Two months later.
Chen Chen stood quietly in the laboratory. His face was rather pale.
Before him, a little white mouse was ceaselessly paddling in a Morris water maze.
This little white mouse was agile in swimming. Although it looked a little confused, it always managed to find the right path quickly after some wrong attempts, finally locating the platform hidden underwater.
No one would be able to tell that these mice were showing signs of severe nerve damage just two weeks ago.
As Chen Chen observed Mouse No. 5 reaching the platform, he gently clicked the timer and said impassively, "28 seconds, 2 seconds faster than yesterday."
Following that, Chen Chen started to fill in the experiment record: