Figure 5.

Impaired novel object recognition memory in c-rel^−/− mice. The object recognition task is based on the natural tendency of mice to investigate a novel object rather than a familiar object, and object recognition memory also depends on hippocampus. During the training day, two identical objects were placed in the open field box. Each mouse was then placed in the middle of box and allowed to freely investigate the objects for 10 min. On the test day (24 h after training), one of the familiar objects was replaced with a novel object, and the amount of time the mouse explored each object was recorded. In this test, wild-type littermate showed statistical significant preference to the novel object (*P < 0.05). However, c-rel^−/− mice did not distinguish the novel object from the familiar object. These results indicate that c-rel^−/− mice have a deficit in hippocampus-dependent object recognition memory. n = 13 wild-type (nine male, four female) and 14 c-rel^−/− (10 male, four female).