Spontaneous Alternation in Aged Mice

Spontaneous alternation was assessed in male and female mice of 20 months age, in a Y-shaped maze (Dere et al., 2014 (link)). Mice were individually placed into the center of a triangle-shaped maze with three identical open arms (7.5 cm × 18 cm × 23.5 cm) and allowed to freely explore the maze for a total of 5 min. Performance of all mice including total number of arm entries, defined as entering with all four paws, was recorded with a video-tracking system (Viewer3, Biobserve GmbH, Bonn, Germany). An alternation ratio, defined as the number of alternating triplets multiplied by 100 and divided by the total number of entries, was calculated.