Topic 5: Anterolateral System Flashcards
mechano-nociceptors
chemo- nociceptors
thermo- nociceptors
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
Aδ fibers
afferent fibers that carry the information of mechanical & chemical stimuli (both pain & no pain stimuli) to brain
What does C fibers doesn’t have? How does this affect its conduction speed?
myelin sheath
lower speed
nociceptors
the receptors that respond to pain stimuli or noxious stimuli
What tract and fibers does 2nd pain follow?
spino-reticulo-thalamic & spinotectal tract
C fibers
C fibers
afferent fibers that carry information of thermal, mechanical & chemical stimuli to brain
What does 2nd pain can evoke?
fear, nausea, other autonomic and affective response
where is the Lissauer’s tract (posterolateral fasiculus) in this picture?
a & b
What tract & fibers does the first pain have?
neospinothalamic tract
Aδ fibers
What does Aδ fibers have? How does this affect its conduction speed?
small myelin sheath
faster speed
Of A fibers, where are the cell bodies in the 1st order neurons of AS? locate them in this picture?
6
dorsal ganglion root
Rexed’ s Laminae
How does the Roman Number works from dorsal -> ventral?
the division of spinal cord gray matter into different regions based on cell types
I -> IX
Of A fibers, Where and when does the pain axons bifurcate?What does it bifurcate into?
at the Lissauer’s tract and before making synaptic connections with 2nd order neurons
ascending & descending fibers
Is Lissauer’s tract white matter or grey matter?
white matters
True of False? Thermo-nociceptors dont respond until stimulus is painful?
true
Character of second pain?Examples?
duller or burning pain
poorly localized & not well tolerated
breaking bond or appendicitis
What are the systems of anterolateral system (AS)? Match each fiber to each system
Neospinothalamic system (A fiber)
Spino-reticulo- thalamic & spinotectal system (C fiber)
Where are the cell bodies of 2nd order neurons of A fibers?
Lamina I
Where are the cell bodies of 3rd order neuron Of A fibers,?
VPL thalamus
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?
through Lissauer’s tract
Lamina I
a& b
At lamina I, in what direction does the axons travel Of A fibers?
contralateral
Is anterolateral pathway grey matter or white matter?
white matter
Of A fibers, where do the cell bodies of 3rd order neurons make synaptic with?
somatosensory cortex
What neurons does the Lamina II activate?
Lamina V - VIII
Character of first pain? Example?
sharp pain but localized and tolerated
paper cut
What region of Rexed’s Laminae does the C fiber project mainly to? Identify it in this pic
Lamina II
b
Of A fibers, when do the axons travel in anterolateral pathway?
after they travel contralateral at lamina I
At Lamina VIII, in what direction does axons travel?
What fiber relating to Lamina VIII?
contralateral side of brain and follow anterolateral white matter pathways
C fibers
Of A fibers, do the axons of 3rd order neurons terminate on the same or different neurons as DCML system?
they terminate on different neurons from DCML system
what are the two systems of second sensory neurons?
spino-reticulo-thalamic system
spinotectal system
Of C fibers, where does the axons of 2nd order neuron make synaptic with?
the brain areas relating to affective and autonomic responses but not the VPL thalamus in A fibers
Function of spino-reticulo-thalamic system?
relaying & integrating nociceptive information contributing to motivational, affective and aversive response of pains
Functions of spinotectal system
for orienting response (through superior colliculus)
descending modulation of pain (periaqueductal grey)
In this figure, what fibe project mainly to #a ?
A fibers
substantia gelatinosa
the gray matter in Lamina II
What does the spinotectal system project to?
superior colliculus
periaqueductal grey
Where does the spino-reticulo-thalamic system project to?
intralaminar thalamus
hypothalamus
reticular formation
What is the reticular formation responsible for?
prefrontal cingulate insular cortices?
arousal
emotional (affective)
Where are the terminal axons of 1st order neuron?
lamina I
What does aspirin do and why does it reduce pain?
it block the conversion of arachidonic acid to prostaglandins
what part of the cortex send input directly to PAG?
ACC
Hyperalgesia. Example?
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
What is the substance that indirectly affect nociceptors?
arachidonic acid
What is prononiceptive?
What pathway does this involve in?
the increases experience in pain
spino-reticulo-thalamic pathway
What happen when we block or inhibit the actions of substances like histamin, serotonin, substance P, bradykinin?
we reduce pain
What does MITN do?
send the direct pain inputs to amygdala & ACC
What part of brain that stress activate?
LC
function of ACC? MCC? dPCC?
emotional awareness/ fight or flight
mismatch error detection/ response selection
sensorimotor orientation
What does SRD & LC do?
enhance the persistent pain
What does MITN hyperexcitability result in?
allodynia/ hyperalgesia
T/F: Pain and stress can’t be seperated?
True
allodynia. Examples?
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
What does chronic pain associated with?
hyperexcitability of ACC & MITN
What are the substances that directly excites/ affect nociceptors?
Histamin, ATP, H+, substance P, serotonin, brady kinin
what is the target for relieving pain & suffering?
pACC
What are the treatments for chronic pain?
treat adrenoreceptors
hypnosis
tMCS (transcranial motor cortex stimulation)
social interaction
manipulate object’s belief that they can control nociceptive stimulus & get reduced pain
What does arachidonic acid convert to?How does the arachidonic acid affect nociceptors?
prostaglandins which block the K+ channel efflux and sensitize nociceptors, further depolarize them
