FIG. 1. Cutaneous hyperalgesia associated with deep somatic noxious stimulation. Pain threshold was unchanged in control areas (left half of line drawing and left portion of bar graph), whereas the pain intensity (DOLS) was increased for the same and a greater intensity (milli- calories [MCI) of stimulation in the area of hyperalgesia (diagramed in the right half of the line drawing and the right portion of the bar graph). The hyperalgesia was produced by a 0.5 mL injection of 6% saline into an intraspinous ligament (X). It was also reported by these subjects that drawing a wisp of cotton across the hyperalgesic skin produced a more vivid touch sen- sation than produced by the same stimulus applied in control areas in the corresponding der- matomes on the opposite (left) side of the back. (Modified from ref. 17.) Click here to see the graphic at a different resolution