In a previous publication [Deacon RMJ, Cholerton LL, Talbot K, Nair-Roberts RG, Sanderson
DJ, Romberg C, et al. Age-dependent and -independent behavioral deficits in Tg2576
mice. Behav Brain Res 2008;189:126-38] we found that very few cognitive tests were
suitable for demonstrating deficits in Tg2576 mice, an amyloid over-expression model
of Alzheimer's disease, even at 23 months of age. However, in a retrospective analysis
of a separate project on these mice, tests of social memory and open field habituation
revealed large cognitive impairments. Controls showed good open field habituation,
but Tg2576 mice were hyperactive and failed to habituate. In the test of social memory
for a juvenile mouse, controls showed considerably less social investigation on the
second meeting, indicating memory of the juvenile, whereas Tg2576 mice did not show
this decrement.As a control for olfactory sensitivity, on which social memory relies,
the ability to find a food pellet hidden under wood chip bedding was assessed. Tg2576
mice found the pellet as quickly as controls. As this test requires digging ability,
this was independently assessed in tests of burrowing and directly observed digging.
In line with previous results and the hippocampal dysfunction characteristic of aged
Tg2576 mice, they both burrowed and dug less than controls.