Figure 1. Illustration of the phases of the spontaneous object recognition task as run in the Y-shaped apparatus. The nearest wall of the apparatus appears transparent for illustrative purposes. The guillotine door is shown raised. At the beginning of each phase, the rat is released from the start box when the experimenter manually raises the guillotine door. In the sample phase, the rat is exposed to identical versions of the same object, one at the end of each exploration arm. At the end of the sample phase, a variable retention delay is imposed. After the retention delay, the rat is reintroduced to the apparatus, which now contains an identical copy of the sample object at the end of one exploration arm and a novel object at the end of the other arm. Normal rats spend more time exploring the novel object.