The phrase "normal mice" refers to mice that do not have any special or different characteristics or traits. They are just regular mice without any unusual or abnormal features. Full definition
By changing the times the lights went on and off during the night each week, the researchers modeled the effects of chronic jet lag in normal mice who were fed a healthy diet. (sciencedaily.com)
The brain activity confirmed their varying behavior: The brain cells of normal mice remained inactive when they were placed in the shock chamber, indicating the subjects recognized their surroundings. (scientificamerican.com)
These mice are different from normal mice in several key brain areas. (sciencenews.org)