Descending Control, M1, Spine

Question 1

Area M1

Answer 1

Primary motor cortex

Question 2

Area S1

Answer 2

Somatosensory cortex

Question 3

Is M1 rostral/caudal to the premotor cortex?

Answer 3

caudal (posterior)

Question 4

Betz cells

Answer 4

-large layer 5 neurons that send AP down descending spinal tract

Question 5

If you were to cut M1 in the frontal plane, describe the areas of processing from medial to lateral…

Answer 5

(Medial) lower extremity, trunk, upper extremity, face (lateral)

Question 6

Which areas of the body have the most innervations in M1?

Answer 6

Face, hands = fine motor control, dexterity (less force)

Question 7

A pulse is sent into a monkey for 50ms, then 500ms, what pattern was noticed?

Answer 7

The longer the stimulus, the more complex movements occurred

Question 8

By viewing EMG readings what did we notice about the order of M1 activation and muscle contraction?

Answer 8

M1 is activated before movement

Question 9

What happens when we move outside of a neurons optimal movement?

Answer 9

The neuron decreases firing (goes silent)

Question 10

Explain the concept of optimal movement

Answer 10

Each neuron is tuned to a particular direction of movement

Question 11

Population vector

Answer 11

average vector from individual M1 neurons

Question 12

What does the population predict (proceed)?

Answer 12

The observed movement vector (M1 fires first!)

Question 13

How is the M1 population vector being used in technology?

Answer 13

-spinal cord injury implants
-can respond w/ mechanical exoskeleton/robots

Question 14

What info is relayed by the ventral posterior medial nucleus (VPM)?

Answer 14

Info about neck/face (think: medial as central as “headquarters)

Question 15

What info is relayed by the ventral posterior lateral nucleus (VPL)?

Answer 15

Info from below neck, body (think: lateral like peripheral and limbs)

Question 16

The motor homunculus of the somatosensory cortex (S1) is a…

Answer 16

somatotopic map of the body

Question 17

What does it mean that S1 is plastic?

Answer 17

Subject to change depending on use (“use it or lose it”)

Question 18

Do phantom limb sensations originate from M1 or S1

Answer 18

S1

Question 19

When do patients experience phantom pain?

Answer 19

-when the S1 is in the process of remapping
-includes shrinking sensations

Question 20

Descending tracts

Answer 20

-send motor commands
-include lateral corticospinal tract (LCT), and ventral corticospinal tract (VCT)

Question 21

Ascending tracts

Answer 21

-send sensory info
-include dorsal column medial lemniscus tract (DCML), ventral spinothalamic tract (VST)

Question 22

Which nerves innervate the face?

Answer 22

cranial (not spinal)

Question 23

Which areas are innervated by the cervical spine region?

Answer 23

neck, arms

Question 24

Which areas are innervated by the thoracic spine?

Answer 24

back, chest, gut

Question 25

Which areas are innervated by the lumbar spine?

Answer 25

Butt, lower back, anterior legs

Question 26

Which areas are innervated by the sacral spine?

Answer 26

Reproductive organs, posterior legs

Question 27

What is the dorsal root of the spinal cord responsible for?

Answer 27

Transmitting sensory info (body to brain)

Question 28

contralateral

Answer 28

opposite side

Question 29

ispilateral

Answer 29

same side

Question 30

In general, the left side of the brain interprets the _______ side of the body

Answer 30

right

Question 31

decussate

Answer 31

switching sides (crossing the midline)

Question 32

Which tract do pain and temperature info travel along?

Answer 32

spinothalamic tract

Question 33

When does the ventral spinothalamic tract (VST) decussate?

Answer 33

-immediately at the level it enters

Question 34

When does the dorsal column medial lemniscus (DCML) decussate?

Answer 34

-at caudal medulla

Question 35

When does the lateral corticospinal (LCST) tract decussate?

Answer 35

-at the caudal medulla -contralateral

Question 36

When does the ventral corticospinal (VCST) tract decussate?

Answer 36

-N/A -bilaterally innervates (ipsilateral)

Question 37

What is the LCST for?

Answer 37

distal muscles

Question 38

What is the VCST for?

Answer 38

proximal muscles

Question 39

What is the VST for?

Answer 39

pain/temperature

Question 40

What is the DCML for?

Answer 40

mechanoreceptors

Question 41

Paraplegia

Answer 41

paralysis of lower body

Question 42

Hemiplegia

Answer 42

paralysis of one side of the body

Question 43

Tetraplegia (quadriplegia)

Answer 43

paralysis of all four limbs

Question 44

Incomplete lesion: central cord syndrome

Answer 44

-tumor -torsion injuries -high fevers

Question 45

Incomplete lesion: anterior cord syndrome

Answer 45

-car accidents

Question 46

Incomplete lesion: Brown-Sequard syndrome (right/left)

Answer 46

-blunt force trauma (or tumor) -stabbing -shot -ischemia (obstruction of blood vessel) -infectious/inflammatory diseases

Question 47

Symptoms of Brown-Sequard syndrome

Answer 47

-contralateral: loss of pain, temp, light touch sense -ipsilateral: loss of motor function, vibration, position, and deep touch

Question 48

Babinski's sign

Answer 48

normal: toes curl abnormal: toes up, and fan

Question 49

febrile

Answer 49

seizures due to high body temps

Question 50

hypesthesia

Answer 50

diminished sense of touch

Question 51

Diagnosing a spinal cord injury (SCI)

Answer 51

-light touch score (cutaneous receptors) -pin prick score (pain/temp) -strength testing

Question 52

Incomplete lesions have not lost total control, what does this mean for rehab?

Answer 52

Is possible for improvement of coordination and limb function