In contrast, quantification of the area occupied by TH immunostaining showed no difference between control and 3xTg-AD mice in the midbrain (Fig. 3d,e, genotype: F1,18 = 0.28, p > 0.05; midbrain subdivision: F2,18 = 226, p < 0.001; genotype × midbrain subdivision: F2,18 = 2.51, p > 0.05). Here, TH is linked to Alzheimer disease.