Answer: Progressive increase in dorsal horn neuron response due to NMDA receptor activation and substance P release (central sensitization).
- A A steady, progressive decrease in perceived pain intensity over repeated identical stimulation events during normal conditions
- B Progressive increase in dorsal horn neuron response due to NMDA receptor activation and substance P release (central sensitization)
- C Little measurable change in dorsal horn neuron firing rate observed over an extended period of time as generally observed in typical laboratory settings
- D Sensitization restricted mainly to peripheral nociceptor nerve terminals, rarely reaching the spinal cord region under usual circumstances
Correct answer: B. Progressive increase in dorsal horn neuron response due to NMDA receptor activation and substance P release (central sensitization)
Explanation: Wind-up: repeated C-fiber stimulation causes progressive increase in dorsal horn WDR neuron firing. Mediated by temporal summation of NMDA activation and substance P. Contributes to chronic pain sensitization.
Structure of a neuron. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Brain, spinal cord, neurons, reflex arcs, and sense organs.