To see how the brain responds to pain emanating from different teeth, researchers led by Clemens Forster of the University of Erlangen-Nuremberg in Germany used fMRI to monitor changes in activity when the upper tooth or the lower tooth was zapped. “At the beginning, we expected a good difference, but that was not the case,” Forster says. Because the same regions were active in both toothaches, the brain — and the person — couldn’t tell where the pain was coming from. “Dentists should be aware that patients aren’t always able to locate the pain,” Forster says. “There are physiological and anatomical reasons for that.”
