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Abstract:

In an effort to study how social isolation and AD interact, we used APP KI mice bearing human transgenes known to cause AD, and isolated part of the mice in order to mimic loneliness in late-life while part of them remained group-housed. We next looked at the effects of isolation on the behaviour and symptomatology typically present in AD patients to tap cognition. Our study reveals mixed results. Results indicate that at before isolation, at the age of 16 and 24 months, APPNL/NL and APPNL-G-F/NL-G-F mice do not differ to a significant extent on both the behavioural level. The APPNL-G-F/NL-G-F differentiated slightly worse between the conditioned context and a new context compared to the APPNL/NL mice. However, the difference appeared to be more pronounced after a period of social isolation. Social isolation had distinct effects on the AD-related anxiogenic and dementia-like phenotype. Spatial learning in the MWM task revealed distinct differences between our two models. After isolation APPNL-G-F/NL-G-F mice used less spatial search strategies, compared to control mice, thus reflecting perseveration and less behavioural flexibility due to the isolation period.