The instrument was purchased from Med Associates. The radial arm maze is a paradigm that is often used to assess working and reference memory in rats and mice.  When investigating working memory, all arms are usually provided with a (food) reward and the animal should visit each arm only once. When used for assessing reference memory, only some of the arms contain a reward and the animal should only visit those baited arms. Visits to an arm more than once or visits to non-baited arms count as working memory errors or reference memory errors, respectively.