A-delta fibers are associated with which trait?

• A. Dull, throbbing pain.
• B. Long-lasting chronic pain.
• C. No nociceptive input.
• D. Sharp, stabbing pain.

Answer: (D)

A-delta fibers transmit fast, myelinated nociceptive signals, producing the initial sharp, well-localized pain you feel immediately after a noxious stimulus. That makes "sharp, stabbing pain" the best description. In contrast, dull, throbbing pain is mainly from unmyelinated C fibers that conduct more slowly and contribute to a lingering ache. The notion of no nociceptive input contradicts what these fibers do, and long-lasting chronic pain involves additional mechanisms beyond the immediate fast pathway.