SOCIAL BEHAVIOURS IN THE 5XFAD MOUSE MODEL OF ALZHEIMER'S DISEASE

Abstract

Social dysfunctions in Alzheimer's disease (AD) are reported in a significant proportion of the patient population, and greatly contribute to the overall societal burden of the disease. While social withdrawal and aggression have been clearly documented in the AD patient population, they have not been well assessed in transgenic mouse models of AD. 5xFAD and control mice were housed in same-sex same-genotype pairs and were tested in behavioural tests aimed at quantifying measures of sociability and aggressive behaviours. Tests included a homecage interaction test, a newly-developed odour plus maze, and the three-chamber sociability test. 5xFAD mice spent similar time interacting with each other in their homecage as control mice. However, 5xFAD mice tended to spend less time in an area containing an unfamiliar social odour (U=13, p=0.07), but significantly more time in an area containing a social stimulus (U=10, p=0.03) compared to control mice. These results suggest a complex interplay between social avoidance and approach behaviours that are dependent on the quality of the social stimuli. Although 5xFAD mice avoid a social odour, they approach a social stimulus, which could indicate increased social withdrawal concomitant with increased aggression. These findings suggest that 5xFAD mice share key aspects of social dysfunctions observed in AD patients. Studies to clarify the interpretation of our findings related to our supposition regarding aggression are currently ongoing.