Topic 5: Anterolateral System

Question 1

mechano-nociceptors

chemo- nociceptors

thermo- nociceptors

Answer 1

the receptors that respond to mechanical damage tissue

the receptors that repond to chemicals released by pain stimuli

the receptors that respond to temperature that causes pain stimuli

Question 2

Aδ fibers

Answer 2

afferent fibers that carry the information of mechanical & chemical stimuli (both pain & no pain stimuli) to brain

Question 3

What does C fibers doesn’t have? How does this affect its conduction speed?

Answer 3

myelin sheath

lower speed

Question 4

nociceptors

Answer 4

the receptors that respond to pain stimuli or noxious stimuli

Question 5

What tract and fibers does 2nd pain follow?

Answer 5

spino-reticulo-thalamic & spinotectal tract

C fibers

Question 6

C fibers

Answer 6

afferent fibers that carry information of thermal, mechanical & chemical stimuli to brain

Question 6

What does 2nd pain can evoke?

Answer 6

fear, nausea, other autonomic and affective response

Question 7

where is the Lissauer’s tract (posterolateral fasiculus) in this picture?

Answer 7

a & b

Question 8

What tract & fibers does the first pain have?

Answer 8

neospinothalamic tract

Aδ fibers

Question 9

What does Aδ fibers have? How does this affect its conduction speed?

Answer 9

small myelin sheath

faster speed

Question 10

Of A fibers, where are the cell bodies in the 1st order neurons of AS? locate them in this picture?

Answer 10

6

dorsal ganglion root

Question 11

Rexed’ s Laminae

How does the Roman Number works from dorsal -> ventral?

Answer 11

the division of spinal cord gray matter into different regions based on cell types

I -> IX

Question 12

Of A fibers, Where and when does the pain axons bifurcate?What does it bifurcate into?

Answer 12

at the Lissauer’s tract and before making synaptic connections with 2nd order neurons

ascending & descending fibers

Question 13

Is Lissauer’s tract white matter or grey matter?

Answer 13

white matters

Question 14

True of False? Thermo-nociceptors dont respond until stimulus is painful?

Answer 14

true

Question 15

Character of second pain?Examples?

Answer 15

duller or burning pain

poorly localized & not well tolerated

breaking bond or appendicitis

Question 16

What are the systems of anterolateral system (AS)? Match each fiber to each system

Answer 16

Neospinothalamic system (A fiber)

Spino-reticulo- thalamic & spinotectal system (C fiber)

Question 17

Where are the cell bodies of 2nd order neurons of A fibers?

Answer 17

Lamina I

Question 18

Where are the cell bodies of 3rd order neuron Of A fibers,?

Answer 18

VPL thalamus

Question 19

Of the A fibers, where does the pain axons trave through after the 1st order of neurons and what does they make synaptic with? In what # does this structured included?

Answer 19

through Lissauer’s tract

Lamina I

a& b

Question 20

At lamina I, in what direction does the axons travel Of A fibers?

Answer 20

contralateral

Question 21

Is anterolateral pathway grey matter or white matter?

Answer 21

white matter

Question 22

Of A fibers, where do the cell bodies of 3rd order neurons make synaptic with?

Answer 22

somatosensory cortex

Question 23

What neurons does the Lamina II activate?

Answer 23

Lamina V - VIII

Question 24

Character of first pain? Example?

Answer 24

sharp pain but localized and tolerated paper cut

Question 25

What region of Rexed's Laminae does the C fiber project mainly to? Identify it in this pic

Answer 25

Lamina II b

Question 26

Of A fibers, when do the axons travel in anterolateral pathway?

Answer 26

after they travel contralateral at lamina I

Question 27

At Lamina VIII, in what direction does axons travel? What fiber relating to Lamina VIII?

Answer 27

contralateral side of brain and follow anterolateral white matter pathways C fibers

Question 28

Of A fibers, do the axons of 3rd order neurons terminate on the same or different neurons as DCML system?

Answer 28

they terminate on different neurons from DCML system

Question 29

what are the two systems of second sensory neurons?

Answer 29

spino-reticulo-thalamic system spinotectal system

Question 30

Of C fibers, where does the axons of 2nd order neuron make synaptic with?

Answer 30

the brain areas relating to affective and autonomic responses but not the VPL thalamus in A fibers

Question 31

Function of spino-reticulo-thalamic system?

Answer 31

relaying & integrating nociceptive information contributing to motivational, affective and aversive response of pains

Question 32

Functions of spinotectal system

Answer 32

for orienting response (through superior colliculus) descending modulation of pain (periaqueductal grey)

Question 33

In this figure, what fibe project mainly to #a ?

Answer 33

A fibers

Question 34

substantia gelatinosa

Answer 34

the gray matter in Lamina II

Question 35

What does the spinotectal system project to?

Answer 35

superior colliculus periaqueductal grey

Question 36

Where does the spino-reticulo-thalamic system project to?

Answer 36

intralaminar thalamus hypothalamus reticular formation

Question 37

What is the reticular formation responsible for? prefrontal cingulate insular cortices?

Answer 37

arousal emotional (affective)

Question 38

Where are the terminal axons of 1st order neuron?

Answer 38

lamina I

Question 39

What does aspirin do and why does it reduce pain?

Answer 39

it block the conversion of arachidonic acid to prostaglandins

Question 40

what part of the cortex send input directly to PAG?

Answer 40

ACC

Question 41

Hyperalgesia. Example?

Answer 41

the increased response to pain stimuli when you burned your finger and got a pin poke it, the already damaged area will response larger than undamaged area

Question 42

What is the substance that indirectly affect nociceptors?

Answer 42

arachidonic acid

Question 43

What is prononiceptive? What pathway does this involve in?

Answer 43

the increases experience in pain spino-reticulo-thalamic pathway

Question 44

What happen when we block or inhibit the actions of substances like histamin, serotonin, substance P, bradykinin?

Answer 44

we reduce pain

Question 45

What does MITN do?

Answer 45

send the direct pain inputs to amygdala & ACC

Question 46

What part of brain that stress activate?

Answer 46

LC

Question 47

function of ACC? MCC? dPCC?

Answer 47

emotional awareness/ fight or flight mismatch error detection/ response selection sensorimotor orientation

Question 48

What does SRD & LC do?

Answer 48

enhance the persistent pain

Question 49

What does MITN hyperexcitability result in?

Answer 49

allodynia/ hyperalgesia

Question 50

T/F: Pain and stress can't be seperated?

Answer 50

True

Question 51

allodynia. Examples?

Answer 51

a painful response to innocuous stimuli with your burn finger, you still feel pain when touch the cotton balls although they dont normally cause pain

Question 52

What does chronic pain associated with?

Answer 52

hyperexcitability of ACC & MITN

Question 53

What are the substances that directly excites/ affect nociceptors?

Answer 53

Histamin, ATP, H+, substance P, serotonin, brady kinin

Question 54

what is the target for relieving pain & suffering?

Answer 54

pACC

Question 55

What are the treatments for chronic pain?

Answer 55

treat adrenoreceptors hypnosis tMCS (transcranial motor cortex stimulation) social interaction manipulate object's belief that they can control nociceptive stimulus & get reduced pain

Question 61

What does arachidonic acid convert to?How does the arachidonic acid affect nociceptors?

Answer 61

prostaglandins which block the K+ channel efflux and sensitize nociceptors, further depolarize them