for 1 h. First, one familiar plastic cartridge was placed in the testing cage, and the animal adapted to this familiar stimulus for an additional 15 min. Second, another familiar plastic cartridge was placed in the testing cage, and behavior was recorded for 5 min. This session served as a control for placing additional (but familiar) targets in the testing area. Finally, a cotton ball soaked in 10% ethanol was placed inside the third familiar plastic cartridge. The scented cartridge was then placed in the cage, and the mouse was videotaped for another 5 min. Latency to approach the cartridge and total time for exploration (sniffing) of the target were measured.
