Fig. 1.

a Experimental design: three different groups of animals were housed under standard conditions in ordinary cages (standard), in an enriched environment (enriched) containing various objects such as horizontal and vertical boards, climbing platform, plastic tubes and tunnels, chains, and small houses or kept in a standard cage and trained daily in a reaching task (reaching) of the dominant forelimb in a Plexiglas chamber. Animals had to grasp 50 food pellets in the first week, which was raised up to 100 pellets per day in the second week. All animals received single daily i.p. BrdU injections from day 2 to day 6. Animals were transcardially perfused for further processing at day 10 or day 42 after the beginning of the experiments. b The graph represents the brain volume of different groups for 2.7 to −5.3 mm refered from Bregma. Bars represent mean ± SD. Asterisks indicate significant differences (P < 0.05)