MAPT and tauopathy: To determine whether the tau 2B8 sdAb could detect tau deposits in vivo in intact animals, homozygous JNPL3 tauopathy mice (17 months of age, n = 8) and heterozygous PS19 mice (6 to 9 months, n = 3) received a single intravenous injection of 2B8 labeled with an NIR tag, VivoTag 680XL, to allow its detection by the IVIS through the intact head (Fig. 6, A to C).