Novel behavioural characteristics of female APP_Swe/PS1δE9 double transgenic mice

Murine models are commonly used to evaluate progression of Alzheimer's disease. APP_Swe/PS1δE9 (APPxPS1) mice have previously been reported to demonstrate impaired learning and memory in the Morris water maze test. However, this paradigm introduces a variety of behaviours that may confound performance of the mice, thus an alternative was sought. A battery of behavioural tests (light-dark test, elevated plus maze, novel object recognition task, social recognition test, cheeseboard task and prepulse inhibition) was used to investigate various behavioural and cognitive domains with relevance to Alzheimer's disease. We found 9-month old female APPxPS1 mice exhibited impaired spatial memory in the reversal cheeseboard task. In addition, task-dependent hyperlocomotion and anxiolytic-like behaviours were observed in the light-dark test. Female APPxPS1 demonstrated intact object recognition memory and sensorimotor gating was not significantly decreased compared to control mice except for one particular interstimulus interval. The social recognition test failed to detect preference for social novelty in control females. In conclusion, this is the first study to describe a memory deficit in female APPxPS1 mice in the hidden cheeseboard task. Transgenic females also exhibited task-dependent reduction in anxiety behaviours and hyperlocomotion. These novel findings enhance our understanding of the behavioural phenotype of APPxPS1 females and present the cheeseboard as a valid alternative to other established spatial memory tests. Furthermore, the task-dependency of some of our findings suggests that behavioural profiling of APPxPS1 transgenic mice should be assessed using a variety of behavioural paradigms.