Impaired Visuospatial Recognition Memory but Normal Object Novelty Detection and Relative Familiarity Judgments in Adult Mice Expressing the APPswe Alzheimer's Disease Mutation.

The present study examined the effects of a human APPswe mutation on object recognition memory in adult Tg2576 mice. The results showed that 14-month old Tg2576 mice were able to detect object novelty as well as control mice, even with delays of up to 24 hr. In addition, transgenic mice showed a normal recency effect and explored the most recently encountered object significantly less than an object encountered earlier in a trial. However, adult Tg2576 mice showed impairments in detecting a change in the relative positions of an array of familiar objects. The results suggest that the formation of representations involving a combination of object identity and spatial information are particularly sensitive to amyloid pathology in adult APPswe mutant mice.