Central mechanisms of Pain Flashcards
what is the Localization and intensity of pain
the Sensation of pain
what is the Emotional response (Psychological component) of pain
Affective component
what is short term pain with an identifiable source
Acute
what is long term pain with a frequently non-identified source
Chronic pain
what meidates Normal pain
A-delta and C-fibers
what mediates Pathological pain (hyperalgesia
Pheripheral and central sensitization
where is oral and facial pain processing done
Caudalis (part of the spinal trigeminal nucleus)
what is the sensory portion of the spinal cord
Medullary dorsal horn
pain vs non-pain senations of the medullary Dorsal Horn
Pain is more on the outer surface (supperficial)
non-pain is found deeper
But there is some overlap
what do Nociceptive specific neurons respond to
to only painful stimuli
what do Wide Dyanmic range neurons respond to
Both painful and non-painful stimuli
Does the PNS have something like wide dynamic range neurons
NO
Cell types found in the medullary dorsal horn
Nociceptive specific neurons
Wide Dynamic range neurons
REceptive fields of the Wide Dynamic Range Neurons in the medullary dorsal horn
HAve large Receptive fields
how is the receptive fields of wide Dynamic range neurons different from that of the PNS
PNS can’t be in 2 different branches
where do Nociceptive specific neurons tuerminate in the medullary dorsal horns
In superficial layers I and II
where do Non-nocicpetive neurons terminate in the medullary dorsal horn
In deeper layers III, IV, and V
where does OVerlap occure in the medullary dorsal horn
In layers II and V
Convergence in the medullary dorsal horn
High degree of convergence
what Afferents converge in the MDH
Nocicpetive and Non-nociceptive afferents
what types of things converge in the MDH
Submodality convergence
what emerges in the MDH
wide dynamic range neurons emerge
what happerents to peripheral affernets of different receptive fields
they converge
what peripheral affernts converge their receptive fields
Cutaneous Joint Muscle Tooth pulp (max and Mandibular) other nerves (SLN: superior laryngeal nerve)
Roll of MDH and referred pain
MDH is the neural substrate for referred pain
spread of pain from the teeth
Spread all along the head due to refered pain
how does MDH help to explain referred pain
Pain and non-pain afferents converge on “pain-signaling” neurons
why can’t convergence on the MDH explain Referred pain alone
Because pain only occures under pathological conditions ( not a normal sensation)
what may cause the MDH to start doing referred pain under pathological conditions
something is preventing the activation of convergent input in MDH under “normal” conditions
Does Peripheral sensitization explain referred pain
Not entirely: peripheral sensitization mostly increases with C-fiber sensitivity
- does not explain larger areas of Pain (increased receptive fields)
How could peripheral sensitization explain the larger areas of pain due to referred pain
following severe nerve injury there could be ephaptic connections between pain and non-pain fibers that could enlarge receptive fields