Abnormal whisker movements in the 3xTg-AD mouse model of Alzheimer's disease

Abstract

Alzheimer's disease is the most frequent form of dementia in elderly people. The triple transgenic (3xTg-AD) mouse model of Alzheimer's Disease is important in biomedical research as these mice develop both neuropathological and behavioural phenotypes. However, their behavioural phenotype is variable, with findings depending on the specific task, as well as the age and sex of the mice. Whisker movements show motor, sensory and cognitive deficits in mouse models of neurodegenerative disease. Therefore, we examined whisker movements in 3, 12.5 and 17-month-old female 3xTg-AD mice and their B6129S/F2 wildtype controls. Mice were filmed using a high-speed video camera (500 fps) in an open arena during a novel object exploration task. Genotype and age differences were found in mice exploring the arena prior to object contact. Prior to whisker contact, the 3-month-old 3xTg-AD mice had smaller whisker angles compared with the wildtype controls, suggesting an early motor phenotype in these mice. Pre-contact mean angular position at 3 months and whisking amplitude at 17 months of age differed between the 3xTg-AD and wildtype mice. During object contact 3xTg-AD mice did not reduce whisker spread as frequently as the wildtype mice at 12.5 and 17 months, which may suggest sensory or attentional deficits. We show that whisker movements are a powerful behavioural measurement tool for capturing behavioural deficits in mouse models that show complex phenotypes, such as the 3xTg-AD mouse model.