Figure 5From: The Rat Grimace Scale: A partially automated method for quantifying pain in the laboratory rat via facial expressions Prominence of individual action units at the peak of apparent spontaneous pain in each assay (see Figure 4). Bars represent mean Ā± SEM difference scores (pain - no pain; n = 23 rats). Overall, all action units were equally prominent statistically (a), and this was also true in each assay considered separately (b). **p< 0.01 (Bonferroni-corrected) compared to other assays. K/C = kaolin/carrageenan.Back to article page