Characterization of Apathy-Like Behaviors in Mouse Models of Down Syndrome.

BACKGROUND

Apathy is a state of decreased interest, lack of initiative, reduced goal-directed activity and blunted emotional responses. Apathy is one of the most common neuropsychiatric symptoms (NPS) in patients with Alzheimer's disease (AD) and is also relatively omnipresent in individuals with Down syndrome (DS). Little is known about the apathy-like behaviors in rodent models of AD and DS.

OBJECTIVE

This study aimed to characterize apathy-like behaviors with aging in two established DS mouse models: Ts65Dn and Dp16.

METHODS

A battery of behavioral tests including nestlet shredding, marble burying, nest building, and burrowing were performed to examine apathy-like behaviors. Individual z-scores for each mouse for each test, and a composite z-score of apathy-like behavior were analyzed for all mice from these behavioral tests.

RESULTS

Analysis of individual test results and composite z-score revealed significant apathy-like behaviors in Ts65Dn mice compared to WT controls. In contrast, Dp16 mice did not exhibit significant apathy-like behaviors.

CONCLUSIONS

Our study is the first to characterize apathy-like behaviors in mouse models of DS with aging and highlights the difference between Ts65Dn and Dp16 DS model mice regarding apathy-like manifestations with aging.