After visual discrimination, the same cohort of M2−/− (n = 8) and wild-type mice (n = 9; one animal had to be excluded due to an eye infection) was tested on rodent PAL, which requires the mice to learn to associate a given object with a particular location, an ability impaired in AD patients, after anticholinergic treatment in rodents (Greig et al. 2005; Bartko et al. 2011b), after forebrain depletion of the vesicular acetylcholine transporter (Al-Onaizi et al. 2017) and after application of the M1-receptor-preferring antagonist dicyclomine (Bartko et al. 2011b). Here, SLC18A3 is linked to eye infection.