Figure 1.

Flowchart of the experiment. Controls were housed in standard 30- by 18-cm cages, whereas runners had 48- by 26-cm housing with free access to a running wheel (1). Mice in both conditions received BrdU (50 μg/g per day) injections for the first 10 days after their housing assignment. After 1 month in their respective environments, mice were tested in the water maze (2) between days 30 and 36 or between days 43 and 49. Mice were anesthetized and decapitated between days 54 and 118; one hemisphere was used for electrophysiology; the other was used for immunocytochemistry (3).