Alzheimer's disease (AD), the most common form of dementia, is an age-dependent progressive neurodegenerative disorder. β-amyloid, a metabolic product of the amyloid precursor protein (APP), plays an important role in the pathogenesis of AD. The Thy1-hAPP(Lond/Swe+) (line 41) transgenic mouse overexpresses human APP751 and contains the London (V717I) and Swedish (K670M/N671L) mutations. Here, we used a battery of behavioral tests to evaluate general activity, cognition, and social behavior in six-month-old male Thy1-hAPP(Lond/Swe+) mice. We found hyperactivity in a novel environment as well as significant deficits in spontaneous alternation behavior. In fear conditioning (FC), Thy1-hAPP(Lond/Swe+) mice did not display deficits in acquisition or in memory retrieval in novel context of tone-cued FC, but they showed significant memory retrieval impairment during contextual testing in an identical environment. Surprisingly, in a standard hidden platform water maze, no significant deficit was detected in mutant mice. However, a delayed-matching-to-place paradigm revealed a significant deficit in Thy1-hAPP(Lond/Swe+) mice. Lastly, in the social novelty session of a three-chamber test, Thy1-hAPP(Lond/Swe+) mice exhibited a significantly decreased interest in a novel versus a familiar stranger compared to control mice. This could possibly be explained by decreased social memory or discrimination and may parallel disturbances in social functioning in human AD patients. In conclusion, the Thy1-hAPP(Lond/Swe+) mouse model of AD displayed a behavioral phenotype that resembles, in part, the cognitive and psychiatric symptoms experienced in AD patients.
Keywords: Alzheimer's disease; amyloid precursor protein; behavior; learning and memory; neurodegenerative disorder; social interaction.