Midterm 2 - Unit 5 Lecture 1

Question 1

How do we produce voluntary movement?

Answer 1

Motor plan – an abstract representation of an intended movement

Question 2

what are the components of motor plan

Answer 2

specify a goal for the action
create the plan
initiate and execute the movement
compare executed movement with the plan on-line

Question 3

How does the brain communicate with the motor neurons in the spinal cord?

Answer 3

Axons from the brain descend through the spinal cord along two major group of path-ways:

lateral and ventromedial pathways

Some originate from the cerebral cortex and others from the brain stem

Question 4

what are the other names for Lower motor Neuron

Answer 4

“Final common pathway”
Alpha motor neuron

Question 5

where does the Lower motor Neuron originate

Answer 5

Spinal cord and Brainstem

Question 6

what muscles do Lower motor Neuron innervate

Answer 6

skeletal muscle

Question 7

Lower motor Neurons are affected by….

Answer 7

descending motor neurons, sensory neurons, and interneurons

Question 8

where do Upper Motor Neuron originate

Answer 8

the cerebral cortex and travel down to the brain stem or spinal cord

Question 9

where do the Upper Motor Neuron terminate

Answer 9

Spinal cord and Brainstem

Question 10

Descending motor pathways are organized into two major groups:

Answer 10

Lateral pathways
Medial pathways

Question 11

what do the Lateral pathways control

Answer 11

control both proximal and distal muscles and are responsible for most voluntary movements of arms and legs

Question 12

what do Medial pathways control

Answer 12

control axial muscles and are responsible for posture, balance, and coarse control of axial and proximal muscles.

Question 13

what is the one lateral motor pathway called

Answer 13

rubrospinal tract

Question 14

what are the 3 medial motor system

Answer 14

vestibulospinal tract
reticulospinal tract
tectospinal tract

Question 15

The lateral corticospinal tract contains over _____ of the ________ present in the corticospinal tract and runs the ___________________

Answer 15

90%, fibres, length off the spinal cord

Question 16

what is the primary responsibility of the lateral corticospinal tract

Answer 16

control the voluntary movement of distal muscles on contralateral limbs.

Question 17

where does the lateral corticospinal tract originate

Answer 17

the primary motor cortex which lies in the precentral gyrus

Question 18

what happens when a when a stimulus is engaged in the lateral corticospinal tract

Answer 18

cell body of the lateral corticospinal tract will send an impulse through the tract that will eventually travel to the anterior horn of the spinal cord

from where it will transmit the impulse via lower motor neurons into the muscle fibers

Question 19

what happens when a motor act is planned to move the leg

Answer 19

an impulse generated from the primary motor cortex will be conducted through the lateral corticospinal tract ipsilaterally

It passes through the posterior limb of the internal capsule

decussates(cross) at the caudal medulla (pyramidal decussation), and then continues to descend contralaterally into the spinal cord

Question 20

what is the anterior corticospinal tract

Answer 20

is a small bundle of descending fibers that connect the cerebral cortex to the spinal cord.

Question 21

where does the anterior corticospinal tract originate

Answer 21

primary motor and premotor areas

Question 22

where do the impulses cross in the anterior corticospinal tract

Answer 22

Remains uncrossed until spinal cord

Question 23

what is the function of the anterior corticospinal tract

Answer 23

Bilaterally activates interneurons and motor neurons of proximal & axial muscles

Question 24

what are the two pathways that are considered these direct connections(Cortex directly to spinal cord) with the spinal cord

Answer 24

Lateral Corticospinal Tract
Anterior (Ventral) Corticospinal Tract

Question 25

where do Brainstem Pathways originate

Answer 25

Originate from Brainstem nuclei to spinal motor neurons

Question 26

Both Medial and Lateral motor system are involved in these brainstem pathways. True or false

Answer 26

true

Question 27

where do Vestibulospinal Tracts originate from

Answer 27

Vestibular nuclei

Question 28

what are the two vestibulospinal tracts

Answer 28

Lateral Vestibulospinal Tract Medial Vestibulospinal Tract

Question 29

where does the Lateral Vestibulospinal Tract project to

Answer 29

projects ipsilaterally down to the lumbar region of the spinal cord

Question 30

function of Lateral Vestibulospinal Tract

Answer 30

helps to maintain an upright and balanced posture by stimulating extensor motor neurons in the legs

