Fig. 3

Chronic treatment (4 weeks) with the combination of vorinostat and tadalafil reversed learning deficits in aged Tg2576 mice. a Scheme showing timeline for treatment, behavioural tasks and sacrifice of mice. FC fear conditioning, MWM Morris water maze. b Freezing behaviour from Tg2576 mice treated with vehicle, vorinostat, tadalafil or the combination (vorinostat and tadalafil) (*p ≤ 0.05). Data represent the percentage of time freezing during a 2-min test. In this and all subsequent figures, results are expressed as mean ± SEM (n = 10–12 per group). c Escape latency of the hidden platform in the MWM test for the Tg2576 mice treated with vehicle, vorinostat, tadalafil or combination (***p ≤ 0.001, Tg2576 mice treated with the combination versus Tg2576 vehicle; ^### p ≤ 0.001, Tg2576 mice treated with the combination versus Tg2576 tadalafil; ^¥¥¥ p ≤ 0.001, Tg2576 treated with vorinostat versus Tg2576 vehicle). d Percentage of time spent in correct quadrant of the probe test (days 4, 7 and 9) (*p ≤ 0.05). e Escape latency in the reversal MWM test for the Tg2576 mice treated with vehicle, vorinostat, tadalafil or combination after the washout period (***p ≤ 0.001 Tg2576 mice treated with the combination versus Tg2576 vehicle) (^¥¥¥ p ≤ 0.001 Tg2576 treated with vorinostat versus Tg2576 vehicle). f Percentage of time spent in correct quadrant during the probe test (day 6) (*p ≤ 0.05)