A(δ) and C fibers are the major pain-conducting nerve fibers, activate only partly the same brain areas, and are differently involved in pain syndromes. Whether a stimulus excites predominantly A(δ) or C fibers is a commonly asked question in basic pain research but a quick test was lacking so far.
Beissner, F., Brandau, A., Henke, C., Felden, L., Baumgärtner, U., Treede, R. D., … Lötsch, J. (2010). Quick discrimination of Adelta and C fiber mediated pain based on three verbal descriptors. PLoS ONE, 5(9). https://doi.org/10.1371/journal.pone.0012944