Question 31

where does the Medial Vestibulospinal Tract project to

Answer 31

projects bilaterally down the spinal cord and triggers the ventral horn of the cervical spinal circuits

Question 32

function of Medial Vestibulospinal Tract

Answer 32

Positioning of head and neck

Question 33

where does the Rubrospinal Tract originate from

Answer 33

Originates from red nucleus

Question 34

where does the Rubrospinal Tract cross the midline

Answer 34

in brainstem

Question 35

what column does the Rubrospinal Tract travel in

Answer 35

lateral column

Question 36

function of Rubrospinal Tract

Answer 36

Involved in Goal-directed limb movements, e.g., reaching, manipulation Influences distal muscles

Question 37

Reticulospinal Tract origin

Answer 37

reticular formation

Question 38

Reticulospinal Tract function

Answer 38

Involved in stabilizing posture

Question 39

Tectospinal Tract origin

Answer 39

superior colliculus

Question 40

Tectospinal Tract function

Answer 40

Thought to pay a role in coordination of head and eye movement

Question 41

Reticulospinal Tract travels in

Answer 41

anterior column to entire cord

Question 42

Tectospinal Tract travels to

Answer 42

travel to cervical spinal cord

Question 43

Cerebral Cortex – Motor Areas

Answer 43

Primary Motor Cortex (M1) Supplementary Motor Area (SMA) Premotor cortex (PMC)

Question 44

Primary Motor Cortex (M1) location

Answer 44

Pre-central Gyrus

Question 45

Primary Motor Cortex (M1) Function

Answer 45

Initiation and execution of movement Specify how actions are to be carried out

Question 46

Primary Motor Cortex (M1) Direct connection go through...

Answer 46

lateral cortical spinal and anterior cortical spinal

Question 47

Primary Motor Cortex (M1) indirect connection go through...

Answer 47

these brain stem pathways

Question 48

Neurons in M1 fire...

Answer 48

immediately before and during voluntary movement

Question 49

Primary Motor Cortex (M1) encodes two aspects of the movement

Answer 49

direction and force

Question 50

what is somatopically mapped

Answer 50

Motor cortices

Question 51

Major Inputs for M1

Answer 51

Premotor and Supplementary motor areas Primary Somatosensory Parietal (area 5) Basal ganglia and cerebellum through thalamus

Question 52

Major Outputs for M1

Answer 52

Basal Ganglia Cerebellum Motor nuclei in brainstem and spinal cord

Question 53

what do the (Association) Motor Areas consist of

Answer 53

Premotor area/cortex (PMA) supplementary motor area (SMA)

Question 54

Premotor area/cortex (PMA) located more

Answer 54

lateral

Question 55

supplementary motor area (SMA) located more

Answer 55

medial and superior

Question 56

(Association) Motor Areas Receive inputs from?

Answer 56

thalamus and other cortical areas

Question 57

Function of Motor Association Areas

Answer 57

PMA and SMA Involved in planning movements Neurons fire well before the movement occurs (as soon as goal is set) and continue to fire during the movement

Question 58

Premotor cortex encodes

Answer 58

what actions are desired

Question 59

M1 encodes

Answer 59

how the actions will be carried out

Question 60

what is a major difference between Motor Association Areas and M1

Answer 60

Doesn’t code for movement force the way M1 does

Question 61

how does the Premotor Area/Cortex (PMA) receive inputs

Answer 61

Receives multisensory inputs Externally cued to generate or activate the plan especially visual signals, used to guide movements Ex: when you realize the change of light from red to green on a stoplight then proceed to let go of brake and press the gas Sequencing motor synergies using sensory cues Involved in preparation for voluntary movements Stimulation causes muscle contractions at multiple joints (same limb) Affects contralateral limbs Influenced by cerebellum via thalamus Affects contralteral limbs

Question 62

is Supplementary Motor Area (SMA) internally or externally initiated

Answer 62

Used in internally initiated (self-motivated) movements Same sequencing role but based more on internal than on external sensory cues, e.g. learned sequences Associated with bimanual control Inter-hemispheric connections between SMAs Influenced by basal ganglia via thalamus

Question 63

mirror neurons

Answer 63

Some PMA neurons fire not only when producing an action but also when seeing someone else make a similar an action.