Rescue of rTg4510 memory impairment by tubastatin treatment. Number of errors made (average ± standard error of the mean (SEM)) while seeking the hidden platform in the radial arm water maze (RAWM). (A) Tubastatin-treated rTg4510 mice performed better in the initial training (5 blocks of three trials) than vehicle-treated littermates (P = 0.002) and were not significantly different from the tubastatin-treated nontransgenic (ntg) mice. (B) Reversal testing on day 3 (blocks 1 to 5) showed rescue of the memory impairment of rTg4510 mice following histone deacetylase 6 inhibition compared with vehicle-treated littermates (two-way ANOVA and Fisher’s PLSD, P < 0.03). No significant difference in either test was detected between vehicle-treated and tubastatin-treated nontransgenic animals (P > 0.05). *P < 0.05, **P < 0.01, *** P < 0.001.