2.8. Novel Object Recognition (NOR) test
On the twenty fourth days after FeCl3 injection, NOR test was performed to assess the effects of Fer-1 on the short-term recognition memory of mice according to the previous investigation (Lueptow, 2017). Briefly, in the habituation phase, mice were placed in a polyvinyl chloride chamber (45 cm × 45 cm × 45 cm) for familiarization. On the next day, mice were allowed to freely explore the arena with two identical objects in the center for 10 min. Twenty-four hours following the training trial, animals were placed in the chamber in which one of the objects was replaced with a novel object with different color and shape. Mice were allowed for 10 min exploratory trial. The exploration time, which meant that the time when the mice explored the familiar or novel object, was recorded in the NOR test. The apparatus and objects were cleaned thoroughly with 75% ethanol solution prior to each trial. The behavioral traits of each mouse were recorded by a video tracking system. The time exploring novel object (N) and exploring familiar object (F) were recorded carefully. The discrimination index was analyzed using the following formula: (N-F)/(N+F) ×100%.