Social isolation in adolescent AD mice: effects on behaviour and functional connectivity

Adolescent transgenic mice with Alzheimer’s disease (AD) will be separated into two groups at random: standard housing and social isolation (SI). In addition, wild-type mice will also be randomly separated into a standard housing and isolation group. Each of the four groups will be tested as outlined below. We expect that SI to exacerbate AD-like symptoms in transgenic mice (see e.g. Huang et al., 2015; Hui, Feng, Zheng, Jin, and Jia, 2017). A range of test will be used to assess different cognitive aspects: working memory (e.g. Y maze), long term memory (e.g. water maze), anxiety (e.g. fear conditioning), exploration behaviour (in open field and social exploration), depression (e.g. forced swim). Functional connectivity (FC) changes in the brain are expected to be observed prior to abeta accumulation in humans likely to develop AD as well as AD mouse models. Areas with most marked early FC changes are regions involved in memory function (e.g. hippocampus, posterior cingulate cortex; i.e. default mode network areas) which are also susceptible to greater abeta accumulation as the pathology progresses. FC changes are therefore of interest when it comes to understanding pathogenesis of AD and may be of interest as early risk markers.