Vacuolation histograms in Tg(BoPrP)Prnp0/0 mice inoculated with BSE, nvCJD, and scrapie prions. The BSE and nvCJD histograms are very similar and both are different from scrapie (Sc). Mean and standard deviations are shown. NC, neocortex; Hp, hippocampus; Th, thalamus; Hb, habenula; Hy, hypothalamus; Cd, caudate nucleus; BF, basal forebrain; BS, pontine and midbrain tegmentum; PG, periaqueductal gray. N = the number of animals analyzed.