Ch. 8: Neuropathic pain, pain matrix, pain syndromes

Question 1

4 mechanisms of neuopathic pain

Answer 1

• ectopic foci
• ephaptic transmission
• central sensitization
• structural reorganization

Question 2

Ephaptic Transmission

Answer 2

• short circuit

- action potential jumps from one demyelinated neuron to another

Question 3

Chronic pain

Answer 3

-in neuropathic pain, pain matrix dysfunction and pain syndromes, the neural mechanisms for regulating pain amplify signals, creating pain in the absence of noxious stimuli

Question 4

Nociceptive chronic pain

Answer 4

• continuing pain stimulus

- pn neurons function properly

Question 5

Central sensitization

Answer 5

• synapse in brainstem/spinal cord transmits more easily
• strong/prolonged pain stimuli make synapse more effective/efficient
• lead to: allodynia, hyperalgesia, postsynaptic neuron spontaneously firing

Question 6

Pain matrix dysfunction

Answer 6

• possible for top down pathways to promot pain signals or create perception of pain with no stimulation
• negative affect/emotion can increase pain perception

Question 7

ectopic foci

Answer 7

• (from another place)
• pain stimulus starts elsewhere (A-delta)
• in areas of demyelination, it may upregulate mechanorec and chemorec into area–can become sensitive to epinephrine

Question 8

Structural Reorganization

Answer 8

• touch neurons (A-beta) branch and send collaterals to 2nd order pain neurons
• so simple touch feels like pain