Fluorescent imaging of NPY+ neurons (green) throughout the brain are shown in addition to neurons in magenta that send projections to the PBN. Credit: J Nicholas Betley Pain may be unpleasant, but in most cases it plays a vital, even lifesaving, role. Short bursts of pain act as warning signals that protect us from harm. When you touch a hot pan, stub your toe, or bump your head, your nervous system instantly delivers an “Ow!” that prompts you to pull back before more damage occurs. The pain