Fig. 1

Overview of behavioral testing. Rats were assessed in the open field (OF) and in the Morris water maze (MWM) at different ages (a). The initial water maze protocol (b) consisted of 4 days of acquisition trials. Subsequent testing was done by more intensive training on two acquisition days (c). At 19 months of age, rats underwent a unique water maze protocol aimed at testing their mental flexibility in a strategy shift paradigm over two consecutive days (d)