Fig.1.

Housing conditions and experimental design. A, Timeline of the experimental procedure. 8-week-old animals were placed into different housing conditions for a period of 3 weeks, which ended with a novel object recognition test including sample phase, a 1.5 h-delay and a 24 h-delay memory test. B, Control condition in eurostandard type II cages, three animals per cage. C, Mice housed in the eurostandard type III cage with a plastic running wheel (RW1), three mice per cage. D, Mice housed in the eurostandard type IV cage with a running wheel, two houses and a tunnel (RW2), six mice per cage. B-D, Scale bars, 10 cm.