Pain

• What is pain vs nociception ?

  Pain is the unpleasant sensory + emotional experience while nociception is the actual encoding of noxious stimuli
• What are the key steps for nociception ?

  • Transduction of the signal = with nerve endings
  • Transmission of the signal with fibers
  • Modulation in spinal chord
  • Integration
• What are the fibers for nociception ?

  A delta and C
• Whats the difference between A delta and C fibers ?

  A delta are MORE myelinated and bigger than C
• What are the fibers used for other somatosensory information?

  A alpha and A beta
• What are the two types of nociceptive channels ?

  TRP and ASIC
• What are TRP channels ?

  They are transient receptor potential that are cationic channels (especially calcium) and are able to detect and transduce information
• What are ASIC channels ?

  Channels that are able to detect pH + acidity
• What is visceral nociception ?

  It is the nociception from organs and is usually triggered by pro inflamatory molecules
• What is usually the pathway in spine for nociceptive info ?

  Transduction with primary neurons then into dorsal horn then to secondary neurons
• Hyperalgesia = increased sensitivity to pain that is due to hyperactivation of secondary neuron using substance P
• Allodynia = is when a non painful stimulus is perceived as painful. This is due to A alpha and beta fibers activating the P substance abnormally
• Ascending pathways involve 4 main groups, which ones ?

  • Brainstem
  • Thalamus
  • Telencephalon
  • Spinothalamic tract
• The brainstem involve 2 key regions, which ones ?

  • PAG
  • Reticular formation
• The telencephalon involves 6 key regions, which ones ?

  • SI
  • SII
  • Insulae
  • Amygdala
  • ACC
  • PFC
• What are pain matrices ?

  Clusters of interconnected brain regions that map out pain
• What is noccieptive matrices ?

  Same principle as pain matrices but this time more focused on the sensory-motor aspect
• What are the 4 structres in the descending pathways ?

  • PAG
  • Reticular formation
  • Cingulate cortex
  • Insulae
• What is also used to describe the descending pathways ?

  The endogenous inhibtion of pain
• At what levels can you modulate pain ?

  • spinal
  • supraspinal
  • cortex
• Whats the main differences between pain and other somatosensory pathways ?

  In pain you have no receptor only nerve endings and the primary neurons goes directly from dorsal horn to the secondary.

  In other somatosensory, you have from the receptor, the DCLM and in the dorsal horn an inhibtiory neuron
• What is the spinal modulation of pain ?


  Involves the gate control
• What is gate control ?

  When you have the possibility to modulate stuff thanks to the structres in the dorsal horn and to substantia gelatinosa
• What is the suprapinal modulation of pain ?

  When you modulate pain through DCNI, using 5HT and NA neurotransmitters in order to activate PAG and reticular formation
• What is the cortex modulation of pain ?

  This is when you modulate pain directly from brain regions like ACC and DLPFC in order to activate endorphinic synapses in other regions like : PAG, reticular formation and other
• What are the 3 types of pain ?

  • Nociceptive
  • Neuropathic
  • Nociplastic
• Which one is can be chronic between : nociceptive neuropathic and nociplastic ?

  Neuropathic and Nociplastic
• Which one involves lesion of nervous tissue between : nociceptive neuropathic and nociplastic ?

  Neuropathic
• Which one involves lesion of NON nervous tissue between : nociceptive neuropathic and nociplastic ?

  Nociceptive
• What are the 2 types of things nociceptive pain can be ?

  Either transitory or prolonged
• What experiments can you do on animals (6 stuff) ?

  • using weight = Ven frey
  • using pressure = Rendal-selitto
  • using behavior = burroing or weight behavior
  • using locomotion = gait analysis
  • using temperature = cold/hot plate, plantar test, acetone-evaporation test
• How to test pain with weight in animals ?

  Ven frey
• How to test pain with pressure in animals ?

  Randall Selitto
• How to test pain with temperature in animals ?

  • Cold or hot plate
  • Plantar test
  • Acetone evaporation test
• How to test pain with behavior in animals ?

  Burroing or weight behavior tests
• How to test pain with locomotion in animals ?

  Gait analysis
• What types of models exist for animals ? (6 types)

  • Inflamatory
  • Neuropathic pain
  • Cancer
  • Arthritic joint pain
  • Muscle
  • Visceral
• What different types of neuropathic pain models can you make ?

  • cortical thalamus
  • spinal chord injury
  • direct nerve injury
  • diabetes and alcoholism
• How to induce arthritic join pain ?

  Inject collagen type 2 antibody OR K/BxN transgenic
• How to induce visceral pain ?

  With acetic acid