and premotor areas

Question 62

reaching is mediated by what

Answer 62

a dorsal pathway running from the posterior occipital cortex to the mediodorsal parietal cortex , and on to the dorsal premotor cortex mediated by dorsal pathway posterior occipital cortex -> mediodorsal parietal cortex -> dorsal premotor cortex

Question 63

grasping is mediated by what

Answer 63

a ventral pathway running from the dorsal extrastriate cortex to the AIP (anterior intraparietal area), and on to the ventral premotor cortex