lecture 1 - clinical pain neuroscience Flashcards
Pain definition
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
Nociception
neural process of encoding noxious stimulus
- transduction
- conduction
- transmission
- perception
- modulation
Biopsychosocial model
the interaction between biospychosocial factors contribute to an individuals pain experience at any given point in time
- biological
- psychological
- social
Clinical model of pain
- signal - from nociceptive or neuropathic generator
- Amplifier - central sensitisation
- Gain setter - descending modulation
noxious stimulus
stimulus that is damaging
nociceptors
high threshold sensory receptor of peripheral nervous system that encodes noxious stimuli
activated by chemical substances
peripheral sensitisation
increased responsiveness and reduced threshold of nociceptive neurons in peripheral tissue
primary hyperalgesia
increased pain from stimulus that normally provokes pain
neuropathic pain
lesion or disease of the somatosensory system, including peripheral neutrons and CNS
- Amplifier
nociceptor input -> cause the biochemical changes and molecular changes in synapse function and structure in dorsal horn neutrons -> amplification of signal (hypersensitive)
- increased size of receptive field
- decreased threshold
- loss of inhibitory neurons
- spontaneous activity of neurons
secondary hyperalgesia
spread of pain hypersensitivity beyond injured area
allodynia
non-noxious stimulus is painful
Quantitative sensory tests
- pressure algometry
2. PPT (pain pressure threshold)
- Gain setter
- descending pathways (brainstem to spinal cord) modulate nociceptive processing and the experience of pain
- facilitatory and inhibitory systems function in concert -to maintain baseline -> injury perturbs balance - causing pain
descending modulation
acts via. pathways in the midbrain and medulla
- PAG: source of descending opioid mediated inhibition
- RVM: facilites or inhibits nociceptive inputs
