Age-related cognitive decline in spatial learning and memory of C57BL/6J mice.

During the last decades, most of the preclinical neurodegenerative research was performed in mouse models of amyloidosis, tauopathies or α-synucleinopathies preferentially maintained on a C57BL/6J background. However, comprehensive neurobehavioural data from C57BL/6J mice outlining the critical point of spontaneous cognitive decline are incomplete. In this study, we aimed for the neurobehavioural phenotyping of hippocampus-dependent spatial learning and memory of aging C57BL/6J mice. Neurobehavioural phenotyping was performed by means of a Morris Water Maze (MWM) and a Novel Object Recognition (NOR) test. MWM measurements revealed signs of age-related memory loss in C57BL/6J animals from the age of 6 months onward. The NOR assessment strengthened latter finding by decreasing discrimination indexes (DI) and recognition indexes (RI) starting from the age of 6 months. Taken together, these findings contribute to the current knowledge of spontaneous cognitive behaviours of this perhaps most widely used mouse strain and serve as a benchmark for dementia mouse models to distinguish spontaneous from pathological neurodegenerative behaviour.