Y-maze spontaneous alteration behavior test

Testing was done in a Y-shaped maze with three black, plastic arms at a 120° angle from each other. After introduction to the center of the maze, the animal was allowed to freely explore the three arms. Over the course of multiple arm entries, mice show a tendency to enter a less recently visited arm. The number of arm entries and the number of triads (any sequence consisting of entries into three different arms) were recorded to calculate the percentage of alternation. An entry is defined when all four limbs are within the arm (50). Between sessions, the maze was cleaned with a 70% ethanol solution. As a measure for spatial egocentric memory, the percentage of alternations that the mouse made was calculated, being the number of triads divided by the maximum possible alternations (i.e., the total number of entries minus 2 × 100). If a mouse scored significantly above 50% alternations (the chance level for choosing the unfamiliar arm), then this was indicative of a functional spatial egocentric memory.