L14 - Pain 3 Flashcards
What has higher threshold: nociceptive or inflammatory?
Nociceptive
Which is spontaneous pain: nociceptive or inflammatory?
Inflammatory
Where does pain perception occur?
The brain
The thalamus is the primary brain region linking sensory receptors to cerebral cortex EXCEPT for
Olfactory
The 3 submodalities of somatic sensation are:
Touch, proprioception and pain
Topographic organisation of spinothalamic tract
C-fibres tend to go to ?
Output neurons are located in lamina _ _ and _ and some of the deeper lamina
Only _% of neurons in spinal cord are projection neurons
Topographic organisation of spinothalamic tract
C-fibres tend to go to periphery of laminae of dorsal horn
Output neurons are located in lamina 1, 4, 5 and some of the deeper lamina
Only 5% of neurons in spinal cord are projection neurons
Brain areas activated by acute pain?
Anterior cingulate gyrus, posterior parietal cortex, Insula, S1, S2
Spinothalamict tract aka anterolateral system aka ventrolateral system - what info does ant and lat pathway convey? When does pathway decussate?
Anterior pathway - info about firm pressure and crude touch (sense that someone has touched you but you can’t localise where)
Lateral pathway - conveys pain and temperature
Decussates at the level of the spinal cord - hence is a contralateral pathway
Brown-Séquard syndrome
Damage to one half of the spinal cord, resulting in paralysis and loss of proprioception on the same (or ipsilateral) side as the injury or lesion, and loss of pain and temperature sensation on the opposite (or contralateral) side as the lesion
Segregation (labelled lines)
1) Topographic
2) Anatomical class of primary nociceptor
3) Response properties
1) Dermatome, organ, tissue structure
2) A delta or C fibre, chemical class
3) Low threshold, high threshold, wide dynamic range, thermosensitive
Intensity theory/Convergence
Strong activation of unspecialised neurons
Specificity theory/Labelled lines
Specialised low and high threshold neurons (LThN, HThN)
Combinatorial coding theory
Network response to activation of LThNs and HThNs
Is the “burning” sensation only attributed to noxious heat?
Burning quality assigned to both noxious heat and cold stimuli. Consequence of that is that we can have false assignments of sensory qualities to those inputs.
Referred visceral pain
Sensory primary afferents which project to the organs (except liver - which has almost no sensory innervation). Visceral pain will remap to somatic regions (e.g. upper GIT pain can extend to upper abdomen or limbs).
Referred visceral pain
Sensory primary afferents which project to the organs (except liver - which has almost no sensory innervation). Visceral pain will remap to somatic regions (e.g. upper GIT pain can extend to upper abdomen or limbs).
