all types of pain are conveyed on to the spinal cord and brain by two different types of fibers—fast-conducting A delta fibers (they’re coated in myelin, so slicker, as it were) and slower-acting C fibers. The swift A delta fibers give you the sharp ouch of a hammer blow; the slower C fibers give you the throbbing pain that follows. Nociceptors only respond to disagreeable (or potentially disagreeable) sensations. Normal touch signals—the feel of your feet against the ground, your hand on a doorknob, your cheek on a satin pillow—are conveyed by different receptors on a separate set of A-beta
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