Cognitive Abilities of Alzheimers Disease Transgenic Mice are Modulated by Social Context and Circadian Rhythm

Anna      Kiryk; Gabriela      Mochol; Robert      K. Filipkowski; Marcin      Wawrzyniak; Victoria      Lioudyno; Ewelina      Knapska; Tomasz      Gorkiewicz; Marcin      Balcerzyk; Szymon      Leski; Fred      Van Leuven; Hans-Peter      Lipp; Daniel      K. Wojcik; Leszek      Kaczmarek

doi:10.2174/156720511798192745

Abstract

In the present study, we used a new training paradigm in the intelliCage automatic behavioral assessment system to investigate cognitive functions of the transgenic mice harboring London mutation of the human amyloid precursor protein (APP.V717I). Three groups of animals: 5-, 12- and 18-24-month old were subjected to both Water Maze training and the IntelliCage-based appetitive conditioning. The spatial memory deficit was observed in all three groups of transgenic mice in both behavioral paradigms. However, the APP mice were capable to learn normally when co-housed with the wild-type (WT) littermates, in contrast to clearly impaired learning observed when the transgenic mice were housed alone. Furthermore, in the transgenic mice kept in the Intellicage alone, the cognitive deficit of the young animals was modulated by the circadian rhythm, namely was prominent only during the active phase of the day. The novel approach to study the transgenic mice cognitive abilities presented in this paper offers new insight into cognitive dysfunctions of the Alzheimers disease mouse model.

Keywords: Circadian rhythm, group learning, individual learning, IntelliCage, social behavior, amyloid precursor protein, IntelliCage system, ageing, sensorimotor